The following commit:
commit 56f3bae70638b33477a6015fd362ccfe354fd3ee
Author: Jim Cromie <[email protected]>
Date: Wed Sep 7 17:14:00 2011 -0600
perf stat: Add --log-fd <N> option to redirect stderr elsewhere
introduced a bug in the way perf stat outputs the results by default, i.e.,
without the --log-fd or --output option. It would default to writing to
file descriptor 0, i.e., stdin. Writing to stdin is allowed and is equivalent
to writing to stdout. However, there is a major difference for any script that
was already capturing the output of perf stat via redirection:
perf stat >/tmp/log .... or perf stat 2>/tmp/log ....
They would not capture anything anymore. They would have to do:
perf stat 0>/tmp/log ...
This breaks compatibility with existing scripts and does not look very
natural.
This patch fixes the problem by looking at output_fd only when it
was modified by user (> 0). It also checks that the value if positive.
Passing --log-fd 0 is ignored.
I would also argue that defaulting to stderr for the results is not
the right thing to do, though this patch does not address this specific
issue.
Signed-off-by: Stephane Eranian <[email protected]>
---
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 36603e4..56e6040 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1179,6 +1179,12 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
fprintf(stderr, "cannot use both --output and --log-fd\n");
usage_with_options(stat_usage, options);
}
+
+ if (output_fd < 0) {
+ fprintf(stderr, "argument to --log-fd must be a > 0\n");
+ usage_with_options(stat_usage, options);
+ }
+
if (!output) {
struct timespec tm;
mode = append_file ? "a" : "w";
@@ -1190,7 +1196,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
}
clock_gettime(CLOCK_REALTIME, &tm);
fprintf(output, "# started on %s\n", ctime(&tm.tv_sec));
- } else if (output_fd != 2) {
+ } else if (output_fd > 0) {
mode = append_file ? "a" : "w";
output = fdopen(output_fd, mode);
if (!output) {
Ping?
On Tue, May 15, 2012 at 1:11 PM, Stephane Eranian <[email protected]> wrote:
>
> The following commit:
>
> commit 56f3bae70638b33477a6015fd362ccfe354fd3ee
> Author: Jim Cromie <[email protected]>
> Date: Wed Sep 7 17:14:00 2011 -0600
>
> perf stat: Add --log-fd <N> option to redirect stderr elsewhere
>
> introduced a bug in the way perf stat outputs the results by default, i.e.,
> without the --log-fd or --output option. It would default to writing to
> file descriptor 0, i.e., stdin. Writing to stdin is allowed and is equivalent
> to writing to stdout. However, there is a major difference for any script that
> was already capturing the output of perf stat via redirection:
>
> perf stat >/tmp/log .... or perf stat 2>/tmp/log ....
>
> They would not capture anything anymore. They would have to do:
> perf stat 0>/tmp/log ...
>
> This breaks compatibility with existing scripts and does not look very
> natural.
>
> This patch fixes the problem by looking at output_fd only when it
> was modified by user (> 0). It also checks that the value if positive.
> Passing --log-fd 0 is ignored.
>
> I would also argue that defaulting to stderr for the results is not
> the right thing to do, though this patch does not address this specific
> issue.
>
> Signed-off-by: Stephane Eranian <[email protected]>
> ---
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 36603e4..56e6040 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -1179,6 +1179,12 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
> fprintf(stderr, "cannot use both --output and --log-fd\n");
> usage_with_options(stat_usage, options);
> }
> +
> + if (output_fd < 0) {
> + fprintf(stderr, "argument to --log-fd must be a > 0\n");
> + usage_with_options(stat_usage, options);
> + }
> +
> if (!output) {
> struct timespec tm;
> mode = append_file ? "a" : "w";
> @@ -1190,7 +1196,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
> }
> clock_gettime(CLOCK_REALTIME, &tm);
> fprintf(output, "# started on %s\n", ctime(&tm.tv_sec));
> - } else if (output_fd != 2) {
> + } else if (output_fd > 0) {
> mode = append_file ? "a" : "w";
> output = fdopen(output_fd, mode);
> if (!output) {
Commit-ID: fc3e4d077d5c7a7bc1ad5bc143895b4e070e5a8b
Gitweb: http://git.kernel.org/tip/fc3e4d077d5c7a7bc1ad5bc143895b4e070e5a8b
Author: Stephane Eranian <[email protected]>
AuthorDate: Tue, 15 May 2012 13:11:11 +0200
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Mon, 11 Jun 2012 11:20:21 -0300
perf stat: Fix default output file
The following commit:
commit 56f3bae70638b33477a6015fd362ccfe354fd3ee
Author: Jim Cromie <[email protected]>
Date: Wed Sep 7 17:14:00 2011 -0600
perf stat: Add --log-fd <N> option to redirect stderr elsewhere
introduced a bug in the way perf stat outputs the results by default,
i.e., without the --log-fd or --output option. It would default to
writing to file descriptor 0, i.e., stdin. Writing to stdin is allowed
and is equivalent to writing to stdout. However, there is a major
difference for any script that was already capturing the output of perf
stat via redirection:
perf stat >/tmp/log .... or perf stat 2>/tmp/log ....
They would not capture anything anymore. They would have to do:
perf stat 0>/tmp/log ...
This breaks compatibility with existing scripts and does not look very
natural.
This patch fixes the problem by looking at output_fd only when it was
modified by user (> 0). It also checks that the value if positive.
Passing --log-fd 0 is ignored.
I would also argue that defaulting to stderr for the results is not the
right thing to do, though this patch does not address this specific
issue.
Signed-off-by: Stephane Eranian <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Jim Cromie <[email protected]>
Link: http://lkml.kernel.org/r/20120515111111.GA9870@quad
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/builtin-stat.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 2625899..07b5c77 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1179,6 +1179,12 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
fprintf(stderr, "cannot use both --output and --log-fd\n");
usage_with_options(stat_usage, options);
}
+
+ if (output_fd < 0) {
+ fprintf(stderr, "argument to --log-fd must be a > 0\n");
+ usage_with_options(stat_usage, options);
+ }
+
if (!output) {
struct timespec tm;
mode = append_file ? "a" : "w";
@@ -1190,7 +1196,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
}
clock_gettime(CLOCK_REALTIME, &tm);
fprintf(output, "# started on %s\n", ctime(&tm.tv_sec));
- } else if (output_fd != 2) {
+ } else if (output_fd > 0) {
mode = append_file ? "a" : "w";
output = fdopen(output_fd, mode);
if (!output) {