ar: fix long filenames handling (bug 611)

function                                             old     new   delta
get_header_ar                                        493     528     +35
read_num                                               -      25     +25

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

1 files changed, 50 insertions, 37 deletions

diff --git a/archival/libunarchive/get_header_ar.c b/archival/libunarchive/get_header_ar.c
index d476a9d24..e6d712d8d 100644
--- a/archival/libunarchive/get_header_ar.c
+++ b/archival/libunarchive/get_header_ar.c
@@ -7,10 +7,20 @@
 #include "libbb.h"
 #include "unarchive.h"
 
+static unsigned read_num(const char *str, int base)
+{
+        /* This code works because
+         * on misformatted numbers bb_strtou returns all-ones */
+        int err = bb_strtou(str, NULL, base);
+        if (err == -1)
+                bb_error_msg_and_die("invalid ar header");
+        return err;
+}
+
 char FAST_FUNC get_header_ar(archive_handle_t *archive_handle)
 {
-        int err;
         file_header_t *typed = archive_handle->file_header;
+        unsigned size;
         union {
                 char raw[60];
                 struct {
@@ -49,57 +59,60 @@ char FAST_FUNC get_header_ar(archive_handle_t *archive_handle)
         if (ar.formatted.magic[0] != '`' || ar.formatted.magic[1] != '\n')
                 bb_error_msg_and_die("invalid ar header");
 
-        /* FIXME: more thorough routine would be in order here */
-        /* (we have something like that in tar) */
-        /* but for now we are lax. This code works because */
-        /* on misformatted numbers bb_strtou returns all-ones */
-        typed->mode = err = bb_strtou(ar.formatted.mode, NULL, 8);
-        if (err == -1) bb_error_msg_and_die("invalid ar header");
-        typed->mtime = err = bb_strtou(ar.formatted.date, NULL, 10);
-        if (err == -1) bb_error_msg_and_die("invalid ar header");
-        typed->uid = err = bb_strtou(ar.formatted.uid, NULL, 10);
-        if (err == -1) bb_error_msg_and_die("invalid ar header");
-        typed->gid = err = bb_strtou(ar.formatted.gid, NULL, 10);
-        if (err == -1) bb_error_msg_and_die("invalid ar header");
-        typed->size = err = bb_strtou(ar.formatted.size, NULL, 10);
-        if (err == -1) bb_error_msg_and_die("invalid ar header");
+        /* FIXME: more thorough routine would be in order here
+         * (we have something like that in tar)
+         * but for now we are lax. */
+        typed->size = size = read_num(ar.formatted.size, 10);
 
-        /* long filenames have '/' as the first character */
+        /* special filenames have '/' as the first character */
         if (ar.formatted.name[0] == '/') {
+                if (ar.formatted.name[1] == ' ') {
+                        /* This is the index of symbols in the file for compilers */
+                        data_skip(archive_handle);
+                        archive_handle->offset += size;
+                        return get_header_ar(archive_handle); /* Return next header */
+                }
 #if ENABLE_FEATURE_AR_LONG_FILENAMES
-                unsigned long_offset;
-
                 if (ar.formatted.name[1] == '/') {
                         /* If the second char is a '/' then this entries data section
                          * stores long filename for multiple entries, they are stored
-                         * in static variable long_names for use in future entries */
-                        ar_long_name_size = typed->size;
-                        ar_long_names = xmalloc(ar_long_name_size);
-                        xread(archive_handle->src_fd, ar_long_names, ar_long_name_size);
-                        archive_handle->offset += ar_long_name_size;
-                        /* This ar entries data section only contained filenames for other records
-                         * they are stored in the static ar_long_names for future reference */
-                        return get_header_ar(archive_handle); /* Return next header */
+                         * in static variable long_names for use in future entries
+                         */
+                        ar_long_name_size = size;
+                        free(ar_long_names);
+                        ar_long_names = xmalloc(size);
+                        xread(archive_handle->src_fd, ar_long_names, size);
+                        archive_handle->offset += size;
+                        /* Return next header */
+                        return get_header_ar(archive_handle);
                 }
+#else
+                bb_error_msg_and_die("long filenames not supported");
+#endif
+        }
+        /* Only size is always present, the rest may be missing in
+         * long filename pseudo file. Thus we decode the rest
+         * after dealing with long filename pseudo file.
+         */
+        typed->mode = read_num(ar.formatted.mode, 8);
+        typed->mtime = read_num(ar.formatted.date, 10);
+        typed->uid = read_num(ar.formatted.uid, 10);
+        typed->gid = read_num(ar.formatted.gid, 10);
 
-                if (ar.formatted.name[1] == ' ') {
-                        /* This is the index of symbols in the file for compilers */
-                        data_skip(archive_handle);
-                        archive_handle->offset += typed->size;
-                        return get_header_ar(archive_handle); /* Return next header */
-                }
+#if ENABLE_FEATURE_AR_LONG_FILENAMES
+        if (ar.formatted.name[0] == '/') {
+                unsigned long_offset;
 
                 /* The number after the '/' indicates the offset in the ar data section
-                 * (saved in variable long_name) that conatains the real filename */
-                long_offset = atoi(&ar.formatted.name[1]);
+                 * (saved in ar_long_names) that conatains the real filename */
+                long_offset = read_num(&ar.formatted.name[1], 10);
                 if (long_offset >= ar_long_name_size) {
                         bb_error_msg_and_die("can't resolve long filename");
                 }
                 typed->name = xstrdup(ar_long_names + long_offset);
-#else
-                bb_error_msg_and_die("long filenames not supported");
+        } else
 #endif
-        } else {
+        {
                 /* short filenames */
                 typed->name = xstrndup(ar.formatted.name, 16);
         }