extra/scron/fhs-compliant.patch

--- a/Makefile	2015-02-12 16:44:53.000000000 +0100
+++ b/Makefile	2023-04-22 03:16:43.372260703 +0200
@@ -2,19 +2,19 @@
 PREFIX = /usr/local
 MANPREFIX = $(PREFIX)/man
 
-BIN = crond
+BIN = scrond
 MAN = scron.1
 
 all: $(BIN)
 
 install: all
-	mkdir -p $(DESTDIR)$(PREFIX)/bin
-	cp -f $(BIN) $(DESTDIR)$(PREFIX)/bin
+	mkdir -p $(DESTDIR)$(PREFIX)/sbin
+	cp -f $(BIN) $(DESTDIR)$(PREFIX)/sbin
 	mkdir -p $(DESTDIR)$(MANPREFIX)/man1
 	cp -f $(MAN) $(DESTDIR)$(MANPREFIX)/man1
 
 uninstall:
-	rm -f $(DESTDIR)$(PREFIX)/bin/$(BIN)
+	rm -f $(DESTDIR)$(PREFIX)/sbin/$(BIN)
 	rm -f $(DESTDIR)$(MANPREFIX)/man1/$(MAN)
 
 clean:
--- /dev/null	2023-04-17 02:00:25.200473975 +0200
+++ b/scrond.c	2023-04-22 03:23:28.719671519 +0200
@@ -0,0 +1,604 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <errno.h>
+#include <limits.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <syslog.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "arg.h"
+#include "queue.h"
+
+#define VERSION "0.4"
+
+#define LEN(x) (sizeof (x) / sizeof *(x))
+
+struct field {
+	enum {
+		ERROR,
+		WILDCARD,
+		NUMBER,
+		RANGE,
+		REPEAT,
+		LIST
+	} type;
+	long *val;
+	int len;
+};
+
+struct ctabentry {
+	struct field min;
+	struct field hour;
+	struct field mday;
+	struct field mon;
+	struct field wday;
+	char *cmd;
+	TAILQ_ENTRY(ctabentry) entry;
+};
+
+struct jobentry {
+	char *cmd;
+	pid_t pid;
+	TAILQ_ENTRY(jobentry) entry;
+};
+
+char *argv0;
+static sig_atomic_t chldreap;
+static sig_atomic_t reload;
+static sig_atomic_t quit;
+static TAILQ_HEAD(, ctabentry) ctabhead = TAILQ_HEAD_INITIALIZER(ctabhead);
+static TAILQ_HEAD(, jobentry) jobhead = TAILQ_HEAD_INITIALIZER(jobhead);
+static char *config = "/etc/crontab";
+static char *pidfile = "/var/run/scrond.pid";
+static int nflag;
+
+static void
+loginfo(const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	if (nflag == 0)
+		vsyslog(LOG_INFO, fmt, ap);
+	else
+		vfprintf(stdout, fmt, ap);
+	fflush(stdout);
+	va_end(ap);
+}
+
+static void
+logwarn(const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	if (nflag == 0)
+		vsyslog(LOG_WARNING, fmt, ap);
+	else
+		vfprintf(stderr, fmt, ap);
+	va_end(ap);
+}
+
+static void
+logerr(const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	if (nflag == 0)
+		vsyslog(LOG_ERR, fmt, ap);
+	else
+		vfprintf(stderr, fmt, ap);
+	va_end(ap);
+}
+
+static void *
+emalloc(size_t size)
+{
+	void *p;
+	p = malloc(size);
+	if (!p) {
+		logerr("error: out of memory\n");
+		if (nflag == 0)
+			unlink(pidfile);
+		exit(EXIT_FAILURE);
+	}
+	return p;
+}
+
+static char *
+estrdup(const char *s)
+{
+	char *p;
+
+	p = strdup(s);
+	if (!p) {
+		logerr("error: out of memory\n");
+		if (nflag == 0)
+			unlink(pidfile);
+		exit(EXIT_FAILURE);
+	}
+	return p;
+}
+
+static void
+runjob(char *cmd)
+{
+	struct jobentry *je;
+	time_t t;
+	pid_t pid;
+
+	t = time(NULL);
+
+	/* If command is already running, skip it */
+	TAILQ_FOREACH(je, &jobhead, entry) {
+		if (strcmp(je->cmd, cmd) == 0) {
+			loginfo("already running %s pid: %d at %s",
+				je->cmd, je->pid, ctime(&t));
+			return;
+		}
+	}
+
+	pid = fork();
+	if (pid < 0) {
+		logerr("error: failed to fork job: %s time: %s",
+		       cmd, ctime(&t));
+		return;
+	} else if (pid == 0) {
+		setsid();
+		loginfo("run: %s pid: %d at %s",
+			cmd, getpid(), ctime(&t));
+		execl("/bin/sh", "/bin/sh", "-c", cmd, (char *)NULL);
+		logerr("error: failed to execute job: %s time: %s",
+		       cmd, ctime(&t));
+		_exit(EXIT_FAILURE);
+	} else {
+		je = emalloc(sizeof(*je));
+		je->cmd = estrdup(cmd);
+		je->pid = pid;
+		TAILQ_INSERT_TAIL(&jobhead, je, entry);
+	}
+}
+
+static void
+waitjob(void)
+{
+	struct jobentry *je, *tmp;
+	int status;
+	time_t t;
+	pid_t pid;
+
+	t = time(NULL);
+
+	while ((pid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
+		je = NULL;
+		TAILQ_FOREACH(tmp, &jobhead, entry) {
+			if (tmp->pid == pid) {
+				je = tmp;
+				break;
+			}
+		}
+		if (je) {
+			TAILQ_REMOVE(&jobhead, je, entry);
+			free(je->cmd);
+			free(je);
+		}
+		if (WIFEXITED(status) == 1)
+			loginfo("complete: pid: %d returned: %d time: %s",
+				pid, WEXITSTATUS(status), ctime(&t));
+		else if (WIFSIGNALED(status) == 1)
+			loginfo("complete: pid: %d terminated by signal: %s time: %s",
+				pid, strsignal(WTERMSIG(status)), ctime(&t));
+		else if (WIFSTOPPED(status) == 1)
+			loginfo("complete: pid: %d stopped by signal: %s time: %s",
+				pid, strsignal(WSTOPSIG(status)), ctime(&t));
+	}
+}
+
+static int
+isleap(int year)
+{
+	if (year % 400 == 0)
+		return 1;
+	if (year % 100 == 0)
+		return 0;
+	return (year % 4 == 0);
+}
+
+static int
+daysinmon(int mon, int year)
+{
+	int days[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+	if (year < 1900)
+		year += 1900;
+	if (isleap(year))
+		days[1] = 29;
+	return days[mon];
+}
+
+static int
+matchentry(struct ctabentry *cte, struct tm *tm)
+{
+	struct {
+		struct field *f;
+		int tm;
+		int len;
+	} matchtbl[] = {
+		{ .f = &cte->min,  .tm = tm->tm_min,  .len = 60 },
+		{ .f = &cte->hour, .tm = tm->tm_hour, .len = 24 },
+		{ .f = &cte->mday, .tm = tm->tm_mday, .len = daysinmon(tm->tm_mon, tm->tm_year) },
+		{ .f = &cte->mon,  .tm = tm->tm_mon,  .len = 12 },
+		{ .f = &cte->wday, .tm = tm->tm_wday, .len = 7  },
+	};
+	size_t i;
+	int j;
+
+	for (i = 0; i < LEN(matchtbl); i++) {
+		switch (matchtbl[i].f->type) {
+		case WILDCARD:
+			continue;
+		case NUMBER:
+			if (matchtbl[i].f->val[0] == matchtbl[i].tm)
+				continue;
+			break;
+		case RANGE:
+			if (matchtbl[i].f->val[0] <= matchtbl[i].tm)
+				if (matchtbl[i].f->val[1] >= matchtbl[i].tm)
+					continue;
+			break;
+		case REPEAT:
+			if (matchtbl[i].tm > 0) {
+				if (matchtbl[i].tm % matchtbl[i].f->val[0] == 0)
+					continue;
+			} else {
+				if (matchtbl[i].len % matchtbl[i].f->val[0] == 0)
+					continue;
+			}
+			break;
+		case LIST:
+			for (j = 0; j < matchtbl[i].f->len; j++)
+				if (matchtbl[i].f->val[j] == matchtbl[i].tm)
+					break;
+			if (j < matchtbl[i].f->len)
+				continue;
+			break;
+		default:
+			break;
+		}
+		break;
+	}
+	if (i != LEN(matchtbl))
+		return 0;
+	return 1;
+}
+
+static int
+parsefield(const char *field, long low, long high, struct field *f)
+{
+	int i;
+	char *e1, *e2;
+	const char *p;
+
+	p = field;
+	while (isdigit(*p))
+		p++;
+
+	f->type = ERROR;
+
+	switch (*p) {
+	case '*':
+		if (strcmp(field, "*") == 0) {
+			f->val = NULL;
+			f->len = 0;
+			f->type = WILDCARD;
+		} else if (strncmp(field, "*/", 2) == 0) {
+			f->val = emalloc(sizeof(*f->val));
+			f->len = 1;
+
+			errno = 0;
+			f->val[0] = strtol(field + 2, &e1, 10);
+			if (e1[0] != '\0' || errno != 0 || f->val[0] == 0)
+				break;
+
+			f->type = REPEAT;
+		}
+		break;
+	case '\0':
+		f->val = emalloc(sizeof(*f->val));
+		f->len = 1;
+
+		errno = 0;
+		f->val[0] = strtol(field, &e1, 10);
+		if (e1[0] != '\0' || errno != 0)
+			break;
+
+		f->type = NUMBER;
+		break;
+	case '-':
+		f->val = emalloc(2 * sizeof(*f->val));
+		f->len = 2;
+
+		errno = 0;
+		f->val[0] = strtol(field, &e1, 10);
+		if (e1[0] != '-' || errno != 0)
+			break;
+
+		errno = 0;
+		f->val[1] = strtol(e1 + 1, &e2, 10);
+		if (e2[0] != '\0' || errno != 0)
+			break;
+
+		f->type = RANGE;
+		break;
+	case ',':
+		for (i = 1; isdigit(*p) || *p == ','; p++)
+			if (*p == ',')
+				i++;
+		f->val = emalloc(i * sizeof(*f->val));
+		f->len = i;
+
+		errno = 0;
+		f->val[0] = strtol(field, &e1, 10);
+		if (f->val[0] < low || f->val[0] > high)
+			break;
+
+		for (i = 1; *e1 == ',' && errno == 0; i++) {
+			errno = 0;
+			f->val[i] = strtol(e1 + 1, &e2, 10);
+			e1 = e2;
+		}
+		if (e1[0] != '\0' || errno != 0)
+			break;
+
+		f->type = LIST;
+		break;
+	default:
+		return -1;
+	}
+
+	for (i = 0; i < f->len; i++)
+		if (f->val[i] < low || f->val[i] > high)
+			f->type = ERROR;
+
+	if (f->type == ERROR) {
+		free(f->val);
+		return -1;
+	}
+
+	return 0;
+}
+
+static void
+freecte(struct ctabentry *cte, int nfields)
+{
+	switch (nfields) {
+	case 6:
+		free(cte->cmd);
+	case 5:
+		free(cte->wday.val);
+	case 4:
+		free(cte->mon.val);
+	case 3:
+		free(cte->mday.val);
+	case 2:
+		free(cte->hour.val);
+	case 1:
+		free(cte->min.val);
+	}
+	free(cte);
+}
+
+static void
+unloadentries(void)
+{
+	struct ctabentry *cte, *tmp;
+
+	for (cte = TAILQ_FIRST(&ctabhead); cte; cte = tmp) {
+		tmp = TAILQ_NEXT(cte, entry);
+		TAILQ_REMOVE(&ctabhead, cte, entry);
+		freecte(cte, 6);
+	}
+}
+
+static int
+loadentries(void)
+{
+	struct ctabentry *cte;
+	FILE *fp;
+	char *line = NULL, *p, *col;
+	int r = 0, y;
+	size_t size = 0;
+	ssize_t len;
+	struct fieldlimits {
+		char *name;
+		long min;
+		long max;
+		struct field *f;
+	} flim[] = {
+		{ "min",  0, 59, NULL },
+		{ "hour", 0, 23, NULL },
+		{ "mday", 1, 31, NULL },
+		{ "mon",  1, 12, NULL },
+		{ "wday", 0, 6,  NULL }
+	};
+	size_t x;
+
+	if ((fp = fopen(config, "r")) == NULL) {
+		logerr("error: can't open %s: %s\n", config, strerror(errno));
+		return -1;
+	}
+
+	for (y = 0; (len = getline(&line, &size, fp)) != -1; y++) {
+		p = line;
+		if (line[0] == '#' || line[0] == '\n' || line[0] == '\0')
+			continue;
+
+		cte = emalloc(sizeof(*cte));
+		flim[0].f = &cte->min;
+		flim[1].f = &cte->hour;
+		flim[2].f = &cte->mday;
+		flim[3].f = &cte->mon;
+		flim[4].f = &cte->wday;
+
+		for (x = 0; x < LEN(flim); x++) {
+			do
+				col = strsep(&p, "\t\n ");
+			while (col && col[0] == '\0');
+
+			if (!col || parsefield(col, flim[x].min, flim[x].max, flim[x].f) < 0) {
+				logerr("error: failed to parse `%s' field on line %d\n",
+						flim[x].name, y + 1);
+				freecte(cte, x);
+				r = -1;
+				break;
+			}
+		}
+
+		if (r == -1)
+			break;
+
+		col = strsep(&p, "\n");
+		if (col)
+			while (col[0] == '\t' || col[0] == ' ')
+				col++;
+		if (!col || col[0] == '\0') {
+			logerr("error: missing `cmd' field on line %d\n",
+			       y + 1);
+			freecte(cte, 5);
+			r = -1;
+			break;
+		}
+		cte->cmd = estrdup(col);
+
+		TAILQ_INSERT_TAIL(&ctabhead, cte, entry);
+	}
+
+	if (r < 0)
+		unloadentries();
+
+	free(line);
+	fclose(fp);
+
+	return r;
+}
+
+static void
+reloadentries(void)
+{
+	unloadentries();
+	if (loadentries() < 0)
+		logwarn("warning: discarding old crontab entries\n");
+}
+
+static void
+sighandler(int sig)
+{
+	switch (sig) {
+	case SIGCHLD:
+		chldreap = 1;
+		break;
+	case SIGHUP:
+		reload = 1;
+		break;
+	case SIGTERM:
+		quit = 1;
+		break;
+	}
+}
+
+static void
+usage(void)
+{
+	fprintf(stderr, VERSION " (c) 2014-2015\n");
+	fprintf(stderr, "usage: %s [-f file] [-n]\n", argv0);
+	fprintf(stderr, "  -f	config file\n");
+	fprintf(stderr, "  -n	do not daemonize\n");
+	exit(EXIT_FAILURE);
+}
+
+int
+main(int argc, char *argv[])
+{
+	FILE *fp;
+	struct ctabentry *cte;
+	time_t t;
+	struct tm *tm;
+	struct sigaction sa;
+
+	ARGBEGIN {
+	case 'n':
+		nflag = 1;
+		break;
+	case 'f':
+		config = EARGF(usage());
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc > 0)
+		usage();
+
+	if (nflag == 0) {
+		openlog(argv[0], LOG_CONS | LOG_PID, LOG_CRON);
+		if (daemon(1, 0) < 0) {
+			logerr("error: failed to daemonize %s\n", strerror(errno));
+			return EXIT_FAILURE;
+		}
+		if ((fp = fopen(pidfile, "w"))) {
+			fprintf(fp, "%d\n", getpid());
+			fclose(fp);
+		}
+	}
+
+	sa.sa_handler = sighandler;
+	sigfillset(&sa.sa_mask);
+	sa.sa_flags = SA_RESTART;
+	sigaction(SIGCHLD, &sa, NULL);
+	sigaction(SIGHUP, &sa, NULL);
+	sigaction(SIGTERM, &sa, NULL);
+
+	loadentries();
+
+	while (1) {
+		t = time(NULL);
+		sleep(60 - t % 60);
+
+		if (quit == 1) {
+			if (nflag == 0)
+				unlink(pidfile);
+			unloadentries();
+			/* Don't wait or kill forked processes, just exit */
+			break;
+		}
+
+		if (reload == 1 || chldreap == 1) {
+			if (reload == 1) {
+				reloadentries();
+				reload = 0;
+			}
+			if (chldreap == 1) {
+				waitjob();
+				chldreap = 0;
+			}
+			continue;
+		}
+
+		TAILQ_FOREACH(cte, &ctabhead, entry) {
+			t = time(NULL);
+			tm = localtime(&t);
+			if (matchentry(cte, tm) == 1)
+				runjob(cte->cmd);
+		}
+	}
+
+	if (nflag == 0)
+		closelog();
+
+	return EXIT_SUCCESS;
+}