tools lib api fs: Move debugfs__strerror_open into tracing_path.c object

Moving debugfs__strerror_open out of api/fs/debugfs.c, because it's not
debugfs specific. It'll be changed to consider tracefs mount as well in
following patches.

Renaming it into tracing_path__strerror_open_tp to fit into the
namespace. No functional change is intended.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
Cc: Raphael Beamonte <raphael.beamonte@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1441180605-24737-6-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/tools/lib/api/fs/tracing_path.c b/tools/lib/api/fs/tracing_path.c
index 1fd6e1f99234..3b3e4f5fc50b 100644
--- a/tools/lib/api/fs/tracing_path.c
+++ b/tools/lib/api/fs/tracing_path.c
@@ -5,6 +5,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
+#include <unistd.h>
 #include "debugfs.h"
 #include "tracefs.h"
 
@@ -81,3 +83,55 @@ void put_tracing_file(char *file)
 {
         free(file);
 }
+
+static int strerror_open(int err, char *buf, size_t size, const char *filename)
+{
+        char sbuf[128];
+
+        switch (err) {
+        case ENOENT:
+                if (debugfs_configured()) {
+                        snprintf(buf, size,
+                                 "Error:\tFile %s/%s not found.\n"
+                                 "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
+                                 debugfs_mountpoint, filename);
+                        break;
+                }
+                snprintf(buf, size, "%s",
+                         "Error:\tUnable to find debugfs\n"
+                         "Hint:\tWas your kernel compiled with debugfs support?\n"
+                         "Hint:\tIs the debugfs filesystem mounted?\n"
+                         "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
+                break;
+        case EACCES: {
+                const char *mountpoint = debugfs_mountpoint;
+
+                if (!access(debugfs_mountpoint, R_OK) && strncmp(filename, "tracing/", 8) == 0) {
+                        const char *tracefs_mntpoint = tracefs_find_mountpoint();
+
+                        if (tracefs_mntpoint)
+                                mountpoint = tracefs_mntpoint;
+                }
+
+                snprintf(buf, size,
+                         "Error:\tNo permissions to read %s/%s\n"
+                         "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
+                         debugfs_mountpoint, filename, mountpoint);
+        }
+                break;
+        default:
+                snprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf)));
+                break;
+        }
+
+        return 0;
+}
+
+int tracing_path__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name)
+{
+        char path[PATH_MAX];
+
+        snprintf(path, PATH_MAX, "tracing/events/%s/%s", sys, name ?: "*");
+
+        return strerror_open(err, buf, size, path);
+}