Add the rt linux 4.1.3-rt3 as base

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

diff --git a/kernel/tools/lib/api/fs/debugfs.c b/kernel/tools/lib/api/fs/debugfs.c
new file mode 100644 (file)
index 0000000..8305b3e
--- /dev/null
+++ b/kernel/tools/lib/api/fs/debugfs.c
@@ -0,0 +1,118 @@
+#define _GNU_SOURCE
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <sys/vfs.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mount.h>
+#include <linux/kernel.h>
+
+#include "debugfs.h"
+
+#ifndef DEBUGFS_DEFAULT_PATH
+#define DEBUGFS_DEFAULT_PATH           "/sys/kernel/debug"
+#endif
+
+char debugfs_mountpoint[PATH_MAX + 1] = DEBUGFS_DEFAULT_PATH;
+
+static const char * const debugfs_known_mountpoints[] = {
+       DEBUGFS_DEFAULT_PATH,
+       "/debug",
+       0,
+};
+
+static bool debugfs_found;
+
+bool debugfs_configured(void)
+{
+       return debugfs_find_mountpoint() != NULL;
+}
+
+/* find the path to the mounted debugfs */
+const char *debugfs_find_mountpoint(void)
+{
+       const char *ret;
+
+       if (debugfs_found)
+               return (const char *)debugfs_mountpoint;
+
+       ret = find_mountpoint("debugfs", (long) DEBUGFS_MAGIC,
+                             debugfs_mountpoint, PATH_MAX + 1,
+                             debugfs_known_mountpoints);
+       if (ret)
+               debugfs_found = true;
+
+       return ret;
+}
+
+/* mount the debugfs somewhere if it's not mounted */
+char *debugfs_mount(const char *mountpoint)
+{
+       /* see if it's already mounted */
+       if (debugfs_find_mountpoint())
+               goto out;
+
+       /* if not mounted and no argument */
+       if (mountpoint == NULL) {
+               /* see if environment variable set */
+               mountpoint = getenv(PERF_DEBUGFS_ENVIRONMENT);
+               /* if no environment variable, use default */
+               if (mountpoint == NULL)
+                       mountpoint = DEBUGFS_DEFAULT_PATH;
+       }
+
+       if (mount(NULL, mountpoint, "debugfs", 0, NULL) < 0)
+               return NULL;
+
+       /* save the mountpoint */
+       debugfs_found = true;
+       strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
+out:
+       return debugfs_mountpoint;
+}
+
+int debugfs__strerror_open(int err, char *buf, size_t size, const char *filename)
+{
+       char sbuf[128];
+
+       switch (err) {
+       case ENOENT:
+               if (debugfs_found) {
+                       snprintf(buf, size,
+                                "Error:\tFile %s/%s not found.\n"
+                                "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
+                                debugfs_mountpoint, filename);
+                       break;
+               }
+               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/%s\n"
+                        "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
+                        debugfs_mountpoint, filename, debugfs_mountpoint);
+               break;
+       default:
+               snprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf)));
+               break;
+       }
+
+       return 0;
+}
+
+int debugfs__strerror_open_tp(int err, char *buf, size_t size, const char *sys, const char *name)
+{
+       char path[PATH_MAX];
+
+       snprintf(path, PATH_MAX, "tracing/events/%s/%s", sys, name ?: "*");
+
+       return debugfs__strerror_open(err, buf, size, path);
+}