[svn-commits] sruffell: linux/trunk r6675 - /linux/trunk/drivers/dahdi/dahdi-base.c

[SVN commits to the Digium repositories]

Author: sruffell
Date: Thu Jun  4 16:14:53 2009
New Revision: 6675

URL: http://svn.asterisk.org/svn-view/dahdi?view=rev&rev=6675
Log:
dahdi-base: Fix bug in procfs handling.

Fix bug in procfs handling where it was possible to get a warning in
lib/vsprintf.c when reading from /proc/dahdi/x.

Patch by: biohumanoid
(closes issue #15252)

Modified:
    linux/trunk/drivers/dahdi/dahdi-base.c

Modified: linux/trunk/drivers/dahdi/dahdi-base.c
URL: http://svn.asterisk.org/svn-view/dahdi/linux/trunk/drivers/dahdi/dahdi-base.c?view=diff&rev=6675&r1=6674&r2=6675
==============================================================================
--- linux/trunk/drivers/dahdi/dahdi-base.c (original)
+++ linux/trunk/drivers/dahdi/dahdi-base.c Thu Jun  4 16:14:53 2009
@@ -552,12 +552,16 @@
 
 static int dahdi_proc_read(char *page, char **start, off_t off, int count, int *eof, void *data)
 {
-	int x, len = 0;
+	int x, len = 0, real_count;
 	long span;
 
-	/* In Linux 2.6, this MUST NOT EXECEED 1024 bytes in one read! */
+	/* In Linux 2.6, page is always PROC_BLOCK_SIZE=(PAGE_SIZE-1024) bytes.
+	 * 0<count<=PROC_BLOCK_SIZE . count=1 will produce an error in
+	 * vsnprintf ('head -c 1 /proc/dahdi/1', 'dd bs=1').
+	 * An ugly hack. Good way: seq_printf (seq_file.c). */
+        real_count = count;
+	count = PAGE_SIZE-1024;
 	span = (long)data;
-
 	if (!span)
 		return 0;
 
@@ -678,10 +682,14 @@
 		/* stop if we've already generated enough */
 		if (len > off + count)
 			break;
-	}
+		/* stop if we're NEAR danger limit. let it be -128 bytes. */
+		if (len > count-128)
+			break;
+	}
+	count = real_count;
 	/* If everything printed so far is before beginning of request */
 	if (len <= off) {
-		off -= len;
+		off = 0;
 		len = 0;
 	}
 	*start = page + off;