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tar: shrink hardlink name handling code

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function                                             old     new   delta
data_extract_all                                    1069    1040     -29

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2015-10-22 13:30:34 +02:00
parent 62ae323df0
commit f167e4503d
1 changed files with 17 additions and 26 deletions
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43
archival/libarchive/data_extract_all.c
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@ -12,12 +12,11 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
file_header_t *file_header = archive_handle->file_header;
int dst_fd;
int res;
char *hard_link;
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
char *dst_name;
char *dst_link;
#else
# define dst_name (file_header->name)
# define dst_link (file_header->link_target)
#endif
#if ENABLE_FEATURE_TAR_SELINUX
@ -31,9 +30,14 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
}
#endif
/* Hard links are encoded as regular files of size 0
* with a nonempty link field */
hard_link = NULL;
if (S_ISREG(file_header->mode) && file_header->size == 0)
hard_link = file_header->link_target;
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
dst_name = file_header->name;
dst_link = file_header->link_target;
if (archive_handle->tar__strip_components) {
unsigned n = archive_handle->tar__strip_components;
do {
@ -47,21 +51,18 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
* Link target is shortened only for hardlinks:
* softlinks restored unchanged.
*/
if (S_ISREG(file_header->mode)
&& file_header->size == 0
&& dst_link
) {
if (hard_link) {
// GNU tar 1.26 does not check that we reached end of link name:
// if "dir/hardlink" is hardlinked to "file",
// tar xvf a.tar --strip-components=1 says:
// tar: hardlink: Cannot hard link to '': No such file or directory
// and continues processing. We silently skip such entries.
dst_link = strchr(dst_link, '/');
if (!dst_link || dst_link[1] == '\0') {
hard_link = strchr(hard_link, '/');
if (!hard_link || hard_link[1] == '\0') {
data_skip(archive_handle);
return;
}
dst_link++;
hard_link++;
}
} while (--n != 0);
}
@ -79,12 +80,7 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
if (archive_handle->ah_flags & ARCHIVE_UNLINK_OLD) {
/* Remove the entry if it exists */
if (!S_ISDIR(file_header->mode)) {
/* Is it hardlink?
* We encode hard links as regular files of size 0 with a symlink */
if (S_ISREG(file_header->mode)
&& file_header->size == 0
&& dst_link
) {
if (hard_link) {
/* Ugly special case:
* tar cf t.tar hardlink1 hardlink2 hardlink1
* results in this tarball structure:
@ -92,7 +88,7 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
* hardlink2 -> hardlink1
* hardlink1 -> hardlink1 <== !!!
*/
if (strcmp(dst_link, dst_name) == 0)
if (strcmp(hard_link, dst_name) == 0)
goto ret;
}
/* Proceed with deleting */
@ -128,19 +124,14 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
}
}
/* Handle hard links separately
* We encode hard links as regular files of size 0 with a symlink */
if (S_ISREG(file_header->mode)
&& file_header->size == 0
&& dst_link
) {
/* Hard link */
res = link(dst_link, dst_name);
/* Handle hard links separately */
if (hard_link) {
res = link(hard_link, dst_name);
if (res != 0 && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)) {
bb_perror_msg("can't create %slink "
"from %s to %s", "hard",
dst_name,
dst_link);
hard_link);
}
/* Hardlinks have no separate mode/ownership, skip chown/chmod */
goto ret;