tar: handle "tar fx TARFILE" etc

function                                             old     new   delta
tar_main                                             702     751     +49

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

1 files changed, 27 insertions, 0 deletions

diff --git a/archival/tar.c b/archival/tar.c
index bd8e5dc99..3c0ceb70d 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -841,6 +841,33 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
 #if ENABLE_FEATURE_TAR_LONG_OPTIONS
         applet_long_options = tar_longopts;
 #endif
+#if ENABLE_DESKTOP
+        if (argv[1][0] != '-') {
+                /* Compat:
+                 * 1st argument without dash handles options with parameters
+                 * differently from dashed one: it takes *next argv[i]*
+                 * as paramenter even if there are more chars in 1st argument:
+                 *  "tar fx TARFILE" - "x" is not taken as f's param
+                 *  but is interpreted as -x option
+                 *  "tar -xf TARFILE" - dashed equivalent of the above
+                 *  "tar -fx ..." - "x" is taken as f's param
+                 * getopt32 wouldn't handle 1st command correctly.
+                 * Unfortunately, people do use such commands.
+                 * We massage argv[1] to work around it by moving 'f'
+                 * to the end of the string.
+                 * More contrived "tar fCx TARFILE DIR" still fails,
+                 * but such commands are much less likely to be used.
+                 */
+                char *f = strchr(argv[1], 'f');
+                if (f) {
+                        while (f[1] != '\0') {
+                                *f = f[1];
+                                f++;
+                        }
+                        *f = 'f';
+                }
+        }
+#endif
         opt = getopt32(argv,
                 "txC:f:Opvk"
                 IF_FEATURE_TAR_CREATE(   "ch"  )