The example is intended for int types, not for strings. So it is not a
bug, it's a feature ;-) But anyway, if you prefer to handle with strings
your are okay by me.
Am Dienstag, den 03.02.2015, 11:51 +0000 schrieb Wang Long:
> echo 99 > /proc/int-fifo ------------> Never return
> echo 1000 > /proc/int-fifo ------------> Never return
>
> this patch fix it.
>
> Signed-off-by: Wang Long <long.wangl...@huawei.com>
> ---
> samples/kfifo/inttype-example.c | 51
> ++++++++++++++++++++++++++++++++---------
> 1 file changed, 40 insertions(+), 11 deletions(-)
>
> diff --git a/samples/kfifo/inttype-example.c b/samples/kfifo/inttype-example.c
> index 8dc3c2e..cc0db5f 100644
> --- a/samples/kfifo/inttype-example.c
> +++ b/samples/kfifo/inttype-example.c
> @@ -6,6 +6,7 @@
> * Released under the GPL version 2 only.
> *
> */
> +#include <asm/uaccess.h>
>
> #include <linux/init.h>
> #include <linux/module.h>
> @@ -23,6 +24,9 @@
> /* name of the proc entry */
> #define PROC_FIFO "int-fifo"
>
> +/* Worst case buffer size needed for holding an integer. */
> +#define PROC_NUMBUF 13
> +
> /* lock for procfs read access */
> static DEFINE_MUTEX(read_lock);
>
> @@ -108,33 +112,58 @@ static int __init testfunc(void)
> static ssize_t fifo_write(struct file *file, const char __user *buf,
> size_t count, loff_t *ppos)
> {
> - int ret;
> - unsigned int copied;
> + char buffer[PROC_NUMBUF];
> + int value;
> + int err;
>
> - if (mutex_lock_interruptible(&write_lock))
> - return -ERESTARTSYS;
> + memset(buffer, 0, sizeof(buffer));
>
> - ret = kfifo_from_user(&test, buf, count, &copied);
> + if (count > sizeof(buffer) - 1)
> + count = sizeof(buffer) - 1;
> + if (copy_from_user(buffer, buf, count)) {
> + err = -EFAULT;
> + goto out;
> + }
>
> - mutex_unlock(&write_lock);
> + err = kstrtoint(strstrip(buffer), 0, &value);
> + if (err)
> + goto out;
> +
> + if (kfifo_is_full(&test)) {
> + err = -EINVAL;
> + goto out;
> + }
>
> - return ret ? ret : copied;
> + if (mutex_lock_interruptible(&write_lock))
> + return -ERESTARTSYS;
> + kfifo_put(&test, value);
> + mutex_unlock(&write_lock);
> +out:
> + return err < 0 ? err : count;
> }
>
> static ssize_t fifo_read(struct file *file, char __user *buf,
> size_t count, loff_t *ppos)
> {
> - int ret;
> - unsigned int copied;
> + char buffer[PROC_NUMBUF * FIFO_SIZE];
> + int value;
> + size_t len = 0;
> + ssize_t ret = -1;
> +
> + memset(buffer, 0, sizeof(buffer));
>
> if (mutex_lock_interruptible(&read_lock))
> return -ERESTARTSYS;
>
> - ret = kfifo_to_user(&test, buf, count, &copied);
> + while (!kfifo_is_empty(&test)){
> + ret = kfifo_get(&test, &value);
> + len = snprintf(buffer, sizeof(buffer), "%s%d\n", buffer, value);
> + }
>
> mutex_unlock(&read_lock);
> + ret = copy_to_user(buf, buffer, len);
>
> - return ret ? ret : copied;
> + return ret ? ret : len;
> }
>
> static const struct file_operations fifo_fops = {
--
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