diff --git a/gnu/stat-time.h b/gnu/stat-time.h
index 1dc4098..7b8428e 100644
--- a/gnu/stat-time.h
+++ b/gnu/stat-time.h
@@ -144,7 +144,7 @@ get_stat_mtime (struct stat const *st)
}
/* Return *ST's birth time, if available; otherwise return a value
- with negative tv_nsec. */
+ with tv_sec and tv_nsec both equal to -1. */
static inline struct timespec
get_stat_birthtime (struct stat const *st)
{
@@ -163,7 +163,7 @@ get_stat_birthtime (struct stat const *st)
t.tv_sec = st->st_ctime;
t.tv_nsec = 0;
#else
- /* Birth time is not supported. Set tv_sec to avoid undefined behavior. */
+ /* Birth time is not supported. */
t.tv_sec = -1;
t.tv_nsec = -1;
/* Avoid a "parameter unused" warning. */
@@ -177,10 +177,12 @@ get_stat_birthtime (struct stat const *st)
using zero. Attempt to work around this problem. Alas, this can
report failure even for valid time stamps. Also, NetBSD
sometimes returns junk in the birth time fields; work around this
- bug if it it is detected. There's no need to detect negative
- tv_nsec junk as negative tv_nsec already indicates an error. */
- if (t.tv_sec == 0 || 1000000000 <= t.tv_nsec)
- t.tv_nsec = -1;
+ bug if it is detected. */
+ if (! (t.tv_sec && 0 <= t.tv_nsec && t.tv_nsec < 1000000000))
+ {
+ t.tv_sec = -1;
+ t.tv_nsec = -1;
+ }
#endif
return t;
diff --git a/src/extract.c b/src/extract.c
index 340beea..3afb95d 100644
--- a/src/extract.c
+++ b/src/extract.c
@@ -119,12 +119,15 @@ struct delayed_link
/* The next delayed link in the list. */
struct delayed_link *next;
- /* The device, inode number and ctime of the placeholder. Use
- ctime, not mtime, to make false matches less likely if some
- other process removes the placeholder. */
+ /* The device, inode number and birthtime of the placeholder.
+ birthtime.tv_nsec is negative if the birthtime is not available.
+ Don't use mtime as this would allow for false matches if some
+ other process removes the placeholder. Don't use ctime as
+ this would cause race conditions and other screwups, e.g.,
+ when restoring hard-linked symlinks. */
dev_t dev;
ino_t ino;
- struct timespec ctime;
+ struct timespec birthtime;
/* True if the link is symbolic. */
bool is_symlink;
@@ -1200,7 +1203,7 @@ create_placeholder_file (char *file_name, bool is_symlink, bool *interdir_made)
delayed_link_head = p;
p->dev = st.st_dev;
p->ino = st.st_ino;
- p->ctime = get_stat_ctime (&st);
+ p->birthtime = get_stat_birthtime (&st);
p->is_symlink = is_symlink;
if (is_symlink)
{
@@ -1265,7 +1268,8 @@ extract_link (char *file_name, int typeflag)
if (ds->change_dir == chdir_current
&& ds->dev == st1.st_dev
&& ds->ino == st1.st_ino
- && timespec_cmp (ds->ctime, get_stat_ctime (&st1)) == 0)
+ && (timespec_cmp (ds->birthtime, get_stat_birthtime (&st1))
+ == 0))
{
struct string_list *p = xmalloc (offsetof (struct string_list, string)
+ strlen (file_name) + 1);
@@ -1638,7 +1642,7 @@ apply_delayed_links (void)
if (fstatat (chdir_fd, source, &st, AT_SYMLINK_NOFOLLOW) == 0
&& st.st_dev == ds->dev
&& st.st_ino == ds->ino
- && timespec_cmp (get_stat_ctime (&st), ds->ctime) == 0)
+ && timespec_cmp (get_stat_birthtime (&st), ds->birthtime) == 0)
{
/* Unlink the placeholder, then create a hard link if possible,
a symbolic link otherwise. */