unzip: support symlinks. Closes 10031

function                                             old     new   delta
unzip_main                                          2519    2667    +148

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

diff --git a/archival/unzip.c b/archival/unzip.c
index d6b8da347f8680007b7b0093decfe8b90373ffd9..44c4a312506b7f776a4f4d6148558bda6c68efa9 100644 (file)
--- 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;