tools lib fs: Adopt debugfs open strerrno method

As this is not specific to an evlist and may be used with other tools.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-a9up9mivx1pzdf5tqrqsx62d@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

 	tools/perf/util/include/asm/hash.h

2 files changed, 29 insertions, 0 deletions

diff --git a/tools/lib/api/fs/debugfs.c b/tools/lib/api/fs/debugfs.c
index 86ea2d7b8845..fb700eed61c2 100644
--- a/tools/lib/api/fs/debugfs.c
+++ b/tools/lib/api/fs/debugfs.c
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -98,3 +99,29 @@ char *debugfs_mount(const char *mountpoint)
 out:
         return debugfs_mountpoint;
 }
+
+int debugfs__strerror_open(int err, char *buf, size_t size)
+{
+        char sbuf[128];
+
+        switch (err) {
+        case ENOENT:
+                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:
+                snprintf(buf, size,
+                         "Error:\tNo permissions to read %s/tracing/events/raw_syscalls\n"
+                         "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
+                         debugfs_mountpoint, debugfs_mountpoint);
+                break;
+        default:
+                snprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf)));
+                break;
+        }
+
+        return 0;
+}
diff --git a/tools/lib/api/fs/debugfs.h b/tools/lib/api/fs/debugfs.h
index f19d3df9609d..afa5043fec61 100644
--- a/tools/lib/api/fs/debugfs.h
+++ b/tools/lib/api/fs/debugfs.h
@@ -26,4 +26,6 @@ char *debugfs_mount(const char *mountpoint);
 
 extern char debugfs_mountpoint[];
 
+int debugfs__strerror_open(int err, char *buf, size_t size);
+
 #endif /* __API_DEBUGFS_H__ */