f167e4503
Denys Vlasenko
2015-10-22
Subject
tar: shrink hardlink name handling code
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Commit Diff GitHub →
archival/libarchive/data_extract_all.c+17 -26
| @@ -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; | |