[PATCH v3 3/3] tracing: make sure the parsed string always terminates with '\0'

changbin.du
2018-01-16T09:11:28Z

From: Changbin Du <changbin.du@intel.com>

Always mark the parsed string with a terminated '\0' even parser expects
another input to be parsed. Thus the users needn't append '0' before
using parsed string if new input is not given.

Signed-off-by: Changbin Du <changbin.du@intel.com>
---
kernel/trace/ftrace.c | 2 --
kernel/trace/trace.c | 4 ++--
kernel/trace/trace_events.c | 2 --
3 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index ccdf366..3addb82 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5010,7 +5010,6 @@ int ftrace_regex_release(struct inode *inode, struct file *file)

parser = &iter->parser;
if (trace_parser_loaded(parser)) {
- parser->buffer[parser->idx] = 0;
ftrace_match_records(iter->hash, parser->buffer, parser->idx);
}

@@ -5324,7 +5323,6 @@ ftrace_graph_release(struct inode *inode, struct file *file)
parser = &fgd->parser;

if (trace_parser_loaded((parser))) {
- parser->buffer[parser->idx] = 0;
ret = ftrace_graph_set_hash(fgd->new_hash,
parser->buffer);
}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b44926e..8f7fea2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -530,8 +530,6 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,
ubuf += ret;
cnt -= ret;

- parser.buffer[parser.idx] = 0;
-
ret = -EINVAL;
if (kstrtoul(parser.buffer, 0, &val))
break;
@@ -1268,6 +1266,8 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
} else if (parser->idx < parser->size - 1) {
parser->cont = true;
parser->buffer[parser->idx++] = ch;
+ /* Make sure the parsed string always terminates with '\0'. */
+ parser->buffer[parser->idx] = 0;
} else {
ret = -EINVAL;
goto out;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index ec0f9aa..7f8027c 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -885,8 +885,6 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
if (*parser.buffer == '!')
set = 0;

- parser.buffer[parser.idx] = 0;
-
ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
if (ret)
goto out_put;
--
2.7.4