Re: [PATCH -v2] lib/notifier-error-inject: fix error when writing errno to debugfs file

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 17.09.22 09:14, Akinobu Mita wrote:
The simple attribute files do not accept a negative value since the
commit 488dac0c9237 ("libfs: fix error cast of negative value in
simple_attr_write()"), so we can no longer use DEFINE_SIMPLE_ATTRIBUTE() to
define a file operations for errno value.

Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()")
Reported-by: Zhao Gongyi <zhaogongyi@xxxxxxxxxx>
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>

But shouldn't we fix simple_attr_write() instead?

I mean, simple_attr_read() might use attr->fmt to print a signed value, but simple_attr_write() fails on signed values now?

I might be wrong, but there is a disconnect. I feel like simple_attr_write() should similarly make decisions based on attr->fmt.

---
v2: Fix Reported-by line

  lib/notifier-error-inject.c | 38 ++++++++++++++++++++++++++++++-------
  1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/lib/notifier-error-inject.c b/lib/notifier-error-inject.c
index 21016b32d313..30ec41f58d53 100644
--- a/lib/notifier-error-inject.c
+++ b/lib/notifier-error-inject.c
@@ -3,20 +3,44 @@
#include "notifier-error-inject.h" -static int debugfs_errno_set(void *data, u64 val)
+static int notifier_err_errno_show(struct seq_file *m, void *data)
  {
-	*(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
+	int *value = m->private;
+
+	seq_printf(m, "%d\n", *value);
+
  	return 0;
  }
-static int debugfs_errno_get(void *data, u64 *val)
+static int notifier_err_errno_open(struct inode *inode, struct file *file)
  {
-	*val = *(int *)data;
-	return 0;
+	return single_open(file, notifier_err_errno_show, inode->i_private);
+}
+
+static ssize_t notifier_err_errno_write(struct file *file, const char __user *ubuf, size_t len,
+					loff_t *offp)
+{
+	struct seq_file *m = file->private_data;
+	int *value = m->private;
+	int ret;
+
+	ret = kstrtoint_from_user(ubuf, len, 0, value);
+	if (ret)
+		return ret;
+
+	*value = clamp(*value, -MAX_ERRNO, 0);
+
+	return len;
  }
-DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,
-			"%lld\n");
+static const struct file_operations fops_errno = {
+	.owner = THIS_MODULE,
+	.open = notifier_err_errno_open,
+	.read = seq_read,
+	.write = notifier_err_errno_write,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
  				struct dentry *parent, int *value)

--
Thanks,

David / dhildenb





[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux