git/refs/files-backend.c
Junio C Hamano 16a592f132 Merge branch 'ps/pseudo-ref-terminology'
Terminology to call various ref-like things are getting
straightened out.

* ps/pseudo-ref-terminology:
  refs: refuse to write pseudorefs
  ref-filter: properly distinuish pseudo and root refs
  refs: pseudorefs are no refs
  refs: classify HEAD as a root ref
  refs: do not check ref existence in `is_root_ref()`
  refs: rename `is_special_ref()` to `is_pseudo_ref()`
  refs: rename `is_pseudoref()` to `is_root_ref()`
  Documentation/glossary: define root refs as refs
  Documentation/glossary: clarify limitations of pseudorefs
  Documentation/glossary: redefine pseudorefs as special refs
2024-05-28 11:17:06 -07:00

3327 lines
91 KiB
C

#include "../git-compat-util.h"
#include "../copy.h"
#include "../environment.h"
#include "../gettext.h"
#include "../hash.h"
#include "../hex.h"
#include "../refs.h"
#include "refs-internal.h"
#include "ref-cache.h"
#include "packed-backend.h"
#include "../ident.h"
#include "../iterator.h"
#include "../dir-iterator.h"
#include "../lockfile.h"
#include "../object.h"
#include "../object-file.h"
#include "../path.h"
#include "../dir.h"
#include "../chdir-notify.h"
#include "../setup.h"
#include "../wrapper.h"
#include "../write-or-die.h"
#include "../revision.h"
#include <wildmatch.h>
/*
* This backend uses the following flags in `ref_update::flags` for
* internal bookkeeping purposes. Their numerical values must not
* conflict with REF_NO_DEREF, REF_FORCE_CREATE_REFLOG, REF_HAVE_NEW,
* or REF_HAVE_OLD, which are also stored in `ref_update::flags`.
*/
/*
* Used as a flag in ref_update::flags when a loose ref is being
* pruned. This flag must only be used when REF_NO_DEREF is set.
*/
#define REF_IS_PRUNING (1 << 4)
/*
* Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
* refs (i.e., because the reference is about to be deleted anyway).
*/
#define REF_DELETING (1 << 5)
/*
* Used as a flag in ref_update::flags when the lockfile needs to be
* committed.
*/
#define REF_NEEDS_COMMIT (1 << 6)
/*
* Used as a flag in ref_update::flags when the ref_update was via an
* update to HEAD.
*/
#define REF_UPDATE_VIA_HEAD (1 << 8)
/*
* Used as a flag in ref_update::flags when a reference has been
* deleted and the ref's parent directories may need cleanup.
*/
#define REF_DELETED_RMDIR (1 << 9)
struct ref_lock {
char *ref_name;
struct lock_file lk;
struct object_id old_oid;
};
struct files_ref_store {
struct ref_store base;
unsigned int store_flags;
char *gitcommondir;
struct ref_cache *loose;
struct ref_store *packed_ref_store;
};
static void clear_loose_ref_cache(struct files_ref_store *refs)
{
if (refs->loose) {
free_ref_cache(refs->loose);
refs->loose = NULL;
}
}
/*
* Create a new submodule ref cache and add it to the internal
* set of caches.
*/
static struct ref_store *files_ref_store_create(struct repository *repo,
const char *gitdir,
unsigned int flags)
{
struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
struct ref_store *ref_store = (struct ref_store *)refs;
struct strbuf sb = STRBUF_INIT;
base_ref_store_init(ref_store, repo, gitdir, &refs_be_files);
refs->store_flags = flags;
get_common_dir_noenv(&sb, gitdir);
refs->gitcommondir = strbuf_detach(&sb, NULL);
refs->packed_ref_store =
packed_ref_store_create(repo, refs->gitcommondir, flags);
chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);
chdir_notify_reparent("files-backend $GIT_COMMONDIR",
&refs->gitcommondir);
return ref_store;
}
/*
* Die if refs is not the main ref store. caller is used in any
* necessary error messages.
*/
static void files_assert_main_repository(struct files_ref_store *refs,
const char *caller)
{
if (refs->store_flags & REF_STORE_MAIN)
return;
BUG("operation %s only allowed for main ref store", caller);
}
/*
* Downcast ref_store to files_ref_store. Die if ref_store is not a
* files_ref_store. required_flags is compared with ref_store's
* store_flags to ensure the ref_store has all required capabilities.
* "caller" is used in any necessary error messages.
*/
static struct files_ref_store *files_downcast(struct ref_store *ref_store,
unsigned int required_flags,
const char *caller)
{
struct files_ref_store *refs;
if (ref_store->be != &refs_be_files)
BUG("ref_store is type \"%s\" not \"files\" in %s",
ref_store->be->name, caller);
refs = (struct files_ref_store *)ref_store;
if ((refs->store_flags & required_flags) != required_flags)
BUG("operation %s requires abilities 0x%x, but only have 0x%x",
caller, required_flags, refs->store_flags);
return refs;
}
static void files_reflog_path(struct files_ref_store *refs,
struct strbuf *sb,
const char *refname)
{
const char *bare_refname;
const char *wtname;
int wtname_len;
enum ref_worktree_type wt_type = parse_worktree_ref(
refname, &wtname, &wtname_len, &bare_refname);
switch (wt_type) {
case REF_WORKTREE_CURRENT:
strbuf_addf(sb, "%s/logs/%s", refs->base.gitdir, refname);
break;
case REF_WORKTREE_SHARED:
case REF_WORKTREE_MAIN:
strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, bare_refname);
break;
case REF_WORKTREE_OTHER:
strbuf_addf(sb, "%s/worktrees/%.*s/logs/%s", refs->gitcommondir,
wtname_len, wtname, bare_refname);
break;
default:
BUG("unknown ref type %d of ref %s", wt_type, refname);
}
}
static void files_ref_path(struct files_ref_store *refs,
struct strbuf *sb,
const char *refname)
{
const char *bare_refname;
const char *wtname;
int wtname_len;
enum ref_worktree_type wt_type = parse_worktree_ref(
refname, &wtname, &wtname_len, &bare_refname);
switch (wt_type) {
case REF_WORKTREE_CURRENT:
strbuf_addf(sb, "%s/%s", refs->base.gitdir, refname);
break;
case REF_WORKTREE_OTHER:
strbuf_addf(sb, "%s/worktrees/%.*s/%s", refs->gitcommondir,
wtname_len, wtname, bare_refname);
break;
case REF_WORKTREE_SHARED:
case REF_WORKTREE_MAIN:
strbuf_addf(sb, "%s/%s", refs->gitcommondir, bare_refname);
break;
default:
BUG("unknown ref type %d of ref %s", wt_type, refname);
}
}
/*
* Manually add refs/bisect, refs/rewritten and refs/worktree, which, being
* per-worktree, might not appear in the directory listing for
* refs/ in the main repo.
*/
static void add_per_worktree_entries_to_dir(struct ref_dir *dir, const char *dirname)
{
const char *prefixes[] = { "refs/bisect/", "refs/worktree/", "refs/rewritten/" };
int ip;
if (strcmp(dirname, "refs/"))
return;
for (ip = 0; ip < ARRAY_SIZE(prefixes); ip++) {
const char *prefix = prefixes[ip];
int prefix_len = strlen(prefix);
struct ref_entry *child_entry;
int pos;
pos = search_ref_dir(dir, prefix, prefix_len);
if (pos >= 0)
continue;
child_entry = create_dir_entry(dir->cache, prefix, prefix_len);
add_entry_to_dir(dir, child_entry);
}
}
static void loose_fill_ref_dir_regular_file(struct files_ref_store *refs,
const char *refname,
struct ref_dir *dir)
{
struct object_id oid;
int flag;
if (!refs_resolve_ref_unsafe(&refs->base, refname, RESOLVE_REF_READING,
&oid, &flag)) {
oidclr(&oid);
flag |= REF_ISBROKEN;
} else if (is_null_oid(&oid)) {
/*
* It is so astronomically unlikely
* that null_oid is the OID of an
* actual object that we consider its
* appearance in a loose reference
* file to be repo corruption
* (probably due to a software bug).
*/
flag |= REF_ISBROKEN;
}
if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
if (!refname_is_safe(refname))
die("loose refname is dangerous: %s", refname);
oidclr(&oid);
flag |= REF_BAD_NAME | REF_ISBROKEN;
}
add_entry_to_dir(dir, create_ref_entry(refname, &oid, flag));
}
/*
* Read the loose references from the namespace dirname into dir
* (without recursing). dirname must end with '/'. dir must be the
* directory entry corresponding to dirname.
*/
static void loose_fill_ref_dir(struct ref_store *ref_store,
struct ref_dir *dir, const char *dirname)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
DIR *d;
struct dirent *de;
int dirnamelen = strlen(dirname);
struct strbuf refname;
struct strbuf path = STRBUF_INIT;
files_ref_path(refs, &path, dirname);
d = opendir(path.buf);
if (!d) {
strbuf_release(&path);
return;
}
strbuf_init(&refname, dirnamelen + 257);
strbuf_add(&refname, dirname, dirnamelen);
while ((de = readdir(d)) != NULL) {
unsigned char dtype;
if (de->d_name[0] == '.')
continue;
if (ends_with(de->d_name, ".lock"))
continue;
strbuf_addstr(&refname, de->d_name);
dtype = get_dtype(de, &path, 1);
if (dtype == DT_DIR) {
strbuf_addch(&refname, '/');
add_entry_to_dir(dir,
create_dir_entry(dir->cache, refname.buf,
refname.len));
} else if (dtype == DT_REG) {
loose_fill_ref_dir_regular_file(refs, refname.buf, dir);
}
strbuf_setlen(&refname, dirnamelen);
}
strbuf_release(&refname);
strbuf_release(&path);
closedir(d);
add_per_worktree_entries_to_dir(dir, dirname);
}
/*
* Add pseudorefs to the ref dir by parsing the directory for any files
* which follow the pseudoref syntax.
*/
static void add_pseudoref_and_head_entries(struct ref_store *ref_store,
struct ref_dir *dir,
const char *dirname)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
struct strbuf path = STRBUF_INIT, refname = STRBUF_INIT;
struct dirent *de;
size_t dirnamelen;
DIR *d;
files_ref_path(refs, &path, dirname);
d = opendir(path.buf);
if (!d) {
strbuf_release(&path);
return;
}
strbuf_addstr(&refname, dirname);
dirnamelen = refname.len;
while ((de = readdir(d)) != NULL) {
unsigned char dtype;
if (de->d_name[0] == '.')
continue;
if (ends_with(de->d_name, ".lock"))
continue;
strbuf_addstr(&refname, de->d_name);
dtype = get_dtype(de, &path, 1);
if (dtype == DT_REG && is_root_ref(de->d_name))
loose_fill_ref_dir_regular_file(refs, refname.buf, dir);
strbuf_setlen(&refname, dirnamelen);
}
strbuf_release(&refname);
strbuf_release(&path);
closedir(d);
}
static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs,
unsigned int flags)
{
if (!refs->loose) {
struct ref_dir *dir;
/*
* Mark the top-level directory complete because we
* are about to read the only subdirectory that can
* hold references:
*/
refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir);
/* We're going to fill the top level ourselves: */
refs->loose->root->flag &= ~REF_INCOMPLETE;
dir = get_ref_dir(refs->loose->root);
if (flags & DO_FOR_EACH_INCLUDE_ROOT_REFS)
add_pseudoref_and_head_entries(dir->cache->ref_store, dir,
refs->loose->root->name);
/*
* Add an incomplete entry for "refs/" (to be filled
* lazily):
*/
add_entry_to_dir(dir, create_dir_entry(refs->loose, "refs/", 5));
}
return refs->loose;
}
static int read_ref_internal(struct ref_store *ref_store, const char *refname,
struct object_id *oid, struct strbuf *referent,
unsigned int *type, int *failure_errno, int skip_packed_refs)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
struct strbuf sb_contents = STRBUF_INIT;
struct strbuf sb_path = STRBUF_INIT;
const char *path;
const char *buf;
struct stat st;
int fd;
int ret = -1;
int remaining_retries = 3;
int myerr = 0;
*type = 0;
strbuf_reset(&sb_path);
files_ref_path(refs, &sb_path, refname);
path = sb_path.buf;
stat_ref:
/*
* We might have to loop back here to avoid a race
* condition: first we lstat() the file, then we try
* to read it as a link or as a file. But if somebody
* changes the type of the file (file <-> directory
* <-> symlink) between the lstat() and reading, then
* we don't want to report that as an error but rather
* try again starting with the lstat().
*
* We'll keep a count of the retries, though, just to avoid
* any confusing situation sending us into an infinite loop.
*/
if (remaining_retries-- <= 0)
goto out;
if (lstat(path, &st) < 0) {
int ignore_errno;
myerr = errno;
if (myerr != ENOENT || skip_packed_refs)
goto out;
if (refs_read_raw_ref(refs->packed_ref_store, refname, oid,
referent, type, &ignore_errno)) {
myerr = ENOENT;
goto out;
}
ret = 0;
goto out;
}
/* Follow "normalized" - ie "refs/.." symlinks by hand */
if (S_ISLNK(st.st_mode)) {
strbuf_reset(&sb_contents);
if (strbuf_readlink(&sb_contents, path, st.st_size) < 0) {
myerr = errno;
if (myerr == ENOENT || myerr == EINVAL)
/* inconsistent with lstat; retry */
goto stat_ref;
else
goto out;
}
if (starts_with(sb_contents.buf, "refs/") &&
!check_refname_format(sb_contents.buf, 0)) {
strbuf_swap(&sb_contents, referent);
*type |= REF_ISSYMREF;
ret = 0;
goto out;
}
/*
* It doesn't look like a refname; fall through to just
* treating it like a non-symlink, and reading whatever it
* points to.
*/
}
/* Is it a directory? */
if (S_ISDIR(st.st_mode)) {
int ignore_errno;
/*
* Even though there is a directory where the loose
* ref is supposed to be, there could still be a
* packed ref:
*/
if (skip_packed_refs ||
refs_read_raw_ref(refs->packed_ref_store, refname, oid,
referent, type, &ignore_errno)) {
myerr = EISDIR;
goto out;
}
ret = 0;
goto out;
}
/*
* Anything else, just open it and try to use it as
* a ref
*/
fd = open(path, O_RDONLY);
if (fd < 0) {
myerr = errno;
if (myerr == ENOENT && !S_ISLNK(st.st_mode))
/* inconsistent with lstat; retry */
goto stat_ref;
else
goto out;
}
strbuf_reset(&sb_contents);
if (strbuf_read(&sb_contents, fd, 256) < 0) {
myerr = errno;
close(fd);
goto out;
}
close(fd);
strbuf_rtrim(&sb_contents);
buf = sb_contents.buf;
ret = parse_loose_ref_contents(buf, oid, referent, type, &myerr);
out:
if (ret && !myerr)
BUG("returning non-zero %d, should have set myerr!", ret);
*failure_errno = myerr;
strbuf_release(&sb_path);
strbuf_release(&sb_contents);
errno = 0;
return ret;
}
static int files_read_raw_ref(struct ref_store *ref_store, const char *refname,
struct object_id *oid, struct strbuf *referent,
unsigned int *type, int *failure_errno)
{
return read_ref_internal(ref_store, refname, oid, referent, type, failure_errno, 0);
}
static int files_read_symbolic_ref(struct ref_store *ref_store, const char *refname,
struct strbuf *referent)
{
struct object_id oid;
int failure_errno, ret;
unsigned int type;
ret = read_ref_internal(ref_store, refname, &oid, referent, &type, &failure_errno, 1);
if (ret)
return ret;
return !(type & REF_ISSYMREF);
}
int parse_loose_ref_contents(const char *buf, struct object_id *oid,
struct strbuf *referent, unsigned int *type,
int *failure_errno)
{
const char *p;
if (skip_prefix(buf, "ref:", &buf)) {
while (isspace(*buf))
buf++;
strbuf_reset(referent);
strbuf_addstr(referent, buf);
*type |= REF_ISSYMREF;
return 0;
}
/*
* FETCH_HEAD has additional data after the sha.
*/
if (parse_oid_hex(buf, oid, &p) ||
(*p != '\0' && !isspace(*p))) {
*type |= REF_ISBROKEN;
*failure_errno = EINVAL;
return -1;
}
return 0;
}
static void unlock_ref(struct ref_lock *lock)
{
rollback_lock_file(&lock->lk);
free(lock->ref_name);
free(lock);
}
/*
* Lock refname, without following symrefs, and set *lock_p to point
* at a newly-allocated lock object. Fill in lock->old_oid, referent,
* and type similarly to read_raw_ref().
*
* The caller must verify that refname is a "safe" reference name (in
* the sense of refname_is_safe()) before calling this function.
*
* If the reference doesn't already exist, verify that refname doesn't
* have a D/F conflict with any existing references. extras and skip
* are passed to refs_verify_refname_available() for this check.
*
* If mustexist is not set and the reference is not found or is
* broken, lock the reference anyway but clear old_oid.
*
* Return 0 on success. On failure, write an error message to err and
* return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
*
* Implementation note: This function is basically
*
* lock reference
* read_raw_ref()
*
* but it includes a lot more code to
* - Deal with possible races with other processes
* - Avoid calling refs_verify_refname_available() when it can be
* avoided, namely if we were successfully able to read the ref
* - Generate informative error messages in the case of failure
*/
static int lock_raw_ref(struct files_ref_store *refs,
const char *refname, int mustexist,
const struct string_list *extras,
struct ref_lock **lock_p,
struct strbuf *referent,
unsigned int *type,
struct strbuf *err)
{
struct ref_lock *lock;
struct strbuf ref_file = STRBUF_INIT;
int attempts_remaining = 3;
int ret = TRANSACTION_GENERIC_ERROR;
int failure_errno;
assert(err);
files_assert_main_repository(refs, "lock_raw_ref");
*type = 0;
/* First lock the file so it can't change out from under us. */
*lock_p = CALLOC_ARRAY(lock, 1);
lock->ref_name = xstrdup(refname);
files_ref_path(refs, &ref_file, refname);
retry:
switch (safe_create_leading_directories(ref_file.buf)) {
case SCLD_OK:
break; /* success */
case SCLD_EXISTS:
/*
* Suppose refname is "refs/foo/bar". We just failed
* to create the containing directory, "refs/foo",
* because there was a non-directory in the way. This
* indicates a D/F conflict, probably because of
* another reference such as "refs/foo". There is no
* reason to expect this error to be transitory.
*/
if (refs_verify_refname_available(&refs->base, refname,
extras, NULL, err)) {
if (mustexist) {
/*
* To the user the relevant error is
* that the "mustexist" reference is
* missing:
*/
strbuf_reset(err);
strbuf_addf(err, "unable to resolve reference '%s'",
refname);
} else {
/*
* The error message set by
* refs_verify_refname_available() is
* OK.
*/
ret = TRANSACTION_NAME_CONFLICT;
}
} else {
/*
* The file that is in the way isn't a loose
* reference. Report it as a low-level
* failure.
*/
strbuf_addf(err, "unable to create lock file %s.lock; "
"non-directory in the way",
ref_file.buf);
}
goto error_return;
case SCLD_VANISHED:
/* Maybe another process was tidying up. Try again. */
if (--attempts_remaining > 0)
goto retry;
/* fall through */
default:
strbuf_addf(err, "unable to create directory for %s",
ref_file.buf);
goto error_return;
}
if (hold_lock_file_for_update_timeout(
&lock->lk, ref_file.buf, LOCK_NO_DEREF,
get_files_ref_lock_timeout_ms()) < 0) {
int myerr = errno;
errno = 0;
if (myerr == ENOENT && --attempts_remaining > 0) {
/*
* Maybe somebody just deleted one of the
* directories leading to ref_file. Try
* again:
*/
goto retry;
} else {
unable_to_lock_message(ref_file.buf, myerr, err);
goto error_return;
}
}
/*
* Now we hold the lock and can read the reference without
* fear that its value will change.
*/
if (files_read_raw_ref(&refs->base, refname, &lock->old_oid, referent,
type, &failure_errno)) {
if (failure_errno == ENOENT) {
if (mustexist) {
/* Garden variety missing reference. */
strbuf_addf(err, "unable to resolve reference '%s'",
refname);
goto error_return;
} else {
/*
* Reference is missing, but that's OK. We
* know that there is not a conflict with
* another loose reference because
* (supposing that we are trying to lock
* reference "refs/foo/bar"):
*
* - We were successfully able to create
* the lockfile refs/foo/bar.lock, so we
* know there cannot be a loose reference
* named "refs/foo".
*
* - We got ENOENT and not EISDIR, so we
* know that there cannot be a loose
* reference named "refs/foo/bar/baz".
*/
}
} else if (failure_errno == EISDIR) {
/*
* There is a directory in the way. It might have
* contained references that have been deleted. If
* we don't require that the reference already
* exists, try to remove the directory so that it
* doesn't cause trouble when we want to rename the
* lockfile into place later.
*/
if (mustexist) {
/* Garden variety missing reference. */
strbuf_addf(err, "unable to resolve reference '%s'",
refname);
goto error_return;
} else if (remove_dir_recursively(&ref_file,
REMOVE_DIR_EMPTY_ONLY)) {
if (refs_verify_refname_available(
&refs->base, refname,
extras, NULL, err)) {
/*
* The error message set by
* verify_refname_available() is OK.
*/
ret = TRANSACTION_NAME_CONFLICT;
goto error_return;
} else {
/*
* We can't delete the directory,
* but we also don't know of any
* references that it should
* contain.
*/
strbuf_addf(err, "there is a non-empty directory '%s' "
"blocking reference '%s'",
ref_file.buf, refname);
goto error_return;
}
}
} else if (failure_errno == EINVAL && (*type & REF_ISBROKEN)) {
strbuf_addf(err, "unable to resolve reference '%s': "
"reference broken", refname);
goto error_return;
} else {
strbuf_addf(err, "unable to resolve reference '%s': %s",
refname, strerror(failure_errno));
goto error_return;
}
/*
* If the ref did not exist and we are creating it,
* make sure there is no existing packed ref that
* conflicts with refname:
*/
if (refs_verify_refname_available(
refs->packed_ref_store, refname,
extras, NULL, err)) {
ret = TRANSACTION_NAME_CONFLICT;
goto error_return;
}
}
ret = 0;
goto out;
error_return:
unlock_ref(lock);
*lock_p = NULL;
out:
strbuf_release(&ref_file);
return ret;
}
struct files_ref_iterator {
struct ref_iterator base;
struct ref_iterator *iter0;
struct repository *repo;
unsigned int flags;
};
static int files_ref_iterator_advance(struct ref_iterator *ref_iterator)
{
struct files_ref_iterator *iter =
(struct files_ref_iterator *)ref_iterator;
int ok;
while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
parse_worktree_ref(iter->iter0->refname, NULL, NULL,
NULL) != REF_WORKTREE_CURRENT)
continue;
if ((iter->flags & DO_FOR_EACH_OMIT_DANGLING_SYMREFS) &&
(iter->iter0->flags & REF_ISSYMREF) &&
(iter->iter0->flags & REF_ISBROKEN))
continue;
if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
!ref_resolves_to_object(iter->iter0->refname,
iter->repo,
iter->iter0->oid,
iter->iter0->flags))
continue;
iter->base.refname = iter->iter0->refname;
iter->base.oid = iter->iter0->oid;
iter->base.flags = iter->iter0->flags;
return ITER_OK;
}
iter->iter0 = NULL;
if (ref_iterator_abort(ref_iterator) != ITER_DONE)
ok = ITER_ERROR;
return ok;
}
static int files_ref_iterator_peel(struct ref_iterator *ref_iterator,
struct object_id *peeled)
{
struct files_ref_iterator *iter =
(struct files_ref_iterator *)ref_iterator;
return ref_iterator_peel(iter->iter0, peeled);
}
static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
{
struct files_ref_iterator *iter =
(struct files_ref_iterator *)ref_iterator;
int ok = ITER_DONE;
if (iter->iter0)
ok = ref_iterator_abort(iter->iter0);
base_ref_iterator_free(ref_iterator);
return ok;
}
static struct ref_iterator_vtable files_ref_iterator_vtable = {
.advance = files_ref_iterator_advance,
.peel = files_ref_iterator_peel,
.abort = files_ref_iterator_abort,
};
static struct ref_iterator *files_ref_iterator_begin(
struct ref_store *ref_store,
const char *prefix, const char **exclude_patterns,
unsigned int flags)
{
struct files_ref_store *refs;
struct ref_iterator *loose_iter, *packed_iter, *overlay_iter;
struct files_ref_iterator *iter;
struct ref_iterator *ref_iterator;
unsigned int required_flags = REF_STORE_READ;
if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
required_flags |= REF_STORE_ODB;
refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
/*
* We must make sure that all loose refs are read before
* accessing the packed-refs file; this avoids a race
* condition if loose refs are migrated to the packed-refs
* file by a simultaneous process, but our in-memory view is
* from before the migration. We ensure this as follows:
* First, we call start the loose refs iteration with its
* `prime_ref` argument set to true. This causes the loose
* references in the subtree to be pre-read into the cache.
* (If they've already been read, that's OK; we only need to
* guarantee that they're read before the packed refs, not
* *how much* before.) After that, we call
* packed_ref_iterator_begin(), which internally checks
* whether the packed-ref cache is up to date with what is on
* disk, and re-reads it if not.
*/
loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs, flags),
prefix, ref_store->repo, 1);
/*
* The packed-refs file might contain broken references, for
* example an old version of a reference that points at an
* object that has since been garbage-collected. This is OK as
* long as there is a corresponding loose reference that
* overrides it, and we don't want to emit an error message in
* this case. So ask the packed_ref_store for all of its
* references, and (if needed) do our own check for broken
* ones in files_ref_iterator_advance(), after we have merged
* the packed and loose references.
*/
packed_iter = refs_ref_iterator_begin(
refs->packed_ref_store, prefix, exclude_patterns, 0,
DO_FOR_EACH_INCLUDE_BROKEN);
overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter);
CALLOC_ARRAY(iter, 1);
ref_iterator = &iter->base;
base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
iter->iter0 = overlay_iter;
iter->repo = ref_store->repo;
iter->flags = flags;
return ref_iterator;
}
/*
* Callback function for raceproof_create_file(). This function is
* expected to do something that makes dirname(path) permanent despite
* the fact that other processes might be cleaning up empty
* directories at the same time. Usually it will create a file named
* path, but alternatively it could create another file in that
* directory, or even chdir() into that directory. The function should
* return 0 if the action was completed successfully. On error, it
* should return a nonzero result and set errno.
* raceproof_create_file() treats two errno values specially:
*
* - ENOENT -- dirname(path) does not exist. In this case,
* raceproof_create_file() tries creating dirname(path)
* (and any parent directories, if necessary) and calls
* the function again.
*
* - EISDIR -- the file already exists and is a directory. In this
* case, raceproof_create_file() removes the directory if
* it is empty (and recursively any empty directories that
* it contains) and calls the function again.
*
* Any other errno causes raceproof_create_file() to fail with the
* callback's return value and errno.
*
* Obviously, this function should be OK with being called again if it
* fails with ENOENT or EISDIR. In other scenarios it will not be
* called again.
*/
typedef int create_file_fn(const char *path, void *cb);
/*
* Create a file in dirname(path) by calling fn, creating leading
* directories if necessary. Retry a few times in case we are racing
* with another process that is trying to clean up the directory that
* contains path. See the documentation for create_file_fn for more
* details.
*
* Return the value and set the errno that resulted from the most
* recent call of fn. fn is always called at least once, and will be
* called more than once if it returns ENOENT or EISDIR.
*/
static int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
{
/*
* The number of times we will try to remove empty directories
* in the way of path. This is only 1 because if another
* process is racily creating directories that conflict with
* us, we don't want to fight against them.
*/
int remove_directories_remaining = 1;
/*
* The number of times that we will try to create the
* directories containing path. We are willing to attempt this
* more than once, because another process could be trying to
* clean up empty directories at the same time as we are
* trying to create them.
*/
int create_directories_remaining = 3;
/* A scratch copy of path, filled lazily if we need it: */
struct strbuf path_copy = STRBUF_INIT;
int ret, save_errno;
/* Sanity check: */
assert(*path);
retry_fn:
ret = fn(path, cb);
save_errno = errno;
if (!ret)
goto out;
if (errno == EISDIR && remove_directories_remaining-- > 0) {
/*
* A directory is in the way. Maybe it is empty; try
* to remove it:
*/
if (!path_copy.len)
strbuf_addstr(&path_copy, path);
if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
goto retry_fn;
} else if (errno == ENOENT && create_directories_remaining-- > 0) {
/*
* Maybe the containing directory didn't exist, or
* maybe it was just deleted by a process that is
* racing with us to clean up empty directories. Try
* to create it:
*/
enum scld_error scld_result;
if (!path_copy.len)
strbuf_addstr(&path_copy, path);
do {
scld_result = safe_create_leading_directories(path_copy.buf);
if (scld_result == SCLD_OK)
goto retry_fn;
} while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
}
out:
strbuf_release(&path_copy);
errno = save_errno;
return ret;
}
static int remove_empty_directories(struct strbuf *path)
{
/*
* we want to create a file but there is a directory there;
* if that is an empty directory (or a directory that contains
* only empty directories), remove them.
*/
return remove_dir_recursively(path, REMOVE_DIR_EMPTY_ONLY);
}
static int create_reflock(const char *path, void *cb)
{
struct lock_file *lk = cb;
return hold_lock_file_for_update_timeout(
lk, path, LOCK_NO_DEREF,
get_files_ref_lock_timeout_ms()) < 0 ? -1 : 0;
}
/*
* Locks a ref returning the lock on success and NULL on failure.
*/
static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
const char *refname,
struct strbuf *err)
{
struct strbuf ref_file = STRBUF_INIT;
struct ref_lock *lock;
files_assert_main_repository(refs, "lock_ref_oid_basic");
assert(err);
CALLOC_ARRAY(lock, 1);
files_ref_path(refs, &ref_file, refname);
/*
* If the ref did not exist and we are creating it, make sure
* there is no existing packed ref whose name begins with our
* refname, nor a packed ref whose name is a proper prefix of
* our refname.
*/
if (is_null_oid(&lock->old_oid) &&
refs_verify_refname_available(refs->packed_ref_store, refname,
NULL, NULL, err))
goto error_return;
lock->ref_name = xstrdup(refname);
if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) {
unable_to_lock_message(ref_file.buf, errno, err);
goto error_return;
}
if (!refs_resolve_ref_unsafe(&refs->base, lock->ref_name, 0,
&lock->old_oid, NULL))
oidclr(&lock->old_oid);
goto out;
error_return:
unlock_ref(lock);
lock = NULL;
out:
strbuf_release(&ref_file);
return lock;
}
struct ref_to_prune {
struct ref_to_prune *next;
struct object_id oid;
char name[FLEX_ARRAY];
};
enum {
REMOVE_EMPTY_PARENTS_REF = 0x01,
REMOVE_EMPTY_PARENTS_REFLOG = 0x02
};
/*
* Remove empty parent directories associated with the specified
* reference and/or its reflog, but spare [logs/]refs/ and immediate
* subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
* REMOVE_EMPTY_PARENTS_REFLOG.
*/
static void try_remove_empty_parents(struct files_ref_store *refs,
const char *refname,
unsigned int flags)
{
struct strbuf buf = STRBUF_INIT;
struct strbuf sb = STRBUF_INIT;
char *p, *q;
int i;
strbuf_addstr(&buf, refname);
p = buf.buf;
for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
while (*p && *p != '/')
p++;
/* tolerate duplicate slashes; see check_refname_format() */
while (*p == '/')
p++;
}
q = buf.buf + buf.len;
while (flags & (REMOVE_EMPTY_PARENTS_REF | REMOVE_EMPTY_PARENTS_REFLOG)) {
while (q > p && *q != '/')
q--;
while (q > p && *(q-1) == '/')
q--;
if (q == p)
break;
strbuf_setlen(&buf, q - buf.buf);
strbuf_reset(&sb);
files_ref_path(refs, &sb, buf.buf);
if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
flags &= ~REMOVE_EMPTY_PARENTS_REF;
strbuf_reset(&sb);
files_reflog_path(refs, &sb, buf.buf);
if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
}
strbuf_release(&buf);
strbuf_release(&sb);
}
/* make sure nobody touched the ref, and unlink */
static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
{
struct ref_transaction *transaction;
struct strbuf err = STRBUF_INIT;
int ret = -1;
if (check_refname_format(r->name, 0))
return;
transaction = ref_store_transaction_begin(&refs->base, &err);
if (!transaction)
goto cleanup;
ref_transaction_add_update(
transaction, r->name,
REF_NO_DEREF | REF_HAVE_NEW | REF_HAVE_OLD | REF_IS_PRUNING,
null_oid(), &r->oid, NULL, NULL, NULL);
if (ref_transaction_commit(transaction, &err))
goto cleanup;
ret = 0;
cleanup:
if (ret)
error("%s", err.buf);
strbuf_release(&err);
ref_transaction_free(transaction);
return;
}
/*
* Prune the loose versions of the references in the linked list
* `*refs_to_prune`, freeing the entries in the list as we go.
*/
static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_to_prune)
{
while (*refs_to_prune) {
struct ref_to_prune *r = *refs_to_prune;
*refs_to_prune = r->next;
prune_ref(refs, r);
free(r);
}
}
/*
* Return true if the specified reference should be packed.
*/
static int should_pack_ref(const char *refname,
const struct object_id *oid, unsigned int ref_flags,
struct pack_refs_opts *opts)
{
struct string_list_item *item;
/* Do not pack per-worktree refs: */
if (parse_worktree_ref(refname, NULL, NULL, NULL) !=
REF_WORKTREE_SHARED)
return 0;
/* Do not pack symbolic refs: */
if (ref_flags & REF_ISSYMREF)
return 0;
/* Do not pack broken refs: */
if (!ref_resolves_to_object(refname, the_repository, oid, ref_flags))
return 0;
if (ref_excluded(opts->exclusions, refname))
return 0;
for_each_string_list_item(item, opts->includes)
if (!wildmatch(item->string, refname, 0))
return 1;
return 0;
}
static int files_pack_refs(struct ref_store *ref_store,
struct pack_refs_opts *opts)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
"pack_refs");
struct ref_iterator *iter;
int ok;
struct ref_to_prune *refs_to_prune = NULL;
struct strbuf err = STRBUF_INIT;
struct ref_transaction *transaction;
transaction = ref_store_transaction_begin(refs->packed_ref_store, &err);
if (!transaction)
return -1;
packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
iter = cache_ref_iterator_begin(get_loose_ref_cache(refs, 0), NULL,
the_repository, 0);
while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
/*
* If the loose reference can be packed, add an entry
* in the packed ref cache. If the reference should be
* pruned, also add it to refs_to_prune.
*/
if (!should_pack_ref(iter->refname, iter->oid, iter->flags, opts))
continue;
/*
* Add a reference creation for this reference to the
* packed-refs transaction:
*/
if (ref_transaction_update(transaction, iter->refname,
iter->oid, NULL, NULL, NULL,
REF_NO_DEREF, NULL, &err))
die("failure preparing to create packed reference %s: %s",
iter->refname, err.buf);
/* Schedule the loose reference for pruning if requested. */
if ((opts->flags & PACK_REFS_PRUNE)) {
struct ref_to_prune *n;
FLEX_ALLOC_STR(n, name, iter->refname);
oidcpy(&n->oid, iter->oid);
n->next = refs_to_prune;
refs_to_prune = n;
}
}
if (ok != ITER_DONE)
die("error while iterating over references");
if (ref_transaction_commit(transaction, &err))
die("unable to write new packed-refs: %s", err.buf);
ref_transaction_free(transaction);
packed_refs_unlock(refs->packed_ref_store);
prune_refs(refs, &refs_to_prune);
strbuf_release(&err);
return 0;
}
/*
* People using contrib's git-new-workdir have .git/logs/refs ->
* /some/other/path/.git/logs/refs, and that may live on another device.
*
* IOW, to avoid cross device rename errors, the temporary renamed log must
* live into logs/refs.
*/
#define TMP_RENAMED_LOG "refs/.tmp-renamed-log"
struct rename_cb {
const char *tmp_renamed_log;
int true_errno;
};
static int rename_tmp_log_callback(const char *path, void *cb_data)
{
struct rename_cb *cb = cb_data;
if (rename(cb->tmp_renamed_log, path)) {
/*
* rename(a, b) when b is an existing directory ought
* to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
* Sheesh. Record the true errno for error reporting,
* but report EISDIR to raceproof_create_file() so
* that it knows to retry.
*/
cb->true_errno = errno;
if (errno == ENOTDIR)
errno = EISDIR;
return -1;
} else {
return 0;
}
}
static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
{
struct strbuf path = STRBUF_INIT;
struct strbuf tmp = STRBUF_INIT;
struct rename_cb cb;
int ret;
files_reflog_path(refs, &path, newrefname);
files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
cb.tmp_renamed_log = tmp.buf;
ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
if (ret) {
if (errno == EISDIR)
error("directory not empty: %s", path.buf);
else
error("unable to move logfile %s to %s: %s",
tmp.buf, path.buf,
strerror(cb.true_errno));
}
strbuf_release(&path);
strbuf_release(&tmp);
return ret;
}
static int write_ref_to_lockfile(struct ref_lock *lock,
const struct object_id *oid,
int skip_oid_verification, struct strbuf *err);
static int commit_ref_update(struct files_ref_store *refs,
struct ref_lock *lock,
const struct object_id *oid, const char *logmsg,
struct strbuf *err);
/*
* Emit a better error message than lockfile.c's
* unable_to_lock_message() would in case there is a D/F conflict with
* another existing reference. If there would be a conflict, emit an error
* message and return false; otherwise, return true.
*
* Note that this function is not safe against all races with other
* processes, and that's not its job. We'll emit a more verbose error on D/f
* conflicts if we get past it into lock_ref_oid_basic().
*/
static int refs_rename_ref_available(struct ref_store *refs,
const char *old_refname,
const char *new_refname)
{
struct string_list skip = STRING_LIST_INIT_NODUP;
struct strbuf err = STRBUF_INIT;
int ok;
string_list_insert(&skip, old_refname);
ok = !refs_verify_refname_available(refs, new_refname,
NULL, &skip, &err);
if (!ok)
error("%s", err.buf);
string_list_clear(&skip, 0);
strbuf_release(&err);
return ok;
}
static int files_copy_or_rename_ref(struct ref_store *ref_store,
const char *oldrefname, const char *newrefname,
const char *logmsg, int copy)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
struct object_id orig_oid;
int flag = 0, logmoved = 0;
struct ref_lock *lock;
struct stat loginfo;
struct strbuf sb_oldref = STRBUF_INIT;
struct strbuf sb_newref = STRBUF_INIT;
struct strbuf tmp_renamed_log = STRBUF_INIT;
int log, ret;
struct strbuf err = STRBUF_INIT;
files_reflog_path(refs, &sb_oldref, oldrefname);
files_reflog_path(refs, &sb_newref, newrefname);
files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
log = !lstat(sb_oldref.buf, &loginfo);
if (log && S_ISLNK(loginfo.st_mode)) {
ret = error("reflog for %s is a symlink", oldrefname);
goto out;
}
if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
&orig_oid, &flag)) {
ret = error("refname %s not found", oldrefname);
goto out;
}
if (flag & REF_ISSYMREF) {
if (copy)
ret = error("refname %s is a symbolic ref, copying it is not supported",
oldrefname);
else
ret = error("refname %s is a symbolic ref, renaming it is not supported",
oldrefname);
goto out;
}
if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
ret = 1;
goto out;
}
if (!copy && log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
oldrefname, strerror(errno));
goto out;
}
if (copy && log && copy_file(tmp_renamed_log.buf, sb_oldref.buf, 0644)) {
ret = error("unable to copy logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
oldrefname, strerror(errno));
goto out;
}
if (!copy && refs_delete_ref(&refs->base, logmsg, oldrefname,
&orig_oid, REF_NO_DEREF)) {
error("unable to delete old %s", oldrefname);
goto rollback;
}
/*
* Since we are doing a shallow lookup, oid is not the
* correct value to pass to delete_ref as old_oid. But that
* doesn't matter, because an old_oid check wouldn't add to
* the safety anyway; we want to delete the reference whatever
* its current value.
*/
if (!copy && refs_resolve_ref_unsafe(&refs->base, newrefname,
RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
NULL, NULL) &&
refs_delete_ref(&refs->base, NULL, newrefname,
NULL, REF_NO_DEREF)) {
if (errno == EISDIR) {
struct strbuf path = STRBUF_INIT;
int result;
files_ref_path(refs, &path, newrefname);
result = remove_empty_directories(&path);
strbuf_release(&path);
if (result) {
error("Directory not empty: %s", newrefname);
goto rollback;
}
} else {
error("unable to delete existing %s", newrefname);
goto rollback;
}
}
if (log && rename_tmp_log(refs, newrefname))
goto rollback;
logmoved = log;
lock = lock_ref_oid_basic(refs, newrefname, &err);
if (!lock) {
if (copy)
error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf);
else
error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
strbuf_release(&err);
goto rollback;
}
oidcpy(&lock->old_oid, &orig_oid);
if (write_ref_to_lockfile(lock, &orig_oid, 0, &err) ||
commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
error("unable to write current sha1 into %s: %s", newrefname, err.buf);
strbuf_release(&err);
goto rollback;
}
ret = 0;
goto out;
rollback:
lock = lock_ref_oid_basic(refs, oldrefname, &err);
if (!lock) {
error("unable to lock %s for rollback: %s", oldrefname, err.buf);
strbuf_release(&err);
goto rollbacklog;
}
flag = log_all_ref_updates;
log_all_ref_updates = LOG_REFS_NONE;
if (write_ref_to_lockfile(lock, &orig_oid, 0, &err) ||
commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
strbuf_release(&err);
}
log_all_ref_updates = flag;
rollbacklog:
if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
error("unable to restore logfile %s from %s: %s",
oldrefname, newrefname, strerror(errno));
if (!logmoved && log &&
rename(tmp_renamed_log.buf, sb_oldref.buf))
error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
oldrefname, strerror(errno));
ret = 1;
out:
strbuf_release(&sb_newref);
strbuf_release(&sb_oldref);
strbuf_release(&tmp_renamed_log);
return ret;
}
static int files_rename_ref(struct ref_store *ref_store,
const char *oldrefname, const char *newrefname,
const char *logmsg)
{
return files_copy_or_rename_ref(ref_store, oldrefname,
newrefname, logmsg, 0);
}
static int files_copy_ref(struct ref_store *ref_store,
const char *oldrefname, const char *newrefname,
const char *logmsg)
{
return files_copy_or_rename_ref(ref_store, oldrefname,
newrefname, logmsg, 1);
}
static int close_ref_gently(struct ref_lock *lock)
{
if (close_lock_file_gently(&lock->lk))
return -1;
return 0;
}
static int commit_ref(struct ref_lock *lock)
{
char *path = get_locked_file_path(&lock->lk);
struct stat st;
if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
/*
* There is a directory at the path we want to rename
* the lockfile to. Hopefully it is empty; try to
* delete it.
*/
size_t len = strlen(path);
struct strbuf sb_path = STRBUF_INIT;
strbuf_attach(&sb_path, path, len, len);
/*
* If this fails, commit_lock_file() will also fail
* and will report the problem.
*/
remove_empty_directories(&sb_path);
strbuf_release(&sb_path);
} else {
free(path);
}
if (commit_lock_file(&lock->lk))
return -1;
return 0;
}
static int open_or_create_logfile(const char *path, void *cb)
{
int *fd = cb;
*fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
return (*fd < 0) ? -1 : 0;
}
/*
* Create a reflog for a ref. If force_create = 0, only create the
* reflog for certain refs (those for which should_autocreate_reflog
* returns non-zero). Otherwise, create it regardless of the reference
* name. If the logfile already existed or was created, return 0 and
* set *logfd to the file descriptor opened for appending to the file.
* If no logfile exists and we decided not to create one, return 0 and
* set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
* return -1.
*/
static int log_ref_setup(struct files_ref_store *refs,
const char *refname, int force_create,
int *logfd, struct strbuf *err)
{
struct strbuf logfile_sb = STRBUF_INIT;
char *logfile;
files_reflog_path(refs, &logfile_sb, refname);
logfile = strbuf_detach(&logfile_sb, NULL);
if (force_create || should_autocreate_reflog(refname)) {
if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
if (errno == ENOENT)
strbuf_addf(err, "unable to create directory for '%s': "
"%s", logfile, strerror(errno));
else if (errno == EISDIR)
strbuf_addf(err, "there are still logs under '%s'",
logfile);
else
strbuf_addf(err, "unable to append to '%s': %s",
logfile, strerror(errno));
goto error;
}
} else {
*logfd = open(logfile, O_APPEND | O_WRONLY);
if (*logfd < 0) {
if (errno == ENOENT || errno == EISDIR) {
/*
* The logfile doesn't already exist,
* but that is not an error; it only
* means that we won't write log
* entries to it.
*/
;
} else {
strbuf_addf(err, "unable to append to '%s': %s",
logfile, strerror(errno));
goto error;
}
}
}
if (*logfd >= 0)
adjust_shared_perm(logfile);
free(logfile);
return 0;
error:
free(logfile);
return -1;
}
static int files_create_reflog(struct ref_store *ref_store, const char *refname,
struct strbuf *err)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
int fd;
if (log_ref_setup(refs, refname, 1, &fd, err))
return -1;
if (fd >= 0)
close(fd);
return 0;
}
static int log_ref_write_fd(int fd, const struct object_id *old_oid,
const struct object_id *new_oid,
const char *committer, const char *msg)
{
struct strbuf sb = STRBUF_INIT;
int ret = 0;
strbuf_addf(&sb, "%s %s %s", oid_to_hex(old_oid), oid_to_hex(new_oid), committer);
if (msg && *msg) {
strbuf_addch(&sb, '\t');
strbuf_addstr(&sb, msg);
}
strbuf_addch(&sb, '\n');
if (write_in_full(fd, sb.buf, sb.len) < 0)
ret = -1;
strbuf_release(&sb);
return ret;
}
static int files_log_ref_write(struct files_ref_store *refs,
const char *refname, const struct object_id *old_oid,
const struct object_id *new_oid, const char *msg,
int flags, struct strbuf *err)
{
int logfd, result;
if (log_all_ref_updates == LOG_REFS_UNSET)
log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
result = log_ref_setup(refs, refname,
flags & REF_FORCE_CREATE_REFLOG,
&logfd, err);
if (result)
return result;
if (logfd < 0)
return 0;
result = log_ref_write_fd(logfd, old_oid, new_oid,
git_committer_info(0), msg);
if (result) {
struct strbuf sb = STRBUF_INIT;
int save_errno = errno;
files_reflog_path(refs, &sb, refname);
strbuf_addf(err, "unable to append to '%s': %s",
sb.buf, strerror(save_errno));
strbuf_release(&sb);
close(logfd);
return -1;
}
if (close(logfd)) {
struct strbuf sb = STRBUF_INIT;
int save_errno = errno;
files_reflog_path(refs, &sb, refname);
strbuf_addf(err, "unable to append to '%s': %s",
sb.buf, strerror(save_errno));
strbuf_release(&sb);
return -1;
}
return 0;
}
/*
* Write oid into the open lockfile, then close the lockfile. On
* errors, rollback the lockfile, fill in *err and return -1.
*/
static int write_ref_to_lockfile(struct ref_lock *lock,
const struct object_id *oid,
int skip_oid_verification, struct strbuf *err)
{
static char term = '\n';
struct object *o;
int fd;
if (!skip_oid_verification) {
o = parse_object(the_repository, oid);
if (!o) {
strbuf_addf(
err,
"trying to write ref '%s' with nonexistent object %s",
lock->ref_name, oid_to_hex(oid));
unlock_ref(lock);
return -1;
}
if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
strbuf_addf(
err,
"trying to write non-commit object %s to branch '%s'",
oid_to_hex(oid), lock->ref_name);
unlock_ref(lock);
return -1;
}
}
fd = get_lock_file_fd(&lock->lk);
if (write_in_full(fd, oid_to_hex(oid), the_hash_algo->hexsz) < 0 ||
write_in_full(fd, &term, 1) < 0 ||
fsync_component(FSYNC_COMPONENT_REFERENCE, get_lock_file_fd(&lock->lk)) < 0 ||
close_ref_gently(lock) < 0) {
strbuf_addf(err,
"couldn't write '%s'", get_lock_file_path(&lock->lk));
unlock_ref(lock);
return -1;
}
return 0;
}
/*
* Commit a change to a loose reference that has already been written
* to the loose reference lockfile. Also update the reflogs if
* necessary, using the specified lockmsg (which can be NULL).
*/
static int commit_ref_update(struct files_ref_store *refs,
struct ref_lock *lock,
const struct object_id *oid, const char *logmsg,
struct strbuf *err)
{
files_assert_main_repository(refs, "commit_ref_update");
clear_loose_ref_cache(refs);
if (files_log_ref_write(refs, lock->ref_name,
&lock->old_oid, oid,
logmsg, 0, err)) {
char *old_msg = strbuf_detach(err, NULL);
strbuf_addf(err, "cannot update the ref '%s': %s",
lock->ref_name, old_msg);
free(old_msg);
unlock_ref(lock);
return -1;
}
if (strcmp(lock->ref_name, "HEAD") != 0) {
/*
* Special hack: If a branch is updated directly and HEAD
* points to it (may happen on the remote side of a push
* for example) then logically the HEAD reflog should be
* updated too.
* A generic solution implies reverse symref information,
* but finding all symrefs pointing to the given branch
* would be rather costly for this rare event (the direct
* update of a branch) to be worth it. So let's cheat and
* check with HEAD only which should cover 99% of all usage
* scenarios (even 100% of the default ones).
*/
int head_flag;
const char *head_ref;
head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
RESOLVE_REF_READING,
NULL, &head_flag);
if (head_ref && (head_flag & REF_ISSYMREF) &&
!strcmp(head_ref, lock->ref_name)) {
struct strbuf log_err = STRBUF_INIT;
if (files_log_ref_write(refs, "HEAD",
&lock->old_oid, oid,
logmsg, 0, &log_err)) {
error("%s", log_err.buf);
strbuf_release(&log_err);
}
}
}
if (commit_ref(lock)) {
strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
unlock_ref(lock);
return -1;
}
unlock_ref(lock);
return 0;
}
static int create_ref_symlink(struct ref_lock *lock, const char *target)
{
int ret = -1;
#ifndef NO_SYMLINK_HEAD
char *ref_path = get_locked_file_path(&lock->lk);
unlink(ref_path);
ret = symlink(target, ref_path);
free(ref_path);
if (ret)
fprintf(stderr, "no symlink - falling back to symbolic ref\n");
#endif
return ret;
}
static int create_symref_lock(struct files_ref_store *refs,
struct ref_lock *lock, const char *refname,
const char *target, struct strbuf *err)
{
if (!fdopen_lock_file(&lock->lk, "w")) {
strbuf_addf(err, "unable to fdopen %s: %s",
get_lock_file_path(&lock->lk), strerror(errno));
return -1;
}
if (fprintf(get_lock_file_fp(&lock->lk), "ref: %s\n", target) < 0) {
strbuf_addf(err, "unable to write to %s: %s",
get_lock_file_path(&lock->lk), strerror(errno));
return -1;
}
return 0;
}
static int files_reflog_exists(struct ref_store *ref_store,
const char *refname)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
struct strbuf sb = STRBUF_INIT;
struct stat st;
int ret;
files_reflog_path(refs, &sb, refname);
ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
strbuf_release(&sb);
return ret;
}
static int files_delete_reflog(struct ref_store *ref_store,
const char *refname)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
struct strbuf sb = STRBUF_INIT;
int ret;
files_reflog_path(refs, &sb, refname);
ret = remove_path(sb.buf);
strbuf_release(&sb);
return ret;
}
static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
{
struct object_id ooid, noid;
char *email_end, *message;
timestamp_t timestamp;
int tz;
const char *p = sb->buf;
/* old SP new SP name <email> SP time TAB msg LF */
if (!sb->len || sb->buf[sb->len - 1] != '\n' ||
parse_oid_hex(p, &ooid, &p) || *p++ != ' ' ||
parse_oid_hex(p, &noid, &p) || *p++ != ' ' ||
!(email_end = strchr(p, '>')) ||
email_end[1] != ' ' ||
!(timestamp = parse_timestamp(email_end + 2, &message, 10)) ||
!message || message[0] != ' ' ||
(message[1] != '+' && message[1] != '-') ||
!isdigit(message[2]) || !isdigit(message[3]) ||
!isdigit(message[4]) || !isdigit(message[5]))
return 0; /* corrupt? */
email_end[1] = '\0';
tz = strtol(message + 1, NULL, 10);
if (message[6] != '\t')
message += 6;
else
message += 7;
return fn(&ooid, &noid, p, timestamp, tz, message, cb_data);
}
static char *find_beginning_of_line(char *bob, char *scan)
{
while (bob < scan && *(--scan) != '\n')
; /* keep scanning backwards */
/*
* Return either beginning of the buffer, or LF at the end of
* the previous line.
*/
return scan;
}
static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
const char *refname,
each_reflog_ent_fn fn,
void *cb_data)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ,
"for_each_reflog_ent_reverse");
struct strbuf sb = STRBUF_INIT;
FILE *logfp;
long pos;
int ret = 0, at_tail = 1;
files_reflog_path(refs, &sb, refname);
logfp = fopen(sb.buf, "r");
strbuf_release(&sb);
if (!logfp)
return -1;
/* Jump to the end */
if (fseek(logfp, 0, SEEK_END) < 0)
ret = error("cannot seek back reflog for %s: %s",
refname, strerror(errno));
pos = ftell(logfp);
while (!ret && 0 < pos) {
int cnt;
size_t nread;
char buf[BUFSIZ];
char *endp, *scanp;
/* Fill next block from the end */
cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
if (fseek(logfp, pos - cnt, SEEK_SET)) {
ret = error("cannot seek back reflog for %s: %s",
refname, strerror(errno));
break;
}
nread = fread(buf, cnt, 1, logfp);
if (nread != 1) {
ret = error("cannot read %d bytes from reflog for %s: %s",
cnt, refname, strerror(errno));
break;
}
pos -= cnt;
scanp = endp = buf + cnt;
if (at_tail && scanp[-1] == '\n')
/* Looking at the final LF at the end of the file */
scanp--;
at_tail = 0;
while (buf < scanp) {
/*
* terminating LF of the previous line, or the beginning
* of the buffer.
*/
char *bp;
bp = find_beginning_of_line(buf, scanp);
if (*bp == '\n') {
/*
* The newline is the end of the previous line,
* so we know we have complete line starting
* at (bp + 1). Prefix it onto any prior data
* we collected for the line and process it.
*/
strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
scanp = bp;
endp = bp + 1;
ret = show_one_reflog_ent(&sb, fn, cb_data);
strbuf_reset(&sb);
if (ret)
break;
} else if (!pos) {
/*
* We are at the start of the buffer, and the
* start of the file; there is no previous
* line, and we have everything for this one.
* Process it, and we can end the loop.
*/
strbuf_splice(&sb, 0, 0, buf, endp - buf);
ret = show_one_reflog_ent(&sb, fn, cb_data);
strbuf_reset(&sb);
break;
}
if (bp == buf) {
/*
* We are at the start of the buffer, and there
* is more file to read backwards. Which means
* we are in the middle of a line. Note that we
* may get here even if *bp was a newline; that
* just means we are at the exact end of the
* previous line, rather than some spot in the
* middle.
*
* Save away what we have to be combined with
* the data from the next read.
*/
strbuf_splice(&sb, 0, 0, buf, endp - buf);
break;
}
}
}
if (!ret && sb.len)
BUG("reverse reflog parser had leftover data");
fclose(logfp);
strbuf_release(&sb);
return ret;
}
static int files_for_each_reflog_ent(struct ref_store *ref_store,
const char *refname,
each_reflog_ent_fn fn, void *cb_data)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ,
"for_each_reflog_ent");
FILE *logfp;
struct strbuf sb = STRBUF_INIT;
int ret = 0;
files_reflog_path(refs, &sb, refname);
logfp = fopen(sb.buf, "r");
strbuf_release(&sb);
if (!logfp)
return -1;
while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
ret = show_one_reflog_ent(&sb, fn, cb_data);
fclose(logfp);
strbuf_release(&sb);
return ret;
}
struct files_reflog_iterator {
struct ref_iterator base;
struct ref_store *ref_store;
struct dir_iterator *dir_iterator;
};
static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
{
struct files_reflog_iterator *iter =
(struct files_reflog_iterator *)ref_iterator;
struct dir_iterator *diter = iter->dir_iterator;
int ok;
while ((ok = dir_iterator_advance(diter)) == ITER_OK) {
if (!S_ISREG(diter->st.st_mode))
continue;
if (check_refname_format(diter->basename,
REFNAME_ALLOW_ONELEVEL))
continue;
iter->base.refname = diter->relative_path;
return ITER_OK;
}
iter->dir_iterator = NULL;
if (ref_iterator_abort(ref_iterator) == ITER_ERROR)
ok = ITER_ERROR;
return ok;
}
static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator UNUSED,
struct object_id *peeled UNUSED)
{
BUG("ref_iterator_peel() called for reflog_iterator");
}
static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
{
struct files_reflog_iterator *iter =
(struct files_reflog_iterator *)ref_iterator;
int ok = ITER_DONE;
if (iter->dir_iterator)
ok = dir_iterator_abort(iter->dir_iterator);
base_ref_iterator_free(ref_iterator);
return ok;
}
static struct ref_iterator_vtable files_reflog_iterator_vtable = {
.advance = files_reflog_iterator_advance,
.peel = files_reflog_iterator_peel,
.abort = files_reflog_iterator_abort,
};
static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
const char *gitdir)
{
struct dir_iterator *diter;
struct files_reflog_iterator *iter;
struct ref_iterator *ref_iterator;
struct strbuf sb = STRBUF_INIT;
strbuf_addf(&sb, "%s/logs", gitdir);
diter = dir_iterator_begin(sb.buf, DIR_ITERATOR_SORTED);
if (!diter) {
strbuf_release(&sb);
return empty_ref_iterator_begin();
}
CALLOC_ARRAY(iter, 1);
ref_iterator = &iter->base;
base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
iter->dir_iterator = diter;
iter->ref_store = ref_store;
strbuf_release(&sb);
return ref_iterator;
}
static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_READ,
"reflog_iterator_begin");
if (!strcmp(refs->base.gitdir, refs->gitcommondir)) {
return reflog_iterator_begin(ref_store, refs->gitcommondir);
} else {
return merge_ref_iterator_begin(
reflog_iterator_begin(ref_store, refs->base.gitdir),
reflog_iterator_begin(ref_store, refs->gitcommondir),
ref_iterator_select, refs);
}
}
/*
* If update is a direct update of head_ref (the reference pointed to
* by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
*/
static int split_head_update(struct ref_update *update,
struct ref_transaction *transaction,
const char *head_ref,
struct string_list *affected_refnames,
struct strbuf *err)
{
struct string_list_item *item;
struct ref_update *new_update;
if ((update->flags & REF_LOG_ONLY) ||
(update->flags & REF_IS_PRUNING) ||
(update->flags & REF_UPDATE_VIA_HEAD))
return 0;
if (strcmp(update->refname, head_ref))
return 0;
/*
* First make sure that HEAD is not already in the
* transaction. This check is O(lg N) in the transaction
* size, but it happens at most once per transaction.
*/
if (string_list_has_string(affected_refnames, "HEAD")) {
/* An entry already existed */
strbuf_addf(err,
"multiple updates for 'HEAD' (including one "
"via its referent '%s') are not allowed",
update->refname);
return TRANSACTION_NAME_CONFLICT;
}
new_update = ref_transaction_add_update(
transaction, "HEAD",
update->flags | REF_LOG_ONLY | REF_NO_DEREF,
&update->new_oid, &update->old_oid,
NULL, NULL, update->msg);
/*
* Add "HEAD". This insertion is O(N) in the transaction
* size, but it happens at most once per transaction.
* Add new_update->refname instead of a literal "HEAD".
*/
if (strcmp(new_update->refname, "HEAD"))
BUG("%s unexpectedly not 'HEAD'", new_update->refname);
item = string_list_insert(affected_refnames, new_update->refname);
item->util = new_update;
return 0;
}
/*
* update is for a symref that points at referent and doesn't have
* REF_NO_DEREF set. Split it into two updates:
* - The original update, but with REF_LOG_ONLY and REF_NO_DEREF set
* - A new, separate update for the referent reference
* Note that the new update will itself be subject to splitting when
* the iteration gets to it.
*/
static int split_symref_update(struct ref_update *update,
const char *referent,
struct ref_transaction *transaction,
struct string_list *affected_refnames,
struct strbuf *err)
{
struct string_list_item *item;
struct ref_update *new_update;
unsigned int new_flags;
/*
* First make sure that referent is not already in the
* transaction. This check is O(lg N) in the transaction
* size, but it happens at most once per symref in a
* transaction.
*/
if (string_list_has_string(affected_refnames, referent)) {
/* An entry already exists */
strbuf_addf(err,
"multiple updates for '%s' (including one "
"via symref '%s') are not allowed",
referent, update->refname);
return TRANSACTION_NAME_CONFLICT;
}
new_flags = update->flags;
if (!strcmp(update->refname, "HEAD")) {
/*
* Record that the new update came via HEAD, so that
* when we process it, split_head_update() doesn't try
* to add another reflog update for HEAD. Note that
* this bit will be propagated if the new_update
* itself needs to be split.
*/
new_flags |= REF_UPDATE_VIA_HEAD;
}
new_update = ref_transaction_add_update(
transaction, referent, new_flags,
update->new_target ? NULL : &update->new_oid,
update->old_target ? NULL : &update->old_oid,
update->new_target, update->old_target, update->msg);
new_update->parent_update = update;
/*
* Change the symbolic ref update to log only. Also, it
* doesn't need to check its old OID value, as that will be
* done when new_update is processed.
*/
update->flags |= REF_LOG_ONLY | REF_NO_DEREF;
update->flags &= ~REF_HAVE_OLD;
/*
* Add the referent. This insertion is O(N) in the transaction
* size, but it happens at most once per symref in a
* transaction. Make sure to add new_update->refname, which will
* be valid as long as affected_refnames is in use, and NOT
* referent, which might soon be freed by our caller.
*/
item = string_list_insert(affected_refnames, new_update->refname);
if (item->util)
BUG("%s unexpectedly found in affected_refnames",
new_update->refname);
item->util = new_update;
return 0;
}
/*
* Check whether the REF_HAVE_OLD and old_oid values stored in update
* are consistent with oid, which is the reference's current value. If
* everything is OK, return 0; otherwise, write an error message to
* err and return -1.
*/
static int check_old_oid(struct ref_update *update, struct object_id *oid,
struct strbuf *err)
{
if (!(update->flags & REF_HAVE_OLD) ||
oideq(oid, &update->old_oid))
return 0;
if (is_null_oid(&update->old_oid))
strbuf_addf(err, "cannot lock ref '%s': "
"reference already exists",
ref_update_original_update_refname(update));
else if (is_null_oid(oid))
strbuf_addf(err, "cannot lock ref '%s': "
"reference is missing but expected %s",
ref_update_original_update_refname(update),
oid_to_hex(&update->old_oid));
else
strbuf_addf(err, "cannot lock ref '%s': "
"is at %s but expected %s",
ref_update_original_update_refname(update),
oid_to_hex(oid),
oid_to_hex(&update->old_oid));
return -1;
}
/*
* Prepare for carrying out update:
* - Lock the reference referred to by update.
* - Read the reference under lock.
* - Check that its old OID value (if specified) is correct, and in
* any case record it in update->lock->old_oid for later use when
* writing the reflog.
* - If it is a symref update without REF_NO_DEREF, split it up into a
* REF_LOG_ONLY update of the symref and add a separate update for
* the referent to transaction.
* - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
* update of HEAD.
*/
static int lock_ref_for_update(struct files_ref_store *refs,
struct ref_update *update,
struct ref_transaction *transaction,
const char *head_ref,
struct string_list *affected_refnames,
struct strbuf *err)
{
struct strbuf referent = STRBUF_INIT;
int mustexist = (update->flags & REF_HAVE_OLD) &&
!is_null_oid(&update->old_oid);
int ret = 0;
struct ref_lock *lock;
files_assert_main_repository(refs, "lock_ref_for_update");
if ((update->flags & REF_HAVE_NEW) && ref_update_has_null_new_value(update))
update->flags |= REF_DELETING;
if (head_ref) {
ret = split_head_update(update, transaction, head_ref,
affected_refnames, err);
if (ret)
goto out;
}
ret = lock_raw_ref(refs, update->refname, mustexist,
affected_refnames,
&lock, &referent,
&update->type, err);
if (ret) {
char *reason;
reason = strbuf_detach(err, NULL);
strbuf_addf(err, "cannot lock ref '%s': %s",
ref_update_original_update_refname(update), reason);
free(reason);
goto out;
}
update->backend_data = lock;
if (update->type & REF_ISSYMREF) {
if (update->flags & REF_NO_DEREF) {
/*
* We won't be reading the referent as part of
* the transaction, so we have to read it here
* to record and possibly check old_oid:
*/
if (!refs_resolve_ref_unsafe(&refs->base,
referent.buf, 0,
&lock->old_oid, NULL)) {
if (update->flags & REF_HAVE_OLD) {
strbuf_addf(err, "cannot lock ref '%s': "
"error reading reference",
ref_update_original_update_refname(update));
ret = TRANSACTION_GENERIC_ERROR;
goto out;
}
}
if (update->old_target) {
if (ref_update_check_old_target(referent.buf, update, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto out;
}
} else if (check_old_oid(update, &lock->old_oid, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto out;
}
} else {
/*
* Create a new update for the reference this
* symref is pointing at. Also, we will record
* and verify old_oid for this update as part
* of processing the split-off update, so we
* don't have to do it here.
*/
ret = split_symref_update(update,
referent.buf, transaction,
affected_refnames, err);
if (ret)
goto out;
}
} else {
struct ref_update *parent_update;
/*
* Even if the ref is a regular ref, if `old_target` is set, we
* check the referent value. Ideally `old_target` should only
* be set for symrefs, but we're strict about its usage.
*/
if (update->old_target) {
if (ref_update_check_old_target(referent.buf, update, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto out;
}
} else if (check_old_oid(update, &lock->old_oid, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto out;
}
/*
* If this update is happening indirectly because of a
* symref update, record the old OID in the parent
* update:
*/
for (parent_update = update->parent_update;
parent_update;
parent_update = parent_update->parent_update) {
struct ref_lock *parent_lock = parent_update->backend_data;
oidcpy(&parent_lock->old_oid, &lock->old_oid);
}
}
if (update->new_target && !(update->flags & REF_LOG_ONLY)) {
if (create_symref_lock(refs, lock, update->refname,
update->new_target, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto out;
}
if (close_ref_gently(lock)) {
strbuf_addf(err, "couldn't close '%s.lock'",
update->refname);
ret = TRANSACTION_GENERIC_ERROR;
goto out;
}
/*
* Once we have created the symref lock, the commit
* phase of the transaction only needs to commit the lock.
*/
update->flags |= REF_NEEDS_COMMIT;
} else if ((update->flags & REF_HAVE_NEW) &&
!(update->flags & REF_DELETING) &&
!(update->flags & REF_LOG_ONLY)) {
if (!(update->type & REF_ISSYMREF) &&
oideq(&lock->old_oid, &update->new_oid)) {
/*
* The reference already has the desired
* value, so we don't need to write it.
*/
} else if (write_ref_to_lockfile(
lock, &update->new_oid,
update->flags & REF_SKIP_OID_VERIFICATION,
err)) {
char *write_err = strbuf_detach(err, NULL);
/*
* The lock was freed upon failure of
* write_ref_to_lockfile():
*/
update->backend_data = NULL;
strbuf_addf(err,
"cannot update ref '%s': %s",
update->refname, write_err);
free(write_err);
ret = TRANSACTION_GENERIC_ERROR;
goto out;
} else {
update->flags |= REF_NEEDS_COMMIT;
}
}
if (!(update->flags & REF_NEEDS_COMMIT)) {
/*
* We didn't call write_ref_to_lockfile(), so
* the lockfile is still open. Close it to
* free up the file descriptor:
*/
if (close_ref_gently(lock)) {
strbuf_addf(err, "couldn't close '%s.lock'",
update->refname);
ret = TRANSACTION_GENERIC_ERROR;
goto out;
}
}
out:
strbuf_release(&referent);
return ret;
}
struct files_transaction_backend_data {
struct ref_transaction *packed_transaction;
int packed_refs_locked;
};
/*
* Unlock any references in `transaction` that are still locked, and
* mark the transaction closed.
*/
static void files_transaction_cleanup(struct files_ref_store *refs,
struct ref_transaction *transaction)
{
size_t i;
struct files_transaction_backend_data *backend_data =
transaction->backend_data;
struct strbuf err = STRBUF_INIT;
for (i = 0; i < transaction->nr; i++) {
struct ref_update *update = transaction->updates[i];
struct ref_lock *lock = update->backend_data;
if (lock) {
unlock_ref(lock);
update->backend_data = NULL;
}
}
if (backend_data) {
if (backend_data->packed_transaction &&
ref_transaction_abort(backend_data->packed_transaction, &err)) {
error("error aborting transaction: %s", err.buf);
strbuf_release(&err);
}
if (backend_data->packed_refs_locked)
packed_refs_unlock(refs->packed_ref_store);
free(backend_data);
}
transaction->state = REF_TRANSACTION_CLOSED;
}
static int files_transaction_prepare(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE,
"ref_transaction_prepare");
size_t i;
int ret = 0;
struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
char *head_ref = NULL;
int head_type;
struct files_transaction_backend_data *backend_data;
struct ref_transaction *packed_transaction = NULL;
assert(err);
if (!transaction->nr)
goto cleanup;
CALLOC_ARRAY(backend_data, 1);
transaction->backend_data = backend_data;
/*
* Fail if a refname appears more than once in the
* transaction. (If we end up splitting up any updates using
* split_symref_update() or split_head_update(), those
* functions will check that the new updates don't have the
* same refname as any existing ones.) Also fail if any of the
* updates use REF_IS_PRUNING without REF_NO_DEREF.
*/
for (i = 0; i < transaction->nr; i++) {
struct ref_update *update = transaction->updates[i];
struct string_list_item *item =
string_list_append(&affected_refnames, update->refname);
if ((update->flags & REF_IS_PRUNING) &&
!(update->flags & REF_NO_DEREF))
BUG("REF_IS_PRUNING set without REF_NO_DEREF");
/*
* We store a pointer to update in item->util, but at
* the moment we never use the value of this field
* except to check whether it is non-NULL.
*/
item->util = update;
}
string_list_sort(&affected_refnames);
if (ref_update_reject_duplicates(&affected_refnames, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
/*
* Special hack: If a branch is updated directly and HEAD
* points to it (may happen on the remote side of a push
* for example) then logically the HEAD reflog should be
* updated too.
*
* A generic solution would require reverse symref lookups,
* but finding all symrefs pointing to a given branch would be
* rather costly for this rare event (the direct update of a
* branch) to be worth it. So let's cheat and check with HEAD
* only, which should cover 99% of all usage scenarios (even
* 100% of the default ones).
*
* So if HEAD is a symbolic reference, then record the name of
* the reference that it points to. If we see an update of
* head_ref within the transaction, then split_head_update()
* arranges for the reflog of HEAD to be updated, too.
*/
head_ref = refs_resolve_refdup(ref_store, "HEAD",
RESOLVE_REF_NO_RECURSE,
NULL, &head_type);
if (head_ref && !(head_type & REF_ISSYMREF)) {
FREE_AND_NULL(head_ref);
}
/*
* Acquire all locks, verify old values if provided, check
* that new values are valid, and write new values to the
* lockfiles, ready to be activated. Only keep one lockfile
* open at a time to avoid running out of file descriptors.
* Note that lock_ref_for_update() might append more updates
* to the transaction.
*/
for (i = 0; i < transaction->nr; i++) {
struct ref_update *update = transaction->updates[i];
ret = lock_ref_for_update(refs, update, transaction,
head_ref, &affected_refnames, err);
if (ret)
goto cleanup;
if (update->flags & REF_DELETING &&
!(update->flags & REF_LOG_ONLY) &&
!(update->flags & REF_IS_PRUNING)) {
/*
* This reference has to be deleted from
* packed-refs if it exists there.
*/
if (!packed_transaction) {
packed_transaction = ref_store_transaction_begin(
refs->packed_ref_store, err);
if (!packed_transaction) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
backend_data->packed_transaction =
packed_transaction;
}
ref_transaction_add_update(
packed_transaction, update->refname,
REF_HAVE_NEW | REF_NO_DEREF,
&update->new_oid, NULL,
NULL, NULL, NULL);
}
}
if (packed_transaction) {
if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
backend_data->packed_refs_locked = 1;
if (is_packed_transaction_needed(refs->packed_ref_store,
packed_transaction)) {
ret = ref_transaction_prepare(packed_transaction, err);
/*
* A failure during the prepare step will abort
* itself, but not free. Do that now, and disconnect
* from the files_transaction so it does not try to
* abort us when we hit the cleanup code below.
*/
if (ret) {
ref_transaction_free(packed_transaction);
backend_data->packed_transaction = NULL;
}
} else {
/*
* We can skip rewriting the `packed-refs`
* file. But we do need to leave it locked, so
* that somebody else doesn't pack a reference
* that we are trying to delete.
*
* We need to disconnect our transaction from
* backend_data, since the abort (whether successful or
* not) will free it.
*/
backend_data->packed_transaction = NULL;
if (ref_transaction_abort(packed_transaction, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
}
}
cleanup:
free(head_ref);
string_list_clear(&affected_refnames, 0);
if (ret)
files_transaction_cleanup(refs, transaction);
else
transaction->state = REF_TRANSACTION_PREPARED;
return ret;
}
static int parse_and_write_reflog(struct files_ref_store *refs,
struct ref_update *update,
struct ref_lock *lock,
struct strbuf *err)
{
if (update->new_target) {
/*
* We want to get the resolved OID for the target, to ensure
* that the correct value is added to the reflog.
*/
if (!refs_resolve_ref_unsafe(&refs->base, update->new_target,
RESOLVE_REF_READING,
&update->new_oid, NULL)) {
/*
* TODO: currently we skip creating reflogs for dangling
* symref updates. It would be nice to capture this as
* zero oid updates however.
*/
return 0;
}
}
if (files_log_ref_write(refs, lock->ref_name, &lock->old_oid,
&update->new_oid, update->msg, update->flags, err)) {
char *old_msg = strbuf_detach(err, NULL);
strbuf_addf(err, "cannot update the ref '%s': %s",
lock->ref_name, old_msg);
free(old_msg);
unlock_ref(lock);
update->backend_data = NULL;
return -1;
}
return 0;
}
static int files_transaction_finish(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
struct files_ref_store *refs =
files_downcast(ref_store, 0, "ref_transaction_finish");
size_t i;
int ret = 0;
struct strbuf sb = STRBUF_INIT;
struct files_transaction_backend_data *backend_data;
struct ref_transaction *packed_transaction;
assert(err);
if (!transaction->nr) {
transaction->state = REF_TRANSACTION_CLOSED;
return 0;
}
backend_data = transaction->backend_data;
packed_transaction = backend_data->packed_transaction;
/* Perform updates first so live commits remain referenced */
for (i = 0; i < transaction->nr; i++) {
struct ref_update *update = transaction->updates[i];
struct ref_lock *lock = update->backend_data;
if (update->flags & REF_NEEDS_COMMIT ||
update->flags & REF_LOG_ONLY) {
if (parse_and_write_reflog(refs, update, lock, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
}
/*
* We try creating a symlink, if that succeeds we continue to the
* next update. If not, we try and create a regular symref.
*/
if (update->new_target && prefer_symlink_refs)
if (!create_ref_symlink(lock, update->new_target))
continue;
if (update->flags & REF_NEEDS_COMMIT) {
clear_loose_ref_cache(refs);
if (commit_ref(lock)) {
strbuf_addf(err, "couldn't set '%s'", lock->ref_name);
unlock_ref(lock);
update->backend_data = NULL;
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
}
}
/*
* Now that updates are safely completed, we can perform
* deletes. First delete the reflogs of any references that
* will be deleted, since (in the unexpected event of an
* error) leaving a reference without a reflog is less bad
* than leaving a reflog without a reference (the latter is a
* mildly invalid repository state):
*/
for (i = 0; i < transaction->nr; i++) {
struct ref_update *update = transaction->updates[i];
if (update->flags & REF_DELETING &&
!(update->flags & REF_LOG_ONLY) &&
!(update->flags & REF_IS_PRUNING)) {
strbuf_reset(&sb);
files_reflog_path(refs, &sb, update->refname);
if (!unlink_or_warn(sb.buf))
try_remove_empty_parents(refs, update->refname,
REMOVE_EMPTY_PARENTS_REFLOG);
}
}
/*
* Perform deletes now that updates are safely completed.
*
* First delete any packed versions of the references, while
* retaining the packed-refs lock:
*/
if (packed_transaction) {
ret = ref_transaction_commit(packed_transaction, err);
ref_transaction_free(packed_transaction);
packed_transaction = NULL;
backend_data->packed_transaction = NULL;
if (ret)
goto cleanup;
}
/* Now delete the loose versions of the references: */
for (i = 0; i < transaction->nr; i++) {
struct ref_update *update = transaction->updates[i];
struct ref_lock *lock = update->backend_data;
if (update->flags & REF_DELETING &&
!(update->flags & REF_LOG_ONLY)) {
update->flags |= REF_DELETED_RMDIR;
if (!(update->type & REF_ISPACKED) ||
update->type & REF_ISSYMREF) {
/* It is a loose reference. */
strbuf_reset(&sb);
files_ref_path(refs, &sb, lock->ref_name);
if (unlink_or_msg(sb.buf, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
}
}
}
clear_loose_ref_cache(refs);
cleanup:
files_transaction_cleanup(refs, transaction);
for (i = 0; i < transaction->nr; i++) {
struct ref_update *update = transaction->updates[i];
if (update->flags & REF_DELETED_RMDIR) {
/*
* The reference was deleted. Delete any
* empty parent directories. (Note that this
* can only work because we have already
* removed the lockfile.)
*/
try_remove_empty_parents(refs, update->refname,
REMOVE_EMPTY_PARENTS_REF);
}
}
strbuf_release(&sb);
return ret;
}
static int files_transaction_abort(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err UNUSED)
{
struct files_ref_store *refs =
files_downcast(ref_store, 0, "ref_transaction_abort");
files_transaction_cleanup(refs, transaction);
return 0;
}
static int ref_present(const char *refname,
const struct object_id *oid UNUSED,
int flags UNUSED,
void *cb_data)
{
struct string_list *affected_refnames = cb_data;
return string_list_has_string(affected_refnames, refname);
}
static int files_initial_transaction_commit(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE,
"initial_ref_transaction_commit");
size_t i;
int ret = 0;
struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
struct ref_transaction *packed_transaction = NULL;
assert(err);
if (transaction->state != REF_TRANSACTION_OPEN)
BUG("commit called for transaction that is not open");
/* Fail if a refname appears more than once in the transaction: */
for (i = 0; i < transaction->nr; i++)
string_list_append(&affected_refnames,
transaction->updates[i]->refname);
string_list_sort(&affected_refnames);
if (ref_update_reject_duplicates(&affected_refnames, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
/*
* It's really undefined to call this function in an active
* repository or when there are existing references: we are
* only locking and changing packed-refs, so (1) any
* simultaneous processes might try to change a reference at
* the same time we do, and (2) any existing loose versions of
* the references that we are setting would have precedence
* over our values. But some remote helpers create the remote
* "HEAD" and "master" branches before calling this function,
* so here we really only check that none of the references
* that we are creating already exists.
*/
if (refs_for_each_rawref(&refs->base, ref_present,
&affected_refnames))
BUG("initial ref transaction called with existing refs");
packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err);
if (!packed_transaction) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
for (i = 0; i < transaction->nr; i++) {
struct ref_update *update = transaction->updates[i];
if ((update->flags & REF_HAVE_OLD) &&
!is_null_oid(&update->old_oid))
BUG("initial ref transaction with old_sha1 set");
if (refs_verify_refname_available(&refs->base, update->refname,
&affected_refnames, NULL,
err)) {
ret = TRANSACTION_NAME_CONFLICT;
goto cleanup;
}
/*
* Add a reference creation for this reference to the
* packed-refs transaction:
*/
ref_transaction_add_update(packed_transaction, update->refname,
update->flags & ~REF_HAVE_OLD,
&update->new_oid, &update->old_oid,
NULL, NULL, NULL);
}
if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
if (initial_ref_transaction_commit(packed_transaction, err)) {
ret = TRANSACTION_GENERIC_ERROR;
}
packed_refs_unlock(refs->packed_ref_store);
cleanup:
if (packed_transaction)
ref_transaction_free(packed_transaction);
transaction->state = REF_TRANSACTION_CLOSED;
string_list_clear(&affected_refnames, 0);
return ret;
}
struct expire_reflog_cb {
reflog_expiry_should_prune_fn *should_prune_fn;
void *policy_cb;
FILE *newlog;
struct object_id last_kept_oid;
unsigned int rewrite:1,
dry_run:1;
};
static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
const char *email, timestamp_t timestamp, int tz,
const char *message, void *cb_data)
{
struct expire_reflog_cb *cb = cb_data;
reflog_expiry_should_prune_fn *fn = cb->should_prune_fn;
if (cb->rewrite)
ooid = &cb->last_kept_oid;
if (fn(ooid, noid, email, timestamp, tz, message, cb->policy_cb))
return 0;
if (cb->dry_run)
return 0; /* --dry-run */
fprintf(cb->newlog, "%s %s %s %"PRItime" %+05d\t%s", oid_to_hex(ooid),
oid_to_hex(noid), email, timestamp, tz, message);
oidcpy(&cb->last_kept_oid, noid);
return 0;
}
static int files_reflog_expire(struct ref_store *ref_store,
const char *refname,
unsigned int expire_flags,
reflog_expiry_prepare_fn prepare_fn,
reflog_expiry_should_prune_fn should_prune_fn,
reflog_expiry_cleanup_fn cleanup_fn,
void *policy_cb_data)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
struct lock_file reflog_lock = LOCK_INIT;
struct expire_reflog_cb cb;
struct ref_lock *lock;
struct strbuf log_file_sb = STRBUF_INIT;
char *log_file;
int status = 0;
struct strbuf err = STRBUF_INIT;
const struct object_id *oid;
memset(&cb, 0, sizeof(cb));
cb.rewrite = !!(expire_flags & EXPIRE_REFLOGS_REWRITE);
cb.dry_run = !!(expire_flags & EXPIRE_REFLOGS_DRY_RUN);
cb.policy_cb = policy_cb_data;
cb.should_prune_fn = should_prune_fn;
/*
* The reflog file is locked by holding the lock on the
* reference itself, plus we might need to update the
* reference if --updateref was specified:
*/
lock = lock_ref_oid_basic(refs, refname, &err);
if (!lock) {
error("cannot lock ref '%s': %s", refname, err.buf);
strbuf_release(&err);
return -1;
}
oid = &lock->old_oid;
/*
* When refs are deleted, their reflog is deleted before the
* ref itself is deleted. This is because there is no separate
* lock for reflog; instead we take a lock on the ref with
* lock_ref_oid_basic().
*
* If a race happens and the reflog doesn't exist after we've
* acquired the lock that's OK. We've got nothing more to do;
* We were asked to delete the reflog, but someone else
* deleted it! The caller doesn't care that we deleted it,
* just that it is deleted. So we can return successfully.
*/
if (!refs_reflog_exists(ref_store, refname)) {
unlock_ref(lock);
return 0;
}
files_reflog_path(refs, &log_file_sb, refname);
log_file = strbuf_detach(&log_file_sb, NULL);
if (!cb.dry_run) {
/*
* Even though holding $GIT_DIR/logs/$reflog.lock has
* no locking implications, we use the lock_file
* machinery here anyway because it does a lot of the
* work we need, including cleaning up if the program
* exits unexpectedly.
*/
if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
struct strbuf err = STRBUF_INIT;
unable_to_lock_message(log_file, errno, &err);
error("%s", err.buf);
strbuf_release(&err);
goto failure;
}
cb.newlog = fdopen_lock_file(&reflog_lock, "w");
if (!cb.newlog) {
error("cannot fdopen %s (%s)",
get_lock_file_path(&reflog_lock), strerror(errno));
goto failure;
}
}
(*prepare_fn)(refname, oid, cb.policy_cb);
refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
(*cleanup_fn)(cb.policy_cb);
if (!cb.dry_run) {
/*
* It doesn't make sense to adjust a reference pointed
* to by a symbolic ref based on expiring entries in
* the symbolic reference's reflog. Nor can we update
* a reference if there are no remaining reflog
* entries.
*/
int update = 0;
if ((expire_flags & EXPIRE_REFLOGS_UPDATE_REF) &&
!is_null_oid(&cb.last_kept_oid)) {
int type;
const char *ref;
ref = refs_resolve_ref_unsafe(&refs->base, refname,
RESOLVE_REF_NO_RECURSE,
NULL, &type);
update = !!(ref && !(type & REF_ISSYMREF));
}
if (close_lock_file_gently(&reflog_lock)) {
status |= error("couldn't write %s: %s", log_file,
strerror(errno));
rollback_lock_file(&reflog_lock);
} else if (update &&
(write_in_full(get_lock_file_fd(&lock->lk),
oid_to_hex(&cb.last_kept_oid), the_hash_algo->hexsz) < 0 ||
write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
close_ref_gently(lock) < 0)) {
status |= error("couldn't write %s",
get_lock_file_path(&lock->lk));
rollback_lock_file(&reflog_lock);
} else if (commit_lock_file(&reflog_lock)) {
status |= error("unable to write reflog '%s' (%s)",
log_file, strerror(errno));
} else if (update && commit_ref(lock)) {
status |= error("couldn't set %s", lock->ref_name);
}
}
free(log_file);
unlock_ref(lock);
return status;
failure:
rollback_lock_file(&reflog_lock);
free(log_file);
unlock_ref(lock);
return -1;
}
static int files_init_db(struct ref_store *ref_store,
int flags,
struct strbuf *err UNUSED)
{
struct files_ref_store *refs =
files_downcast(ref_store, REF_STORE_WRITE, "init_db");
struct strbuf sb = STRBUF_INIT;
/*
* We need to create a "refs" dir in any case so that older versions of
* Git can tell that this is a repository. This serves two main purposes:
*
* - Clients will know to stop walking the parent-directory chain when
* detecting the Git repository. Otherwise they may end up detecting
* a Git repository in a parent directory instead.
*
* - Instead of failing to detect a repository with unknown reference
* format altogether, old clients will print an error saying that
* they do not understand the reference format extension.
*/
strbuf_addf(&sb, "%s/refs", ref_store->gitdir);
safe_create_dir(sb.buf, 1);
adjust_shared_perm(sb.buf);
/*
* There is no need to create directories for common refs when creating
* a worktree ref store.
*/
if (!(flags & REFS_INIT_DB_IS_WORKTREE)) {
/*
* Create .git/refs/{heads,tags}
*/
strbuf_reset(&sb);
files_ref_path(refs, &sb, "refs/heads");
safe_create_dir(sb.buf, 1);
strbuf_reset(&sb);
files_ref_path(refs, &sb, "refs/tags");
safe_create_dir(sb.buf, 1);
}
strbuf_release(&sb);
return 0;
}
struct ref_storage_be refs_be_files = {
.name = "files",
.init = files_ref_store_create,
.init_db = files_init_db,
.transaction_prepare = files_transaction_prepare,
.transaction_finish = files_transaction_finish,
.transaction_abort = files_transaction_abort,
.initial_transaction_commit = files_initial_transaction_commit,
.pack_refs = files_pack_refs,
.rename_ref = files_rename_ref,
.copy_ref = files_copy_ref,
.iterator_begin = files_ref_iterator_begin,
.read_raw_ref = files_read_raw_ref,
.read_symbolic_ref = files_read_symbolic_ref,
.reflog_iterator_begin = files_reflog_iterator_begin,
.for_each_reflog_ent = files_for_each_reflog_ent,
.for_each_reflog_ent_reverse = files_for_each_reflog_ent_reverse,
.reflog_exists = files_reflog_exists,
.create_reflog = files_create_reflog,
.delete_reflog = files_delete_reflog,
.reflog_expire = files_reflog_expire
};