[PATCH] OProfile: allow normal user to trigger sample dumps

From: John Levon <levon@movementarian.org>

In 2.4, OProfile allowed normal users to trigger sample dumps (useful under
low sample load).  The patch below, by Will Cohen, allows this for 2.6 too.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/oprofile/oprofile_files.c

@@ -90,7 +90,7 @@ static struct file_operations dump_fops = {
 void oprofile_create_files(struct super_block * sb, struct dentry * root)
 {
 	oprofilefs_create_file(sb, root, "enable", &enable_fops);
-	oprofilefs_create_file(sb, root, "dump", &dump_fops);
+	oprofilefs_create_file_perm(sb, root, "dump", &dump_fops, 0666);
 	oprofilefs_create_file(sb, root, "buffer", &event_buffer_fops);
 	oprofilefs_create_ulong(sb, root, "buffer_size", &fs_buffer_size);
 	oprofilefs_create_ulong(sb, root, "buffer_watershed", &fs_buffer_watershed);

drivers/oprofile/oprofilefs.c

@@ -165,7 +165,8 @@ static struct file_operations ulong_ro_fops = {
 
 
 static struct dentry * __oprofilefs_create_file(struct super_block * sb,
-	struct dentry * root, char const * name, struct file_operations * fops)
+	struct dentry * root, char const * name, struct file_operations * fops,
+	int perm)
 {
 	struct dentry * dentry;
 	struct inode * inode;
@@ -176,7 +177,7 @@ static struct dentry * __oprofilefs_create_file(struct super_block * sb,
 	dentry = d_alloc(root, &qname);
 	if (!dentry)
 		return 0;
-	inode = oprofilefs_get_inode(sb, S_IFREG | 0644);
+	inode = oprofilefs_get_inode(sb, S_IFREG | perm);
 	if (!inode) {
 		dput(dentry);
 		return 0;
@@ -190,7 +191,8 @@ static struct dentry * __oprofilefs_create_file(struct super_block * sb,
 int oprofilefs_create_ulong(struct super_block * sb, struct dentry * root,
 	char const * name, unsigned long * val)
 {
-	struct dentry * d = __oprofilefs_create_file(sb, root, name, &ulong_fops);
+	struct dentry * d = __oprofilefs_create_file(sb, root, name,
+						     &ulong_fops, 0644);
 	if (!d)
 		return -EFAULT;
 
@@ -202,7 +204,8 @@ int oprofilefs_create_ulong(struct super_block * sb, struct dentry * root,
 int oprofilefs_create_ro_ulong(struct super_block * sb, struct dentry * root,
 	char const * name, unsigned long * val)
 {
-	struct dentry * d = __oprofilefs_create_file(sb, root, name, &ulong_ro_fops);
+	struct dentry * d = __oprofilefs_create_file(sb, root, name,
+						     &ulong_ro_fops, 0444);
 	if (!d)
 		return -EFAULT;
 
@@ -227,7 +230,8 @@ static struct file_operations atomic_ro_fops = {
 int oprofilefs_create_ro_atomic(struct super_block * sb, struct dentry * root,
 	char const * name, atomic_t * val)
 {
-	struct dentry * d = __oprofilefs_create_file(sb, root, name, &atomic_ro_fops);
+	struct dentry * d = __oprofilefs_create_file(sb, root, name,
+						     &atomic_ro_fops, 0444);
 	if (!d)
 		return -EFAULT;
 
@@ -239,7 +243,16 @@ int oprofilefs_create_ro_atomic(struct super_block * sb, struct dentry * root,
 int oprofilefs_create_file(struct super_block * sb, struct dentry * root,
 	char const * name, struct file_operations * fops)
 {
-	if (!__oprofilefs_create_file(sb, root, name, fops))
+	if (!__oprofilefs_create_file(sb, root, name, fops, 0644))
+		return -EFAULT;
+	return 0;
+}
+
+
+int oprofilefs_create_file_perm(struct super_block * sb, struct dentry * root,
+	char const * name, struct file_operations * fops, int perm)
+{
+	if (!__oprofilefs_create_file(sb, root, name, fops, perm))
 		return -EFAULT;
 	return 0;
 }

include/linux/oprofile.h

@@ -66,6 +66,9 @@ extern void oprofile_add_sample(unsigned long eip, unsigned int is_kernel,
 int oprofilefs_create_file(struct super_block * sb, struct dentry * root,
 	char const * name, struct file_operations * fops);
 
+int oprofilefs_create_file_perm(struct super_block * sb, struct dentry * root,
+	char const * name, struct file_operations * fops, int perm);
+ 
 /** Create a file for read/write access to an unsigned long. */
 int oprofilefs_create_ulong(struct super_block * sb, struct dentry * root,
 	char const * name, ulong * val);