iostat didn't display target device information when a symbolic

link was specified as a parameter. This is now fixed.

Mail from Peter Schiffer <pschiffe@redhat.com> 30/01/2012

Hello Sebastien,

my name is Peter Schiffer and I am a new maintainer of sysstat package in RHEL and Fedora.

We have found the following issue:
iostat does not display target device information when a symbolic link is specified as a parameter

example:
Linux 2.6.32-202.el6.x86_64 (localhost.localdomain)     11/30/11  _x86_64_        (16 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
                   0.04      0.00         0.05       0.04      0.00   99.87

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn

I am proposing one solution how this could be fixed. What is your opinion about it?

Thanks,

peter

symlinks.patch

diff -upr sysstat-10.0.3.old/common.c sysstat-10.0.3/common.c
--- sysstat-10.0.3.old/common.c	2011-11-20 16:38:04.000000000 +0100
+++ sysstat-10.0.3/common.c	2012-01-30 15:54:28.856597845 +0100
@@ -379,10 +379,10 @@ int get_win_height(void)

 /*
  ***************************************************************************
- * Remove /dev from path name.
+ * Canonicalize and remove /dev from path name.
  *
  * IN:
- * @name	Device name (may begins with "/dev/")
+ * @name	Device name (may begins with "/dev/" or can be a symlink)
  *
  * RETURNS:
  * Device basename.
@@ -390,10 +390,33 @@ int get_win_height(void)
  */
 char *device_name(char *name)
 {
-	if (!strncmp(name, "/dev/", 5))
-		return name + 5;
+	char *out;
+	char *resolved_name;

-	return name;
+	/* realpath() creates new string, so we need to free it later. */
+	resolved_name = realpath(name, 0);
+
+	/* If path doesn't exists, just copy the input and return it. We have to
+	   copy because result of this function is always freed. */
+	if (!resolved_name) {
+		out = (char *)calloc(1, sizeof(name));
+		strncpy(out, name, sizeof(name));
+
+		return out;
+	}
+
+	/* We need to copy the path without "/dev/" prefix because we cannot free
+	   'resolved_name + 5' string. */
+	if (!strncmp(resolved_name, "/dev/", 5)) {
+		out = (char *)calloc(1, sizeof(resolved_name) - 4);
+		strncpy(out, resolved_name + 5, sizeof(resolved_name) - 4);
+
+		free(resolved_name);
+
+		return out;
+	}
+
+	return resolved_name;
 }

 /*
diff -upr sysstat-10.0.3.old/iostat.c sysstat-10.0.3/iostat.c
--- sysstat-10.0.3.old/iostat.c	2011-11-20 16:38:04.000000000 +0100
+++ sysstat-10.0.3/iostat.c	2012-01-30 15:57:41.551553692 +0100
@@ -274,6 +274,8 @@ int update_dev_list(int *dlist_idx, char
 		strncpy(sdli->dev_name, device_name, MAX_NAME_LEN - 1);
 	}

+	free(device_name);
+
 	return i;
 }

diff --git a/CHANGES b/CHANGES
index 66f81abb6b2dea352136bfc44bf1048a986626e8..f7183d68dd875f84c4b1b0e71145be0b6eac0512 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,9 @@ Changes:
 xxxx/xx/xx: Version 10.0.4 - Sebastien Godard (sysstat <at> orange.fr)
        * [Andrey Borzenkov]: Don't take virtual devices into account in
          sar -b results.
+       * [Peter Schiffer]: iostat didn't display target device
+         information when a symbolic link was specified as a parameter.
+         This is now fixed.
        * configure script updated: Added --disable-stripping option.
          Using this option tells configure to NOT strip object files.
        * FAQ updated.

diff --git a/CREDITS b/CREDITS
index 918a943a1848effb565e5f42d3bebe980d32e60c..383b66daf379b37b7a4094e1094ce1f5f5ad5fac 100644 (file)
--- a/CREDITS
+++ b/CREDITS
@@ -198,6 +198,7 @@ I would also thank the following people for their hints or bug reports
        Tan Shao Yi <tansy@tan[...].org>
        Yibin Shen <zituan@taobao.com>
        Lee Schermerhorn <lee.schermerhorn@hp.[...].com>
+       Peter Schiffer <pschiffe@red[...].com>
        Benno Schulenberg <bensberg@jus[...].net>
        Michel Simoni <m_simoni@clu[...].fr>
        Gabrielle Singleton <gelle@umi[...].edu>

diff --git a/common.c b/common.c
index dad20c6a85c2fbd4ec4a916a2fd3748456511939..2e3aa7072531d9129af342f970dbd08b87f3f77e 100644 (file)
--- a/common.c
+++ b/common.c
@@ -1,6 +1,6 @@
 /*
  * sar, sadc, sadf, mpstat and iostat 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 *
@@ -379,10 +379,10 @@ int get_win_height(void)
 
 /*
  ***************************************************************************
- * Remove /dev from path name.
+ * Canonicalize and remove /dev from path name.
  *
  * IN:
- * @name       Device name (may begins with "/dev/")
+ * @name       Device name (may begin with "/dev/" or can be a symlink).
  *
  * RETURNS:
  * Device basename.
@@ -390,10 +390,27 @@ int get_win_height(void)
  */
 char *device_name(char *name)
 {
-       if (!strncmp(name, "/dev/", 5))
-               return name + 5;
+       static char out[MAX_FILE_LEN];
+       char *resolved_name;
+       int i = 0;
 
-       return name;
+       /* realpath() creates new string, so we need to free it later */
+       resolved_name = realpath(name, NULL);
+
+       /* If path doesn't exist, just return input */
+       if (!resolved_name) {
+               return name;
+       }
+
+       if (!strncmp(resolved_name, "/dev/", 5)) {
+               i = 5;
+       }
+       strncpy(out, resolved_name + i, MAX_FILE_LEN);
+       out[MAX_FILE_LEN - 1] = '\0';
+
+       free(resolved_name);
+               
+       return out;
 }
 
 /*