2017-12-06 05:18:48

by Federico Vaga

Subject: [PATCH] trace-cmd:show: be picky on user argument 'cpu'

Before this patch the following command worked without errors:

trace-cmd show -c b

This command opens the CPU0 files. From `strace(1)`:

openat(AT_FDCWD, "/sys/kernel/tracing/per_cpu/cpu0/trace", O_RDONLY) = 3

Signed-off-by: Federico Vaga <[email protected]>
---
trace-show.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/trace-show.c b/trace-show.c
index f13db31..7d04012 100644
--- a/trace-show.c
+++ b/trace-show.c
@@ -149,7 +149,14 @@ void trace_show(int argc, char **argv)
file = "snapshot";

if (cpu) {
- snprintf(cpu_path, 128, "per_cpu/cpu%d/%s", atoi(cpu), file);
+ char *endptr;
+ long val;
+
+ errno = 0;
+ val = strtol(cpu, &endptr, 0);
+ if (errno || cpu == endptr)
+ die("Invalid CPU index '%s'", cpu);
+ snprintf(cpu_path, 128, "per_cpu/cpu%ld/%s", val, file);
file = cpu_path;
}

--
2.14.3

2018-05-03 16:19:55

by Steven Rostedt

Subject: Re: [PATCH] trace-cmd:show: be picky on user argument 'cpu'

On Wed, 6 Dec 2017 06:12:12 +0100
Federico Vaga <[email protected]> wrote:

> Before this patch the following command worked without errors:
>
> trace-cmd show -c b
>
> This command opens the CPU0 files. From `strace(1)`:
>
> openat(AT_FDCWD, "/sys/kernel/tracing/per_cpu/cpu0/trace", O_RDONLY) = 3

Thanks, I just applied it. Will push it out shortly.

-- Steve

>
> Signed-off-by: Federico Vaga <[email protected]>
> ---
> trace-show.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/trace-show.c b/trace-show.c
> index f13db31..7d04012 100644
> --- a/trace-show.c
> +++ b/trace-show.c
> @@ -149,7 +149,14 @@ void trace_show(int argc, char **argv)
> file = "snapshot";
>
> if (cpu) {
> - snprintf(cpu_path, 128, "per_cpu/cpu%d/%s", atoi(cpu), file);
> + char *endptr;
> + long val;
> +
> + errno = 0;
> + val = strtol(cpu, &endptr, 0);
> + if (errno || cpu == endptr)
> + die("Invalid CPU index '%s'", cpu);
> + snprintf(cpu_path, 128, "per_cpu/cpu%ld/%s", val, file);
> file = cpu_path;
> }
>