nommu: fix cases where we mangle argv[0][0]

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

archival/cpio.c

@@ -384,6 +384,7 @@ int cpio_main(int argc UNUSED_PARAM, char **argv)
 			goto dump;
 		}
 		/* parent */
+		USE_FOR_NOMMU(argv[-optind][0] &= 0x7f); /* undo fork_or_rexec() damage */
 		xchdir(*argv++);
 		close(pp.wr);
 		xmove_fd(pp.rd, STDIN_FILENO);

include/libbb.h

@@ -981,6 +981,9 @@ enum {
 # define bb_daemonize(flags)                bb_daemonize_or_rexec(flags, bogus)
 #else
   extern bool re_execed;
+  /* Note: re_exec() and fork_or_rexec() do argv[0][0] |= 0x80 on NOMMU!
+   * _Parent_ needs to undo it if it doesn't want to have argv[0] mangled.
+   */
   void re_exec(char **argv) NORETURN FAST_FUNC;
   pid_t fork_or_rexec(char **argv) FAST_FUNC;
   int  BUG_fork_is_unavailable_on_nommu(void) FAST_FUNC;

init/bootchartd.c

@@ -418,6 +418,8 @@ int bootchartd_main(int argc UNUSED_PARAM, char **argv)
 
 	/* parent */
 
+	USE_FOR_NOMMU(argv[0][0] &= 0x7f); /* undo fork_or_rexec() damage */
+
 	if (DO_SIGNAL_SYNC) {
 		/* Wait for logger child to set handlers, then unpause it.
 		 * Otherwise with short-lived PROG (e.g. "bootchartd start true")

networking/httpd.c

@@ -2243,6 +2243,7 @@ static void mini_httpd_nommu(int server_socket, int argc, char **argv)
 			/* Run a copy of ourself in inetd mode */
 			re_exec(argv_copy);
 		}
+		argv_copy[0][0] &= 0x7f;
 		/* parent, or vfork failed */
 		close(n);
 	} /* while (1) */