*: move getopt reset code to better place(s)

1 files changed, 23 insertions, 4 deletions

diff --git a/libbb/getopt32.c b/libbb/getopt32.c
index 2452eb0..80d5d28 100644
--- a/libbb/getopt32.c
+++ b/libbb/getopt32.c
@@ -473,11 +473,30 @@ getopt32(char **argv, const char *applet_opts, ...)
 		}
 	}
 
-	/* In case getopt32 was already called, reinit some state */
+	/* In case getopt32 was already called:
+	 * reset the libc getopt() function, which keeps internal state.
+	 *
+	 * BSD-derived getopt() functions require that optind be set to 1 in
+	 * order to reset getopt() state.  This used to be generally accepted
+	 * way of resetting getopt().  However, glibc's getopt()
+	 * has additional getopt() state beyond optind, and requires that
+	 * optind be set to zero to reset its state.  So the unfortunate state of
+	 * affairs is that BSD-derived versions of getopt() misbehave if
+	 * optind is set to 0 in order to reset getopt(), and glibc's getopt()
+	 * will core dump if optind is set 1 in order to reset getopt().
+	 * 
+	 * More modern versions of BSD require that optreset be set to 1 in
+	 * order to reset getopt().   Sigh.  Standards, anyone?
+	 */
+#ifdef __GLIBC__
+	optind = 0;
+#else /* BSD style */
 	optind = 1;
-	/* optarg = NULL; opterr = 0; optopt = 0; ?? */
+	/* optreset = 1; */
+#endif
+	/* optarg = NULL; opterr = 0; optopt = 0; - do we need this?? */
 
-	/* Note: just "getopt() <= 0" will not work good for
+	/* Note: just "getopt() <= 0" will not work well for
 	 * "fake" short options, like this one:
 	 * wget $'-\203' "Test: test" http://kernel.org/
 	 * (supposed to act as --header, but doesn't) */
@@ -487,7 +506,7 @@ getopt32(char **argv, const char *applet_opts, ...)
 #else
 	while ((c = getopt(argc, argv, applet_opts)) != -1) {
 #endif
-		c &= 0xff; /* fight libc's sign extends */
+		c &= 0xff; /* fight libc's sign extension */
  loop_arg_is_opt:
 		for (on_off = complementary; on_off->opt != c; on_off++) {
 			/* c==0 if long opt have non NULL flag */