perf tools: Factor sysfs code into generic fs object

Moving sysfs code into generic fs object and preparing it to carry
procfs support.

This should be merged with tools/lib/lk/debugfs.c at some point in the
future.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1383660887-1734-2-git-send-email-jolsa@redhat.com
[ Added fs__ namespace qualifier to some more functions ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 107 insertions, 0 deletions

diff --git a/tools/perf/util/fs.c b/tools/perf/util/fs.c
new file mode 100644
index 000000000000..a2413e842a02
--- /dev/null
+++ b/tools/perf/util/fs.c
@@ -0,0 +1,107 @@
+
+/* TODO merge/factor into tools/lib/lk/debugfs.c */
+
+#include "util.h"
+#include "util/fs.h"
+
+static const char * const sysfs__fs_known_mountpoints[] = {
+	"/sys",
+	0,
+};
+
+struct fs {
+	const char		*name;
+	const char * const	*mounts;
+	char			 path[PATH_MAX + 1];
+	bool			 found;
+	long			 magic;
+};
+
+enum {
+	FS__SYSFS = 0,
+};
+
+static struct fs fs__entries[] = {
+	[FS__SYSFS] = {
+		.name	= "sysfs",
+		.mounts	= sysfs__fs_known_mountpoints,
+		.magic	= SYSFS_MAGIC,
+	},
+};
+
+static bool fs__read_mounts(struct fs *fs)
+{
+	bool found = false;
+	char type[100];
+	FILE *fp;
+
+	fp = fopen("/proc/mounts", "r");
+	if (fp == NULL)
+		return NULL;
+
+	while (!found &&
+	       fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
+		      fs->path, type) == 2) {
+
+		if (strcmp(type, fs->name) == 0)
+			found = true;
+	}
+
+	fclose(fp);
+	return fs->found = found;
+}
+
+static int fs__valid_mount(const char *fs, long magic)
+{
+	struct statfs st_fs;
+
+	if (statfs(fs, &st_fs) < 0)
+		return -ENOENT;
+	else if (st_fs.f_type != magic)
+		return -ENOENT;
+
+	return 0;
+}
+
+static bool fs__check_mounts(struct fs *fs)
+{
+	const char * const *ptr;
+
+	ptr = fs->mounts;
+	while (*ptr) {
+		if (fs__valid_mount(*ptr, fs->magic) == 0) {
+			fs->found = true;
+			strcpy(fs->path, *ptr);
+			return true;
+		}
+		ptr++;
+	}
+
+	return false;
+}
+
+static const char *fs__get_mountpoint(struct fs *fs)
+{
+	if (fs__check_mounts(fs))
+		return fs->path;
+
+	return fs__read_mounts(fs) ? fs->path : NULL;
+}
+
+static const char *fs__find_mountpoint(int idx)
+{
+	struct fs *fs = &fs__entries[idx];
+
+	if (fs->found)
+		return (const char *)fs->path;
+
+	return fs__get_mountpoint(fs);
+}
+
+#define FIND_MOUNTPOINT(name, idx)		\
+const char *name##_find_mountpoint(void)	\
+{						\
+	return fs__find_mountpoint(idx);	\
+}
+
+FIND_MOUNTPOINT(sysfs, FS__SYSFS);