getopt-gnu: avoid crash in glibc getopt

Use of "W;" in an option string may be rare, but we might as well
avoid crashing on it.

* m4/getopt.m4 (gl_GETOPT_CHECK_HEADRS): Detect the problem.
* tests/test-getopt.h (test_getopt): Enhance test.
* tests/test-getopt_long.h (test_getopt_long): Likewise.
* doc/posix-functions/getopt.texi (getopt): Document it.
* doc/glibc-functions/getopt_long.texi (getopt_long): Likewise.
* doc/glibc-functions/getopt_long_only.texi (getopt_long_only):
Likewise.

Signed-off-by: Eric Blake <eblake@redhat.com>

2 files changed, 42 insertions, 0 deletions

diff --git a/tests/test-getopt.h b/tests/test-getopt.h
index 9c877b3d18..e3fc589f53 100644
--- a/tests/test-getopt.h
+++ b/tests/test-getopt.h
@@ -1365,5 +1365,28 @@ test_getopt (void)
       ASSERT (optind == 3);
       ASSERT (!output);
     }
+
+  /* Check that 'W' does not dump core:
+     http://sourceware.org/bugzilla/show_bug.cgi?id=12922
+     Technically, POSIX says the presence of ';' in the opt-string
+     gives unspecified behavior, so we only test this when GNU compliance
+     is desired.  */
+  for (start = OPTIND_MIN; start <= 1; start++)
+    {
+      int argc = 0;
+      const char *argv[10];
+      int c;
+      int pos = ftell (stderr);
+
+      argv[argc++] = "program";
+      argv[argc++] = "-W";
+      argv[argc++] = "dummy";
+      argv[argc] = NULL;
+      optind = start;
+      opterr = 1;
+      ASSERT (getopt (argc, (char **) argv, "W;") == 'W');
+      ASSERT (ftell (stderr) == pos);
+      ASSERT (optind == 2);
+    }
 #endif /* GNULIB_TEST_GETOPT_GNU */
 }
diff --git a/tests/test-getopt_long.h b/tests/test-getopt_long.h
index 7a748674ae..c1035b1664 100644
--- a/tests/test-getopt_long.h
+++ b/tests/test-getopt_long.h
@@ -314,6 +314,25 @@ test_getopt_long (void)
       }
   }
 
+  /* Test that 'W' does not dump core:
+     http://sourceware.org/bugzilla/show_bug.cgi?id=12922  */
+  {
+    int argc = 0;
+    const char *argv[10];
+    int option_index;
+    int c;
+
+    argv[argc++] = "program";
+    argv[argc++] = "-W";
+    argv[argc++] = "dummy";
+    argv[argc] = NULL;
+    optind = 1;
+    opterr = 0;
+    c = do_getopt_long (argc, argv, "W;", NULL, &option_index);
+    ASSERT (c == 'W');
+    ASSERT (optind == 2);
+  }
+
   /* Test processing of boolean short options.  */
   for (start = 0; start <= 1; start++)
     {