Commit f367540c authored by Joe Stringer's avatar Joe Stringer Committed by Arnaldo Carvalho de Melo

tools lib bpf: Add BPF program pinning APIs

Add new APIs to pin a BPF program (or specific instances) to the
filesystem.  The user can specify the path full path within a BPF
filesystem to pin the program.

bpf_program__pin_instance(prog, path, n) will pin the nth instance of
'prog' to the specified path.

bpf_program__pin(prog, path) will create the directory 'path' (if it
does not exist) and pin each instance within that directory. For
instance, path/0, path/1, path/2.

Committer notes:

- Add missing headers for mkdir()

- Check strdup() for failure

- Check snprintf >= size, not >, as == also means truncated, see 'man
  snprintf', return value.

- Conditionally define BPF_FS_MAGIC, as it isn't in magic.h in older
  systems and we're not yet having a tools/include/uapi/linux/magic.h
  copy.

- Do not include linux/magic.h, not present in older distros.
Signed-off-by: default avatarJoe Stringer <joe@ovn.org>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20170126212001.14103-2-joe@ovn.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 9c68ae98
...@@ -4,6 +4,7 @@ ...@@ -4,6 +4,7 @@
* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2015 Huawei Inc. * Copyright (C) 2015 Huawei Inc.
* Copyright (C) 2017 Nicira, Inc.
* *
* This program is free software; you can redistribute it and/or * This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public * modify it under the terms of the GNU Lesser General Public
...@@ -22,6 +23,7 @@ ...@@ -22,6 +23,7 @@
#include <stdlib.h> #include <stdlib.h>
#include <stdio.h> #include <stdio.h>
#include <stdarg.h> #include <stdarg.h>
#include <libgen.h>
#include <inttypes.h> #include <inttypes.h>
#include <string.h> #include <string.h>
#include <unistd.h> #include <unistd.h>
...@@ -32,6 +34,10 @@ ...@@ -32,6 +34,10 @@
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/bpf.h> #include <linux/bpf.h>
#include <linux/list.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 <libelf.h>
#include <gelf.h> #include <gelf.h>
...@@ -42,6 +48,10 @@ ...@@ -42,6 +48,10 @@
#define EM_BPF 247 #define EM_BPF 247
#endif #endif
#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC 0xcafe4a11
#endif
#define __printf(a, b) __attribute__((format(printf, a, b))) #define __printf(a, b) __attribute__((format(printf, a, b)))
__printf(1, 2) __printf(1, 2)
...@@ -1237,6 +1247,116 @@ int bpf_object__load(struct bpf_object *obj) ...@@ -1237,6 +1247,116 @@ int bpf_object__load(struct bpf_object *obj)
return err; 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) void bpf_object__close(struct bpf_object *obj)
{ {
size_t i; size_t i;
......
...@@ -106,6 +106,9 @@ void *bpf_program__priv(struct bpf_program *prog); ...@@ -106,6 +106,9 @@ void *bpf_program__priv(struct bpf_program *prog);
const char *bpf_program__title(struct bpf_program *prog, bool needs_copy); const char *bpf_program__title(struct bpf_program *prog, bool needs_copy);
int bpf_program__fd(struct bpf_program *prog); int bpf_program__fd(struct bpf_program *prog);
int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
int instance);
int bpf_program__pin(struct bpf_program *prog, const char *path);
struct bpf_insn; struct bpf_insn;
......
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