Make hrSWRunPath use argv[0], instead of p_comm. hrSWRunName is supposed

to be a descriptive name, where hrSWRunPath should give the full path to
the binary. While argv[0] can contain any of a simple binary name, the
full path, or a custom name given by the application itself, it gives us
the option to retrieve both pieces of information. This is also the
same distinction made by netsnmp.

This also keeps the default command column from top(1) and snmptop in
sync, and now allows for identical output in the column between `top -C`
and `snmptop -Cpa`

OK tb@

1 files changed, 52 insertions, 15 deletions

diff --git a/libexec/snmpd/snmpd_metrics/mib.c b/libexec/snmpd/snmpd_metrics/mib.c
index 8c3e8eb32bb..8a0f5eb061c 100644
--- a/libexec/snmpd/snmpd_metrics/mib.c
+++ b/libexec/snmpd/snmpd_metrics/mib.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mib.c,v 1.5 2023/10/24 18:16:05 martijn Exp $	*/
+/*	$OpenBSD: mib.c,v 1.6 2023/10/24 18:27:26 martijn Exp $	*/
 
 /*
  * Copyright (c) 2022 Martijn van Duren <martijn@openbsd.org>
@@ -108,7 +108,9 @@ int	 kinfo_proc_comp(const void *, const void *);
 int	 kinfo_proc(u_int32_t, struct kinfo_proc **);
 void	 kinfo_timer_cb(int, short, void *);
 void	 kinfo_proc_free(void);
-int	 kinfo_args(struct kinfo_proc *, char **);
+int	 kinfo_args(struct kinfo_proc *, char ***);
+int	 kinfo_path(struct kinfo_proc *, char **);
+int	 kinfo_parameters(struct kinfo_proc *, char **);
 
 /* IF-MIB */
 struct agentx_index *ifIdx;
@@ -675,13 +677,21 @@ mib_hrswrun(struct agentx_varbind *vb)
 
 	if (obj == hrSWRunIndex)
 		agentx_varbind_integer(vb, kinfo->p_pid);
-	else if (obj == hrSWRunName || obj == hrSWRunPath)
+	else if (obj == hrSWRunName)
 		agentx_varbind_string(vb, kinfo->p_comm);
-	else if (obj == hrSWRunID)
+ 	else if (obj == hrSWRunPath) {
+		if (kinfo_path(kinfo, &s) == -1) {
+			log_warn("kinfo_path");
+			agentx_varbind_error(vb);
+			return;
+		}
+		
+		agentx_varbind_string(vb, s);
+	} else if (obj == hrSWRunID)
 		agentx_varbind_oid(vb, AGENTX_OID(0, 0));
 	else if (obj == hrSWRunParameters) {
-		if (kinfo_args(kinfo, &s) == -1) {
-			log_warn("kinfo_args");
+		if (kinfo_parameters(kinfo, &s) == -1) {
+			log_warn("kinfo_parameters");
 			agentx_varbind_error(vb);
 			return;
 		}
@@ -824,25 +834,22 @@ kinfo_proc_free(void)
 }
 
 int
-kinfo_args(struct kinfo_proc *kinfo, char **s)
+kinfo_args(struct kinfo_proc *kinfo, char ***s)
 {
-	static char		 str[128];
 	static char		*buf = NULL;
 	static size_t		 buflen = 128;
 
 	int			 mib[] = { CTL_KERN, KERN_PROC_ARGS,
 				    kinfo->p_pid, KERN_PROC_ARGV };
-	char			*nbuf, **argv;
+	char			*nbuf;
 
+	*s = NULL;
 	if (buf == NULL) {
 		buf = malloc(buflen);
 		if (buf == NULL)
 			return (-1);
 	}
 
-	str[0] = '\0';
-	*s = str;
-
 	while (sysctl(mib, nitems(mib), buf, &buflen, NULL, 0) == -1) {
 		if (errno != ENOMEM) {
 			/* some errors are expected, dont get too upset */
@@ -857,11 +864,41 @@ kinfo_args(struct kinfo_proc *kinfo, char **s)
 		buflen += 128;
 	}
 
-	argv = (char **)buf;
-	if (argv[0] == NULL)
-		return (0);
+	*s = (char **)buf;
+	return (0);
+}
+
+int
+kinfo_path(struct kinfo_proc *kinfo, char **s)
+{
+	static char		 str[129];
+	char			**argv;
+
+	if (kinfo_args(kinfo, &argv) == -1)
+		return (-1);
+
+	str[0] = '\0';
+	*s = str;
+	if (argv != NULL && argv[0] != NULL)
+		strlcpy(str, argv[0], sizeof(str));
+	return (0);
+}
 
+int
+kinfo_parameters(struct kinfo_proc *kinfo, char **s)
+{
+	static char		 str[129];
+	char			**argv;
+
+	if (kinfo_args(kinfo, &argv) == -1)
+		return (-1);
+
+	str[0] = '\0';
+	*s = str;
+	if (argv == NULL || argv[0] == NULL)
+		return (0);
 	argv++;
+
 	while (*argv != NULL) {
 		strlcat(str, *argv, sizeof(str));
 		argv++;