From: Sebastien <seb@kluane.home>
Date: Sun, 1 Jul 2012 19:29:44 +0000 (+0200)
Subject: sar: Use /sys/dev/block/major:minor links to determine devices real name.
X-Git-Tag: v10.1.1~9
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c39b9ca0deac7799d4e6b5074905e280c5752b80;p=sysstat

sar: Use /sys/dev/block/major:minor links to determine devices real name.

Now use /sys/dev/block/major:minor links to determine devices real name.
This is used as the first option now, before using sysstat.ioconf
configuration file.

Mail from Peter Schiffer (pschiffe@redhat.com) 20/06/2012:

I am sending you a patch which is looking into
/sys/dev/block/major:minor link to determine the device name. This
should work for any device, but I let it as the last option when
determining devname. What do you think?
---

diff --git a/CHANGES b/CHANGES
index 685ed7d..2d10aee 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2,6 +2,8 @@ Changes:
 
 xxxx/xx/xx: Version 10.1.1 - Sebastien Godard (sysstat <at> orange.fr)
 	* Added option -[0-9]* to sar to show data of that days ago.
+	* [Peter Schiffer]: sar: Use /sys/dev/block/major:minor links
+	  to determine devices real name.
 
 2012/05/16: Version 10.0.5 - Sebastien Godard (sysstat <at> orange.fr)
 	* [Alain Chereau]: Options -g and -T added to iostat. These
diff --git a/common.h b/common.h
index 283cd3f..b70ea66 100644
--- a/common.h
+++ b/common.h
@@ -54,6 +54,7 @@
 #define INTERRUPTS		"/proc/interrupts"
 #define MEMINFO			"/proc/meminfo"
 #define SYSFS_BLOCK		"/sys/block"
+#define SYSFS_DEV_BLOCK		"/sys/dev/block"
 #define SYSFS_DEVCPU		"/sys/devices/system/cpu"
 #define SYSFS_TIME_IN_STATE	"cpufreq/stats/time_in_state"
 #define S_STAT			"stat"
diff --git a/sa_common.c b/sa_common.c
index 925b93e..18a08f9 100644
--- a/sa_common.c
+++ b/sa_common.c
@@ -1,6 +1,6 @@
 /*
  * sar and sadf common routines.
- * (C) 1999-2011 by Sebastien GODARD (sysstat <at> orange.fr)
+ * (C) 1999-2012 by Sebastien GODARD (sysstat <at> orange.fr)
  *
  ***************************************************************************
  * This program is free software; you can redistribute it and/or modify it *
@@ -27,6 +27,7 @@
 #include <unistd.h>	/* For STDOUT_FILENO, among others */
 #include <dirent.h>
 #include <fcntl.h>
+#include <libgen.h>
 #include <sys/types.h>
 #include <sys/ioctl.h>
 
@@ -111,6 +112,44 @@ void free_structures(struct activity *act[])
 	}
 }
 
+/*
+  ***************************************************************************
+  * Try to get device real name from sysfs tree.
+  * 
+  * IN:
+  * @major	Major number of the device.
+  * @minor	Minor number of the device.
+  *
+  * RETURNS:
+  * The name of the device, which may be the real name (as it appears in /dev)
+  * or NULL.
+  ***************************************************************************
+  */
+char *get_devname_from_sysfs(unsigned int major, unsigned int minor)
+{
+	static char link[32], target[PATH_MAX];
+	char *devname;
+	ssize_t r;
+
+	snprintf(link, 32, "%s/%d:%d", SYSFS_DEV_BLOCK, major, minor);
+
+	/* Get full path to device knowing its major and minor numbers */
+	r = readlink(link, target, PATH_MAX);
+	if (r <= 0 || r >= PATH_MAX) {
+		return (NULL);
+	}
+
+	target[r] = '\0';
+
+	/* Get device name */
+	devname = basename(target);
+	if (!devname || strnlen(devname, FILENAME_MAX) == 0) {
+		return (NULL);
+	}
+
+	return (devname);
+}
+
 /*
  ***************************************************************************
  * Get device real name if possible.
@@ -138,11 +177,15 @@ char *get_devname(unsigned int major, unsigned int minor, int pretty)
 	if (!pretty)
 		return (buf);
 
+	name = get_devname_from_sysfs(major, minor);
+	if (name != NULL)
+		return (name);
+	
 	name = ioc_name(major, minor);
-	if ((name == NULL) || !strcmp(name, K_NODEV))
-		return (buf);
+	if ((name != NULL) && strcmp(name, K_NODEV))
+		return (name);
 
-	return (name);
+	return (buf);
 }
 
 /*