| 1 | /*
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| 2 | * openpty() tries to open a pty; applications won't have to
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| 3 | * duplicate this code all the time (or change it if the system
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| 4 | * pty interface changes).
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| 5 | *
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| 6 | * First version by Ben Gras <beng@few.vu.nl>,
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| 7 | * Initially heavily based on telnetd/pty.c
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| 8 | * by Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>.
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| 9 | *
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| 10 | */
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| 11 | #include <libutil.h>
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| 12 | #include <termios.h>
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| 13 | #include <fcntl.h>
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| 14 | #include <grp.h>
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| 15 | #include <string.h>
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| 16 | #include <stdlib.h>
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| 17 | #include <errno.h>
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| 18 | #include <stdio.h>
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| 19 | #include <unistd.h>
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| 20 | #include <sys/types.h>
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| 21 | #include <sys/stat.h>
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| 22 | #include <sys/ioc_tty.h>
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| 23 |
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| 24 | #define DEV_DIR "/dev"
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| 25 |
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| 26 | /*
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| 27 | * Allocate a PTY, by trying to open one repeatedly.
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| 28 | */
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| 29 | int openpty(int *amaster, int *aslave, char *name,
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| 30 | struct termios *termp, struct winsize *winp)
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| 31 | {
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| 32 | char buff[128], temp[128];
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| 33 | register int i, j;
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| 34 | int pty_fd = -1, gr;
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| 35 | static char tty_name[128];
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| 36 | struct group *ttygroup;
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| 37 | gid_t tty_gid = 0;
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| 38 |
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| 39 | if(!amaster || !aslave) {
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| 40 | errno = EINVAL;
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| 41 | return -1;
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| 42 | }
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| 43 |
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| 44 | for(i = 'p'; i < 'w'; i++) {
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| 45 | j = 0;
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| 46 | do {
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| 47 | sprintf(buff, "%s/pty%c%c",
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| 48 | DEV_DIR, i, (j < 10) ? j + '0' : j + 'a' - 10);
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| 49 |
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| 50 | if((*amaster = open(buff, O_RDWR)) >= 0) {
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| 51 | sprintf(tty_name, "%s/tty%c%c", DEV_DIR,
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| 52 | i, (j < 10) ? j + '0' : j + 'a' - 10);
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| 53 | if((*aslave = open(tty_name, O_RDWR)) >= 0)
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| 54 | break;
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| 55 | }
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| 56 | close(*amaster);
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| 57 |
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| 58 | j++;
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| 59 | if (j == 16) break;
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| 60 | } while(1);
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| 61 |
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| 62 | /* Did we find one? */
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| 63 | if (j < 16) break;
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| 64 | }
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| 65 | if (*amaster < 0) { errno = ENOENT; return(-1); }
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| 66 |
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| 67 | setgrent();
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| 68 | ttygroup = getgrnam("tty");
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| 69 | endgrent();
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| 70 | if(ttygroup) tty_gid = ttygroup->gr_gid;
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| 71 |
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| 72 | if(name) strcpy(name, tty_name);
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| 73 |
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| 74 | /* Ignore errors on these. */
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| 75 | chown(tty_name, getuid(), tty_gid);
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| 76 | chmod(tty_name, 0620); /* -rw--w---- */
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| 77 | if(termp) tcsetattr(*aslave, TCSAFLUSH, termp);
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| 78 | if(winp) ioctl(*aslave, TIOCSWINSZ, winp);
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| 79 |
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| 80 | return(0);
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| 81 | }
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| 82 |
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