From cd140a5c1f456f50897af4a2e9a23d228a5fe719 Mon Sep 17 00:00:00 2001 From: Guillaume Chazarain Date: Sun, 8 Jan 2006 01:02:43 -0800 Subject: [PATCH] [PATCH] kmsg_write: don't return printk return value kmsg_write returns with printk, so some programs may be confused by a successful write() with a return value different than the buffer length. # /bin/echo something > /dev/kmsg /bin/echo: write error: Inappropriate ioctl for device The drawbacks is that the printk return value can no more be quickly checked from userspace. Signed-off-by: Guillaume Chazarain Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/mem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 91dd669273e0..a85f3a361442 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -817,7 +817,7 @@ static ssize_t kmsg_write(struct file * file, const char __user * buf, size_t count, loff_t *ppos) { char *tmp; - int ret; + ssize_t ret; tmp = kmalloc(count + 1, GFP_KERNEL); if (tmp == NULL) @@ -826,6 +826,9 @@ static ssize_t kmsg_write(struct file * file, const char __user * buf, if (!copy_from_user(tmp, buf, count)) { tmp[count] = 0; ret = printk("%s", tmp); + if (ret > count) + /* printk can add a prefix */ + ret = count; } kfree(tmp); return ret;