sysutils/nut*: Add upslog support for multiple UPSs

upslog is a utility that logs UPS status at regular intervals, specified
by the -i option. Unfortunately upslog supports only on UPS. For sites
that need to monitor multiple UPSs the options are to cobble an rc script
for each or doctor up the nut_upslog.in script to support cloning of the
script. Unfortunately an rc script capable of being cloned would become
the source of more PRs and would require significanly more tehcnical
documentation that by itself might become confusing for the average
system administrator.

Therefore a new -m option is added to support multiple UPSs using the
same invocation of upslog. The patch parses a -m option and forks
almost immediately following the getopt(3) invokation to monitor each
individual UPS using a separate upslog process. This is not ideal but
better than scripting. Lightweight threads might be a better solution.

An rc.conf exemple of how to use this new feature:
nut_upslog_flags="-p /var/db/nut/upslog.pid -m ups1@localhost,/var/log/nut\
/ups1.log,/var/db/nut/ups1.pid -m ups1@localhost,/var/log/nut/ups2.log,/var\
/db/nut/ups2.pid"

Sending a TERM signal to the parent PID, kill `cat /var/db/nut/upslog.pid`,
will terminate the entire process tree.

This patch submitted upstream, is in the process of being refined and
accepted.

PR:		265963
Reported by:	vvd@unislabs.com

1 files changed, 166 insertions, 0 deletions

diff --git a/sysutils/nut/files/patch-clients_upslog.c b/sysutils/nut/files/patch-clients_upslog.c
new file mode 100644
index 000000000000..1602d8b65067
--- /dev/null
+++ b/sysutils/nut/files/patch-clients_upslog.c
@@ -0,0 +1,166 @@
+--- clients/upslog.c.orig	2022-08-26 15:25:00.233023000 -0700
++++ clients/upslog.c	2022-08-26 15:26:30.983822000 -0700
+@@ -32,6 +32,10 @@
+  */
+ 
+ #include "common.h"
++#include <signal.h>
++#include <unistd.h>
++#include <sys/types.h>
++#include <sys/wait.h>
+ #include "nut_platform.h"
+ #include "upsclient.h"
+ 
+@@ -41,17 +45,32 @@
+ #include "upslog.h"
+ 
+ 	static	int	reopen_flag = 0, exit_flag = 0;
++	static	int	wait_status;
+ 	static	uint16_t	port;
+ 	static	char	*upsname, *hostname;
+ 	static	UPSCONN_t	ups;
+ 
+ 	static	FILE	*logfile;
+-	static	const	char *logfn, *monhost;
++	static	char *logfn, *monhost;
+ 	static	sigset_t	nut_upslog_sigmask;
+ 	static	char	logbuffer[LARGEBUF], *logformat;
+ 
+ 	static	flist_t	*fhead = NULL;
++	struct 	monhost_child {
++		char	*monhost;
++		char	*logfn;
++		char	*pidfilebase;
++		pid_t	pid;
++		struct	monhost_child	*next;
++	};
++	static	struct	monhost_child *monhost_child_anchor = NULL;
++	static	struct	monhost_child *monhost_child_current = NULL;
++	static	struct	monhost_child *monhost_child_prev = NULL;
++	static	struct	sigaction upslog_sigaction;
++	static	int	trapped_signals[] = { SIGHUP, SIGINT, SIGTERM, SIGCHLD };
++	static	pid_t	daemon_pid;
+ 
++
+ #define DEFAULT_LOGFORMAT "%TIME @Y@m@d @H@M@S% %VAR battery.charge% " \
+ 		"%VAR input.voltage% %VAR ups.load% [%VAR ups.status%] " \
+ 		"%VAR ups.temperature% %VAR input.frequency%"
+@@ -131,6 +150,8 @@
+ 	printf("  -p <pidbase>  - Base name for PID file (defaults to \"%s\")\n", prog);
+ 	printf("  -s <ups>	- Monitor UPS <ups> - <upsname>@<host>[:<port>]\n");
+ 	printf("        	- Example: -s myups@server\n");
++	printf("  -m <tuple>	- Monitor UPS <ups,logfile,pidfile>,\n");
++	printf("		- Example: -m myups@server,/var/log/myups.log,/var/run/myups.pid\n");
+ 	printf("  -u <user>	- Switch to <user> if started as root\n");
+ 
+ 	printf("\n");
+@@ -393,9 +414,25 @@
+ 	 * -u <username>
+ 	 */
+ 
++static void term_handler(int signo)
++{
++	if (signo != SIGCHLD && monhost_child_anchor != NULL) {
++		for (monhost_child_current = monhost_child_anchor;
++		     monhost_child_current != NULL;
++		     monhost_child_current = monhost_child_current->next
++		) {
++			kill(monhost_child_current->pid, signo);
++		}
++
++		if (signo != SIGHUP)
++			fatalx(EXIT_FAILURE, "Killed by user");
++	}
++}
++
+ int main(int argc, char **argv)
+ {
+ 	int	interval = 30, i, foreground = -1;
++	size_t	monhost_len = 0, mh;
+ 	const char	*prog = xbasename(argv[0]);
+ 	time_t	now, nextpoll = 0;
+ 	const char	*user = NULL;
+@@ -407,7 +444,7 @@
+ 
+ 	printf("Network UPS Tools %s %s\n", prog, UPS_VERSION);
+ 
+-	while ((i = getopt(argc, argv, "+hs:l:i:f:u:Vp:FB")) != -1) {
++	while ((i = getopt(argc, argv, "+hs:l:i:f:u:Vp:FBm:")) != -1) {
+ 		switch(i) {
+ 			case 'h':
+ 				help(prog);
+@@ -415,6 +452,33 @@
+ 				break;
+ #endif
+ 
++			case 'm': { /* var scope */
++				char *m_arg, *s;
++
++				monhost_child_prev = monhost_child_current;
++				monhost_child_current = xmalloc(sizeof(struct monhost_child));
++				if (monhost_child_anchor == NULL)
++					monhost_child_anchor = monhost_child_current;
++				else
++					monhost_child_prev->next = monhost_child_current;
++				monhost_child_current->next = NULL;
++				monhost_len++;
++
++				/* Be sure to not mangle original optarg, nor rely on its longevity */
++				s = xstrdup(optarg);
++				m_arg = s;
++				monhost_child_current->monhost = xstrdup(strsep(&m_arg, ","));
++				if (!m_arg)
++					fatalx(EXIT_FAILURE, "Argument '-m upsspec,logfile,pidfile' requires exactly 3 components in the tuple");
++				monhost_child_current->logfn = xstrdup(strsep(&m_arg, ","));
++				if (!m_arg)
++					fatalx(EXIT_FAILURE, "Argument '-m upsspec,logfile,pidfile' requires exactly 3 components in the tuple");
++				monhost_child_current->pidfilebase = xstrdup(strsep(&m_arg, ","));
++				if (m_arg) /* Had a third comma - also unexpected! */
++					fatalx(EXIT_FAILURE, "Argument '-m upsspec,logfile,pidfile' requires exactly 3 components in the tuple");
++				free(s);
++				} /* var scope */
++				break;
+ 			case 's':
+ 				monhost = optarg;
+ 				break;
+@@ -477,6 +541,40 @@
+ 
+ 		for (i = 3; i < argc; i++)
+ 			snprintfcat(logformat, LARGEBUF, "%s ", argv[i]);
++	}
++
++	if (monhost_child_anchor != NULL) {
++		if (foreground > 0)
++			daemon_pid = 0;
++		else
++			daemon_pid = fork();
++		if (!daemon_pid) {
++			for (monhost_child_current = monhost_child_anchor;
++			     monhost_child_current != NULL;
++			     monhost_child_current = monhost_child_current->next) {
++				if ((monhost_child_current->pid = fork()) == 0) {
++					monhost = monhost_child_current->monhost;
++					logfn = monhost_child_current->logfn;
++					pidfilebase = monhost_child_current->pidfilebase;
++					foreground = 1;
++					break;
++				}
++			}
++			if (monhost_child_anchor->pid) {	/* parent */
++				for (mh = 0; mh < sizeof(trapped_signals)/sizeof(trapped_signals[0]); mh++) {
++					upslog_sigaction.sa_handler = &term_handler;
++					sigfillset(&upslog_sigaction.sa_mask);
++					upslog_sigaction.sa_flags = SA_NOCLDSTOP | SA_NOCLDWAIT;
++					sigaction(trapped_signals[mh], &upslog_sigaction, NULL);
++				}
++				become_user(get_user_pwent(user));
++				writepid(pidfilebase);
++				while(wait(&wait_status) > 0);
++				exit(EXIT_SUCCESS);
++			}
++		} else {
++			exit(EXIT_SUCCESS);
++		}
+ 	}
+ 
+ 	if (!monhost)