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freebsd/usr.sbin/watch/watch.c
Jilles Tjoelker 79e6a2c01e watch: Do not mess up the tty modes on early error.
Record the initial state earlier, so it is always safe to restore it.

One way this happens is if watch(8) is started by a user that does not have
access to /dev/snp. The result is "staircase effect" during later commands.

PR:		bin/153052
MFC after:	1 week
2013-09-05 19:02:03 +00:00

442 lines
8.6 KiB
C

/*
* Copyright (c) 1995 Ugen J.S.Antsilevich
*
* Redistribution and use in source forms, with and without modification,
* are permitted provided that this entire comment appears intact.
*
* Redistribution in binary form may occur without any restrictions.
* Obviously, it would be nice if you gave credit where credit is due
* but requiring it would be too onerous.
*
* This software is provided ``AS IS'' without any warranties of any kind.
*
* Snoop stuff.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/filio.h>
#include <sys/snoop.h>
#include <sys/stat.h>
#include <sys/linker.h>
#include <sys/module.h>
#include <err.h>
#include <errno.h>
#include <locale.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <termcap.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#define MSG_INIT "Snoop started."
#define MSG_OFLOW "Snoop stopped due to overflow. Reconnecting."
#define MSG_CLOSED "Snoop stopped due to tty close. Reconnecting."
#define MSG_CHANGE "Snoop device change by user request."
#define MSG_NOWRITE "Snoop device change due to write failure."
#define DEV_NAME_LEN 1024 /* for /dev/ttyXX++ */
#define MIN_SIZE 256
#define CHR_SWITCH 24 /* Ctrl+X */
#define CHR_CLEAR 23 /* Ctrl+V */
static void clear(void);
static void timestamp(const char *);
static void set_tty(void);
static void unset_tty(void);
static void fatal(int, const char *);
static int open_snp(void);
static void cleanup(int);
static void usage(void) __dead2;
static void setup_scr(void);
static void attach_snp(void);
static void detach_snp(void);
static void set_dev(const char *);
static void ask_dev(char *, const char *);
int opt_reconn_close = 0;
int opt_reconn_oflow = 0;
int opt_interactive = 1;
int opt_timestamp = 0;
int opt_write = 0;
int opt_no_switch = 0;
const char *opt_snpdev;
char dev_name[DEV_NAME_LEN];
int snp_io;
int std_in = 0, std_out = 1;
int clear_ok = 0;
struct termios otty;
char tbuf[1024], gbuf[1024];
static void
clear(void)
{
if (clear_ok)
tputs(gbuf, 1, putchar);
fflush(stdout);
}
static void
timestamp(const char *buf)
{
time_t t;
char btmp[1024];
clear();
printf("\n---------------------------------------------\n");
t = time(NULL);
strftime(btmp, 1024, "Time: %d %b %H:%M", localtime(&t));
printf("%s\n", btmp);
printf("%s\n", buf);
printf("---------------------------------------------\n");
fflush(stdout);
}
static void
set_tty(void)
{
struct termios ntty;
ntty = otty;
ntty.c_lflag &= ~ICANON; /* disable canonical operation */
ntty.c_lflag &= ~ECHO;
#ifdef FLUSHO
ntty.c_lflag &= ~FLUSHO;
#endif
#ifdef PENDIN
ntty.c_lflag &= ~PENDIN;
#endif
#ifdef IEXTEN
ntty.c_lflag &= ~IEXTEN;
#endif
ntty.c_cc[VMIN] = 1; /* minimum of one character */
ntty.c_cc[VTIME] = 0; /* timeout value */
ntty.c_cc[VINTR] = 07; /* ^G */
ntty.c_cc[VQUIT] = 07; /* ^G */
tcsetattr(std_in, TCSANOW, &ntty);
}
static void
unset_tty(void)
{
tcsetattr(std_in, TCSANOW, &otty);
}
static void
fatal(int error, const char *buf)
{
unset_tty();
if (buf)
errx(error, "fatal: %s", buf);
else
exit(error);
}
static int
open_snp(void)
{
int f, mode;
if (opt_write)
mode = O_RDWR;
else
mode = O_RDONLY;
if (opt_snpdev == NULL)
f = open(_PATH_DEV "snp", mode);
else
f = open(opt_snpdev, mode);
if (f == -1)
fatal(EX_OSFILE, "cannot open snoop device");
return (f);
}
static void
cleanup(int signo __unused)
{
if (opt_timestamp)
timestamp("Logging Exited.");
close(snp_io);
unset_tty();
exit(EX_OK);
}
static void
usage(void)
{
fprintf(stderr, "usage: watch [-ciotnW] [tty name]\n");
exit(EX_USAGE);
}
static void
setup_scr(void)
{
char *cbuf = gbuf, *term;
if (!opt_interactive)
return;
if ((term = getenv("TERM")))
if (tgetent(tbuf, term) == 1)
if (tgetstr("cl", &cbuf))
clear_ok = 1;
set_tty();
clear();
}
static void
detach_snp(void)
{
int fd;
fd = -1;
ioctl(snp_io, SNPSTTY, &fd);
}
static void
attach_snp(void)
{
int snp_tty;
snp_tty = open(dev_name, O_RDONLY | O_NONBLOCK);
if (snp_tty < 0)
fatal(EX_DATAERR, "can't open device");
if (ioctl(snp_io, SNPSTTY, &snp_tty) != 0)
fatal(EX_UNAVAILABLE, "cannot attach to tty");
close(snp_tty);
if (opt_timestamp)
timestamp("Logging Started.");
}
static void
set_dev(const char *name)
{
char buf[DEV_NAME_LEN];
struct stat sb;
if (strlen(name) > 5 && !strncmp(name, _PATH_DEV, sizeof _PATH_DEV - 1)) {
snprintf(buf, sizeof buf, "%s", name);
} else {
if (strlen(name) == 2)
sprintf(buf, "%s%s", _PATH_TTY, name);
else
sprintf(buf, "%s%s", _PATH_DEV, name);
}
if (*name == '\0' || stat(buf, &sb) < 0)
fatal(EX_DATAERR, "bad device name");
if ((sb.st_mode & S_IFMT) != S_IFCHR)
fatal(EX_DATAERR, "must be a character device");
strncpy(dev_name, buf, DEV_NAME_LEN);
attach_snp();
}
void
ask_dev(char *dbuf, const char *msg)
{
char buf[DEV_NAME_LEN];
int len;
clear();
unset_tty();
if (msg)
printf("%s\n", msg);
if (dbuf)
printf("Enter device name [%s]:", dbuf);
else
printf("Enter device name:");
if (fgets(buf, DEV_NAME_LEN - 1, stdin)) {
len = strlen(buf);
if (buf[len - 1] == '\n')
buf[len - 1] = '\0';
if (buf[0] != '\0' && buf[0] != ' ')
strcpy(dbuf, buf);
}
set_tty();
}
#define READB_LEN 5
int
main(int ac, char *av[])
{
int ch, res, rv, nread;
size_t b_size = MIN_SIZE;
char *buf, chb[READB_LEN];
fd_set fd_s;
(void) setlocale(LC_TIME, "");
if (isatty(std_out))
opt_interactive = 1;
else
opt_interactive = 0;
while ((ch = getopt(ac, av, "Wciotnf:")) != -1)
switch (ch) {
case 'W':
opt_write = 1;
break;
case 'c':
opt_reconn_close = 1;
break;
case 'i':
opt_interactive = 1;
break;
case 'o':
opt_reconn_oflow = 1;
break;
case 't':
opt_timestamp = 1;
break;
case 'n':
opt_no_switch = 1;
break;
case 'f':
opt_snpdev = optarg;
break;
case '?':
default:
usage();
}
tcgetattr(std_in, &otty);
if (modfind("snp") == -1)
if (kldload("snp") == -1 || modfind("snp") == -1)
warn("snp module not available");
signal(SIGINT, cleanup);
snp_io = open_snp();
setup_scr();
if (*(av += optind) == NULL) {
if (opt_interactive && !opt_no_switch)
ask_dev(dev_name, MSG_INIT);
else
fatal(EX_DATAERR, "no device name given");
} else
strncpy(dev_name, *av, DEV_NAME_LEN);
set_dev(dev_name);
if (!(buf = (char *) malloc(b_size)))
fatal(EX_UNAVAILABLE, "malloc failed");
FD_ZERO(&fd_s);
for (;;) {
if (opt_interactive)
FD_SET(std_in, &fd_s);
FD_SET(snp_io, &fd_s);
res = select(snp_io + 1, &fd_s, NULL, NULL, NULL);
if (opt_interactive && FD_ISSET(std_in, &fd_s)) {
if ((res = ioctl(std_in, FIONREAD, &nread)) != 0)
fatal(EX_OSERR, "ioctl(FIONREAD)");
if (nread > READB_LEN)
nread = READB_LEN;
rv = read(std_in, chb, nread);
if (rv == -1 || rv != nread)
fatal(EX_IOERR, "read (stdin) failed");
switch (chb[0]) {
case CHR_CLEAR:
clear();
break;
case CHR_SWITCH:
if (!opt_no_switch) {
detach_snp();
ask_dev(dev_name, MSG_CHANGE);
set_dev(dev_name);
break;
}
default:
if (opt_write) {
rv = write(snp_io, chb, nread);
if (rv == -1 || rv != nread) {
detach_snp();
if (opt_no_switch)
fatal(EX_IOERR,
"write failed");
ask_dev(dev_name, MSG_NOWRITE);
set_dev(dev_name);
}
}
}
}
if (!FD_ISSET(snp_io, &fd_s))
continue;
if ((res = ioctl(snp_io, FIONREAD, &nread)) != 0)
fatal(EX_OSERR, "ioctl(FIONREAD)");
switch (nread) {
case SNP_OFLOW:
if (opt_reconn_oflow)
attach_snp();
else if (opt_interactive && !opt_no_switch) {
ask_dev(dev_name, MSG_OFLOW);
set_dev(dev_name);
} else
cleanup(-1);
break;
case SNP_DETACH:
case SNP_TTYCLOSE:
if (opt_reconn_close)
attach_snp();
else if (opt_interactive && !opt_no_switch) {
ask_dev(dev_name, MSG_CLOSED);
set_dev(dev_name);
} else
cleanup(-1);
break;
default:
if (nread < (b_size / 2) && (b_size / 2) > MIN_SIZE) {
free(buf);
if (!(buf = (char *) malloc(b_size / 2)))
fatal(EX_UNAVAILABLE, "malloc failed");
b_size = b_size / 2;
}
if (nread > b_size) {
b_size = (nread % 2) ? (nread + 1) : (nread);
free(buf);
if (!(buf = (char *) malloc(b_size)))
fatal(EX_UNAVAILABLE, "malloc failed");
}
rv = read(snp_io, buf, nread);
if (rv == -1 || rv != nread)
fatal(EX_IOERR, "read failed");
rv = write(std_out, buf, nread);
if (rv == -1 || rv != nread)
fatal(EX_IOERR, "write failed");
}
} /* While */
return(0);
}