src/libs/bsd/readpassphrase.c

   1 /*      $OpenBSD: readpassphrase.c,v 1.20 2007/10/30 12:03:48 millert Exp $     */
   2
   3 /*
   4  * Copyright (c) 2000-2002, 2007 Todd C. Miller <Todd.Miller@courtesan.com>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  * Sponsored in part by the Defense Advanced Research Projects
  19  * Agency (DARPA) and Air Force Research Laboratory, Air Force
  20  * Materiel Command, USAF, under agreement number F39502-99-1-0512.
  21  */
  22
  23 #include <ctype.h>
  24 #include <errno.h>
  25 #include <fcntl.h>
  26 #include <paths.h>
  27 #include <pwd.h>
  28 #include <signal.h>
  29 #include <string.h>
  30 #include <termios.h>
  31 #include <unistd.h>
  32 #include <readpassphrase.h>
  33
  34 #ifndef TCSASOFT
  35 #define TCSASOFT 0
  36 #endif
  37
  38 static volatile sig_atomic_t signo;
  39
  40 static void handler(int);
  41
  42 char *
  43 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
  44 {
  45         ssize_t nr;
  46         int input, output, save_errno;
  47         char ch, *p, *end;
  48         struct termios term, oterm;
  49         struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
  50         struct sigaction savetstp, savettin, savettou, savepipe;
  51
  52         /* I suppose we could alloc on demand in this case (XXX). */
  53         if (bufsiz == 0) {
  54                 errno = EINVAL;
  55                 return(NULL);
  56         }
  57
  58 restart:
  59         signo = 0;
  60         nr = -1;
  61         save_errno = 0;
  62         /*
  63          * Read and write to /dev/tty if available.  If not, read from
  64          * stdin and write to stderr unless a tty is required.
  65          */
  66         if ((flags & RPP_STDIN) ||
  67             (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
  68                 if (flags & RPP_REQUIRE_TTY) {
  69                         errno = ENOTTY;
  70                         return(NULL);
  71                 }
  72                 input = STDIN_FILENO;
  73                 output = STDERR_FILENO;
  74         }
  75
  76         /*
  77          * Catch signals that would otherwise cause the user to end
  78          * up with echo turned off in the shell.  Don't worry about
  79          * things like SIGXCPU and SIGVTALRM for now.
  80          */
  81         sigemptyset(&sa.sa_mask);
  82         sa.sa_flags = 0;                /* don't restart system calls */
  83         sa.sa_handler = handler;
  84         (void)sigaction(SIGALRM, &sa, &savealrm);
  85         (void)sigaction(SIGHUP, &sa, &savehup);
  86         (void)sigaction(SIGINT, &sa, &saveint);
  87         (void)sigaction(SIGPIPE, &sa, &savepipe);
  88         (void)sigaction(SIGQUIT, &sa, &savequit);
  89         (void)sigaction(SIGTERM, &sa, &saveterm);
  90         (void)sigaction(SIGTSTP, &sa, &savetstp);
  91         (void)sigaction(SIGTTIN, &sa, &savettin);
  92         (void)sigaction(SIGTTOU, &sa, &savettou);
  93
  94         /* Turn off echo if possible. */
  95         if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
  96                 memcpy(&term, &oterm, sizeof(term));
  97                 if (!(flags & RPP_ECHO_ON))
  98                         term.c_lflag &= ~(ECHO | ECHONL);
  99 #ifdef VSTATUS
 100                 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
 101                         term.c_cc[VSTATUS] = _POSIX_VDISABLE;
 102 #endif
 103                 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
 104         } else {
 105                 memset(&term, 0, sizeof(term));
 106                 term.c_lflag |= ECHO;
 107                 memset(&oterm, 0, sizeof(oterm));
 108                 oterm.c_lflag |= ECHO;
 109         }
 110
 111         /* No I/O if we are already backgrounded. */
 112         if (signo != SIGTTOU && signo != SIGTTIN) {
 113                 if (!(flags & RPP_STDIN))
 114                         (void)write(output, prompt, strlen(prompt));
 115                 end = buf + bufsiz - 1;
 116                 p = buf;
 117                 while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
 118                         if (p < end) {
 119                                 if ((flags & RPP_SEVENBIT))
 120                                         ch &= 0x7f;
 121                                 if (isalpha(ch)) {
 122                                         if ((flags & RPP_FORCELOWER))
 123                                                 ch = (char)tolower(ch);
 124                                         if ((flags & RPP_FORCEUPPER))
 125                                                 ch = (char)toupper(ch);
 126                                 }
 127                                 *p++ = ch;
 128                         }
 129                 }
 130                 *p = '\0';
 131                 save_errno = errno;
 132                 if (!(term.c_lflag & ECHO))
 133                         (void)write(output, "\n", 1);
 134         }
 135
 136         /* Restore old terminal settings and signals. */
 137         if (memcmp(&term, &oterm, sizeof(term)) != 0) {
 138                 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
 139                     errno == EINTR)
 140                         continue;
 141         }
 142         (void)sigaction(SIGALRM, &savealrm, NULL);
 143         (void)sigaction(SIGHUP, &savehup, NULL);
 144         (void)sigaction(SIGINT, &saveint, NULL);
 145         (void)sigaction(SIGQUIT, &savequit, NULL);
 146         (void)sigaction(SIGPIPE, &savepipe, NULL);
 147         (void)sigaction(SIGTERM, &saveterm, NULL);
 148         (void)sigaction(SIGTSTP, &savetstp, NULL);
 149         (void)sigaction(SIGTTIN, &savettin, NULL);
 150         (void)sigaction(SIGTTOU, &savettou, NULL);
 151         if (input != STDIN_FILENO)
 152                 (void)close(input);
 153
 154         /*
 155          * If we were interrupted by a signal, resend it to ourselves
 156          * now that we have restored the signal handlers.
 157          */
 158         if (signo) {
 159                 kill(getpid(), signo);
 160                 switch (signo) {
 161                 case SIGTSTP:
 162                 case SIGTTIN:
 163                 case SIGTTOU:
 164                         goto restart;
 165                 }
 166         }
 167
 168         if (save_errno)
 169                 errno = save_errno;
 170         return(nr == -1 ? NULL : buf);
 171 }
 172
 173 #if 0
 174 char *
 175 getpass(const char *prompt)
 176 {
 177         static char buf[_PASSWORD_LEN + 1];
 178
 179         return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
 180 }
 181 #endif
 182
 183 static void handler(int s)
 184 {
 185
 186         signo = s;
 187 }