tar: fix interaction of delayed symlink and hardlink creation

function                                             old     new   delta
create_or_remember_link                                -     106    +106
create_links_from_list                                 -      93     +93
find_applet_by_name                                  124     128      +4
unzip_main                                          2724    2726      +2
data_extract_all                                     891     873     -18
create_symlinks_from_list                             64       -     -64
create_or_remember_symlink                            94       -     -94
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 2/1 up/down: 205/-176)           Total: 29 bytes

Signed-off-by: Harald van Dijk <harald@gigawatt.nl>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 19 insertions, 20 deletions

diff --git a/archival/libarchive/data_extract_all.c b/archival/libarchive/data_extract_all.c
index 8fa69ff..4c95db4 100644
--- a/archival/libarchive/data_extract_all.c
+++ b/archival/libarchive/data_extract_all.c
@@ -122,13 +122,10 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
 
 	/* Handle hard links separately */
 	if (hard_link) {
-		res = link(hard_link, dst_name);
-		if (res != 0) {
-			/* shared message */
-			bb_perror_msg("can't create %slink '%s' to '%s'",
-				"hard",	dst_name, hard_link
-			);
-		}
+		create_or_remember_link(&archive_handle->link_placeholders,
+				hard_link,
+				dst_name,
+				1);
 		/* Hardlinks have no separate mode/ownership, skip chown/chmod */
 		goto ret;
 	}
@@ -195,9 +192,10 @@ void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
 		 *
 		 * Untarring bug.tar would otherwise place evil.py in '/tmp'.
 		 */
-		create_or_remember_symlink(&archive_handle->symlink_placeholders,
+		create_or_remember_link(&archive_handle->link_placeholders,
 				file_header->link_target,
-				dst_name);
+				dst_name,
+				0);
 		break;
 	case S_IFSOCK:
 	case S_IFBLK:
diff --git a/archival/libarchive/get_header_ar.c b/archival/libarchive/get_header_ar.c
index adcde46..7ce9c61 100644
--- a/archival/libarchive/get_header_ar.c
+++ b/archival/libarchive/get_header_ar.c
@@ -126,7 +126,7 @@ char FAST_FUNC get_header_ar(archive_handle_t *archive_handle)
 			struct archive_handle_t *sa = archive_handle->dpkg__sub_archive;
 			while (archive_handle->dpkg__action_data_subarchive(sa) == EXIT_SUCCESS)
 				continue;
-			create_symlinks_from_list(sa->symlink_placeholders);
+			create_links_from_list(sa->link_placeholders);
 		} else
 #endif
 			archive_handle->action_data(archive_handle);
diff --git a/archival/libarchive/unsafe_symlink_target.c b/archival/libarchive/unsafe_symlink_target.c
index 8dcafea..f8dc803 100644
--- a/archival/libarchive/unsafe_symlink_target.c
+++ b/archival/libarchive/unsafe_symlink_target.c
@@ -5,13 +5,14 @@
 #include "libbb.h"
 #include "bb_archive.h"
 
-void FAST_FUNC create_or_remember_symlink(llist_t **symlink_placeholders,
+void FAST_FUNC create_or_remember_link(llist_t **link_placeholders,
 		const char *target,
-		const char *linkname)
+		const char *linkname,
+		int hard_link)
 {
-	if (target[0] == '/' || strstr(target, "..")) {
-		llist_add_to(symlink_placeholders,
-			xasprintf("%s%c%s", linkname, '\0', target)
+	if (hard_link || target[0] == '/' || strstr(target, "..")) {
+		llist_add_to_end(link_placeholders,
+			xasprintf("%c%s%c%s", hard_link, linkname, '\0', target)
 		);
 		return;
 	}
@@ -23,17 +24,17 @@ void FAST_FUNC create_or_remember_symlink(llist_t **symlink_placeholders,
 	}
 }
 
-void FAST_FUNC create_symlinks_from_list(llist_t *list)
+void FAST_FUNC create_links_from_list(llist_t *list)
 {
 	while (list) {
 		char *target;
 
-		target = list->data + strlen(list->data) + 1;
-		if (symlink(target, list->data)) {
+		target = list->data + 1 + strlen(list->data + 1) + 1;
+		if ((*list->data ? link : symlink) (target, list->data + 1)) {
 			/* shared message */
 			bb_error_msg_and_die("can't create %slink '%s' to '%s'",
-				"sym",
-				list->data, target
+				*list->data ? "hard" : "sym",
+				list->data + 1, target
 			);
 		}
 		list = list->link;