From: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
This removes the open coded parsing of a word sent in by the user
and replaces it with copy_strtok_from_user.
Also removes cnt < 0 check since cnt is unsigned.
Also uses (*ppos) += cnt, instead of file->pos += cnt.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
kernel/trace/ftrace.c | 103 ++++++++++++++++++++++++++++---------------------
1 files changed, 59 insertions(+), 44 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 5a3a06b..4ecce15 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1690,11 +1690,13 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos, int enable)
{
struct ftrace_iterator *iter;
- char ch;
+ unsigned int copied;
size_t read = 0;
+ int len, skip;
ssize_t ret;
+ char *buf;
- if (!cnt || cnt < 0)
+ if (!cnt)
return 0;
mutex_lock(&ftrace_regex_lock);
@@ -1710,58 +1712,71 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
iter->buffer_idx = 0;
}
- ret = get_user(ch, ubuf++);
- if (ret)
- goto out;
- read++;
- cnt--;
+ if (iter->flags & FTRACE_ITER_CONT) {
+ /*
+ * We split on a word, continue from where
+ * we left off.
+ */
+ buf = &iter->buffer[iter->buffer_idx];
+ len = FTRACE_BUFF_MAX - iter->buffer_idx;
+ /* Stop on leading spaces */
+ skip = 0;
+ } else {
+ buf = iter->buffer;
+ /* iter->buffer is size of FTRACE_BUF_MAX + 1 */
+ len = FTRACE_BUFF_MAX;
+ iter->buffer_idx = 0;
+ /* Skip over any leading spaces */
+ skip = 1;
+ }
- if (!(iter->flags & ~FTRACE_ITER_CONT)) {
- /* skip white space */
- while (cnt && isspace(ch)) {
- ret = get_user(ch, ubuf++);
- if (ret)
+ ret = copy_strtok_from_user(buf, ubuf, len, cnt, &copied, skip, SPACES);
+
+ if (ret == -EAGAIN) {
+ if (copied) {
+ /* we split on a word */
+ iter->buffer_idx += copied;
+ if (iter->buffer_idx >= FTRACE_BUFF_MAX) {
+ /* too big of a word */
+ iter->buffer_idx = 0;
+ iter->flags &= ~FTRACE_ITER_CONT;
+ ret = -EINVAL;
goto out;
- read++;
- cnt--;
- }
+ }
- if (isspace(ch)) {
- file->f_pos += read;
- ret = read;
+ (*ppos) += cnt;
+ ret = cnt;
+ iter->flags |= FTRACE_ITER_CONT;
goto out;
}
-
- iter->buffer_idx = 0;
- }
-
- while (cnt && !isspace(ch)) {
- if (iter->buffer_idx < FTRACE_BUFF_MAX)
- iter->buffer[iter->buffer_idx++] = ch;
- else {
- ret = -EINVAL;
+ /* We only read white space. */
+ if (!(iter->flags & FTRACE_ITER_CONT)) {
+ (*ppos) += cnt;
+ ret = cnt;
goto out;
}
- ret = get_user(ch, ubuf++);
- if (ret)
- goto out;
- read++;
- cnt--;
+
+ /*
+ * We read white space but we are also at the end
+ * of a word in the buffer. Continue processing.
+ */
+ ret = cnt;
}
- if (isspace(ch)) {
- iter->filtered++;
- iter->buffer[iter->buffer_idx] = 0;
- ret = ftrace_process_regex(iter->buffer,
- iter->buffer_idx, enable);
- if (ret)
- goto out;
- iter->buffer_idx = 0;
- } else
- iter->flags |= FTRACE_ITER_CONT;
+ if (ret < 0)
+ goto out;
+ /* NULL terminate the string */
+ buf[copied] = 0;
- file->f_pos += read;
+ read = ret;
+
+ ret = ftrace_process_regex(iter->buffer, iter->buffer_idx, enable);
+ if (ret)
+ goto out;
+ iter->buffer_idx = 0;
+
+ (*ppos) += read;
ret = read;
out:
--
1.5.6.5
--
--
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