appl/login/read_string.c

   1 /*
   2  * Copyright (c) 1997 - 2000 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "login_locl.h"
  35
  36 RCSID("$Id$");
  37
  38 static sig_atomic_t intr_flag;
  39
  40 static void
  41 intr(int sig)
  42 {
  43     intr_flag++;
  44 }
  45
  46 #ifndef NSIG
  47 #define NSIG 47
  48 #endif
  49
  50 int
  51 read_string(const char *prompt, char *buf, size_t len, int echo)
  52 {
  53     struct sigaction sigs[NSIG];
  54     int oksigs[NSIG];
  55     struct sigaction sa;
  56     FILE *tty;
  57     int ret = 0;
  58     int of = 0;
  59     int i;
  60     int c;
  61     char *p;
  62
  63     struct termios t_new, t_old;
  64
  65     memset(&oksigs, 0, sizeof(oksigs));
  66
  67     memset(&sa, 0, sizeof(sa));
  68     sa.sa_handler = intr;
  69     sigemptyset(&sa.sa_mask);
  70     sa.sa_flags = 0;
  71     for(i = 1; i < sizeof(sigs) / sizeof(sigs[0]); i++)
  72         if (i != SIGALRM)
  73             if (sigaction(i, &sa, &sigs[i]) == 0)
  74                 oksigs[i] = 1;
  75
  76     if((tty = fopen("/dev/tty", "r")) == NULL)
  77         tty = stdin;
  78
  79     fprintf(stderr, "%s", prompt);
  80     fflush(stderr);
  81
  82     if(echo == 0){
  83         tcgetattr(fileno(tty), &t_old);
  84         memcpy(&t_new, &t_old, sizeof(t_new));
  85         t_new.c_lflag &= ~ECHO;
  86         tcsetattr(fileno(tty), TCSANOW, &t_new);
  87     }
  88     intr_flag = 0;
  89     p = buf;
  90     while(intr_flag == 0){
  91         c = getc(tty);
  92         if(c == EOF){
  93             if(!ferror(tty))
  94                 ret = 1;
  95             break;
  96         }
  97         if(c == '\n')
  98             break;
  99         if(of == 0)
 100             *p++ = c;
 101         of = (p == buf + len);
 102     }
 103     if(of)
 104         p--;
 105     *p = 0;
 106
 107     if(echo == 0){
 108         printf("\n");
 109         tcsetattr(fileno(tty), TCSANOW, &t_old);
 110     }
 111
 112     if(tty != stdin)
 113         fclose(tty);
 114
 115     for(i = 1; i < sizeof(sigs) / sizeof(sigs[0]); i++)
 116         if (oksigs[i])
 117             sigaction(i, &sigs[i], NULL);
 118
 119     if(ret)
 120         return -3;
 121     if(intr_flag)
 122         return -2;
 123     if(of)
 124         return -1;
 125     return 0;
 126 }
 127
 128
 129 #if 0
 130 int main()
 131 {
 132     char s[128];
 133     int ret;
 134     ret = read_string("foo: ", s, sizeof(s), 0);
 135     printf("%d ->%s<-\n", ret, s);
 136 }
 137 #endif