mdw@git.distorted.org.uk Git - sgt/putty/blob - unix/pty.c

   1 #define _XOPEN_SOURCE
   2 #define _XOPEN_SOURCE_EXTENDED
   3 #include <features.h>
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <unistd.h>
   9 #include <fcntl.h>
  10 #include <termios.h>
  11 #include <sys/ioctl.h>
  12
  13 #include "putty.h"
  14
  15 #ifndef FALSE
  16 #define FALSE 0
  17 #endif
  18 #ifndef TRUE
  19 #define TRUE 1
  20 #endif
  21
  22 int pty_master_fd;
  23 char **pty_argv;
  24
  25 static void pty_size(void);
  26
  27 /*
  28  * Called to set up the pty.
  29  *
  30  * Returns an error message, or NULL on success.
  31  *
  32  * Also places the canonical host name into `realhost'. It must be
  33  * freed by the caller.
  34  */
  35 static char *pty_init(char *host, int port, char **realhost, int nodelay)
  36 {
  37     int slavefd;
  38     char name[FILENAME_MAX];
  39     pid_t pid;
  40
  41     pty_master_fd = open("/dev/ptmx", O_RDWR);
  42
  43     if (pty_master_fd < 0) {
  44         perror("/dev/ptmx: open");
  45         exit(1);
  46     }
  47
  48     if (grantpt(pty_master_fd) < 0) {
  49         perror("grantpt");
  50         exit(1);
  51     }
  52
  53     if (unlockpt(pty_master_fd) < 0) {
  54         perror("unlockpt");
  55         exit(1);
  56     }
  57
  58     name[FILENAME_MAX-1] = '\0';
  59     strncpy(name, ptsname(pty_master_fd), FILENAME_MAX-1);
  60
  61     slavefd = open(name, O_RDWR);
  62     if (slavefd < 0) {
  63         perror("slave pty: open");
  64         exit(1);
  65     }
  66
  67     /*
  68      * Fork and execute the command.
  69      */
  70     pid = fork();
  71     if (pid < 0) {
  72         perror("fork");
  73         exit(1);
  74     }
  75
  76     if (pid == 0) {
  77         int i;
  78         /*
  79          * We are the child.
  80          */
  81         close(pty_master_fd);
  82         close(0);
  83         close(1);
  84         close(2);
  85         fcntl(slavefd, F_SETFD, 0);    /* don't close on exec */
  86         dup2(slavefd, 0);
  87         dup2(slavefd, 1);
  88         dup2(slavefd, 2);
  89         setsid();
  90         setpgrp();
  91         tcsetpgrp(slavefd, getpgrp());
  92         /* Close everything _else_, for tidiness. */
  93         for (i = 3; i < 1024; i++)
  94             close(i);
  95         if (pty_argv)
  96             execvp(pty_argv[0], pty_argv);
  97         else
  98             execl(getenv("SHELL"), getenv("SHELL"), NULL);
  99         /*
 100          * If we're here, exec has gone badly foom.
 101          */
 102         perror("exec");
 103         exit(127);
 104     } else {
 105         close(slavefd);
 106     }
 107
 108     return NULL;
 109 }
 110
 111 /*
 112  * Called to send data down the pty.
 113  */
 114 static int pty_send(char *buf, int len)
 115 {
 116     while (len > 0) {
 117         int ret = write(pty_master_fd, buf, len);
 118         if (ret < 0) {
 119             perror("write pty master");
 120             exit(1);
 121         }
 122         buf += ret;
 123         len -= ret;
 124     }
 125     return 0;
 126 }
 127
 128 /*
 129  * Called to query the current socket sendability status.
 130  */
 131 static int pty_sendbuffer(void)
 132 {
 133     return 0;
 134 }
 135
 136 /*
 137  * Called to set the size of the window
 138  */
 139 static void pty_size(void)
 140 {
 141     struct winsize size;
 142
 143     size.ws_row = (unsigned short)rows;
 144     size.ws_col = (unsigned short)cols;
 145     ioctl(pty_master_fd, TIOCSWINSZ, (void *)&size);
 146     return;
 147 }
 148
 149 /*
 150  * Send special codes.
 151  */
 152 static void pty_special(Telnet_Special code)
 153 {
 154     /* Do nothing! */
 155     return;
 156 }
 157
 158 static Socket pty_socket(void)
 159 {
 160     return NULL;                       /* shouldn't ever be needed */
 161 }
 162
 163 static int pty_sendok(void)
 164 {
 165     return 1;
 166 }
 167
 168 static void pty_unthrottle(int backlog)
 169 {
 170     /* do nothing */
 171 }
 172
 173 static int pty_ldisc(int option)
 174 {
 175     return 0;                          /* neither editing nor echoing */
 176 }
 177
 178 static int pty_exitcode(void)
 179 {
 180     /* Shouldn't ever be required */
 181     return 0;
 182 }
 183
 184 Backend pty_backend = {
 185     pty_init,
 186     pty_send,
 187     pty_sendbuffer,
 188     pty_size,
 189     pty_special,
 190     pty_socket,
 191     pty_exitcode,
 192     pty_sendok,
 193     pty_ldisc,
 194     pty_unthrottle,
 195     1
 196 };