1 files changed, 124 insertions, 0 deletions

diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
new file mode 100644
index 000000000000..5b5eb788996e
--- /dev/null
+++ b/tools/lib/api/fs/fs.c
@@ -0,0 +1,124 @@
+/* TODO merge/factor in debugfs.c here */
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/vfs.h>
+
+#include "debugfs.h"
+#include "fs.h"
+
+static const char * const sysfs__fs_known_mountpoints[] = {
+        "/sys",
+        0,
+};
+
+static const char * const procfs__known_mountpoints[] = {
+        "/proc",
+        0,
+};
+
+struct fs {
+        const char              *name;
+        const char * const      *mounts;
+        char                     path[PATH_MAX + 1];
+        bool                     found;
+        long                     magic;
+};
+
+enum {
+        FS__SYSFS  = 0,
+        FS__PROCFS = 1,
+};
+
+static struct fs fs__entries[] = {
+        [FS__SYSFS] = {
+                .name   = "sysfs",
+                .mounts = sysfs__fs_known_mountpoints,
+                .magic  = SYSFS_MAGIC,
+        },
+        [FS__PROCFS] = {
+                .name   = "proc",
+                .mounts = procfs__known_mountpoints,
+                .magic  = PROC_SUPER_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__mountpoint(int idx)
+{
+        struct fs *fs = &fs__entries[idx];
+
+        if (fs->found)
+                return (const char *)fs->path;
+
+        return fs__get_mountpoint(fs);
+}
+
+#define FS__MOUNTPOINT(name, idx)       \
+const char *name##__mountpoint(void)    \
+{                                       \
+        return fs__mountpoint(idx);     \
+}
+
+FS__MOUNTPOINT(sysfs,  FS__SYSFS);
+FS__MOUNTPOINT(procfs, FS__PROCFS);