[PATCH 15/31] tools lib api fs: Add FSTYPE__mount() method

From: Arnaldo Carvalho de Melo
Date: Fri Sep 04 2015 - 12:54:41 EST


From: Jiri Olsa <jolsa@xxxxxxxxxx>

Adding FSTYPE__mount (where FSTYPE is, as of now, one of sysfs, procfs,
debugfs, tracefs) method that tries to mount the filesystem in case no
mount of FSTYPE is found.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Raphael Beamonte <raphael.beamonte@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1441180605-24737-12-git-send-email-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/lib/api/fs/fs.c | 44 +++++++++++++++++++++++++++++++++++++++-----
tools/lib/api/fs/fs.h | 15 +++++++++++----
2 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
index ef16d2a83a27..bc93baf33fff 100644
--- a/tools/lib/api/fs/fs.c
+++ b/tools/lib/api/fs/fs.c
@@ -9,6 +9,7 @@
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
+#include <sys/mount.h>

#include "debugfs.h"
#include "fs.h"
@@ -215,16 +216,49 @@ static const char *fs__mountpoint(int idx)
return fs__get_mountpoint(fs);
}

-#define FS__MOUNTPOINT(name, idx) \
+static const char *mount_overload(struct fs *fs)
+{
+ size_t name_len = strlen(fs->name);
+ /* "PERF_" + name + "_ENVIRONMENT" + '\0' */
+ char upper_name[5 + name_len + 12 + 1];
+
+ snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
+ mem_toupper(upper_name, name_len);
+
+ return getenv(upper_name) ?: *fs->mounts;
+}
+
+static const char *fs__mount(int idx)
+{
+ struct fs *fs = &fs__entries[idx];
+ const char *mountpoint;
+
+ if (fs__mountpoint(idx))
+ return (const char *)fs->path;
+
+ mountpoint = mount_overload(fs);
+
+ if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
+ return NULL;
+
+ return fs__check_mounts(fs) ? fs->path : NULL;
+}
+
+#define FS(name, idx) \
const char *name##__mountpoint(void) \
{ \
return fs__mountpoint(idx); \
+} \
+ \
+const char *name##__mount(void) \
+{ \
+ return fs__mount(idx); \
}

-FS__MOUNTPOINT(sysfs, FS__SYSFS);
-FS__MOUNTPOINT(procfs, FS__PROCFS);
-FS__MOUNTPOINT(debugfs, FS__DEBUGFS);
-FS__MOUNTPOINT(tracefs, FS__TRACEFS);
+FS(sysfs, FS__SYSFS);
+FS(procfs, FS__PROCFS);
+FS(debugfs, FS__DEBUGFS);
+FS(tracefs, FS__TRACEFS);

int filename__read_int(const char *filename, int *value)
{
diff --git a/tools/lib/api/fs/fs.h b/tools/lib/api/fs/fs.h
index 9013227ae0d1..a9627ea5e6ae 100644
--- a/tools/lib/api/fs/fs.h
+++ b/tools/lib/api/fs/fs.h
@@ -9,10 +9,17 @@
#define PATH_MAX 4096
#endif

-const char *sysfs__mountpoint(void);
-const char *procfs__mountpoint(void);
-const char *debugfs__mountpoint(void);
-const char *tracefs__mountpoint(void);
+#define FS(name) \
+ const char *name##__mountpoint(void); \
+ const char *name##__mount(void);
+
+FS(sysfs)
+FS(procfs)
+FS(debugfs)
+FS(tracefs)
+
+#undef FS
+

int filename__read_int(const char *filename, int *value);
int sysctl__read_int(const char *sysctl, int *value);
--
2.1.0

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