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| author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-12-10 19:11:12 -0500 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-12-10 20:06:13 -0500 |
| commit | 92c9292ae9c521e63e826d6ade3ceff7e7151020 (patch) | |
| tree | c9d3969e4d8b6a6ec1f79d066f6b785c013d2975 | |
| parent | 378a9ddddafc583c50a8ef2d33d06abf7df3109e (diff) | |
| download | libtracefs-92c9292ae9c521e63e826d6ade3ceff7e7151020.tar.gz | |
libtracefs: Have tracefs_{tracing,debug}_dir() make sure it's still mounted
The test to test tracefs_tracing_dir() actually did not mount the
tracing_dir but only returned where it was mounted. This was because the
setup of the tests already called tracefs_tracing_dir() and set the static
variable to it. As the tracefs_tracing_dir() function already found the
mounted tracefs file system, it cached the location. The test unmounted
it, and then called tracefs_tracing_dir(), and since that returned a path,
the test assumed (incorrectly) that it was mounted.
Have tracefs_tracing_dir() and tracefs_debug_dir() check to make sure each
time that the cached directory is still mounted by checking for a
file/directory in it.
For tracefs, it checks to see if "trace" exists.
For debugfs, it checks to see if "tracing" exists.
Link: https://lore.kernel.org/linux-trace-devel/20221210191112.749f045c@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
| -rw-r--r-- | src/tracefs-utils.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/src/tracefs-utils.c b/src/tracefs-utils.c index ae249de..9acf2ad 100644 --- a/src/tracefs-utils.c +++ b/src/tracefs-utils.c @@ -230,6 +230,16 @@ int tracefs_set_tracing_dir(char *tracing_dir) return 0; } +/* Used to check if the directory is still mounted */ +static int test_dir(const char *dir, const char *file) +{ + char path[strlen(dir) + strlen(file) + 2]; + struct stat st; + + sprintf(path, "%s/%s", dir, file); + return stat(path, &st) < 0 ? 0 : 1; +} + /** * tracefs_tracing_dir - Get tracing directory * @@ -240,10 +250,11 @@ const char *tracefs_tracing_dir(void) { static const char *tracing_dir; + /* Do not check custom_tracing_dir */ if (custom_tracing_dir) return custom_tracing_dir; - if (tracing_dir) + if (tracing_dir && test_dir(tracing_dir, "trace")) return tracing_dir; tracing_dir = find_tracing_dir(false, true); @@ -261,7 +272,7 @@ const char *tracefs_debug_dir(void) { static const char *debug_dir; - if (debug_dir) + if (debug_dir && test_dir(debug_dir, "tracing")) return debug_dir; debug_dir = find_tracing_dir(true, true); |