From f38163772cb8ca25c440393132e8678e65437320 Mon Sep 17 00:00:00 2001 From: David Oberhollenzer Date: Sun, 16 Sep 2018 21:52:46 +0200 Subject: Add simple cron implementation Signed-off-by: David Oberhollenzer --- crond/Makemodule.am | 9 ++++ crond/gcrond.h | 37 ++++++++++++++ crond/main.c | 139 ++++++++++++++++++++++++++++++++++++++++++++++++++++ crond/runjob.c | 87 ++++++++++++++++++++++++++++++++ 4 files changed, 272 insertions(+) create mode 100644 crond/Makemodule.am create mode 100644 crond/gcrond.h create mode 100644 crond/main.c create mode 100644 crond/runjob.c (limited to 'crond') diff --git a/crond/Makemodule.am b/crond/Makemodule.am new file mode 100644 index 0000000..51960e9 --- /dev/null +++ b/crond/Makemodule.am @@ -0,0 +1,9 @@ +if GCROND +gcrond_SOURCES = crond/main.c crond/gcrond.h crond/runjob.c +gcrond_CPPFLAGS = $(AM_CPPFLAGS) +gcrond_CFLAGS = $(AM_CFLAGS) +gcrond_LDFLAGS = $(AM_LDFLAGS) +gcrond_LDADD = libcron.a libinit.a libcfg.a + +sbin_PROGRAMS += gcrond +endif diff --git a/crond/gcrond.h b/crond/gcrond.h new file mode 100644 index 0000000..4cc2417 --- /dev/null +++ b/crond/gcrond.h @@ -0,0 +1,37 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +/* + * Copyright (C) 2018 - David Oberhollenzer + * + * 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 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +#ifndef GCROND_H +#define GCROND_H + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "crontab.h" +#include "config.h" +#include "util.h" + +int runjob(crontab_t *tab); + +#endif /* GCROND_H */ + diff --git a/crond/main.c b/crond/main.c new file mode 100644 index 0000000..d7cc33e --- /dev/null +++ b/crond/main.c @@ -0,0 +1,139 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +/* + * Copyright (C) 2018 - David Oberhollenzer + * + * 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 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +#include "gcrond.h" + +static crontab_t *jobs; +static sig_atomic_t run = 1; +static sig_atomic_t rescan = 1; + +static void read_config(void) +{ + if (cronscan(GCRONDIR, &jobs)) { + fputs("Error reading configuration. Continuing anyway.\n", + stderr); + } +} + +static void cleanup_config(void) +{ + crontab_t *t; + + while (jobs != NULL) { + t = jobs; + jobs = jobs->next; + delcron(t); + } +} + +static int calc_timeout(void) +{ + time_t now = time(NULL), future; + struct tm tmstruct; + crontab_t mask, *t; + int minutes; + + for (minutes = 0; minutes < 120; ++minutes) { + future = now + minutes * 60; + + localtime_r(&future, &tmstruct); + cron_tm_to_mask(&mask, &tmstruct); + + for (t = jobs; t != NULL; t = t->next) { + if (cron_should_run(t, &mask)) + goto out; + } + } +out: + return minutes ? minutes * 60 : 60; +} + +static void runjobs(void) +{ + time_t now = time(NULL); + struct tm tmstruct; + crontab_t mask, *t; + + localtime_r(&now, &tmstruct); + cron_tm_to_mask(&mask, &tmstruct); + + for (t = jobs; t != NULL; t = t->next) { + if (cron_should_run(t, &mask)) + runjob(t); + } +} + +static void sighandler(int signo) +{ + switch (signo) { + case SIGINT: + case SIGTERM: + run = 0; + break; + case SIGHUP: + rescan = 1; + break; + } +} + +int main(void) +{ + struct timespec stime; + struct sigaction act; + crontab_t *t; + int timeout; + pid_t pid; + + memset(&act, 0, sizeof(act)); + act.sa_handler = sighandler; + sigaction(SIGINT, &act, NULL); + sigaction(SIGTERM, &act, NULL); + sigaction(SIGHUP, &act, NULL); + + while (run) { + if (rescan == 1) { + cleanup_config(); + read_config(); + timeout = 60; + rescan = 0; + } else { + runjobs(); + timeout = calc_timeout(); + } + + stime.tv_sec = timeout; + stime.tv_nsec = 0; + + while (nanosleep(&stime, &stime) != 0 && run && !rescan) { + if (errno != EINTR) { + perror("nanosleep"); + break; + } + } + + while ((pid = waitpid(-1, NULL, WNOHANG)) != -1) { + for (t = jobs; t != NULL; t = t->next) { + if (t->pid == pid) { + t->pid = -1; + break; + } + } + } + } + + return EXIT_SUCCESS; +} diff --git a/crond/runjob.c b/crond/runjob.c new file mode 100644 index 0000000..7650748 --- /dev/null +++ b/crond/runjob.c @@ -0,0 +1,87 @@ +/* SPDX-License-Identifier: GPL-3.0-or-later */ +/* + * Copyright (C) 2018 - David Oberhollenzer + * + * 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 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +#include "gcrond.h" + +int runjob(crontab_t *tab) +{ + struct sigaction act; + pid_t pid; + exec_t *e; + int ret; + + if (tab->exec == NULL) + return 0; + + pid = fork(); + if (pid == -1) { + perror("fork"); + return -1; + } + + if (pid != 0) { + tab->pid = pid; + return 0; + } + + /* XXX: inside the child process */ + memset(&act, 0, sizeof(act)); + act.sa_handler = SIG_DFL; + sigaction(SIGINT, &act, NULL); + sigaction(SIGTERM, &act, NULL); + sigaction(SIGHUP, &act, NULL); + + if (setup_tty(tab->ctty, tab->tty_truncate)) + exit(EXIT_FAILURE); + + if (tab->gid != 0) { + if (setresgid(tab->gid, tab->gid, tab->gid)) { + perror("setgid"); + exit(EXIT_FAILURE); + } + } + + if (tab->uid != 0) { + if (setresuid(tab->uid, tab->uid, tab->uid)) { + perror("setuid"); + exit(EXIT_FAILURE); + } + } + + if (tab->exec->next == NULL) + argv_exec(tab->exec); + + for (e = tab->exec; e != NULL; e = e->next) { + pid = fork(); + if (pid == -1) { + perror("fork"); + exit(EXIT_FAILURE); + } + + if (pid == 0) + argv_exec(e); + + while (waitpid(pid, &ret, 0) != pid) + ; + + ret = WIFEXITED(ret) ? WEXITSTATUS(ret) : EXIT_FAILURE; + if (ret != EXIT_SUCCESS) + break; + } + + exit(ret); +} -- cgit v1.2.3