git/refs.c
Junio C Hamano 26a063a10b Fix refs.c;:repack_without_ref() clean-up path
The function repack_without_ref() passes a lock-file structure
on the stack to hold_lock_file_for_update(), which in turn
registers it to be cleaned up via atexit().  This is a big
no-no.

This is the same bug James Bottomley fixed with commit
31f584c242.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-10-01 11:41:00 -07:00

872 lines
20 KiB
C

#include "refs.h"
#include "cache.h"
#include <errno.h>
struct ref_list {
struct ref_list *next;
unsigned char flag; /* ISSYMREF? ISPACKED? */
unsigned char sha1[20];
char name[FLEX_ARRAY];
};
static const char *parse_ref_line(char *line, unsigned char *sha1)
{
/*
* 42: the answer to everything.
*
* In this case, it happens to be the answer to
* 40 (length of sha1 hex representation)
* +1 (space in between hex and name)
* +1 (newline at the end of the line)
*/
int len = strlen(line) - 42;
if (len <= 0)
return NULL;
if (get_sha1_hex(line, sha1) < 0)
return NULL;
if (!isspace(line[40]))
return NULL;
line += 41;
if (isspace(*line))
return NULL;
if (line[len] != '\n')
return NULL;
line[len] = 0;
return line;
}
static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
int flag, struct ref_list *list)
{
int len;
struct ref_list **p = &list, *entry;
/* Find the place to insert the ref into.. */
while ((entry = *p) != NULL) {
int cmp = strcmp(entry->name, name);
if (cmp > 0)
break;
/* Same as existing entry? */
if (!cmp)
return list;
p = &entry->next;
}
/* Allocate it and add it in.. */
len = strlen(name) + 1;
entry = xmalloc(sizeof(struct ref_list) + len);
hashcpy(entry->sha1, sha1);
memcpy(entry->name, name, len);
entry->flag = flag;
entry->next = *p;
*p = entry;
return list;
}
/*
* Future: need to be in "struct repository"
* when doing a full libification.
*/
struct cached_refs {
char did_loose;
char did_packed;
struct ref_list *loose;
struct ref_list *packed;
} cached_refs;
static void free_ref_list(struct ref_list *list)
{
struct ref_list *next;
for ( ; list; list = next) {
next = list->next;
free(list);
}
}
static void invalidate_cached_refs(void)
{
struct cached_refs *ca = &cached_refs;
if (ca->did_loose && ca->loose)
free_ref_list(ca->loose);
if (ca->did_packed && ca->packed)
free_ref_list(ca->packed);
ca->loose = ca->packed = NULL;
ca->did_loose = ca->did_packed = 0;
}
static struct ref_list *get_packed_refs(void)
{
if (!cached_refs.did_packed) {
struct ref_list *refs = NULL;
FILE *f = fopen(git_path("packed-refs"), "r");
if (f) {
struct ref_list *list = NULL;
char refline[PATH_MAX];
while (fgets(refline, sizeof(refline), f)) {
unsigned char sha1[20];
const char *name = parse_ref_line(refline, sha1);
if (!name)
continue;
list = add_ref(name, sha1, REF_ISPACKED, list);
}
fclose(f);
refs = list;
}
cached_refs.packed = refs;
cached_refs.did_packed = 1;
}
return cached_refs.packed;
}
static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
{
DIR *dir = opendir(git_path("%s", base));
if (dir) {
struct dirent *de;
int baselen = strlen(base);
char *ref = xmalloc(baselen + 257);
memcpy(ref, base, baselen);
if (baselen && base[baselen-1] != '/')
ref[baselen++] = '/';
while ((de = readdir(dir)) != NULL) {
unsigned char sha1[20];
struct stat st;
int flag;
int namelen;
if (de->d_name[0] == '.')
continue;
namelen = strlen(de->d_name);
if (namelen > 255)
continue;
if (has_extension(de->d_name, ".lock"))
continue;
memcpy(ref + baselen, de->d_name, namelen+1);
if (stat(git_path("%s", ref), &st) < 0)
continue;
if (S_ISDIR(st.st_mode)) {
list = get_ref_dir(ref, list);
continue;
}
if (!resolve_ref(ref, sha1, 1, &flag)) {
error("%s points nowhere!", ref);
continue;
}
list = add_ref(ref, sha1, flag, list);
}
free(ref);
closedir(dir);
}
return list;
}
static struct ref_list *get_loose_refs(void)
{
if (!cached_refs.did_loose) {
cached_refs.loose = get_ref_dir("refs", NULL);
cached_refs.did_loose = 1;
}
return cached_refs.loose;
}
/* We allow "recursive" symbolic refs. Only within reason, though */
#define MAXDEPTH 5
const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
{
int depth = MAXDEPTH, len;
char buffer[256];
static char ref_buffer[256];
if (flag)
*flag = 0;
for (;;) {
const char *path = git_path("%s", ref);
struct stat st;
char *buf;
int fd;
if (--depth < 0)
return NULL;
/* Special case: non-existing file.
* Not having the refs/heads/new-branch is OK
* if we are writing into it, so is .git/HEAD
* that points at refs/heads/master still to be
* born. It is NOT OK if we are resolving for
* reading.
*/
if (lstat(path, &st) < 0) {
struct ref_list *list = get_packed_refs();
while (list) {
if (!strcmp(ref, list->name)) {
hashcpy(sha1, list->sha1);
if (flag)
*flag |= REF_ISPACKED;
return ref;
}
list = list->next;
}
if (reading || errno != ENOENT)
return NULL;
hashclr(sha1);
return ref;
}
/* Follow "normalized" - ie "refs/.." symlinks by hand */
if (S_ISLNK(st.st_mode)) {
len = readlink(path, buffer, sizeof(buffer)-1);
if (len >= 5 && !memcmp("refs/", buffer, 5)) {
buffer[len] = 0;
strcpy(ref_buffer, buffer);
ref = ref_buffer;
if (flag)
*flag |= REF_ISSYMREF;
continue;
}
}
/*
* Anything else, just open it and try to use it as
* a ref
*/
fd = open(path, O_RDONLY);
if (fd < 0)
return NULL;
len = read(fd, buffer, sizeof(buffer)-1);
close(fd);
/*
* Is it a symbolic ref?
*/
if (len < 4 || memcmp("ref:", buffer, 4))
break;
buf = buffer + 4;
len -= 4;
while (len && isspace(*buf))
buf++, len--;
while (len && isspace(buf[len-1]))
len--;
buf[len] = 0;
memcpy(ref_buffer, buf, len + 1);
ref = ref_buffer;
if (flag)
*flag |= REF_ISSYMREF;
}
if (len < 40 || get_sha1_hex(buffer, sha1))
return NULL;
return ref;
}
int create_symref(const char *ref_target, const char *refs_heads_master)
{
const char *lockpath;
char ref[1000];
int fd, len, written;
const char *git_HEAD = git_path("%s", ref_target);
#ifndef NO_SYMLINK_HEAD
if (prefer_symlink_refs) {
unlink(git_HEAD);
if (!symlink(refs_heads_master, git_HEAD))
return 0;
fprintf(stderr, "no symlink - falling back to symbolic ref\n");
}
#endif
len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
if (sizeof(ref) <= len) {
error("refname too long: %s", refs_heads_master);
return -1;
}
lockpath = mkpath("%s.lock", git_HEAD);
fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
written = write(fd, ref, len);
close(fd);
if (written != len) {
unlink(lockpath);
error("Unable to write to %s", lockpath);
return -2;
}
if (rename(lockpath, git_HEAD) < 0) {
unlink(lockpath);
error("Unable to create %s", git_HEAD);
return -3;
}
if (adjust_shared_perm(git_HEAD)) {
unlink(lockpath);
error("Unable to fix permissions on %s", lockpath);
return -4;
}
return 0;
}
int read_ref(const char *ref, unsigned char *sha1)
{
if (resolve_ref(ref, sha1, 1, NULL))
return 0;
return -1;
}
static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
void *cb_data)
{
int retval;
struct ref_list *packed = get_packed_refs();
struct ref_list *loose = get_loose_refs();
while (packed && loose) {
struct ref_list *entry;
int cmp = strcmp(packed->name, loose->name);
if (!cmp) {
packed = packed->next;
continue;
}
if (cmp > 0) {
entry = loose;
loose = loose->next;
} else {
entry = packed;
packed = packed->next;
}
if (strncmp(base, entry->name, trim))
continue;
if (is_null_sha1(entry->sha1))
continue;
if (!has_sha1_file(entry->sha1)) {
error("%s does not point to a valid object!", entry->name);
continue;
}
retval = fn(entry->name + trim, entry->sha1,
entry->flag, cb_data);
if (retval)
return retval;
}
packed = packed ? packed : loose;
while (packed) {
if (!strncmp(base, packed->name, trim)) {
retval = fn(packed->name + trim, packed->sha1,
packed->flag, cb_data);
if (retval)
return retval;
}
packed = packed->next;
}
return 0;
}
int head_ref(each_ref_fn fn, void *cb_data)
{
unsigned char sha1[20];
int flag;
if (resolve_ref("HEAD", sha1, 1, &flag))
return fn("HEAD", sha1, flag, cb_data);
return 0;
}
int for_each_ref(each_ref_fn fn, void *cb_data)
{
return do_for_each_ref("refs/", fn, 0, cb_data);
}
int for_each_tag_ref(each_ref_fn fn, void *cb_data)
{
return do_for_each_ref("refs/tags/", fn, 10, cb_data);
}
int for_each_branch_ref(each_ref_fn fn, void *cb_data)
{
return do_for_each_ref("refs/heads/", fn, 11, cb_data);
}
int for_each_remote_ref(each_ref_fn fn, void *cb_data)
{
return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
}
/* NEEDSWORK: This is only used by ssh-upload and it should go; the
* caller should do resolve_ref or read_ref like everybody else. Or
* maybe everybody else should use get_ref_sha1() instead of doing
* read_ref().
*/
int get_ref_sha1(const char *ref, unsigned char *sha1)
{
if (check_ref_format(ref))
return -1;
return read_ref(mkpath("refs/%s", ref), sha1);
}
/*
* Make sure "ref" is something reasonable to have under ".git/refs/";
* We do not like it if:
*
* - any path component of it begins with ".", or
* - it has double dots "..", or
* - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
* - it ends with a "/".
*/
static inline int bad_ref_char(int ch)
{
return (((unsigned) ch) <= ' ' ||
ch == '~' || ch == '^' || ch == ':' ||
/* 2.13 Pattern Matching Notation */
ch == '?' || ch == '*' || ch == '[');
}
int check_ref_format(const char *ref)
{
int ch, level;
const char *cp = ref;
level = 0;
while (1) {
while ((ch = *cp++) == '/')
; /* tolerate duplicated slashes */
if (!ch)
return -1; /* should not end with slashes */
/* we are at the beginning of the path component */
if (ch == '.' || bad_ref_char(ch))
return -1;
/* scan the rest of the path component */
while ((ch = *cp++) != 0) {
if (bad_ref_char(ch))
return -1;
if (ch == '/')
break;
if (ch == '.' && *cp == '.')
return -1;
}
level++;
if (!ch) {
if (level < 2)
return -1; /* at least of form "heads/blah" */
return 0;
}
}
}
static struct ref_lock *verify_lock(struct ref_lock *lock,
const unsigned char *old_sha1, int mustexist)
{
if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
error("Can't verify ref %s", lock->ref_name);
unlock_ref(lock);
return NULL;
}
if (hashcmp(lock->old_sha1, old_sha1)) {
error("Ref %s is at %s but expected %s", lock->ref_name,
sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
unlock_ref(lock);
return NULL;
}
return lock;
}
static int remove_empty_dir_recursive(char *path, int len)
{
DIR *dir = opendir(path);
struct dirent *e;
int ret = 0;
if (!dir)
return -1;
if (path[len-1] != '/')
path[len++] = '/';
while ((e = readdir(dir)) != NULL) {
struct stat st;
int namlen;
if ((e->d_name[0] == '.') &&
((e->d_name[1] == 0) ||
((e->d_name[1] == '.') && e->d_name[2] == 0)))
continue; /* "." and ".." */
namlen = strlen(e->d_name);
if ((len + namlen < PATH_MAX) &&
strcpy(path + len, e->d_name) &&
!lstat(path, &st) &&
S_ISDIR(st.st_mode) &&
!remove_empty_dir_recursive(path, len + namlen))
continue; /* happy */
/* path too long, stat fails, or non-directory still exists */
ret = -1;
break;
}
closedir(dir);
if (!ret) {
path[len] = 0;
ret = rmdir(path);
}
return ret;
}
static int remove_empty_directories(char *file)
{
/* 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.
*/
char path[PATH_MAX];
int len = strlen(file);
if (len >= PATH_MAX) /* path too long ;-) */
return -1;
strcpy(path, file);
return remove_empty_dir_recursive(path, len);
}
static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int *flag)
{
char *ref_file;
const char *orig_ref = ref;
struct ref_lock *lock;
struct stat st;
int last_errno = 0;
int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
lock = xcalloc(1, sizeof(struct ref_lock));
lock->lock_fd = -1;
ref = resolve_ref(ref, lock->old_sha1, mustexist, flag);
if (!ref && errno == EISDIR) {
/* we are trying to lock foo but we used to
* have foo/bar which now does not exist;
* it is normal for the empty directory 'foo'
* to remain.
*/
ref_file = git_path("%s", orig_ref);
if (remove_empty_directories(ref_file)) {
last_errno = errno;
error("there are still refs under '%s'", orig_ref);
goto error_return;
}
ref = resolve_ref(orig_ref, lock->old_sha1, mustexist, flag);
}
if (!ref) {
last_errno = errno;
error("unable to resolve reference %s: %s",
orig_ref, strerror(errno));
goto error_return;
}
if (is_null_sha1(lock->old_sha1)) {
/* The ref did not exist and we are creating it.
* Make sure there is no existing ref that is packed
* whose name begins with our refname, nor a ref whose
* name is a proper prefix of our refname.
*/
int namlen = strlen(ref); /* e.g. 'foo/bar' */
struct ref_list *list = get_packed_refs();
while (list) {
/* list->name could be 'foo' or 'foo/bar/baz' */
int len = strlen(list->name);
int cmplen = (namlen < len) ? namlen : len;
const char *lead = (namlen < len) ? list->name : ref;
if (!strncmp(ref, list->name, cmplen) &&
lead[cmplen] == '/') {
error("'%s' exists; cannot create '%s'",
list->name, ref);
goto error_return;
}
list = list->next;
}
}
lock->lk = xcalloc(1, sizeof(struct lock_file));
lock->ref_name = xstrdup(ref);
lock->log_file = xstrdup(git_path("logs/%s", ref));
ref_file = git_path("%s", ref);
lock->force_write = lstat(ref_file, &st) && errno == ENOENT;
if (safe_create_leading_directories(ref_file)) {
last_errno = errno;
error("unable to create directory for %s", ref_file);
goto error_return;
}
lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, 1);
return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
error_return:
unlock_ref(lock);
errno = last_errno;
return NULL;
}
struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
{
char refpath[PATH_MAX];
if (check_ref_format(ref))
return NULL;
strcpy(refpath, mkpath("refs/%s", ref));
return lock_ref_sha1_basic(refpath, old_sha1, NULL);
}
struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1)
{
return lock_ref_sha1_basic(ref, old_sha1, NULL);
}
static struct lock_file packlock;
static int repack_without_ref(const char *refname)
{
struct ref_list *list, *packed_ref_list;
int fd;
int found = 0;
packed_ref_list = get_packed_refs();
for (list = packed_ref_list; list; list = list->next) {
if (!strcmp(refname, list->name)) {
found = 1;
break;
}
}
if (!found)
return 0;
memset(&packlock, 0, sizeof(packlock));
fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
if (fd < 0)
return error("cannot delete '%s' from packed refs", refname);
for (list = packed_ref_list; list; list = list->next) {
char line[PATH_MAX + 100];
int len;
if (!strcmp(refname, list->name))
continue;
len = snprintf(line, sizeof(line), "%s %s\n",
sha1_to_hex(list->sha1), list->name);
/* this should not happen but just being defensive */
if (len > sizeof(line))
die("too long a refname '%s'", list->name);
write_or_die(fd, line, len);
}
return commit_lock_file(&packlock);
}
int delete_ref(const char *refname, unsigned char *sha1)
{
struct ref_lock *lock;
int err, i, ret = 0, flag = 0;
lock = lock_ref_sha1_basic(refname, sha1, &flag);
if (!lock)
return 1;
if (!(flag & REF_ISPACKED)) {
/* loose */
i = strlen(lock->lk->filename) - 5; /* .lock */
lock->lk->filename[i] = 0;
err = unlink(lock->lk->filename);
if (err) {
ret = 1;
error("unlink(%s) failed: %s",
lock->lk->filename, strerror(errno));
}
lock->lk->filename[i] = '.';
}
/* removing the loose one could have resurrected an earlier
* packed one. Also, if it was not loose we need to repack
* without it.
*/
ret |= repack_without_ref(refname);
err = unlink(lock->log_file);
if (err && errno != ENOENT)
fprintf(stderr, "warning: unlink(%s) failed: %s",
lock->log_file, strerror(errno));
invalidate_cached_refs();
unlock_ref(lock);
return ret;
}
void unlock_ref(struct ref_lock *lock)
{
if (lock->lock_fd >= 0) {
close(lock->lock_fd);
/* Do not free lock->lk -- atexit() still looks at them */
if (lock->lk)
rollback_lock_file(lock->lk);
}
free(lock->ref_name);
free(lock->log_file);
free(lock);
}
static int log_ref_write(struct ref_lock *lock,
const unsigned char *sha1, const char *msg)
{
int logfd, written, oflags = O_APPEND | O_WRONLY;
unsigned maxlen, len;
char *logrec;
const char *committer;
if (log_all_ref_updates) {
if (safe_create_leading_directories(lock->log_file) < 0)
return error("unable to create directory for %s",
lock->log_file);
oflags |= O_CREAT;
}
logfd = open(lock->log_file, oflags, 0666);
if (logfd < 0) {
if (!log_all_ref_updates && errno == ENOENT)
return 0;
return error("Unable to append to %s: %s",
lock->log_file, strerror(errno));
}
committer = git_committer_info(1);
if (msg) {
maxlen = strlen(committer) + strlen(msg) + 2*40 + 5;
logrec = xmalloc(maxlen);
len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
sha1_to_hex(lock->old_sha1),
sha1_to_hex(sha1),
committer,
msg);
}
else {
maxlen = strlen(committer) + 2*40 + 4;
logrec = xmalloc(maxlen);
len = snprintf(logrec, maxlen, "%s %s %s\n",
sha1_to_hex(lock->old_sha1),
sha1_to_hex(sha1),
committer);
}
written = len <= maxlen ? write(logfd, logrec, len) : -1;
free(logrec);
close(logfd);
if (written != len)
return error("Unable to append to %s", lock->log_file);
return 0;
}
int write_ref_sha1(struct ref_lock *lock,
const unsigned char *sha1, const char *logmsg)
{
static char term = '\n';
if (!lock)
return -1;
if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
unlock_ref(lock);
return 0;
}
if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
write(lock->lock_fd, &term, 1) != 1
|| close(lock->lock_fd) < 0) {
error("Couldn't write %s", lock->lk->filename);
unlock_ref(lock);
return -1;
}
invalidate_cached_refs();
if (log_ref_write(lock, sha1, logmsg) < 0) {
unlock_ref(lock);
return -1;
}
if (commit_lock_file(lock->lk)) {
error("Couldn't set %s", lock->ref_name);
unlock_ref(lock);
return -1;
}
lock->lock_fd = -1;
unlock_ref(lock);
return 0;
}
int read_ref_at(const char *ref, unsigned long at_time, unsigned char *sha1)
{
const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
char *tz_c;
int logfd, tz;
struct stat st;
unsigned long date;
unsigned char logged_sha1[20];
logfile = git_path("logs/%s", ref);
logfd = open(logfile, O_RDONLY, 0);
if (logfd < 0)
die("Unable to read log %s: %s", logfile, strerror(errno));
fstat(logfd, &st);
if (!st.st_size)
die("Log %s is empty.", logfile);
logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
close(logfd);
lastrec = NULL;
rec = logend = logdata + st.st_size;
while (logdata < rec) {
if (logdata < rec && *(rec-1) == '\n')
rec--;
lastgt = NULL;
while (logdata < rec && *(rec-1) != '\n') {
rec--;
if (*rec == '>')
lastgt = rec;
}
if (!lastgt)
die("Log %s is corrupt.", logfile);
date = strtoul(lastgt + 1, &tz_c, 10);
if (date <= at_time) {
if (lastrec) {
if (get_sha1_hex(lastrec, logged_sha1))
die("Log %s is corrupt.", logfile);
if (get_sha1_hex(rec + 41, sha1))
die("Log %s is corrupt.", logfile);
if (hashcmp(logged_sha1, sha1)) {
tz = strtoul(tz_c, NULL, 10);
fprintf(stderr,
"warning: Log %s has gap after %s.\n",
logfile, show_rfc2822_date(date, tz));
}
}
else if (date == at_time) {
if (get_sha1_hex(rec + 41, sha1))
die("Log %s is corrupt.", logfile);
}
else {
if (get_sha1_hex(rec + 41, logged_sha1))
die("Log %s is corrupt.", logfile);
if (hashcmp(logged_sha1, sha1)) {
tz = strtoul(tz_c, NULL, 10);
fprintf(stderr,
"warning: Log %s unexpectedly ended on %s.\n",
logfile, show_rfc2822_date(date, tz));
}
}
munmap((void*)logdata, st.st_size);
return 0;
}
lastrec = rec;
}
rec = logdata;
while (rec < logend && *rec != '>' && *rec != '\n')
rec++;
if (rec == logend || *rec == '\n')
die("Log %s is corrupt.", logfile);
date = strtoul(rec + 1, &tz_c, 10);
tz = strtoul(tz_c, NULL, 10);
if (get_sha1_hex(logdata, sha1))
die("Log %s is corrupt.", logfile);
munmap((void*)logdata, st.st_size);
fprintf(stderr, "warning: Log %s only goes back to %s.\n",
logfile, show_rfc2822_date(date, tz));
return 0;
}