Add netns configuration for /etc/atoprc

The default rule is splitting netns by blank space.
And make sure the netns path exits.

Signed-off-by: Fei Li <[email protected]>

Author: ShirleyFei

atop.c

@@ -254,6 +254,7 @@ static struct {
 	{	"atopsarflags",		do_atopsarflags,	0, },
 	{	"perfevents",		do_perfevents,		0, },
 	{	"pacctdir",		do_pacctdir,		1, },
+	{	"netns",		do_netns,		1, },
 };
 
 /*

photosyst.c

@@ -3120,3 +3120,36 @@ int getothernetns(struct shmbuf *shmp) {
 
 	exit(0);
 }
+
+void
+do_netns(char *name, char *val)
+{
+	char *pernetns, *validnetns;
+	int ns = 0;
+	struct stat nsstat;
+
+	if ( strlen(val) == 0 )
+		return;
+
+	validnetns = malloc( (MAXNETNS - 1) * NETNSNAMELEN * sizeof(char) );
+	strncpy(validnetns, val, (MAXNETNS - 1) * NETNSNAMELEN);
+
+	/* split netns by blank space */
+	pernetns = strtok(validnetns, " ");
+	while (pernetns)
+	{
+		/* valid if this file exits, and later setns() will prove the netns is available */
+		if ( stat(pernetns, &nsstat) )
+		{
+			fprintf(stderr, "netns %s stat failed, errno is %d\n", pernetns, errno);
+			pernetns = strtok(NULL, " ");
+			continue;
+		}
+
+		strncpy(othernetns[ns], pernetns, sizeof(othernetns[ns]));
+		if (++ns >= MAXNETNS - 1)
+			break;
+		pernetns = strtok(NULL, " ");
+	}
+	free(validnetns);
+}

photosyst.h

@@ -468,6 +468,7 @@ void	photosyst (struct sstat *);
 void	deviatsyst(struct sstat *, struct sstat *, struct sstat *, long);
 void	totalsyst (char,           struct sstat *, struct sstat *);
 void	do_perfevents(char *, char *);
+void	do_netns(char *, char *);
 
 #define	PHYNETMAX	8
 struct snmp {