2015-09-19 11:00 GMT-04:00 Jiri Olsa <jo...@redhat.com>:
> On Sat, Sep 19, 2015 at 08:50:19AM -0600, David Ahern wrote:
>> On 9/19/15 8:47 AM, Jiri Olsa wrote:
>>
>> >diff --git a/tools/lib/api/fs/tracing_path.c
>> >b/tools/lib/api/fs/tracing_path.c
>> >index 38aca2dd1946..0406a7d5c891 100644
>> >--- a/tools/lib/api/fs/tracing_path.c
>> >+++ b/tools/lib/api/fs/tracing_path.c
>> >@@ -12,12 +12,14 @@
>> > #include "tracing_path.h"
>> >
>> >
>> >+char tracing_mnt[PATH_MAX + 1] = "/sys/kernel/debug";
>> > char tracing_path[PATH_MAX + 1] = "/sys/kernel/debug/tracing";
>> > char tracing_events_path[PATH_MAX + 1] =
>> > "/sys/kernel/debug/tracing/events";
>>
>> why all the +1s? null terminator has to fit within PATH_MAX as well.
>
> good question.. can't see a reason ATM
It is quite weird actually, it seems there is multiple occurrences of
that, without any comment to explain why that +1, even if the #define
of PATH_MAX in limits.h specify that that size also counts nul.
Most of these occurrences are linked to perf though, but there's also
fs/ocfs2/aops.c, scripts/docproc.c and usr/gen_init_cpio.c.
Perhaps a mistake that started somewhere and that was propagated
looking at the original mistake?
> jirka
>
>>
>> >
>> >
>> > static void __tracing_path_set(const char *tracing, const char
>> > *mountpoint)
>> > {
>> >+ snprintf(tracing_mnt, sizeof(tracing_mnt), "%s", mountpoint);
>> > snprintf(tracing_path, sizeof(tracing_path), "%s/%s",
>> > mountpoint, tracing);
>> > snprintf(tracing_events_path, sizeof(tracing_events_path), "%s/%s%s",
>> >@@ -109,19 +111,10 @@ static int strerror_open(int err, char *buf, size_t
>> >size, const char *filename)
>> > "Hint:\tTry 'sudo mount -t debugfs nodev
>> > /sys/kernel/debug'");
>> > break;
>> > case EACCES: {
>> >- const char *mountpoint = debugfs__mountpoint();
>> >-
>> >- if (!access(mountpoint, R_OK) && strncmp(filename, "tracing/",
>> >8) == 0) {
>> >- const char *tracefs_mntpoint = tracefs__mountpoint();
>> >-
>> >- if (tracefs_mntpoint)
>> >- mountpoint = tracefs__mountpoint();
>> >- }
>> >-
>> > snprintf(buf, size,
>> > "Error:\tNo permissions to read %s/%s\n"
>> > "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
>> >- tracing_events_path, filename, mountpoint);
>> >+ tracing_events_path, filename, tracing_mnt);
>> > }
>> > break;
>> > default:
>> >
>>
>> LGTM.
>>
>> David
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