Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / tools / lib / api / fs / fs.c

diff --git a/kernel/tools/lib/api/fs/fs.c b/kernel/tools/lib/api/fs/fs.c
new file mode 100644 (file)
index 0000000..128ef63
--- /dev/null
+++ b/kernel/tools/lib/api/fs/fs.c
@@ -0,0 +1,199 @@
+/* TODO merge/factor in debugfs.c here */
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/vfs.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.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 ((long)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 void mem_toupper(char *f, size_t len)
+{
+       while (len) {
+               *f = toupper(*f);
+               f++;
+               len--;
+       }
+}
+
+/*
+ * Check for "NAME_PATH" environment variable to override fs location (for
+ * testing). This matches the recommendation in Documentation/sysfs-rules.txt
+ * for SYSFS_PATH.
+ */
+static bool fs__env_override(struct fs *fs)
+{
+       char *override_path;
+       size_t name_len = strlen(fs->name);
+       /* name + "_PATH" + '\0' */
+       char upper_name[name_len + 5 + 1];
+       memcpy(upper_name, fs->name, name_len);
+       mem_toupper(upper_name, name_len);
+       strcpy(&upper_name[name_len], "_PATH");
+
+       override_path = getenv(upper_name);
+       if (!override_path)
+               return false;
+
+       fs->found = true;
+       strncpy(fs->path, override_path, sizeof(fs->path));
+       return true;
+}
+
+static const char *fs__get_mountpoint(struct fs *fs)
+{
+       if (fs__env_override(fs))
+               return fs->path;
+
+       if (fs__check_mounts(fs))
+               return fs->path;
+
+       if (fs__read_mounts(fs))
+               return fs->path;
+
+       return 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);
+
+int filename__read_int(const char *filename, int *value)
+{
+       char line[64];
+       int fd = open(filename, O_RDONLY), err = -1;
+
+       if (fd < 0)
+               return -1;
+
+       if (read(fd, line, sizeof(line)) > 0) {
+               *value = atoi(line);
+               err = 0;
+       }
+
+       close(fd);
+       return err;
+}
+
+int sysctl__read_int(const char *sysctl, int *value)
+{
+       char path[PATH_MAX];
+       const char *procfs = procfs__mountpoint();
+
+       if (!procfs)
+               return -1;
+
+       snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
+
+       return filename__read_int(path, value);
+}