diff options
Diffstat (limited to 'reference/C/CONTRIB/OR_USING_C/b.1.c')
| -rw-r--r-- | reference/C/CONTRIB/OR_USING_C/b.1.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/OR_USING_C/b.1.c b/reference/C/CONTRIB/OR_USING_C/b.1.c new file mode 100644 index 0000000..422b975 --- /dev/null +++ b/reference/C/CONTRIB/OR_USING_C/b.1.c @@ -0,0 +1,176 @@ +#include <sys/param.h> +#include <sys/ioctl.h> +#include <sys/file.h> +#include <signal.h> +#include <stdio.h> + +ptyopen(cmd, ifp, ofp) +char *cmd; +FILE **ifp, **ofp; +{ + int i; + char *args[16]; + register int tty; + long ldisc, lmode; + register char *s, *t; + struct sgttyb sgttyb; + struct tchars tchars; + struct ltchars ltchars; + char ttybuf[16], ptybuf[16]; + + /* + * Split up the arguments in the command + * into an argv-like structure. + */ + i = 0; + s = cmd; + + while (*s) { + /* + * Skip white space. + */ + while ((*s == ' ') || (*s == '\t')) + *s++ = NULL; + + args[i++] = s; + + /* + * Skip over this word to next white space. + */ + while ((*s != NULL) && (*s != ' ') && (*s != '\t')) + s++; + } + args[i] = NULL; + /* + * Get a pseudo-tty. We do this by cycling through all + * the possible names. The operating system will not + * allow us to open a master which is already in use, + * so we simply go until the open succeeds. + */ + for (s = "pqrs"; *s != NULL; s++) { + for (t = "0123456789abcdef"; *t != NULL; t++) { + sprintf(ptybuf, "/dev/pty%c%c", *s, *t); + if ((tty = open(ptybuf, O_RDWR)) >= 0) + goto out; + } + } +out: + /* + * If s and t are NULL, we ran out of pseudo ttys + * before we found one we can use. + */ + if ((*s == NULL) && (*t == NULL)) + return(-1); + /* + * Change "ptyXX" (master) to "ttyXX" (slave). + */ + strcpy(ttybuf, ptybuf); + ttybuf[5] = 't'; + /* + * Get the modes of the current terminal. We + * will duplicate these on the pseudo terminal. + */ + ioctl(0, TIOCGETD, &ldisc); + ioctl(0, TIOCLGET, &lmode); + ioctl(0, TIOCGETP, &sgttyb); + ioctl(0, TIOCGETC, &tchars); + ioctl(0, TIOCGLTC, <chars); + /* + * Fork a child process. + */ + if ((i = fork()) < 0) { + close(tty); + return(-1); + } + + /* + * In the child... + */ + if (i == 0) { + /* + * Close all open files. + */ + for (i = 0; i < NOFILE; i++) + close(i); + + /* + * Clear the controlling tty. This means + * that we will not have a controlling + * tty until we open another terminal + * device. + */ + if ((i = open("/dev/tty", O_RDWR)) >= 0) { + ioctl(i, TIOCNOTTY, 0); + close(i); + } + + /* + * Make our controlling tty the pseudo tty. + * This happens because we cleared our + * original controlling terminal above. + */ + i = open(ttybuf, O_RDWR); + + /* + * Set stdin, stdout, and stderr to be the + * pseudo terminal. + */ + dup2(i, 0); + dup2(i, 1); + dup2(i, 2); + + /* + * Set the pseudo terminal's tty modes to + * those of the original terminal. We + * turn off ECHO and CBREAK modes, since + * we don't want characters "typed" to be + * printed. + */ + sgttyb.sg_flags &= ~ECHO; + sgttyb.sg_flags &= ~CRMOD; + + ioctl(0, TIOCSETD, &ldisc); + ioctl(0, TIOCLGET, &lmode); + ioctl(0, TIOCSETP, &sgttyb); + ioctl(0, TIOCSETC, &tchars); + ioctl(0, TIOCSLTC, <chars); + + /* + * Set the process group of the process + * to be the process group of the + * terminal. + */ + ioctl(0, TIOCGPGRP, &i); + setpgrp(0, i); + + /* + * Now change the process group of the + * terminal and process to be the + * process id; this takes them out + * of the calling process's process + * group. + */ + i = getpid(); + + ioctl(0, TIOCSPGRP, &i); + setpgrp(0, i); + + /* + * Execute the program. + */ + execv(*args, args); + + exit(1); + } + + /* + * Set up the input and output file pointers + * so that they can write and read the pseudo + * terminal. + */ + *ifp = fdopen(tty, "w"); + *ofp = fdopen(tty, "r"); + + return(0); +} + |