minix/commands/simple/modem.c

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2005-04-21 16:53:53 +02:00
/* modem - Put modem into DIALIN or DIALOUT mode. Author: F. van Kempen */
/* Exit: 0 OK, suspended/restarted GETTY
* 1 UNIX error
* 2 Process busy
* Version: 1.3 12/30/89
*
* Author: F. van Kempen, MicroWalt Corporation
*
* All fancy stuff removed, see getty.c. Kees J. Bot.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <utmp.h>
#include <errno.h>
char PATH_UTMP[] = "/etc/utmp"; /* current logins */
_PROTOTYPE(void usage , (void));
_PROTOTYPE(int main , (int argc , char *argv []));
_PROTOTYPE(void sendcodes , (char *tty, char *codes));
void usage()
{
fprintf(stderr,
"Usage: modem [-sio] [-I in-codes] [-O out-codes] line [command args ...]\n");
exit(1);
}
main(argc, argv)
int argc;
char *argv[];
{
struct utmp entry;
char devtty[1024], *tty;
char **command;
int ex_code = 0;
int fd, i, slot, getty;
struct stat st;
enum { TOGGLE, DIALIN, DIALOUT } mode= TOGGLE;
int silent = 0;
_PROTOTYPE(void (*hsig), (int));
_PROTOTYPE(void (*isig), (int));
_PROTOTYPE(void (*qsig), (int));
_PROTOTYPE(void (*tsig), (int));
pid_t pid;
int r, status;
uid_t uid = getuid();
gid_t gid = getgid();
char *in_codes, *out_codes;
i = 1;
while (i < argc && argv[i][0] == '-') {
char *opt = argv[i++] + 1;
if (opt[0] == '-' && opt[1] == 0) break;
while (*opt != 0) {
switch (*opt++) {
case 's': /* silent mode */
silent = 1;
break;
case 'i': /* DIAL-IN mode: suspend GETTY */
mode = DIALIN;
break;
case 'o': /* DIAL-OUT mode: restart GETTY */
mode = DIALOUT;
break;
case 'I': /* code to switch modem to dial-in */
if (*opt == 0) {
if (i == argc) usage();
opt = argv[i++];
}
in_codes = opt;
opt = "";
break;
case 'O': /* code to switch modem to dial-out */
if (*opt == 0) {
if (i == argc) usage();
opt = argv[i++];
}
out_codes = opt;
opt = "";
break;
default:
usage();
}
}
}
if (i == argc) usage();
tty = argv[i++]; /* Modem line */
if (mode != TOGGLE && i != argc) usage();
command = argv + i; /* Command to execute (if any). */
if (strchr(tty, '/') == NULL) {
strcpy(devtty, "/dev/");
strncat(devtty, tty, 1024 - 6);
tty = devtty;
}
if (stat(tty, &st) < 0) {
fprintf(stderr, "modem: %s: %s\n", tty, strerror(errno));
exit(1);
}
if (!S_ISCHR(st.st_mode)) {
fprintf(stderr, "%s is not a tty\n", tty);
exit(1);
}
/* Find the utmp slot number for the line. */
if ((fd= open(tty, O_RDONLY)) < 0 || (slot= fttyslot(fd)) == 0) {
fprintf(stderr, "modem: %s: %s\n", tty, strerror(errno));
exit(1);
}
close(fd);
/* Read the UTMP file to find out the PID and STATUS of the GETTY. */
entry.ut_type= 0;
if ((fd = open(PATH_UTMP, O_RDONLY)) < 0
|| lseek(fd, (off_t) slot * sizeof(entry), SEEK_SET) < 0
|| read(fd, &entry, sizeof(entry)) < 0
) {
fprintf(stderr, "modem: cannot read UTMP !\n");
exit(1);
}
close(fd);
hsig= signal(SIGHUP, SIG_IGN);
isig= signal(SIGINT, SIG_IGN);
qsig= signal(SIGQUIT, SIG_IGN);
tsig= signal(SIGTERM, SIG_IGN);
/* Process the terminal entry if we got one. */
switch (entry.ut_type) {
case LOGIN_PROCESS: /* getty waiting for a call */
getty = 1;
break;
case USER_PROCESS: /* login or user-shell */
if (!silent) fprintf(stderr, "modem: line is busy.\n");
exit(2);
break;
default:
getty = 0;
}
for (i = (mode == TOGGLE) ? 0 : 1; i < 2; i++) {
/* Now perform the desired action (DIALIN or DIALOUT). */
switch (mode) {
case DIALOUT:
case TOGGLE:
if (getty) kill(entry.ut_pid, SIGUSR1); /* suspend getty */
chown(tty, uid, st.st_gid); /* give line to user */
chmod(tty, 0600);
if (out_codes != NULL) sendcodes(tty, out_codes);
if (!silent) printf("modem on %s set for dialout.\n", tty);
break;
case DIALIN:
if (in_codes != NULL) sendcodes(tty, in_codes);
chown(tty, 0, st.st_gid); /* revoke access */
chmod(tty, 0600);
if (getty) kill(entry.ut_pid, SIGUSR2); /* restart getty */
if (!silent) printf("modem on %s set for dialin.\n", tty);
}
if (mode == TOGGLE) {
/* Start the command to run */
pid_t pid;
int status;
switch ((pid = fork())) {
case -1:
fprintf(stderr, "modem: fork(): %s\n", strerror(errno));
ex_code= 1;
break;
case 0:
setgid(gid);
setuid(uid);
(void) signal(SIGHUP, hsig);
(void) signal(SIGINT, isig);
(void) signal(SIGQUIT, qsig);
(void) signal(SIGTERM, tsig);
execvp(command[0], command);
fprintf(stderr, "modem: %s: %s\n",
command[0], strerror(errno));
_exit(127);
default:
while ((r= wait(&status)) != pid) {
if (r == -1 && errno != EINTR) break;
}
if (r == -1 || status != 0) ex_code = 1;
}
mode = DIALIN;
}
}
exit(ex_code);
}
void sendcodes(tty, codes)
char *tty, *codes;
{
int fd;
int c;
char buf[1024], *bp = buf;
if ((fd = open(tty, O_RDWR|O_NONBLOCK)) < 0) {
fprintf(stderr, "modem: can't send codes to %s: %s\n",
tty, strerror(errno));
return;
}
while ((c = *codes++) != 0) {
fprintf(stderr, "%d\n", __LINE__);
if (c == '\\') {
if ((c = *codes++) == 0) break;
if (c == 'r') c= '\r';
if (c == 'n') c= '\n';
}
*bp++ = c;
if (bp == buf + sizeof(buf) || c == '\r' || c == '\n') {
fprintf(stderr, "%d\n", __LINE__);
write(fd, buf, bp - buf);
fprintf(stderr, "%d\n", __LINE__);
do {sleep(1);
fprintf(stderr, "%d\n", __LINE__);
fprintf(stderr, "%d\n", read(fd, buf, sizeof(buf)));
}while (read(fd, buf, sizeof(buf)) > 0);
fprintf(stderr, "%d\n", __LINE__);
bp = buf;
}
}
if (bp > buf) {
fprintf(stderr, "%d\n", __LINE__);
write(fd, buf, bp - buf);
fprintf(stderr, "%d\n", __LINE__);
do sleep(1); while (read(fd, buf, sizeof(buf)) > 0);
fprintf(stderr, "%d\n", __LINE__);
}
close(fd);
}