82 lines
1.7 KiB
C
82 lines
1.7 KiB
C
/*
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* openpty() tries to open a pty; applications won't have to
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* duplicate this code all the time (or change it if the system
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* pty interface changes).
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*
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* First version by Ben Gras <beng@few.vu.nl>,
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* Initially heavily based on telnetd/pty.c
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* by Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>.
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*
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*/
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#include <libutil.h>
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#include <termios.h>
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#include <fcntl.h>
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#include <grp.h>
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#include <string.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/ioc_tty.h>
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#define DEV_DIR "/dev"
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/*
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* Allocate a PTY, by trying to open one repeatedly.
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*/
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int openpty(int *amaster, int *aslave, char *name,
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struct termios *termp, struct winsize *winp)
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{
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char buff[128];
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register int i, j;
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static char tty_name[128];
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struct group *ttygroup;
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gid_t tty_gid = 0;
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if(!amaster || !aslave) {
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errno = EINVAL;
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return -1;
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}
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for(i = 'p'; i < 'w'; i++) {
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j = 0;
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do {
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sprintf(buff, "%s/pty%c%c",
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DEV_DIR, i, (j < 10) ? j + '0' : j + 'a' - 10);
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if((*amaster = open(buff, O_RDWR)) >= 0) {
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sprintf(tty_name, "%s/tty%c%c", DEV_DIR,
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i, (j < 10) ? j + '0' : j + 'a' - 10);
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if((*aslave = open(tty_name, O_RDWR)) >= 0)
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break;
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}
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close(*amaster);
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j++;
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if (j == 16) break;
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} while(1);
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/* Did we find one? */
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if (j < 16) break;
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}
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if (*amaster < 0) { errno = ENOENT; return(-1); }
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setgrent();
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ttygroup = getgrnam("tty");
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endgrent();
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if(ttygroup) tty_gid = ttygroup->gr_gid;
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if(name) strcpy(name, tty_name);
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/* Ignore errors on these. */
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chown(tty_name, getuid(), tty_gid);
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chmod(tty_name, 0620); /* -rw--w---- */
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if(termp) tcsetattr(*aslave, TCSAFLUSH, termp);
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if(winp) ioctl(*aslave, TIOCSWINSZ, winp);
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return(0);
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}
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