From: Bostjan Skufca <bostjan@a2o.si>
Date: Fri, 2 Sep 2011 00:35:38 +0000 (-0400)
Subject: irq plugin: Implement collection of non-numeric interrupts.
X-Git-Tag: collectd-4.10.4~5
X-Git-Url: https://git.tokkee.org/?p=collectd.git;a=commitdiff_plain;h=66bdee8d4c974e893826335977e1cc52410380eb

irq plugin: Implement collection of non-numeric interrupts.

Hi all!

I've created a patch that enables collectd to collect all irqs present in
/proc/interrupts, with numeric and string names (NMI, LOC, RES, etc).

Two notices:
a) Unfortunately I was unable to build collectd from git repo (build.sh
   failures), therefore I created this patch for latest stable release: 4.10.1
b) I am fairly unexperienced in C programming, so please inform me gently of my
   mistakes:) But I am already using a patched version and it works fine.

Any feedback on code quality or recommendations are welcome.

Change-Id: Ia17bd953921051dfe53e838b76672adbef9e73c3
Signed-off-by: Florian Forster <octo@collectd.org>
---

diff --git a/src/irq.c b/src/irq.c
index 401cc6f9..70d6b5ab 100644
--- a/src/irq.c
+++ b/src/irq.c
@@ -29,8 +29,6 @@
 # error "No applicable input method."
 #endif
 
-#define BUFSIZE 128
-
 /*
  * (Module-)Global variables
  */
@@ -41,8 +39,8 @@ static const char *config_keys[] =
 };
 static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
 
-static unsigned int *irq_list;
-static unsigned int irq_list_num;
+static char         **irq_list;
+static unsigned int   irq_list_num = 0;
 
 /* 
  * irq_list_action:
@@ -55,11 +53,9 @@ static int irq_config (const char *key, const char *value)
 {
 	if (strcasecmp (key, "Irq") == 0)
 	{
-		unsigned int *temp;
-		unsigned int irq;
-		char *endptr;
+		char **temp;
 
-		temp = (unsigned int *) realloc (irq_list, (irq_list_num + 1) * sizeof (unsigned int *));
+		temp = realloc (irq_list, (irq_list_num + 1) * sizeof (*irq_list));
 		if (temp == NULL)
 		{
 			fprintf (stderr, "irq plugin: Cannot allocate more memory.\n");
@@ -68,19 +64,13 @@ static int irq_config (const char *key, const char *value)
 		}
 		irq_list = temp;
 
-		/* Clear errno, because we need it to see if an error occured. */
-		errno = 0;
-
-		irq = strtol(value, &endptr, 10);
-		if ((endptr == value) || (errno != 0))
+		irq_list[irq_list_num] = strdup (value);
+		if (irq_list[irq_list_num] == NULL)
 		{
-			fprintf (stderr, "irq plugin: Irq value is not a "
-					"number: `%s'\n", value);
-			ERROR ("irq plugin: Irq value is not a "
-					"number: `%s'", value);
+			ERROR ("irq plugin: strdup(3) failed.");
 			return (1);
 		}
-		irq_list[irq_list_num] = irq;
+
 		irq_list_num++;
 	}
 	else if (strcasecmp (key, "IgnoreSelected") == 0)
@@ -102,27 +92,26 @@ static int irq_config (const char *key, const char *value)
  * both, `submit' and `write' to give client and server the ability to
  * ignore certain stuff..
  */
-static int check_ignore_irq (const unsigned int irq)
+static int check_ignore_irq (const char *irq)
 {
-	int i;
+	unsigned int i;
 
 	if (irq_list_num < 1)
 		return (0);
 
-	for (i = 0; (unsigned int)i < irq_list_num; i++)
-		if (irq == irq_list[i])
+	for (i = 0; i < irq_list_num; i++)
+		if (strcmp (irq, irq_list[i]) == 0)
 			return (irq_list_action);
 
 	return (1 - irq_list_action);
 }
 
-static void irq_submit (unsigned int irq, counter_t value)
+static void irq_submit (const char *irq_name, counter_t value)
 {
 	value_t values[1];
 	value_list_t vl = VALUE_LIST_INIT;
-	int status;
 
-	if (check_ignore_irq (irq))
+	if (check_ignore_irq (irq_name))
 		return;
 
 	values[0].counter = value;
@@ -132,23 +121,15 @@ static void irq_submit (unsigned int irq, counter_t value)
 	sstrncpy (vl.host, hostname_g, sizeof (vl.host));
 	sstrncpy (vl.plugin, "irq", sizeof (vl.plugin));
 	sstrncpy (vl.type, "irq", sizeof (vl.type));
-
-	status = ssnprintf (vl.type_instance, sizeof (vl.type_instance),
-			"%u", irq);
-	if ((status < 1) || ((unsigned int)status >= sizeof (vl.type_instance)))
-		return;
+	sstrncpy (vl.type_instance, irq_name, sizeof (vl.type_instance));
 
 	plugin_dispatch_values (&vl);
 } /* void irq_submit */
 
 static int irq_read (void)
 {
-#undef BUFSIZE
-#define BUFSIZE 256
-
 	FILE *fh;
-	char buffer[BUFSIZE];
-	unsigned int irq;
+	char buffer[1024];
 	unsigned long long irq_value;
 	unsigned long long value;
 	char *endptr;
@@ -164,32 +145,48 @@ static int irq_read (void)
 				sstrerror (errno, errbuf, sizeof (errbuf)));
 		return (-1);
 	}
-	while (fgets (buffer, BUFSIZE, fh) != NULL)
+	while (fgets (buffer, sizeof (buffer), fh) != NULL)
 	{
+		char *irq_name;
+		size_t irq_name_len;
+
 		fields_num = strsplit (buffer, fields, 64);
 		if (fields_num < 2)
 			continue;
 
-		errno = 0;    /* To distinguish success/failure after call */
-		irq = strtol (fields[0], &endptr, 10);
+		irq_name = fields[0];
+		irq_name_len = strlen (irq_name);
+		if (irq_name_len < 2)
+			continue;
 
-		if ((endptr == fields[0]) || (errno != 0) || (*endptr != ':'))
+		/* Check if irq name ends with colon.
+		 * Otherwise it's a header. */
+		if (irq_name[irq_name_len - 1] != ':')
 			continue;
 
+		irq_name[irq_name_len - 1] = 0;
+		irq_name_len--;
+
 		irq_value = 0;
 		for (i = 1; i < fields_num; i++)
 		{
 			errno = 0;
+			endptr = NULL;
 			value = strtoull (fields[i], &endptr, 10);
 
-			if ((*endptr != '\0') || (errno != 0))
+			/* Ignore all fields following a non-numeric field. */
+			if ((errno != 0) || (endptr == NULL) || (*endptr != 0))
 				break;
 
 			irq_value += value;
 		} /* for (i) */
 
+		/* No valid fields -> do not submit anything. */
+		if (i <= 1)
+			continue;
+
 		/* Force 32bit wrap-around */
-		irq_submit (irq, irq_value % 4294967296ULL);
+		irq_submit (irq_name, irq_value % 4294967296ULL);
 	}
 
 	fclose (fh);
@@ -203,5 +200,3 @@ void module_register (void)
 			config_keys, config_keys_num);
 	plugin_register_read ("irq", irq_read);
 } /* void module_register */
-
-#undef BUFSIZE