[master] 44ddf0360 mgt: Make an attempt to raise RLIMIT_MEMLOCK to infinity, set soft limit

[Nils Goroll]

commit 44ddf036003e30fc4046038eabf95e30b7410fd2
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Mon Sep 23 16:55:20 2024 +0200

    mgt: Make an attempt to raise RLIMIT_MEMLOCK to infinity, set soft limit
    
    Try to raise the hard limit to infinity, then use as the soft (current) limit
    whatever the hard (max) limit is.
    
    Motivated by #4193

diff --git a/bin/varnishd/mgt/mgt_main.c b/bin/varnishd/mgt/mgt_main.c
index 1b8e49f27..4edc1f0a3 100644
--- a/bin/varnishd/mgt/mgt_main.c
+++ b/bin/varnishd/mgt/mgt_main.c
@@ -42,6 +42,7 @@
 #include <string.h>
 #include <syslog.h>
 #include <unistd.h>
+#include <sys/resource.h>
 #include <sys/stat.h>
 #include <sys/socket.h>
 
@@ -636,6 +637,7 @@ main(int argc, char * const *argv)
 	pid_t pid;
 	struct arg_list *alp;
 	int first_arg = 1;
+	struct rlimit rlim;
 
 	if (argc == 2 && !strcmp(argv[1], "--optstring")) {
 		printf("%s\n", opt_spec);
@@ -873,6 +875,14 @@ main(int argc, char * const *argv)
 		    workdir, VAS_errtxt(errno));
 
 	VJ_master(JAIL_MASTER_SYSTEM);
+	/* try to raise to max (ignore error), then set _cur to whatever we got */
+	rlim.rlim_cur = 0;
+	rlim.rlim_max = RLIM_INFINITY;
+	(void)setrlimit(RLIMIT_MEMLOCK, &rlim);
+	AZ(getrlimit(RLIMIT_MEMLOCK, &rlim));
+	rlim.rlim_cur = rlim.rlim_max;
+	AZ(setrlimit(RLIMIT_MEMLOCK, &rlim));
+
 	AZ(system("rm -rf vmod_cache vext_cache worker_tmpdir"));
 	VJ_master(JAIL_MASTER_LOW);