Seed random() on startup from /dev/urandom so vtmpfile actually

returns random file names

bin/varnishd/varnishd.c

@@ -364,6 +364,8 @@ main(int argc, char * const *argv)
 	for (o = getdtablesize(); o > STDERR_FILENO; o--)
 		(void)close(o);
 
+	AZ(seed_random());
+
 	mgt_got_fd(STDERR_FILENO);
 
 	setbuf(stdout, NULL);

include/libvarnish.h

@@ -99,6 +99,7 @@ struct timeval TIM_timeval(double t);
 void VCS_Message(const char *);
 
 /* from libvarnish/vtmpfile.c */
+int seed_random(void);
 int vtmpfile(char *);
 char *vreadfile(const char *pfx, const char *fn, ssize_t *sz);
 char *vreadfd(int fd, ssize_t *sz);

lib/libvarnish/vtmpfile.c

@@ -40,6 +40,22 @@
 
 #include "libvarnish.h"
 
+int
+seed_random(void)
+{
+	int fd;
+	unsigned seed;
+
+	fd = open("/dev/urandom", O_RDONLY);
+	if (fd == -1)
+		return (1);
+	if (read(fd, &seed, sizeof seed) != sizeof seed)
+		return (1);
+	(void)close(fd);
+	srandom(seed);
+	return (0);
+}
+
 int
 vtmpfile(char *template)
 {