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-rw-r--r--toys/other/watch.c186
1 files changed, 186 insertions, 0 deletions
diff --git a/toys/other/watch.c b/toys/other/watch.c
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index 00000000..ab51148c
--- /dev/null
+++ b/toys/other/watch.c
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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
+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 (toys.optflags&FLAG_b) putchar('\b');
+ if (toys.optflags&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
+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 (!(toys.optflags&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
+ memset(fds, 0, sizeof(fds));
+ TT.pid = xpopen_both((toys.optflags&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);
+}