From: Marco Migliori <sgerwk@aol.com>
Date: Thu, 2 Nov 2017 15:30:05 +0000 (+0100)
Subject: cronnext can read additional crontabs from files
X-Git-Tag: cronie-1.5.2~12
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=1b7318c9c2d8350559e0c3320cf6226fcf57e2fd;p=cronie

cronnext can read additional crontabs from files
---

diff --git a/man/cronnext.1 b/man/cronnext.1
index 4a120f8..621b882 100644
--- a/man/cronnext.1
+++ b/man/cronnext.1
@@ -4,8 +4,11 @@ cronnext \- time of next job cron will execute
 .SH SYNOPSIS
 .TP 9
 .B cronnext
-[\fB-i \fIusers\fR] [\fB-e \fIusers\fR] [\fB-s\fR] [\fB-t \fItime\fR]
+[\fB-i \fIusers\fR] [\fB-e \fIusers\fR] [\fB-s\fR]
+[\fB-a\fR]
+[\fB-t \fItime\fR]
 [\fB-v\fR] [\fB-h\fR] [\fB-V\fR]
+[file]...
 .SH DESCRIPTION
 Determine the time cron will execute the next job.  Without arguments, it
 prints that time considering all crontabs, in number of seconds since the
@@ -13,6 +16,10 @@ Epoch.  This number can be converted into other formats using
 .BR date (1),
 like
 .B date --date @43243254
+
+The file arguments are optional. If provided,
+.I cronnext
+uses them as crontabs instead of the ones installed in the system.
 .SH OPTIONS
 .TP
 .BI "\-i " user,user,user,...
@@ -24,12 +31,16 @@ for the system crontab.
 Do not consider the crontabs of the specified users.
 .TP
 .B \-s
-Do not consider the system crontab, usually
+Do not consider the system crontab, usually the
 .I /etc/crontab
 file.  The system crontab usually contains the hourly, daily, weekly and
 montly crontabs, which might be better dealt with
 .BR anacron (8).
 .TP
+.BI \-a
+Use the crontabs installed in the system in addition to the ones passed as
+file arguments. This is implicit if no file is passed.
+.TP
 .BI "\-t " time
 Determine the next job from this time, instead of now.  The time is
 expressed in number of seconds since the Epoch, as obtained for example by
diff --git a/src/cronnext.c b/src/cronnext.c
index 8a52e87..e5d743c 100644
--- a/src/cronnext.c
+++ b/src/cronnext.c
@@ -207,17 +207,14 @@ int matchuser(char *user, char *list) {
 /*
  * find next sheduled job
  */
-time_t cronnext(time_t start,
+time_t cronnext(cron_db database,
+		time_t start,
 		char *include, char *exclude, int system,
 		int verbose) {
 	time_t closest, next;
-	static cron_db database = {NULL, NULL, (time_t) 0};
 	user *u;
 	entry *e;
 
-	/* load crontabs */
-	load_database(&database);
-
 	/* find next sheduled time */
 	closest = -1;
 	for (u = database.head; u; u = u->next) {
@@ -245,15 +242,49 @@ time_t cronnext(time_t start,
 	return closest;
 }
 
+/*
+ * load installed crontabs and/or crontab files
+ */
+cron_db database(int installed, char **additional) {
+	cron_db db = {NULL, NULL, (time_t) 0};
+	struct passwd pw;
+	int fd;
+	user *u;
+
+	if (installed)
+		load_database(&db);
+
+	for ( ; *additional != NULL; additional++) {
+		fd = open(*additional, O_RDONLY);
+		if (fd == -1) {
+			perror(*additional);
+			continue;
+		}
+		memset(&pw, 0, sizeof(pw));
+		pw.pw_name = *additional;
+		pw.pw_passwd = "";
+		pw.pw_dir = ".";
+		u = load_user(fd, &pw, *additional, *additional, *additional);
+		if (u == NULL) {
+			printf("cannot load crontab %s\n", *additional);
+			continue;
+		}
+		link_user(&db, u);
+	}
+
+	return db;
+}
+
 void usage() {
 	fprintf(stderr, "Find the time of the next scheduled cron job.\n");
 	fprintf(stderr, "Usage:\n");
-	fprintf(stderr, " cronnext [options]\n");
+	fprintf(stderr, " cronnext [options] [file ...]\n");
 	fprintf(stderr, "\n");
 	fprintf(stderr, "Options:\n");
 	fprintf(stderr, " -i users  include only the crontab of these users\n");
 	fprintf(stderr, " -e users  exclude the crontab of these users\n");
 	fprintf(stderr, " -s        do not include the system crontab\n");
+	fprintf(stderr, " -a        examine installed crontabs even if files are given\n");
 	fprintf(stderr, " -t time   start from this time (seconds since epoch)\n");
 	fprintf(stderr, " -v        verbose mode\n");
 	fprintf(stderr, " -h        this help\n");
@@ -273,9 +304,12 @@ int main(int argn, char *argv[]) {
 	exclude = NULL;
 	system = 1;
 	start = time(NULL);
+	int installed = 0;
 	verbose = 0;
 
-	while (-1 != (opt = getopt(argn, argv, "i:e:st:vhV"))) {
+	cron_db db;
+
+	while (-1 != (opt = getopt(argn, argv, "i:e:ast:vhV"))) {
 		switch (opt) {
 		case 'i':
 			include = optarg;
@@ -283,6 +317,9 @@ int main(int argn, char *argv[]) {
 		case 'e':
 			exclude = optarg;
 			break;
+		case 'a':
+			installed = 1;
+			break;
 		case 's':
 			system = 0;
 			break;
@@ -314,8 +351,11 @@ int main(int argn, char *argv[]) {
 	/* "load,pars" for debugging loading and parsing, "" for nothing
 	   see globals.h for symbolic names and macros.h for meaning */
 
+	/* load database */
+	db = database(installed || argv[optind] == NULL, argv + optind);
+
 	/* print time of next scheduled command */
-	next = cronnext(start, include, exclude, system, verbose);
+	next = cronnext(db, start, include, exclude, system, verbose);
 	if (next == -1) {
 		if (verbose)
 			printf("no job scheduled\n");