tools lib bpf: Add BPF program pinning APIs

[karo-tx-linux.git] / tools / lib / bpf / libbpf.c

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index e6cd62b1264b96572de2e5447a8bbc4b7008cbbd..c4465b2fddf653da68dc4d632ecee753b075ae1f 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
  * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
  * Copyright (C) 2015 Huawei Inc.
+ * Copyright (C) 2017 Nicira, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -22,6 +23,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
+#include <libgen.h>
 #include <inttypes.h>
 #include <string.h>
 #include <unistd.h>
@@ -32,6 +34,10 @@
 #include <linux/kernel.h>
 #include <linux/bpf.h>
 #include <linux/list.h>
+#include <linux/limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
 #include <libelf.h>
 #include <gelf.h>
 
@@ -42,6 +48,10 @@
 #define EM_BPF 247
 #endif
 
+#ifndef BPF_FS_MAGIC
+#define BPF_FS_MAGIC           0xcafe4a11
+#endif
+
 #define __printf(a, b) __attribute__((format(printf, a, b)))
 
 __printf(1, 2)
@@ -1237,6 +1247,116 @@ out:
        return err;
 }
 
+static int check_path(const char *path)
+{
+       struct statfs st_fs;
+       char *dname, *dir;
+       int err = 0;
+
+       if (path == NULL)
+               return -EINVAL;
+
+       dname = strdup(path);
+       if (dname == NULL)
+               return -ENOMEM;
+
+       dir = dirname(dname);
+       if (statfs(dir, &st_fs)) {
+               pr_warning("failed to statfs %s: %s\n", dir, strerror(errno));
+               err = -errno;
+       }
+       free(dname);
+
+       if (!err && st_fs.f_type != BPF_FS_MAGIC) {
+               pr_warning("specified path %s is not on BPF FS\n", path);
+               err = -EINVAL;
+       }
+
+       return err;
+}
+
+int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
+                             int instance)
+{
+       int err;
+
+       err = check_path(path);
+       if (err)
+               return err;
+
+       if (prog == NULL) {
+               pr_warning("invalid program pointer\n");
+               return -EINVAL;
+       }
+
+       if (instance < 0 || instance >= prog->instances.nr) {
+               pr_warning("invalid prog instance %d of prog %s (max %d)\n",
+                          instance, prog->section_name, prog->instances.nr);
+               return -EINVAL;
+       }
+
+       if (bpf_obj_pin(prog->instances.fds[instance], path)) {
+               pr_warning("failed to pin program: %s\n", strerror(errno));
+               return -errno;
+       }
+       pr_debug("pinned program '%s'\n", path);
+
+       return 0;
+}
+
+static int make_dir(const char *path)
+{
+       int err = 0;
+
+       if (mkdir(path, 0700) && errno != EEXIST)
+               err = -errno;
+
+       if (err)
+               pr_warning("failed to mkdir %s: %s\n", path, strerror(-err));
+       return err;
+}
+
+int bpf_program__pin(struct bpf_program *prog, const char *path)
+{
+       int i, err;
+
+       err = check_path(path);
+       if (err)
+               return err;
+
+       if (prog == NULL) {
+               pr_warning("invalid program pointer\n");
+               return -EINVAL;
+       }
+
+       if (prog->instances.nr <= 0) {
+               pr_warning("no instances of prog %s to pin\n",
+                          prog->section_name);
+               return -EINVAL;
+       }
+
+       err = make_dir(path);
+       if (err)
+               return err;
+
+       for (i = 0; i < prog->instances.nr; i++) {
+               char buf[PATH_MAX];
+               int len;
+
+               len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
+               if (len < 0)
+                       return -EINVAL;
+               else if (len >= PATH_MAX)
+                       return -ENAMETOOLONG;
+
+               err = bpf_program__pin_instance(prog, buf, i);
+               if (err)
+                       return err;
+       }
+
+       return 0;
+}
+
 void bpf_object__close(struct bpf_object *obj)
 {
        size_t i;