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/* watch.c - Execute a program periodically
*
* Copyright 2013 Sandeep Sharma <sandeep.jack2756@gmail.com>
* Copyright 2013 Kyungwan Han <asura321@gmail.com>
*
* No standard. See http://man7.org/linux/man-pages/man1/watch.1.html
*
* TODO: trailing combining characters
USE_WATCH(NEWTOY(watch, "^<1n%<100=2000tebx", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_LOCALE))
config WATCH
bool "watch"
default y
help
usage: watch [-teb] [-n SEC] PROG ARGS
Run PROG every -n seconds, showing output. Hit q to quit.
-n Loop period in seconds (default 2)
-t Don't print header
-e Exit on error
-b Beep on command error
-x Exec command directly (vs "sh -c")
*/
#define FOR_watch
#include "toys.h"
GLOBALS(
int n;
pid_t pid, oldpid;
)
// When a child process exits, stop tracking them. Handle errors for -be
static void watch_child(int sig)
{
int status;
pid_t pid = wait(&status);
status = WIFEXITED(status) ? WEXITSTATUS(status) : WTERMSIG(status)+127;
if (status) {
// TODO should this be beep()?
if (FLAG(b)) putchar('\b');
if (FLAG(e)) {
printf("Exit status %d\r\n", status);
tty_reset();
_exit(status);
}
}
if (pid == TT.oldpid) TT.oldpid = 0;
else if (pid == TT.pid) TT.pid = 0;
}
// Return early for low-ascii characters with special behavior,
// discard remaining low ascii, escape other unprintable chars normally
static int watch_escape(FILE *out, int cols, int wc)
{
if (wc==27 || (wc>=7 && wc<=13)) return -1;
if (wc < 32) return 0;
return crunch_escape(out, cols, wc);
}
void watch_main(void)
{
char *cmdv[] = {"/bin/sh", "-c", 0, 0}, *cmd, *ss;
long long now, then = millitime();
unsigned width, height, i, cmdlen, len, xx = xx, yy = yy, active = active;
struct pollfd pfd[2];
pid_t pid = 0;
int fds[2], cc;
// Assemble header line in cmd, cmdlen, and cmdv
for (i = TT.n%1000, len = i ? 3 : 1; i && !(i%10); i /= 10) len--;
len = sprintf(toybuf, "Every %u.%0*us:", TT.n/1000, len, i)+1;
cmdlen = len;
for (i = 0; toys.optargs[i]; i++) len += strlen(toys.optargs[i])+1;
ss = stpcpy(cmd = xmalloc(len), toybuf);
cmdv[2] = cmd+cmdlen;
for (i = 0; toys.optargs[i]; i++) ss += sprintf(ss, " %s",toys.optargs[i]);
cmdlen = ss-cmd;
// Need to poll on process output and stdin
memset(pfd, 0, sizeof(pfd));
pfd[0].events = pfd[1].events = POLLIN;
xsignal_flags(SIGCHLD, watch_child, SA_RESTART|SA_NOCLDSTOP);
for (;;) {
// Time for a new period?
if ((now = millitime())>=then) {
// Incrementing then instead of adding offset to now avoids drift,
// loop is in case we got suspend/resumed and need to skip periods
while ((then += TT.n)<=now);
start_redraw(&width, &height);
// redraw the header
if (!FLAG(t)) {
time_t t = time(0);
int pad, ctimelen;
// Get and measure time string, trimming gratuitous \n
ctimelen = strlen(ss = ctime(&t));
if (ss[ctimelen-1]=='\n') ss[--ctimelen] = 0;
// print cmdline, then * or ' ' (showing truncation), then ctime
pad = width-++ctimelen;
if (pad>0) draw_trim(cmd, -pad, pad);
printf("%c", pad<cmdlen ? '*' : ' ');
if (width) xputs(ss+(width>ctimelen ? 0 : width-1));
if (yy>=3) xprintf("\r\n");
xx = 0;
yy = 2;
}
// If child didn't exit, send TERM signal to current and KILL to previous
if (TT.oldpid>0) kill(TT.oldpid, SIGKILL);
if (TT.pid>0) kill(TT.pid, SIGTERM);
TT.oldpid = pid;
if (fds[0]>0) close(fds[0]);
if (fds[1]>0) close(fds[1]);
// Spawn child process
fds[0] = fds[1] = -1;
TT.pid = xpopen_both(FLAG(x) ? toys.optargs : cmdv, fds);
pfd[1].fd = fds[1];
active = 1;
}
// Fetch data from child process or keyboard, with timeout
len = 0;
xpoll(pfd, 1+(active && yy<height), then-now);
if (pfd[0].revents&POLLIN) {
memset(toybuf, 0, 16);
cc = scan_key_getsize(toybuf, 0, &width, &height);
// TODO: ctrl-Z suspend
// TODO if (cc == -3) redraw();
if (cc == 3 || tolower(cc) == 'q') xexit();
}
if (pfd[0].revents&POLLHUP) xexit();
if (active) {
if (pfd[1].revents&POLLIN) len = read(fds[1], toybuf, sizeof(toybuf)-1);
if (pfd[1].revents&POLLHUP) active = 0;
}
// Measure output, trim to available display area. Escape low ascii so
// we don't have to try to parse ansi escapes. TODO: parse ansi escapes.
if (len<1) continue;
ss = toybuf;
toybuf[len] = 0;
while (yy<height) {
if (xx==width) {
xx = 0;
if (++yy>=height) break;
}
xx += crunch_str(&ss, width-xx, stdout, 0, watch_escape);
if (xx==width) {
xx = 0;
if (++yy>=height) break;
continue;
}
if (ss-toybuf==len || *ss>27) break;
cc = *ss++;
if (cc==27) continue; // TODO
// Handle BEL BS HT LF VT FF CR
if (cc>=10 && cc<=12) {
if (++yy>=height) break;
if (cc=='\n') putchar('\r'), xx = 0;
}
putchar(cc);
if (cc=='\b' && xx) xx--;
else if (cc=='\t') {
xx = (xx|7)+1;
if (xx>width-1) xx = width-1;
}
}
}
if (CFG_TOYBOX_FREE) free(cmd);
}
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