unzip: support symlinks. Closes 10031

function                                             old     new   delta
unzip_main                                          2519    2667    +148

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 48 insertions, 13 deletions

diff --git a/archival/unzip.c b/archival/unzip.c
index d6b8da347..44c4a3125 100644
--- a/archival/unzip.c
+++ b/archival/unzip.c
@@ -334,6 +334,38 @@ static void unzip_create_leading_dirs(const char *fn)
         free(name);
 }
 
+static void unzip_extract_symlink(zip_header_t *zip, const char *dst_fn)
+{
+        char *target;
+
+        if (zip->fmt.ucmpsize > 0xfff) /* no funny business please */
+                bb_error_msg_and_die("bad archive");
+
+        if (zip->fmt.method == 0) {
+                /* Method 0 - stored (not compressed) */
+                target = xzalloc(zip->fmt.ucmpsize + 1);
+                xread(zip_fd, target, zip->fmt.ucmpsize);
+        } else {
+#if 1
+                bb_error_msg_and_die("compressed symlink is not supported");
+#else
+                transformer_state_t xstate;
+                init_transformer_state(&xstate);
+                xstate.mem_output_size_max = zip->fmt.ucmpsize;
+                /* ...unpack... */
+                if (!xstate.mem_output_buf)
+                        WTF();
+                target = xstate.mem_output_buf;
+                target = xrealloc(target, xstate.mem_output_size + 1);
+                target[xstate.mem_output_size] = '\0';
+#endif
+        }
+//TODO: libbb candidate
+        if (symlink(target, dst_fn))
+                bb_perror_msg_and_die("can't create symlink '%s'", dst_fn);
+        free(target);
+}
+
 static void unzip_extract(zip_header_t *zip, int dst_fd)
 {
         transformer_state_t xstate;
@@ -346,12 +378,6 @@ static void unzip_extract(zip_header_t *zip, int dst_fd)
                 return;
         }
 
-// NB: to support symlinks, need to extract symlink target. A-la:
-// xstate.mem_output_size_max = zip->fmt.ucmpsize;
-// ...unpack...
-// if (xstate.mem_output_buf) { success, xstate.mem_output_size is the size }
-// Although archives I've seen have fmt.method == 0 for symlinks.
-
         init_transformer_state(&xstate);
         xstate.bytes_in = zip->fmt.cmpsize;
         xstate.src_fd = zip_fd;
@@ -719,7 +745,6 @@ int unzip_main(int argc, char **argv)
                         if ((cdf.fmt.version_made_by >> 8) == 3) {
                                 /* This archive is created on Unix */
                                 dir_mode = file_mode = (cdf.fmt.external_attributes >> 16);
-//TODO: if (S_ISLNK(file_mode)) this is a symlink
                         }
                 }
 #endif
@@ -833,7 +858,7 @@ int unzip_main(int argc, char **argv)
                 }
  check_file:
                 /* Extract file */
-                if (stat(dst_fn, &stat_buf) == -1) {
+                if (lstat(dst_fn, &stat_buf) == -1) {
                         /* File does not exist */
                         if (errno != ENOENT) {
                                 bb_perror_msg_and_die("can't stat '%s'", dst_fn);
@@ -854,6 +879,7 @@ int unzip_main(int argc, char **argv)
                         goto do_open_and_extract;
                 printf("replace %s? [y]es, [n]o, [A]ll, [N]one, [r]ename: ", dst_fn);
                 my_fgets80(key_buf);
+//TODO: redo lstat + ISREG check! user input could have taken a long time!
 
                 switch (key_buf[0]) {
                 case 'A':
@@ -862,7 +888,8 @@ int unzip_main(int argc, char **argv)
  do_open_and_extract:
                         unzip_create_leading_dirs(dst_fn);
 #if ENABLE_FEATURE_UNZIP_CDF
-                        dst_fd = xopen3(dst_fn, O_WRONLY | O_CREAT | O_TRUNC, file_mode);
+                        if (!S_ISLNK(file_mode))
+                                dst_fd = xopen3(dst_fn, O_WRONLY | O_CREAT | O_TRUNC, file_mode);
 #else
                         dst_fd = xopen(dst_fn, O_WRONLY | O_CREAT | O_TRUNC);
 #endif
@@ -872,10 +899,18 @@ int unzip_main(int argc, char **argv)
                                         ? " extracting: %s\n"
                                         : */ "  inflating: %s\n", dst_fn);
                         }
-                        unzip_extract(&zip, dst_fd);
-                        if (dst_fd != STDOUT_FILENO) {
-                                /* closing STDOUT is potentially bad for future business */
-                                close(dst_fd);
+#if ENABLE_FEATURE_UNZIP_CDF
+                        if (S_ISLNK(file_mode)) {
+                                if (dst_fd != STDOUT_FILENO) /* no -p */
+                                        unzip_extract_symlink(&zip, dst_fn);
+                        } else
+#endif
+                        {
+                                unzip_extract(&zip, dst_fd);
+                                if (dst_fd != STDOUT_FILENO) {
+                                        /* closing STDOUT is potentially bad for future business */
+                                        close(dst_fd);
+                                }
                         }
                         break;