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procps/watch.c

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/*
* watch -- execute a program repeatedly, displaying output fullscreen
*
* Based on the original 1991 'watch' by Tony Rems <rembo@unisoft.com>
* (with mods and corrections by Francois Pinard).
*
* Substantially reworked, new features (differences option, SIGWINCH
* handling, unlimited command length, long line handling) added Apr
* 1999 by Mike Coleman <mkc@acm.org>.
*
* Changes by Albert Cahalan, 2002-2003.
* stderr handling, exec, and beep option added by Morty Abzug, 2008
* Unicode Support added by Jarrod Lowe <procps@rrod.net> in 2009.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "c.h"
#include "config.h"
#include "fileutils.h"
#include "nls.h"
#include "strutils.h"
#include "xalloc.h"
#include <ctype.h>
#include <errno.h>
#include <getopt.h>
#include <locale.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#ifdef WITH_WATCH8BIT
# include <wchar.h>
# include <wctype.h>
# include <ncursesw/ncurses.h>
#else
# include <ncurses.h>
#endif /* WITH_WATCH8BIT */
#ifdef FORCE_8BIT
# undef isprint
# define isprint(x) ( (x>=' '&&x<='~') || (x>=0xa0) )
#endif
/* Boolean command line options */
static int flags;
#define WATCH_DIFF (1 << 1)
#define WATCH_CUMUL (1 << 2)
#define WATCH_EXEC (1 << 3)
#define WATCH_BEEP (1 << 4)
#define WATCH_COLOR (1 << 5)
#define WATCH_ERREXIT (1 << 6)
#define WATCH_CHGEXIT (1 << 7)
static int curses_started = 0;
static long height = 24, width = 80;
static int screen_size_changed = 0;
static int first_screen = 1;
static int show_title = 2; /* number of lines used, 2 or 0 */
static int precise_timekeeping = 0;
#define min(x,y) ((x) > (y) ? (y) : (x))
#define MAX_ANSIBUF 100
static void __attribute__ ((__noreturn__))
usage(FILE * out)
{
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %s [options] command\n"), program_invocation_short_name);
fputs(USAGE_OPTIONS, out);
fputs(_(" -b, --beep beep if command has a non-zero exit\n"), out);
fputs(_(" -c, --color interpret ANSI color and style sequences\n"), out);
fputs(_(" -d, --differences[=<permanent>]\n"
" highlight changes between updates\n"), out);
fputs(_(" -e, --errexit exit if command has a non-zero exit\n"), out);
fputs(_(" -g, --chgexit exit when output from command changes\n"), out);
fputs(_(" -n, --interval <secs> seconds to wait between updates\n"), out);
fputs(_(" -p, --precise attempt run command in precise intervals\n"), out);
fputs(_(" -t, --no-title turn off header\n"), out);
fputs(_(" -x, --exec pass command to exec instead of \"sh -c\"\n"), out);
fputs(USAGE_SEPARATOR, out);
fputs(USAGE_HELP, out);
fputs(_(" -v, --version output version information and exit\n"), out);
fprintf(out, USAGE_MAN_TAIL("watch(1)"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
static int nr_of_colors;
static int attributes;
static int fg_col;
static int bg_col;
static void reset_ansi(void)
{
attributes = A_NORMAL;
fg_col = 0;
bg_col = 0;
}
static void init_ansi_colors(void)
{
short ncurses_colors[] = {
-1, COLOR_BLACK, COLOR_RED, COLOR_GREEN, COLOR_YELLOW,
COLOR_BLUE, COLOR_MAGENTA, COLOR_CYAN, COLOR_WHITE
};
nr_of_colors = sizeof(ncurses_colors) / sizeof(short);
for (bg_col = 0; bg_col < nr_of_colors; bg_col++)
for (fg_col = 0; fg_col < nr_of_colors; fg_col++)
init_pair(bg_col * nr_of_colors + fg_col + 1, ncurses_colors[fg_col], ncurses_colors[bg_col]);
reset_ansi();
}
static void set_ansi_attribute(const int attrib)
{
switch (attrib) {
case -1: /* restore last settings */
break;
case 0: /* restore default settings */
reset_ansi();
break;
case 1: /* set bold / increased intensity */
attributes |= A_BOLD;
break;
case 2: /* set decreased intensity (if supported) */
attributes |= A_DIM;
break;
#ifdef A_ITALIC
case 3: /* set italic (if supported) */
attributes |= A_ITALIC;
break;
#endif
case 4: /* set underline */
attributes |= A_UNDERLINE;
break;
case 5: /* set blinking */
attributes |= A_BLINK;
break;
case 7: /* set inversed */
attributes |= A_REVERSE;
break;
case 21: /* unset bold / increased intensity */
attributes &= ~A_BOLD;
break;
case 22: /* unset bold / any intensity modifier */
attributes &= ~(A_BOLD | A_DIM);
break;
#ifdef A_ITALIC
case 23: /* unset italic */
attributes &= ~A_ITALIC;
break;
#endif
case 24: /* unset underline */
attributes &= ~A_UNDERLINE;
break;
case 25: /* unset blinking */
attributes &= ~A_BLINK;
break;
case 27: /* unset inversed */
attributes &= ~A_REVERSE;
break;
default:
if (attrib >= 30 && attrib <= 37) { /* set foreground color */
fg_col = attrib - 30 + 1;
} else if (attrib >= 40 && attrib <= 47) { /* set background color */
bg_col = attrib - 40 + 1;
}
}
attrset(attributes | COLOR_PAIR(bg_col * nr_of_colors + fg_col + 1));
}
static void process_ansi(FILE * fp)
{
int i, c;
char buf[MAX_ANSIBUF];
char *numstart, *endptr;
c = getc(fp);
if (c != '[') {
ungetc(c, fp);
return;
}
for (i = 0; i < MAX_ANSIBUF; i++) {
c = getc(fp);
/* COLOUR SEQUENCE ENDS in 'm' */
if (c == 'm') {
buf[i] = '\0';
break;
}
if (c < '0' && c > '9' && c != ';') {
while (--i >= 0)
ungetc(buf[i], fp);
return;
}
buf[i] = (char)c;
}
/*
* buf now contains a semicolon-separated list of decimal integers,
* each indicating an attribute to apply.
* For example, buf might contain "0;1;31", derived from the color
* escape sequence "<ESC>[0;1;31m". There can be 1 or more
* attributes to apply, but typically there are between 1 and 3.
*/
if (*endptr == '\0') set_ansi_attribute(0); /* [m treated as [0m */
for (endptr = numstart = buf; *endptr != '\0'; numstart = endptr + 1)
set_ansi_attribute(strtol(numstart, &endptr, 10));
}
static void __attribute__ ((__noreturn__)) do_exit(int status)
{
if (curses_started)
endwin();
exit(status);
}
/* signal handler */
static void die(int notused __attribute__ ((__unused__)))
{
do_exit(EXIT_SUCCESS);
}
static void winch_handler(int notused __attribute__ ((__unused__)))
{
screen_size_changed = 1;
}
static char env_col_buf[24];
static char env_row_buf[24];
static int incoming_cols;
static int incoming_rows;
static void get_terminal_size(void)
{
struct winsize w;
if (!incoming_cols) {
/* have we checked COLUMNS? */
const char *s = getenv("COLUMNS");
incoming_cols = -1;
if (s && *s) {
long t;
char *endptr;
t = strtol(s, &endptr, 0);
if (!*endptr && 0 < t)
incoming_cols = t;
width = incoming_cols;
snprintf(env_col_buf, sizeof env_col_buf, "COLUMNS=%ld",
width);
putenv(env_col_buf);
}
}
if (!incoming_rows) {
/* have we checked LINES? */
const char *s = getenv("LINES");
incoming_rows = -1;
if (s && *s) {
long t;
char *endptr;
t = strtol(s, &endptr, 0);
if (!*endptr && 0 < t)
incoming_rows = t;
height = incoming_rows;
snprintf(env_row_buf, sizeof env_row_buf, "LINES=%ld",
height);
putenv(env_row_buf);
}
}
if (ioctl(STDERR_FILENO, TIOCGWINSZ, &w) == 0) {
if (incoming_cols < 0 || incoming_rows < 0) {
if (incoming_rows < 0 && w.ws_row > 0) {
height = w.ws_row;
snprintf(env_row_buf, sizeof env_row_buf,
"LINES=%ld", height);
putenv(env_row_buf);
}
if (incoming_cols < 0 && w.ws_col > 0) {
width = w.ws_col;
snprintf(env_col_buf, sizeof env_col_buf,
"COLUMNS=%ld", width);
putenv(env_col_buf);
}
}
}
}
/* get current time in usec */
typedef unsigned long long watch_usec_t;
#define USECS_PER_SEC (1000000ull)
static watch_usec_t get_time_usec()
{
struct timeval now;
gettimeofday(&now, NULL);
return USECS_PER_SEC * now.tv_sec + now.tv_usec;
}
#ifdef WITH_WATCH8BIT
/* read a wide character from a popen'd stream */
#define MAX_ENC_BYTES 16
wint_t my_getwc(FILE * s);
wint_t my_getwc(FILE * s)
{
/* assuming no encoding ever consumes more than 16 bytes */
char i[MAX_ENC_BYTES];
int byte = 0;
int convert;
int x;
wchar_t rval;
while (1) {
i[byte] = getc(s);
if (i[byte] == EOF) {
return WEOF;
}
byte++;
errno = 0;
mbtowc(NULL, NULL, 0);
convert = mbtowc(&rval, i, byte);
x = errno;
if (convert > 0) {
/* legal conversion */
return rval;
}
if (byte == MAX_ENC_BYTES) {
while (byte > 1) {
/* at least *try* to fix up */
ungetc(i[--byte], s);
}
errno = -EILSEQ;
return WEOF;
}
}
}
#endif /* WITH_WATCH8BIT */
#ifdef WITH_WATCH8BIT
static void output_header(wchar_t *restrict wcommand, int wcommand_columns, int wcommand_characters, double interval)
#else
static void output_header(char *restrict command, double interval)
#endif /* WITH_WATCH8BIT */
{
time_t t = time(NULL);
char *ts = ctime(&t);
int tsl = strlen(ts);
char *header;
/*
* left justify interval and command, right justify time,
* clipping all to fit window width
*/
int hlen = asprintf(&header, _("Every %.1fs: "), interval);
/*
* the rules:
* width < tsl : print nothing
* width < tsl + hlen + 1: print ts
* width = tsl + hlen + 1: print header, ts
* width < tsl + hlen + 4: print header, ..., ts
* width < tsl + hlen + wcommand_columns: print header,
* truncated wcommand, ..., ts
* width > "": print header, wcomand, ts
* this is slightly different from how it used to be
*/
if (width < tsl) {
free(header);
return;
}
if (tsl + hlen + 1 <= width) {
mvaddstr(0, 0, header);
if (tsl + hlen + 2 <= width) {
if (width < tsl + hlen + 4) {
mvaddstr(0, width - tsl - 4, "... ");
} else {
#ifdef WITH_WATCH8BIT
if (width < tsl + hlen + wcommand_columns) {
/* print truncated */
int available = width - tsl - hlen;
int in_use = wcommand_columns;
int wcomm_len = wcommand_characters;
while (available - 4 < in_use) {
wcomm_len--;
in_use = wcswidth(wcommand, wcomm_len);
}
mvaddnwstr(0, hlen, wcommand, wcomm_len);
mvaddstr(0, width - tsl - 4, "... ");
} else {
mvaddwstr(0, hlen, wcommand);
}
#else
mvaddnstr(0, hlen, command, width - tsl - hlen);
#endif /* WITH_WATCH8BIT */
}
}
}
mvaddstr(0, width - tsl + 1, ts);
free(header);
return;
}
static int run_command(char *restrict command, char **restrict command_argv)
{
FILE *p;
int x, y;
int oldeolseen = 1;
int pipefd[2];
pid_t child;
int exit_early = 0;
int status;
/* allocate pipes */
if (pipe(pipefd) < 0)
xerr(7, _("unable to create IPC pipes"));
/* flush stdout and stderr, since we're about to do fd stuff */
fflush(stdout);
fflush(stderr);
/* fork to prepare to run command */
child = fork();
if (child < 0) { /* fork error */
xerr(2, _("unable to fork process"));
} else if (child == 0) { /* in child */
close(pipefd[0]); /* child doesn't need read side of pipe */
close(1); /* prepare to replace stdout with pipe */
if (dup2(pipefd[1], 1) < 0) { /* replace stdout with write side of pipe */
xerr(3, _("dup2 failed"));
}
close(pipefd[1]); /* once duped, the write fd isn't needed */
dup2(1, 2); /* stderr should default to stdout */
if (flags & WATCH_EXEC) { /* pass command to exec instead of system */
if (execvp(command_argv[0], command_argv) == -1) {
xerr(4, _("unable to execute '%s'"),
command_argv[0]);
}
} else {
status = system(command); /* watch manpage promises sh quoting */
/* propagate command exit status as child exit status */
if (!WIFEXITED(status)) { /* child exits nonzero if command does */
exit(EXIT_FAILURE);
} else {
exit(WEXITSTATUS(status));
}
}
}
/* otherwise, we're in parent */
close(pipefd[1]); /* close write side of pipe */
if ((p = fdopen(pipefd[0], "r")) == NULL)
xerr(5, _("fdopen"));
reset_ansi();
for (y = show_title; y < height; y++) {
int eolseen = 0, tabpending = 0, tabwaspending = 0;
if (flags & WATCH_COLOR)
set_ansi_attribute(-1);
#ifdef WITH_WATCH8BIT
wint_t carry = WEOF;
#endif
for (x = 0; x < width; x++) {
#ifdef WITH_WATCH8BIT
wint_t c = ' ';
#else
int c = ' ';
#endif
int attr = 0;
if (tabwaspending && (flags & WATCH_COLOR))
set_ansi_attribute(-1);
tabwaspending = 0;
if (!eolseen) {
/* if there is a tab pending, just
* spit spaces until the next stop
* instead of reading characters */
if (!tabpending)
#ifdef WITH_WATCH8BIT
do {
if (carry == WEOF) {
c = my_getwc(p);
} else {
c = carry;
carry = WEOF;
}
} while (c != WEOF && !iswprint(c)
&& c < 128
&& wcwidth(c) == 0
&& c != L'\n'
&& c != L'\t'
&& (c != L'\033'
|| !(flags & WATCH_COLOR)));
#else
do
c = getc(p);
while (c != EOF && !isprint(c)
&& c != '\n'
&& c != '\t'
&& (c != L'\033'
|| !(flags & WATCH_COLOR)));
#endif
if (c == L'\033' && (flags & WATCH_COLOR)) {
x--;
process_ansi(p);
continue;
}
if (c == L'\n')
if (!oldeolseen && x == 0) {
x = -1;
continue;
} else
eolseen = 1;
else if (c == L'\t')
tabpending = 1;
#ifdef WITH_WATCH8BIT
if (x == width - 1 && wcwidth(c) == 2) {
y++;
x = -1; /* process this double-width */
carry = c; /* character on the next line */
continue; /* because it won't fit here */
}
if (c == WEOF || c == L'\n' || c == L'\t') {
c = L' ';
if (flags & WATCH_COLOR)
attrset(A_NORMAL);
}
#else
if (c == EOF || c == '\n' || c == '\t') {
c = ' ';
if (flags & WATCH_COLOR)
attrset(A_NORMAL);
}
#endif
if (tabpending && (((x + 1) % 8) == 0)) {
tabpending = 0;
tabwaspending = 1;
}
}
move(y, x);
if (!first_screen && !exit_early && (flags & WATCH_CHGEXIT)) {
#ifdef WITH_WATCH8BIT
cchar_t oldc;
in_wch(&oldc);
exit_early = (wchar_t) c != oldc.chars[0];
#else
chtype oldch = inch();
unsigned char oldc = oldch & A_CHARTEXT;
exit_early = (unsigned char)c != oldc;
#endif
}
if (flags & WATCH_DIFF) {
#ifdef WITH_WATCH8BIT
cchar_t oldc;
in_wch(&oldc);
attr = !first_screen
&& ((wchar_t) c != oldc.chars[0]
||
((flags & WATCH_CUMUL)
&& (oldc.attr & A_ATTRIBUTES)));
#else
chtype oldch = inch();
unsigned char oldc = oldch & A_CHARTEXT;
attr = !first_screen
&& ((unsigned char)c != oldc
||
((flags & WATCH_CUMUL)
&& (oldch & A_ATTRIBUTES)));
#endif
}
if (attr)
standout();
#ifdef WITH_WATCH8BIT
addnwstr((wchar_t *) & c, 1);
#else
addch(c);
#endif
if (attr)
standend();
#ifdef WITH_WATCH8BIT
if (wcwidth(c) == 0) {
x--;
}
if (wcwidth(c) == 2) {
x++;
}
#endif
}
oldeolseen = eolseen;
}
fclose(p);
/* harvest child process and get status, propagated from command */
if (waitpid(child, &status, 0) < 0)
xerr(8, _("waitpid"));
/* if child process exited in error, beep if option_beep is set */
if ((!WIFEXITED(status) || WEXITSTATUS(status))) {
if (flags & WATCH_BEEP)
beep();
if (flags & WATCH_ERREXIT) {
mvaddstr(height - 1, 0,
_("command exit with a non-zero status, press a key to exit"));
refresh();
fgetc(stdin);
endwin();
exit(8);
}
}
first_screen = 0;
refresh();
return exit_early;
}
int main(int argc, char *argv[])
{
int optc;
double interval = 2;
char *command;
char **command_argv;
int command_length = 0; /* not including final \0 */
watch_usec_t next_loop; /* next loop time in us, used for precise time
* keeping only */
#ifdef WITH_WATCH8BIT
wchar_t *wcommand = NULL;
int wcommand_columns = 0; /* not including final \0 */
int wcommand_characters = 0; /* not including final \0 */
#endif /* WITH_WATCH8BIT */
static struct option longopts[] = {
{"color", no_argument, 0, 'c'},
{"differences", optional_argument, 0, 'd'},
{"help", no_argument, 0, 'h'},
{"interval", required_argument, 0, 'n'},
{"beep", no_argument, 0, 'b'},
{"errexit", no_argument, 0, 'e'},
{"chgexit", no_argument, 0, 'g'},
{"exec", no_argument, 0, 'x'},
{"precise", no_argument, 0, 'p'},
{"no-title", no_argument, 0, 't'},
{"version", no_argument, 0, 'v'},
{0, 0, 0, 0}
};
#ifdef HAVE_PROGRAM_INVOCATION_NAME
program_invocation_name = program_invocation_short_name;
#endif
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
while ((optc =
getopt_long(argc, argv, "+bced::ghn:pvtx", longopts, (int *)0))
!= EOF) {
switch (optc) {
case 'b':
flags |= WATCH_BEEP;
break;
case 'c':
flags |= WATCH_COLOR;
break;
case 'd':
flags |= WATCH_DIFF;
if (optarg)
flags |= WATCH_CUMUL;
break;
case 'e':
flags |= WATCH_ERREXIT;
break;
case 'g':
flags |= WATCH_CHGEXIT;
break;
case 't':
show_title = 0;
break;
case 'x':
flags |= WATCH_EXEC;
break;
case 'n':
interval = strtod_or_err(optarg, _("failed to parse argument"));
if (interval < 0.1)
interval = 0.1;
if (interval > UINT_MAX)
interval = UINT_MAX;
break;
case 'p':
precise_timekeeping = 1;
break;
case 'h':
usage(stdout);
break;
case 'v':
printf(PROCPS_NG_VERSION);
return EXIT_SUCCESS;
default:
usage(stderr);
break;
}
}
if (optind >= argc)
usage(stderr);
/* save for later */
command_argv = &(argv[optind]);
command = xstrdup(argv[optind++]);
command_length = strlen(command);
for (; optind < argc; optind++) {
char *endp;
int s = strlen(argv[optind]);
/* space and \0 */
command = xrealloc(command, command_length + s + 2);
endp = command + command_length;
*endp = ' ';
memcpy(endp + 1, argv[optind], s);
/* space then string length */
command_length += 1 + s;
command[command_length] = '\0';
}
#ifdef WITH_WATCH8BIT
/* convert to wide for printing purposes */
/*mbstowcs(NULL, NULL, 0); */
wcommand_characters = mbstowcs(NULL, command, 0);
if (wcommand_characters < 0) {
fprintf(stderr, _("unicode handling error\n"));
exit(EXIT_FAILURE);
}
wcommand =
(wchar_t *) malloc((wcommand_characters + 1) * sizeof(wcommand));
if (wcommand == NULL) {
fprintf(stderr, _("unicode handling error (malloc)\n"));
exit(EXIT_FAILURE);
}
mbstowcs(wcommand, command, wcommand_characters + 1);
wcommand_columns = wcswidth(wcommand, -1);
#endif /* WITH_WATCH8BIT */
get_terminal_size();
/* Catch keyboard interrupts so we can put tty back in a sane
* state. */
signal(SIGINT, die);
signal(SIGTERM, die);
signal(SIGHUP, die);
signal(SIGWINCH, winch_handler);
/* Set up tty for curses use. */
curses_started = 1;
initscr();
if (flags & WATCH_COLOR) {
if (has_colors()) {
start_color();
use_default_colors();
init_ansi_colors();
} else {
flags |= WATCH_COLOR;
}
}
nonl();
noecho();
cbreak();
if (precise_timekeeping)
next_loop = get_time_usec();
while (1) {
if (screen_size_changed) {
get_terminal_size();
resizeterm(height, width);
clear();
/* redrawwin(stdscr); */
screen_size_changed = 0;
first_screen = 1;
}
if (show_title)
#ifdef WITH_WATCH8BIT
output_header(wcommand, wcommand_columns, wcommand_characters, interval);
#else
output_header(command, interval);
#endif /* WITH_WATCH8BIT */
if (run_command(command, command_argv))
break;
if (precise_timekeeping) {
watch_usec_t cur_time = get_time_usec();
next_loop += USECS_PER_SEC * interval;
if (cur_time < next_loop)
usleep(next_loop - cur_time);
} else
if (interval < UINT_MAX / USECS_PER_SEC)
usleep(interval * USECS_PER_SEC);
else
sleep(interval);
}
endwin();
return EXIT_SUCCESS;
}
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