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-rw-r--r--misc-utils/waitpid.c255
1 files changed, 255 insertions, 0 deletions
diff --git a/misc-utils/waitpid.c b/misc-utils/waitpid.c
new file mode 100644
index 0000000..b01a2f0
--- /dev/null
+++ b/misc-utils/waitpid.c
@@ -0,0 +1,255 @@
+/*
+ * waitpid(1) - wait for process termination
+ *
+ * Copyright (C) 2022 Thomas Weißschuh <thomas@t-8ch.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <sys/epoll.h>
+#include <sys/timerfd.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <getopt.h>
+
+#include "pidfd-utils.h"
+#include "c.h"
+#include "nls.h"
+#include "xalloc.h"
+#include "strutils.h"
+#include "exitcodes.h"
+#include "timeutils.h"
+#include "optutils.h"
+
+#define EXIT_TIMEOUT_EXPIRED 3
+
+#define TIMEOUT_SOCKET_IDX UINT64_MAX
+
+#define err_nosys(exitcode, ...) \
+ err(errno == ENOSYS ? EXIT_NOTSUPP : exitcode, __VA_ARGS__)
+
+static bool verbose = false;
+static struct timespec timeout;
+static bool allow_exited = false;
+static size_t count;
+
+static pid_t *parse_pids(size_t n_strings, char * const *strings)
+{
+ pid_t *pids = xcalloc(n_strings, sizeof(*pids));
+
+ for (size_t i = 0; i < n_strings; i++)
+ pids[i] = strtopid_or_err(strings[i], _("failed to parse pid"));
+
+ return pids;
+}
+
+static int *open_pidfds(size_t n_pids, pid_t *pids)
+{
+ int *pidfds = xcalloc(n_pids, sizeof(*pidfds));
+
+ for (size_t i = 0; i < n_pids; i++) {
+ pidfds[i] = pidfd_open(pids[i], 0);
+ if (pidfds[i] == -1) {
+ if (allow_exited && errno == ESRCH) {
+ warnx(_("PID %d has exited, skipping"), pids[i]);
+ continue;
+ }
+ err_nosys(EXIT_FAILURE, _("could not open pid %u"), pids[i]);
+ }
+ }
+
+ return pidfds;
+}
+
+static int open_timeoutfd(void)
+{
+ int fd;
+ struct itimerspec timer = {};
+
+ if (!timeout.tv_sec && !timeout.tv_nsec)
+ return -1;
+
+ timer.it_value = timeout;
+
+ fd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
+ if (fd == -1)
+ err_nosys(EXIT_FAILURE, _("could not create timerfd"));
+
+ if (timerfd_settime(fd, 0, &timer, NULL))
+ err_nosys(EXIT_FAILURE, _("could not set timer"));
+
+ return fd;
+
+}
+
+static size_t add_listeners(int epll, size_t n_pids, int * const pidfds, int timeoutfd)
+{
+ size_t skipped = 0;
+ struct epoll_event evt = {
+ .events = EPOLLIN,
+ };
+
+ if (timeoutfd != -1) {
+ evt.data.u64 = TIMEOUT_SOCKET_IDX;
+ if (epoll_ctl(epll, EPOLL_CTL_ADD, timeoutfd, &evt))
+ err_nosys(EXIT_FAILURE, _("could not add timerfd"));
+ }
+
+ for (size_t i = 0; i < n_pids; i++) {
+ if (pidfds[i] == -1) {
+ skipped++;
+ continue;
+ }
+ evt.data.u64 = i;
+ if (epoll_ctl(epll, EPOLL_CTL_ADD, pidfds[i], &evt))
+ err_nosys(EXIT_FAILURE, _("could not add listener"));
+ }
+
+ return n_pids - skipped;
+}
+
+static void wait_for_exits(int epll, size_t active_pids, pid_t * const pids,
+ int * const pidfds)
+{
+ while (active_pids) {
+ struct epoll_event evt;
+ int ret, fd;
+
+ ret = epoll_wait(epll, &evt, 1, -1);
+ if (ret == -1) {
+ if (errno == EINTR)
+ continue;
+ else
+ err_nosys(EXIT_FAILURE, _("failure during wait"));
+ }
+ if (evt.data.u64 == TIMEOUT_SOCKET_IDX) {
+ if (verbose)
+ printf(_("Timeout expired\n"));
+ exit(EXIT_TIMEOUT_EXPIRED);
+ }
+ if (verbose)
+ printf(_("PID %d finished\n"), pids[evt.data.u64]);
+ assert((size_t) ret <= active_pids);
+ fd = pidfds[evt.data.u64];
+ epoll_ctl(epll, EPOLL_CTL_DEL, fd, NULL);
+ active_pids -= ret;
+ }
+}
+
+static void __attribute__((__noreturn__)) usage(void)
+{
+ FILE *out = stdout;
+
+ fputs(USAGE_HEADER, out);
+ fprintf(out, _(" %s [options] pid...\n"), program_invocation_short_name);
+
+ fputs(USAGE_OPTIONS, out);
+ fputs(_(" -v, --verbose be more verbose\n"), out);
+ fputs(_(" -t, --timeout=<timeout> wait at most timeout seconds\n"), out);
+ fputs(_(" -e, --exited allow exited PIDs\n"), out);
+ fputs(_(" -c, --count=<count> number of process exits to wait for\n"), out);
+
+ fputs(USAGE_SEPARATOR, out);
+ fprintf(out, USAGE_HELP_OPTIONS(25));
+
+ fprintf(out, USAGE_MAN_TAIL("waitpid(1)"));
+
+ exit(EXIT_SUCCESS);
+}
+
+static int parse_options(int argc, char **argv)
+{
+ int c;
+ static const struct option longopts[] = {
+ { "verbose", no_argument, NULL, 'v' },
+ { "timeout", required_argument, NULL, 't' },
+ { "exited", no_argument, NULL, 'e' },
+ { "count", required_argument, NULL, 'c' },
+ { "version", no_argument, NULL, 'V' },
+ { "help", no_argument, NULL, 'h' },
+ { 0 }
+ };
+ static const ul_excl_t excl[] = { /* rows and cols in ASCII order */
+ { 'c', 'e' },
+ { 0 }
+ };
+ int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
+
+ while ((c = getopt_long (argc, argv, "vVht:c:e", longopts, NULL)) != -1) {
+
+ err_exclusive_options(c, longopts, excl, excl_st);
+
+ switch (c) {
+ case 'v':
+ verbose = true;
+ break;
+ case 't':
+ strtotimespec_or_err(optarg, &timeout,
+ _("Could not parse timeout"));
+ break;
+ case 'e':
+ allow_exited = true;
+ break;
+ case 'c':
+ count = str2num_or_err(optarg, 10, _("Invalid count"),
+ 1, INT64_MAX);
+ break;
+ case 'V':
+ print_version(EXIT_SUCCESS);
+ case 'h':
+ usage();
+ default:
+ errtryhelp(EXIT_FAILURE);
+ }
+ }
+
+ return optind;
+}
+
+int main(int argc, char **argv)
+{
+ int pid_idx, epoll, timeoutfd, *pidfds;
+ size_t n_pids, active_pids;
+
+ setlocale(LC_ALL, "");
+ bindtextdomain(PACKAGE, LOCALEDIR);
+ textdomain(PACKAGE);
+
+ pid_idx = parse_options(argc, argv);
+ n_pids = argc - pid_idx;
+ if (!n_pids)
+ errx(EXIT_FAILURE, _("no PIDs specified"));
+
+ if (count && count > n_pids)
+ errx(EXIT_FAILURE,
+ _("can't want for %zu of %zu PIDs"), count, n_pids);
+
+ pid_t *pids = parse_pids(argc - pid_idx, argv + pid_idx);
+
+ pidfds = open_pidfds(n_pids, pids);
+ timeoutfd = open_timeoutfd();
+ epoll = epoll_create(n_pids);
+ if (epoll == -1)
+ err_nosys(EXIT_FAILURE, _("could not create epoll"));
+
+ active_pids = add_listeners(epoll, n_pids, pidfds, timeoutfd);
+ if (count)
+ active_pids = min(active_pids, count);
+ wait_for_exits(epoll, active_pids, pids, pidfds);
+}