git/tmp-objdir.c
Jeff King d70a9eb611 strvec: rename struct fields
The "argc" and "argv" names made sense when the struct was argv_array,
but now they're just confusing. Let's rename them to "nr" (which we use
for counts elsewhere) and "v" (which is rather terse, but reads well
when combined with typical variable names like "args.v").

Note that we have to update all of the callers immediately. Playing
tricks with the preprocessor is hard here, because we wouldn't want to
rewrite unrelated tokens.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30 19:18:06 -07:00

293 lines
6.4 KiB
C

#include "cache.h"
#include "tmp-objdir.h"
#include "dir.h"
#include "sigchain.h"
#include "string-list.h"
#include "strbuf.h"
#include "strvec.h"
#include "quote.h"
#include "object-store.h"
struct tmp_objdir {
struct strbuf path;
struct strvec env;
};
/*
* Allow only one tmp_objdir at a time in a running process, which simplifies
* our signal/atexit cleanup routines. It's doubtful callers will ever need
* more than one, and we can expand later if so. You can have many such
* tmp_objdirs simultaneously in many processes, of course.
*/
static struct tmp_objdir *the_tmp_objdir;
static void tmp_objdir_free(struct tmp_objdir *t)
{
strbuf_release(&t->path);
strvec_clear(&t->env);
free(t);
}
static int tmp_objdir_destroy_1(struct tmp_objdir *t, int on_signal)
{
int err;
if (!t)
return 0;
if (t == the_tmp_objdir)
the_tmp_objdir = NULL;
/*
* This may use malloc via strbuf_grow(), but we should
* have pre-grown t->path sufficiently so that this
* doesn't happen in practice.
*/
err = remove_dir_recursively(&t->path, 0);
/*
* When we are cleaning up due to a signal, we won't bother
* freeing memory; it may cause a deadlock if the signal
* arrived while libc's allocator lock is held.
*/
if (!on_signal)
tmp_objdir_free(t);
return err;
}
int tmp_objdir_destroy(struct tmp_objdir *t)
{
return tmp_objdir_destroy_1(t, 0);
}
static void remove_tmp_objdir(void)
{
tmp_objdir_destroy(the_tmp_objdir);
}
static void remove_tmp_objdir_on_signal(int signo)
{
tmp_objdir_destroy_1(the_tmp_objdir, 1);
sigchain_pop(signo);
raise(signo);
}
/*
* These env_* functions are for setting up the child environment; the
* "replace" variant overrides the value of any existing variable with that
* "key". The "append" variant puts our new value at the end of a list,
* separated by PATH_SEP (which is what separate values in
* GIT_ALTERNATE_OBJECT_DIRECTORIES).
*/
static void env_append(struct strvec *env, const char *key, const char *val)
{
struct strbuf quoted = STRBUF_INIT;
const char *old;
/*
* Avoid quoting if it's not necessary, for maximum compatibility
* with older parsers which don't understand the quoting.
*/
if (*val == '"' || strchr(val, PATH_SEP)) {
strbuf_addch(&quoted, '"');
quote_c_style(val, &quoted, NULL, 1);
strbuf_addch(&quoted, '"');
val = quoted.buf;
}
old = getenv(key);
if (!old)
strvec_pushf(env, "%s=%s", key, val);
else
strvec_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);
strbuf_release(&quoted);
}
static void env_replace(struct strvec *env, const char *key, const char *val)
{
strvec_pushf(env, "%s=%s", key, val);
}
static int setup_tmp_objdir(const char *root)
{
char *path;
int ret = 0;
path = xstrfmt("%s/pack", root);
ret = mkdir(path, 0777);
free(path);
return ret;
}
struct tmp_objdir *tmp_objdir_create(void)
{
static int installed_handlers;
struct tmp_objdir *t;
if (the_tmp_objdir)
BUG("only one tmp_objdir can be used at a time");
t = xmalloc(sizeof(*t));
strbuf_init(&t->path, 0);
strvec_init(&t->env);
strbuf_addf(&t->path, "%s/incoming-XXXXXX", get_object_directory());
/*
* Grow the strbuf beyond any filename we expect to be placed in it.
* If tmp_objdir_destroy() is called by a signal handler, then
* we should be able to use the strbuf to remove files without
* having to call malloc.
*/
strbuf_grow(&t->path, 1024);
if (!mkdtemp(t->path.buf)) {
/* free, not destroy, as we never touched the filesystem */
tmp_objdir_free(t);
return NULL;
}
the_tmp_objdir = t;
if (!installed_handlers) {
atexit(remove_tmp_objdir);
sigchain_push_common(remove_tmp_objdir_on_signal);
installed_handlers++;
}
if (setup_tmp_objdir(t->path.buf)) {
tmp_objdir_destroy(t);
return NULL;
}
env_append(&t->env, ALTERNATE_DB_ENVIRONMENT,
absolute_path(get_object_directory()));
env_replace(&t->env, DB_ENVIRONMENT, absolute_path(t->path.buf));
env_replace(&t->env, GIT_QUARANTINE_ENVIRONMENT,
absolute_path(t->path.buf));
return t;
}
/*
* Make sure we copy packfiles and their associated metafiles in the correct
* order. All of these ends_with checks are slightly expensive to do in
* the midst of a sorting routine, but in practice it shouldn't matter.
* We will have a relatively small number of packfiles to order, and loose
* objects exit early in the first line.
*/
static int pack_copy_priority(const char *name)
{
if (!starts_with(name, "pack"))
return 0;
if (ends_with(name, ".keep"))
return 1;
if (ends_with(name, ".pack"))
return 2;
if (ends_with(name, ".idx"))
return 3;
return 4;
}
static int pack_copy_cmp(const char *a, const char *b)
{
return pack_copy_priority(a) - pack_copy_priority(b);
}
static int read_dir_paths(struct string_list *out, const char *path)
{
DIR *dh;
struct dirent *de;
dh = opendir(path);
if (!dh)
return -1;
while ((de = readdir(dh)))
if (de->d_name[0] != '.')
string_list_append(out, de->d_name);
closedir(dh);
return 0;
}
static int migrate_paths(struct strbuf *src, struct strbuf *dst);
static int migrate_one(struct strbuf *src, struct strbuf *dst)
{
struct stat st;
if (stat(src->buf, &st) < 0)
return -1;
if (S_ISDIR(st.st_mode)) {
if (!mkdir(dst->buf, 0777)) {
if (adjust_shared_perm(dst->buf))
return -1;
} else if (errno != EEXIST)
return -1;
return migrate_paths(src, dst);
}
return finalize_object_file(src->buf, dst->buf);
}
static int migrate_paths(struct strbuf *src, struct strbuf *dst)
{
size_t src_len = src->len, dst_len = dst->len;
struct string_list paths = STRING_LIST_INIT_DUP;
int i;
int ret = 0;
if (read_dir_paths(&paths, src->buf) < 0)
return -1;
paths.cmp = pack_copy_cmp;
string_list_sort(&paths);
for (i = 0; i < paths.nr; i++) {
const char *name = paths.items[i].string;
strbuf_addf(src, "/%s", name);
strbuf_addf(dst, "/%s", name);
ret |= migrate_one(src, dst);
strbuf_setlen(src, src_len);
strbuf_setlen(dst, dst_len);
}
string_list_clear(&paths, 0);
return ret;
}
int tmp_objdir_migrate(struct tmp_objdir *t)
{
struct strbuf src = STRBUF_INIT, dst = STRBUF_INIT;
int ret;
if (!t)
return 0;
strbuf_addbuf(&src, &t->path);
strbuf_addstr(&dst, get_object_directory());
ret = migrate_paths(&src, &dst);
strbuf_release(&src);
strbuf_release(&dst);
tmp_objdir_destroy(t);
return ret;
}
const char **tmp_objdir_env(const struct tmp_objdir *t)
{
if (!t)
return NULL;
return t->env.v;
}
void tmp_objdir_add_as_alternate(const struct tmp_objdir *t)
{
add_to_alternates_memory(t->path.buf);
}