Rich Felker suggested removing dprintf() from watch, and one thing led to
another... This adds bb_xspawn() support, which does vfork/exec. (I don't know why using a static instead of a local adds ~40 bytes, but using the local doesn't work...)
This commit is contained in:
Rob Landley
parent
69d863b6c6
commit
399d2b5c24
@ -4,20 +4,7 @@
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*
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* Copyright (C) 2001 by Michael Habermann <mhabermann@gmx.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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/* BB_AUDIT SUSv3 N/A */
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@ -41,23 +28,18 @@
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int watch_main(int argc, char **argv)
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{
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const int header_len = 40;
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time_t t;
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pid_t pid;
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int width, len;
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unsigned period = 2;
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int old_stdout;
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int len, len2;
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char **watched_argv;
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char header[header_len + 1];
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char **watched_argv, *header;
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if (argc < 2) {
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bb_show_usage();
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}
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if (argc < 2) bb_show_usage();
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get_terminal_width_height(1, &width, 0);
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header = xzalloc(width--);
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/* don't use getopt, because it permutes the arguments */
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++argv;
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if ((argc > 3) && !strcmp(*argv, "-n")
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) {
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if ((argc > 3) && !strcmp(*argv, "-n")) {
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period = bb_xgetularg10_bnd(argv[1], 1, UINT_MAX);
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argv += 2;
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}
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@ -65,44 +47,22 @@ int watch_main(int argc, char **argv)
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/* create header */
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len = snprintf(header, header_len, "Every %ds:", period);
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/* Don't bother checking for len < 0, as it should never happen.
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* But, just to be prepared... */
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assert(len >= 0);
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do {
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len2 = strlen(*argv);
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if (len + len2 >= header_len-1) {
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break;
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}
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header[len] = ' ';
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memcpy(header+len+1, *argv, len2);
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len += len2+1;
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} while (*++argv);
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header[len] = 0;
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/* thanks to lye, who showed me how to redirect stdin/stdout */
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old_stdout = dup(STDOUT_FILENO);
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len = snprintf(header, width, "Every %ds:", period);
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while (*argv && len<width)
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snprintf(header+len, width-len, " %s", *(argv++));
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while (1) {
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time(&t);
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/* Use dprintf to avoid fflush()ing stdout. */
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if (dprintf(1, "\033[H\033[J%-*s%s\n", header_len, header, ctime(&t)) < 0) {
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bb_perror_msg_and_die("printf");
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}
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char *thyme;
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time_t t;
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pid = vfork(); /* vfork, because of ucLinux */
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if (pid > 0) {
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//parent
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wait(0);
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sleep(period);
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} else if (0 == pid) {
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//child
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dup2(old_stdout, STDOUT_FILENO);
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execvp(*watched_argv, watched_argv);
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bb_perror_msg_and_die("%s", *watched_argv);
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} else {
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bb_perror_msg_and_die("vfork");
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}
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time(&t);
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thyme = ctime(&t);
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len = strlen(thyme);
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if (len < width) header[width-len] = 0;
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printf("\033[H\033[J%s %s\n", header, thyme);
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waitpid(bb_xspawn(watched_argv),0,0);
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sleep(period);
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}
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}
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@ -146,6 +146,8 @@ extern void bb_fflush_stdout_and_exit(int retval) ATTRIBUTE_NORETURN;
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extern void xstat(const char *filename, struct stat *buf);
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extern int bb_xsocket(int domain, int type, int protocol);
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extern pid_t bb_spawn(char **argv);
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extern pid_t bb_xspawn(char **argv);
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extern void bb_xdaemon(int nochdir, int noclose);
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extern void bb_xbind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen);
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extern void bb_xlisten(int s, int backlog);
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@ -182,3 +182,37 @@ void bb_xfflush_stdout(void)
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}
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}
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#endif
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#ifdef L_spawn
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// This does a fork/exec in one call, using vfork().
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pid_t bb_spawn(char **argv)
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{
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static int failed;
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pid_t pid;
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// Be nice to nommu machines.
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failed = 0;
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pid = vfork();
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if (pid < 0) return pid;
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if (!pid) {
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execvp(*argv, argv);
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// We're sharing a stack with blocked parent, let parent know we failed
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// and then exit to unblock parent (but don't run atexit() stuff, which
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// would screw up parent.)
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failed = -1;
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_exit(0);
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}
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return failed ? failed : pid;
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}
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#endif
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#ifdef L_xspawn
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pid_t bb_xspawn(char **argv)
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{
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pid_t pid = bb_spawn(argv);
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if (pid < 0) bb_perror_msg_and_die("%s", *argv);
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return pid;
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}
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#endif
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