PR 9871 (partial) fix. Removed some embedded-C in ioblock.stp/vfs.stp.

* tapset/dev.stp: Added a bdevname() script function.
* tapset/ioblock.stp: Rewrote the embedded-C devname function to just use
  bdevname() script function.
* tapset/vfs.stp: Removed embedded-C __bdevname() C function.  Calls
  bdevname() script function instead.
* tapset/string.stp: Added isdigit() function.

4 files changed, 42 insertions, 29 deletions

diff --git a/tapset/dev.stp b/tapset/dev.stp
index 80449324..2c22031a 100644
--- a/tapset/dev.stp
+++ b/tapset/dev.stp
@@ -1,5 +1,5 @@
-// Device numbering tapset
-// Copyright (C) 2008 Red Hat Corp.
+// Device tapset
+// Copyright (C) 2008, 2010 Red Hat Corp.
 //
 // This file is part of systemtap, and is free software.  You can
 // redistribute it and/or modify it under the terms of the GNU General
@@ -31,3 +31,25 @@ function usrdev2kerndev:long(dev:long)
 %{ /* pure */
     THIS->__retvalue = new_decode_dev(THIS->dev);
 %}
+
+function bdevname:string(bdev:long)
+{
+	if (bdev == 0)
+		return "N/A"
+
+	hd = @cast(bdev, "block_device")->bd_disk
+
+	if (@cast(bdev, "block_device")->bd_part)
+		partno = @cast(bdev, "block_device")->bd_part->partno
+	else
+		partno = MINOR(@cast(bdev, "block_device")->bd_dev)
+			- @cast(bdev, "block_device")->bd_disk->first_minor;
+
+	if (!partno)
+		return kernel_string(@cast(hd, "gendisk")->disk_name)
+	disk_name = kernel_string(@cast(hd, "gendisk")->disk_name)
+	if (isdigit(substr(disk_name, strlen(disk_name) - 1, 1)))
+		return sprintf("%sp%d", disk_name, partno)
+	else
+		return sprintf("%s%d", disk_name, partno)
+}
diff --git a/tapset/ioblock.stp b/tapset/ioblock.stp
index 761e7df7..6376ac23 100644
--- a/tapset/ioblock.stp
+++ b/tapset/ioblock.stp
@@ -62,18 +62,9 @@ function __bio_start_sect:long(bio:long)
 
 /* returns the block device name */
 function __bio_devname:string(bio:long)
-%{ /* pure */
-    char b[BDEVNAME_SIZE];
-    struct bio *bio = (struct bio *)(long)THIS->bio;
-    struct block_device *bdev = kread(&(bio->bi_bdev));
-	if (bdev == NULL) {
-		strlcpy(THIS->__retvalue, "N/A", MAXSTRINGLEN);
-	} else {
-		const char *name = bdevname(bdev, b); /* FIXME: deref hazard! */
-		deref_string(THIS->__retvalue, name, MAXSTRINGLEN);
-	}
-	CATCH_DEREF_FAULT();
-%}
+{
+    return bdevname(@cast(bio, "bio")->bi_bdev)
+}
 
 global BIO_READ = 0, BIO_WRITE = 1
 
diff --git a/tapset/string.stp b/tapset/string.stp
index d03e5570..9f2c150d 100644
--- a/tapset/string.stp
+++ b/tapset/string.stp
@@ -164,3 +164,17 @@ function strtol:long(str:string, base:long)
 %{ /* pure */ /* unprivileged */
 	THIS->__retvalue = simple_strtol(THIS->str, NULL, THIS->base);
 %}
+
+/**
+ * sfunction isdigit - Checks for a digit.
+ * @str: String to check.
+ *
+ * Description: Checks for a digit (0 through 9) as the first
+ * character of a string.  Returns non-zero if true, and a zero if
+ * false.
+ */
+function isdigit:long(str:string)
+%{ /* pure */ /* unprivileged */
+	THIS->__retvalue = isdigit(THIS->str[0]);
+%}
+
diff --git a/tapset/vfs.stp b/tapset/vfs.stp
index 5a38a924..cd5365f0 100644
--- a/tapset/vfs.stp
+++ b/tapset/vfs.stp
@@ -16,20 +16,6 @@
 
 /* generic vfs probes */
 
-/* helper functions */
-function __bdevname:string (bdev:long) %{ /* pure */
-	char b[BDEVNAME_SIZE];
-	struct block_device *bdev = (struct block_device *)(long)THIS->bdev;
-	if (bdev == NULL) {
-		strlcpy(THIS->__retvalue, "N/A", MAXSTRINGLEN);
-	} else {
-		const char *name = bdevname(bdev, b); /* FIXME: deref hazard! */
-		deref_string(THIS->__retvalue, name, MAXSTRINGLEN);
-	}
-
-	CATCH_DEREF_FAULT();
-%}
-
 /*
   We don't want to have to do a bdevname() call every time
   we want a devname, so we'll hash them here.
@@ -42,7 +28,7 @@ function __find_bdevname:string(dev:long, bdev:long)
 	if (dev in __devnames)
 		return __devnames[dev]
 	else
-		return __devnames[dev] = __bdevname(bdev)
+		return __devnames[dev] = bdevname(bdev)
 }
 
 function ppos_pos:long (ppos:long) %{ /* pure */