From: Benjamin Gilbert <bgilbert@cs.cmu.edu>
Date: Tue, 3 Jun 2014 20:15:24 +0000 (-0400)
Subject: hddtemp: Lift 1024-byte response limit
X-Git-Tag: collectd-5.7.0~72^2~2
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=6bd86ee138ba0652f5d0a90b4744a0e34faf2066;p=collectd.git

hddtemp: Lift 1024-byte response limit

Dynamically scale the response buffer, up to a maximum of 1 MB.
---

diff --git a/src/hddtemp.c b/src/hddtemp.c
index 4840e14a..4e275dc8 100644
--- a/src/hddtemp.c
+++ b/src/hddtemp.c
@@ -40,6 +40,7 @@
 # include <netinet/in.h>
 # include <netinet/tcp.h>
 # include <libgen.h> /* for basename */
+# include <assert.h>
 
 #if HAVE_LINUX_MAJOR_H
 # include <linux/major.h>
@@ -47,6 +48,7 @@
 
 #define HDDTEMP_DEF_HOST "127.0.0.1"
 #define HDDTEMP_DEF_PORT "7634"
+#define HDDTEMP_MAX_RECV_BUF (1 << 20)
 
 static const char *config_keys[] =
 {
@@ -81,11 +83,15 @@ static char hddtemp_port[16];
  *  we need to create a new socket each time. Is there another way?
  *  Hm, maybe we can re-use the `sockaddr' structure? -octo
  */
-static int hddtemp_query_daemon (char *buffer, int buffer_size)
+static char *hddtemp_query_daemon (void)
 {
 	int fd;
 	ssize_t status;
+
+	char *buffer;
+	int buffer_size;
 	int buffer_fill;
+	char *new_buffer;
 
 	const char *host;
 	const char *port;
@@ -116,7 +122,7 @@ static int hddtemp_query_daemon (char *buffer, int buffer_size)
 				(ai_return == EAI_SYSTEM)
 				? sstrerror (errno, errbuf, sizeof (errbuf))
 				: gai_strerror (ai_return));
-		return (-1);
+		return (NULL);
 	}
 
 	fd = -1;
@@ -156,16 +162,41 @@ static int hddtemp_query_daemon (char *buffer, int buffer_size)
 	if (fd < 0)
 	{
 		ERROR ("hddtemp plugin: Could not connect to daemon.");
-		return (-1);
+		return (NULL);
 	}
 
 	/* receive data from the hddtemp daemon */
-	memset (buffer, '\0', buffer_size);
-
+	buffer = NULL;
+	buffer_size = 0;
 	buffer_fill = 0;
-	while ((status = read (fd, buffer + buffer_fill, buffer_size - buffer_fill)) != 0)
+	while (1)
 	{
-		if (status == -1)
+		if (buffer_fill >= buffer_size - 1)
+		{
+			if (buffer_size == 0)
+				buffer_size = 1024;
+			else
+				buffer_size *= 2;
+			if (buffer_size > HDDTEMP_MAX_RECV_BUF)
+			{
+				WARNING ("hddtemp plugin: Message from hddtemp has been "
+						"truncated.");
+				break;
+			}
+			new_buffer = realloc (buffer, buffer_size);
+			if (new_buffer == NULL) {
+				close (fd);
+				free (buffer);
+				ERROR ("hddtemp plugin: Allocation failed.");
+				return (NULL);
+			}
+			buffer = new_buffer;
+		}
+		status = read (fd, buffer + buffer_fill, buffer_size - buffer_fill - 1);
+		if (status == 0) {
+			break;
+		}
+		else if (status == -1)
 		{
 			char errbuf[1024];
 
@@ -175,30 +206,25 @@ static int hddtemp_query_daemon (char *buffer, int buffer_size)
 			ERROR ("hddtemp plugin: Error reading from socket: %s",
 					sstrerror (errno, errbuf, sizeof (errbuf)));
 			close (fd);
-			return (-1);
+			free (buffer);
+			return (NULL);
 		}
 		buffer_fill += status;
-
-		if (buffer_fill >= buffer_size)
-			break;
 	}
 
-	if (buffer_fill >= buffer_size)
-	{
-		buffer[buffer_size - 1] = '\0';
-		WARNING ("hddtemp plugin: Message from hddtemp has been "
-				"truncated.");
-	}
-	else if (buffer_fill == 0)
+	if (buffer_fill == 0)
 	{
 		WARNING ("hddtemp plugin: Peer has unexpectedly shut down "
 				"the socket. Buffer: `%s'", buffer);
 		close (fd);
-		return (-1);
+		free (buffer);
+		return (NULL);
 	}
 
+	assert (buffer_fill < buffer_size);
+	buffer[buffer_fill] = '\0';
 	close (fd);
-	return (0);
+	return (buffer);
 }
 
 static int hddtemp_config (const char *key, const char *value)
@@ -242,7 +268,7 @@ static void hddtemp_submit (char *type_instance, double value)
 
 static int hddtemp_read (void)
 {
-	char buf[1024];
+	char *buf;
 	char *ptr;
 	char *saveptr;
 	char *name;
@@ -251,7 +277,8 @@ static int hddtemp_read (void)
 	char *mode;
 
 	/* get data from daemon */
-	if (hddtemp_query_daemon (buf, sizeof (buf)) < 0)
+	buf = hddtemp_query_daemon ();
+	if (buf == NULL)
 		return (-1);
 
 	/* NB: strtok_r will eat up "||" and leading "|"'s */
@@ -280,6 +307,7 @@ static int hddtemp_read (void)
 		hddtemp_submit (name, temperature_value);
 	}
 	
+	free (buf);
 	return (0);
 } /* int hddtemp_read */