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