diplodocus.org Git - nmh/blob - test/runpty.c

   1 /*
   2  * runpty.c - Run a process under a pseudo-tty
   3  *
   4  * This code is Copyright (c) 2017, by the authors of nmh.  See the
   5  * COPYRIGHT file in the root directory of the nmh distribution for
   6  * complete copyright information.
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <fcntl.h>
  13 #include <termios.h>
  14 #include <unistd.h>
  15 #include <sys/types.h>
  16 #include <sys/wait.h>
  17 #include <sys/select.h>
  18 #include <time.h>
  19 #include <errno.h>
  20
  21 #define COMMAND_TIMEOUT 30
  22
  23 int
  24 main(int argc, char *argv[])
  25 {
  26     int master_in, master_out, slave, cc, status;
  27     time_t starttime, now;
  28     const char *slavename;
  29     pid_t child;
  30     unsigned char readbuf[1024];
  31     FILE *output;
  32
  33     if (argc < 3) {
  34         fprintf(stderr, "Usage: %s output-filename command [arguments ...]\n",
  35                 argv[0]);
  36         exit(1);
  37     }
  38
  39     if ((master_in = posix_openpt(O_RDWR | O_NOCTTY)) < 0) {
  40         fprintf(stderr, "Unable to open master pseudo-tty: %s\n",
  41                 strerror(errno));
  42         exit(1);
  43     }
  44
  45     if ((master_out = posix_openpt(O_RDWR | O_NOCTTY)) < 0) {
  46         fprintf(stderr, "Unable to open master pseudo-tty: %s\n",
  47                 strerror(errno));
  48         exit(1);
  49     }
  50
  51     if (grantpt(master_in) < 0) {
  52         fprintf(stderr, "Unable to grant permissions to master pty: %s\n",
  53                 strerror(errno));
  54         exit(1);
  55     }
  56
  57     if (grantpt(master_out) < 0) {
  58         fprintf(stderr, "Unable to grant permissions to master pty: %s\n",
  59                 strerror(errno));
  60         exit(1);
  61     }
  62
  63     if (unlockpt(master_in) < 0) {
  64         fprintf(stderr, "Unable to unlock master pty: %s\n", strerror(errno));
  65         exit(1);
  66     }
  67
  68     if (unlockpt(master_out) < 0) {
  69         fprintf(stderr, "Unable to unlock master pty: %s\n", strerror(errno));
  70         exit(1);
  71     }
  72
  73     child = fork();
  74
  75     /*
  76      * Start the child process if we are in the child; open the two
  77      * slave pseudo-ttys and close the masters after we are done with them.
  78      */
  79
  80     if (child == 0) {
  81         if (!(slavename = ptsname(master_in))) {
  82             fprintf(stderr, "Unable to determine name of slave pty: %s\n",
  83                     strerror(errno));
  84             exit(1);
  85         }
  86
  87         if ((slave = open(slavename, O_RDWR)) < 0) {
  88             fprintf(stderr, "Unable to open slave pty \"%s\": %s\n", slavename,
  89                     strerror(errno));
  90             exit(1);
  91         }
  92
  93         dup2(slave, STDIN_FILENO);
  94         close(slave);
  95         close(master_in);
  96
  97         if (!(slavename = ptsname(master_out))) {
  98             fprintf(stderr, "Unable to determine name of slave pty: %s\n",
  99                     strerror(errno));
 100             exit(1);
 101         }
 102
 103         if ((slave = open(slavename, O_RDWR | O_NOCTTY)) < 0) {
 104             fprintf(stderr, "Unable to open slave pty \"%s\": %s\n", slavename,
 105                     strerror(errno));
 106             exit(1);
 107         }
 108
 109         dup2(slave, STDOUT_FILENO);
 110         dup2(slave, STDERR_FILENO);
 111         close(slave);
 112         close(master_out);
 113
 114         execvp(argv[2], argv + 2);
 115
 116         fprintf(stderr, "execvp(%s) failed: %s\n", argv[2], strerror(errno));
 117         exit(1);
 118
 119     } else if (child < 0) {
 120         fprintf(stderr, "fork() failed: %s\n", strerror(errno));
 121         exit(1);
 122     }
 123
 124     if (!(output = fopen(argv[1], "w"))) {
 125         fprintf(stderr, "Unable to open \"%s\" for output: %s\n", argv[1],
 126                 strerror(errno));
 127         exit(1);
 128     }
 129
 130     starttime = time(NULL);
 131
 132     for (;;) {
 133         fd_set readfds;
 134         struct timeval tv;
 135
 136         FD_ZERO(&readfds);
 137
 138         FD_SET(master_out, &readfds);
 139
 140         /*
 141          * After we get our first bit of data, close the master pty
 142          * connected to standard input on our slave; that will generate
 143          * an EOF.
 144          */
 145
 146         tv.tv_sec = starttime + COMMAND_TIMEOUT - time(NULL);
 147         if (tv.tv_sec < 0)
 148             tv.tv_sec = 0;
 149         tv.tv_usec = 0;
 150
 151         cc = select(master_out + 1, &readfds, NULL, NULL, &tv);
 152
 153         if (cc < 0) {
 154             fprintf(stderr, "select() failed: %s\n", strerror(errno));
 155             exit(1);
 156         }
 157
 158         if (cc > 0 && FD_ISSET(master_out, &readfds)) {
 159             cc = read(master_out, readbuf, sizeof(readbuf));
 160
 161             if (cc <= 0)
 162                 break;
 163
 164             fwrite(readbuf, 1, cc, output);
 165
 166             if (master_in != -1) {
 167                 close(master_in);
 168                 master_in = -1;
 169             }
 170         }
 171
 172         now = time(NULL);
 173         if (now >= starttime + COMMAND_TIMEOUT) {
 174             fprintf(stderr, "Command execution timed out: %ld to %ld: %d\n",
 175                 starttime, now, cc);
 176             break;
 177         }
 178     }
 179
 180     if (master_in != -1)
 181         close(master_in);
 182     close(master_out);
 183     fclose(output);
 184
 185     waitpid(child, &status, 0);
 186
 187     exit(0);
 188 }