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Merge branch 'jc/tmp-objdir'

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The code to clean temporary object directories (used for
quarantine) tried to remove them inside its signal handler, which
was a no-no.

* jc/tmp-objdir:
  tmp-objdir: skip clean up when handling a signal
This commit is contained in:
Junio C Hamano
2022-10-17 14:56:33 -07:00
parent 272be0db8b 22613b25ec
commit aff81ec1c8
1 changed files with 4 additions and 36 deletions
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40
tmp-objdir.c
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@ -18,7 +18,7 @@ struct tmp_objdir {
/* /*
* Allow only one tmp_objdir at a time in a running process, which simplifies * 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 * our 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 * more than one, and we can expand later if so. You can have many such
* tmp_objdirs simultaneously in many processes, of course. * tmp_objdirs simultaneously in many processes, of course.
*/ */
@ -31,7 +31,7 @@ static void tmp_objdir_free(struct tmp_objdir *t)
free(t); free(t);
} }
static int tmp_objdir_destroy_1(struct tmp_objdir *t, int on_signal) int tmp_objdir_destroy(struct tmp_objdir *t)
{ {
int err; int err;
@ -41,44 +41,21 @@ static int tmp_objdir_destroy_1(struct tmp_objdir *t, int on_signal)
if (t == the_tmp_objdir) if (t == the_tmp_objdir)
the_tmp_objdir = NULL; the_tmp_objdir = NULL;
if (!on_signal && t->prev_odb) if (t->prev_odb)
restore_primary_odb(t->prev_odb, t->path.buf); restore_primary_odb(t->prev_odb, t->path.buf);
/*
* 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); err = remove_dir_recursively(&t->path, 0);
/* tmp_objdir_free(t);
* 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; return err;
} }
int tmp_objdir_destroy(struct tmp_objdir *t)
{
return tmp_objdir_destroy_1(t, 0);
}
static void remove_tmp_objdir(void) static void remove_tmp_objdir(void)
{ {
tmp_objdir_destroy(the_tmp_objdir); 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);
}
void tmp_objdir_discard_objects(struct tmp_objdir *t) void tmp_objdir_discard_objects(struct tmp_objdir *t)
{ {
remove_dir_recursively(&t->path, REMOVE_DIR_KEEP_TOPLEVEL); remove_dir_recursively(&t->path, REMOVE_DIR_KEEP_TOPLEVEL);
@ -152,14 +129,6 @@ struct tmp_objdir *tmp_objdir_create(const char *prefix)
*/ */
strbuf_addf(&t->path, "%s/tmp_objdir-%s-XXXXXX", get_object_directory(), prefix); strbuf_addf(&t->path, "%s/tmp_objdir-%s-XXXXXX", get_object_directory(), prefix);
/*
* 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)) { if (!mkdtemp(t->path.buf)) {
/* free, not destroy, as we never touched the filesystem */ /* free, not destroy, as we never touched the filesystem */
tmp_objdir_free(t); tmp_objdir_free(t);
@ -169,7 +138,6 @@ struct tmp_objdir *tmp_objdir_create(const char *prefix)
the_tmp_objdir = t; the_tmp_objdir = t;
if (!installed_handlers) { if (!installed_handlers) {
atexit(remove_tmp_objdir); atexit(remove_tmp_objdir);
sigchain_push_common(remove_tmp_objdir_on_signal);
installed_handlers++; installed_handlers++;
} }