Re: [PATCH] tools lib api fs: Store tracing mountpoint for better error message

From: Jiri Olsa
Date: Sat Sep 19 2015 - 11:01:42 EST


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

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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