freebsd-dev/usr.sbin/watch/watch.c
csjp 3e592b9646 By default, the watch utility will attempt to open /dev/snp0, if
another process already has /dev/snp0 open, the snp(4) will return
EBUSY, in which case watch will try to open /dev/snp1..9. Currently
watch does not check errno to see if the failure was a result of EBUSY.

This results in watch making futile attempts to open snp0..snp9 even
though devices may not exist or the caller does not have permissions
to access the device.

In addition to this, it attempts to setup the screen for snooping even
though it may not ever get an snp device.

So this patch does two things
1) Checks errno for EBUSY, if open(2) fails for another reason
   print that reason and exit.
2) setup the terminal for snooping after the snp descriptor has
   been obtained.

Approved by:	bmilekic (mentor)
2004-08-10 01:49:46 +00:00

447 lines
8.9 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;
dev_t snp_tty;
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;
tcgetattr (std_in, &otty);
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)
{
char snp[] = {_PATH_DEV "snpX"};
char c;
int f, mode, pos;
pos = strlen(snp) - 1;
if (opt_write)
mode = O_RDWR;
else
mode = O_RDONLY;
if (opt_snpdev == NULL)
for (c = '0'; c <= '9'; c++) {
snp[pos] = c;
if ((f = open(snp, mode)) < 0) {
if (errno == EBUSY)
continue;
err(1, "open %s", snp);
}
return f;
}
else
if ((f = open(opt_snpdev, mode)) != -1)
return (f);
fatal(EX_OSFILE, "cannot open snoop device");
return (0);
}
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)
{
dev_t dev;
dev = NODEV;
ioctl(snp_io, SNPSTTY, &dev);
}
static void
attach_snp(void)
{
if (ioctl(snp_io, SNPSTTY, &snp_tty) != 0)
fatal(EX_UNAVAILABLE, "cannot attach to 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");
snp_tty = sb.st_rdev;
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();
}
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);
while (1) {
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);
}