dnsd: fixes various segfaults.

[oweals/busybox.git] / libbb / bb_askpass.c

diff --git a/libbb/bb_askpass.c b/libbb/bb_askpass.c
index 1ae1520d9bd9b85e4d28fe7811528868d2704547..3ad0e97cdd46b79e8f7a5242c109f0028176bb22 100644 (file)
--- a/libbb/bb_askpass.c
+++ b/libbb/bb_askpass.c
@@ -5,83 +5,73 @@
  *
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <stdio.h>
-#include <string.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <signal.h>
 #include <termios.h>
-#include <sys/ioctl.h>
-#define PWD_BUFFER_SIZE 256
 
+#include "libbb.h"
 
 /* do nothing signal handler */
-static void askpass_timeout(int ignore)
+static void askpass_timeout(int ATTRIBUTE_UNUSED ignore)
 {
 }
 
-char *bb_askpass(int timeout, const char * prompt)
+char *bb_askpass(int timeout, const char *prompt)
 {
-       char *ret;
-       int i, size;
-       struct sigaction sa;
-       struct termios old, new;
-       static char passwd[PWD_BUFFER_SIZE];
+       /* Was static char[BIGNUM] */
+       enum { sizeof_passwd = 128 };
+       static char *passwd;
 
-       tcgetattr(STDIN_FILENO, &old);
-
-       size = sizeof(passwd);
-       ret = passwd;
-       memset(passwd, 0, size);
+       char *ret;
+       int i;
+       struct sigaction sa, oldsa;
+       struct termios tio, oldtio;
 
-       fputs(prompt, stdout);
-       fflush(stdout);
+       if (!passwd)
+               passwd = xmalloc(sizeof_passwd);
+       memset(passwd, 0, sizeof_passwd);
 
-       tcgetattr(STDIN_FILENO, &new);
-       new.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
-       new.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
-       tcsetattr(STDIN_FILENO, TCSANOW, &new);
+       tcgetattr(STDIN_FILENO, &oldtio);
+       tcflush(STDIN_FILENO, TCIFLUSH);
+       tio = oldtio;
+       tio.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
+       tio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
+       tcsetattr(STDIN_FILENO, TCSANOW, &tio);
 
+       memset(&sa, 0, sizeof(sa));
+       /* sa.sa_flags = 0; - no SA_RESTART! */
+       /* SIGINT and SIGALRM will interrupt read below */
+       sa.sa_handler = askpass_timeout;
+       sigaction(SIGINT, &sa, &oldsa);
        if (timeout) {
-               sa.sa_flags = 0;
-               sa.sa_handler = askpass_timeout;
-               sigaction(SIGALRM, &sa, NULL);
+               sigaction_set(SIGALRM, &sa);
                alarm(timeout);
        }
 
-       if (read(STDIN_FILENO, passwd, size-1) <= 0) {
-               ret = NULL;
-       } else {
-               for(i = 0; i < size && passwd[i]; i++) {
-                       if (passwd[i]== '\r' || passwd[i] == '\n') {
-                               passwd[i]= 0;
-                               break;
-                       }
-               }
+       fputs(prompt, stdout);
+       fflush(stdout);
+       ret = NULL;
+       /* On timeout or Ctrl-C, read will hopefully be interrupted,
+        * and we return NULL */
+       if (read(STDIN_FILENO, passwd, sizeof_passwd - 1) > 0) {
+               ret = passwd;
+               i = 0;
+               /* Last byte is guaranteed to be 0
+                  (read did not overwrite it) */
+               do {
+                       if (passwd[i] == '\r' || passwd[i] == '\n')
+                               passwd[i] = '\0';
+               } while (passwd[i++]);
        }
 
        if (timeout) {
                alarm(0);
        }
+       sigaction_set(SIGINT, &oldsa);
 
-       tcsetattr(STDIN_FILENO, TCSANOW, &old);
-       fputs("\n", stdout);
+       tcsetattr(STDIN_FILENO, TCSANOW, &oldtio);
+       bb_putchar('\n');
        fflush(stdout);
        return ret;
 }
-