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Message-Id: <20200716052926.10933-1-Tony.Ambardar@gmail.com>
Date: Wed, 15 Jul 2020 22:29:26 -0700
From: Tony Ambardar <tony.ambardar@...il.com>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>
Cc: Tony Ambardar <Tony.Ambardar@...il.com>, netdev@...r.kernel.org,
bpf@...r.kernel.org, Quentin Monnet <quentin@...valent.com>
Subject: [PATCH bpf-next v2] bpftool: use only nftw for file tree parsing
The bpftool sources include code to walk file trees, but use multiple
frameworks to do so: nftw and fts. While nftw conforms to POSIX/SUSv3 and
is widely available, fts is not conformant and less common, especially on
non-glibc systems. The inconsistent framework usage hampers maintenance
and portability of bpftool, in particular for embedded systems.
Standardize code usage by rewriting one fts-based function to use nftw.
Clean up related function warnings by using "const char *" arguments and
fixing an unsafe call to dirname().
These changes help in building bpftool against musl for OpenWrt.
Signed-off-by: Tony Ambardar <Tony.Ambardar@...il.com>
---
V2:
* use _GNU_SOURCE to pull in getpagesize(), getline(), nftw() definitions
* use "const char *" in open_obj_pinned() and open_obj_pinned_any()
* make dirname() safely act on a string copy
---
tools/bpf/bpftool/common.c | 129 +++++++++++++++++++++----------------
tools/bpf/bpftool/main.h | 4 +-
2 files changed, 76 insertions(+), 57 deletions(-)
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 29f4e7611ae8..7c2e52fc5784 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -1,10 +1,11 @@
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2017-2018 Netronome Systems, Inc. */
+#define _GNU_SOURCE
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
-#include <fts.h>
+#include <ftw.h>
#include <libgen.h>
#include <mntent.h>
#include <stdbool.h>
@@ -160,24 +161,36 @@ int mount_tracefs(const char *target)
return err;
}
-int open_obj_pinned(char *path, bool quiet)
+int open_obj_pinned(const char *path, bool quiet)
{
- int fd;
+ char *pname;
+ int fd = -1;
+
+ pname = strdup(path);
+ if (pname == NULL) {
+ if (!quiet)
+ p_err("bpf obj get (%s): %s", path, strerror(errno));
+ goto out_ret;
+ }
+
- fd = bpf_obj_get(path);
+ fd = bpf_obj_get(pname);
if (fd < 0) {
if (!quiet)
- p_err("bpf obj get (%s): %s", path,
- errno == EACCES && !is_bpffs(dirname(path)) ?
+ p_err("bpf obj get (%s): %s", pname,
+ errno == EACCES && !is_bpffs(dirname(pname)) ?
"directory not in bpf file system (bpffs)" :
strerror(errno));
- return -1;
+ goto out_free;
}
+out_free:
+ free(pname);
+out_ret:
return fd;
}
-int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type)
+int open_obj_pinned_any(const char *path, enum bpf_obj_type exp_type)
{
enum bpf_obj_type type;
int fd;
@@ -367,68 +380,74 @@ void print_hex_data_json(uint8_t *data, size_t len)
jsonw_end_array(json_wtr);
}
-int build_pinned_obj_table(struct pinned_obj_table *tab,
- enum bpf_obj_type type)
+static struct pinned_obj_table *build_fn_table; /* params for nftw cb*/
+static enum bpf_obj_type build_fn_type;
+
+static int do_build_table_cb(const char *fpath, const struct stat *sb,
+ int typeflag, struct FTW *ftwbuf)
{
struct bpf_prog_info pinned_info = {};
struct pinned_obj *obj_node = NULL;
__u32 len = sizeof(pinned_info);
- struct mntent *mntent = NULL;
enum bpf_obj_type objtype;
+ int fd, err = 0;
+
+ if (typeflag != FTW_F)
+ goto out_ret;
+ fd = open_obj_pinned(fpath, true);
+ if (fd < 0)
+ goto out_ret;
+
+ objtype = get_fd_type(fd);
+ if (objtype != build_fn_type)
+ goto out_close;
+
+ memset(&pinned_info, 0, sizeof(pinned_info));
+ if (bpf_obj_get_info_by_fd(fd, &pinned_info, &len)) {
+ p_err("can't get obj info: %s", strerror(errno));
+ goto out_close;
+ }
+
+ obj_node = malloc(sizeof(*obj_node));
+ if (!obj_node) {
+ p_err("mem alloc failed");
+ err = -1;
+ goto out_close;
+ }
+
+ memset(obj_node, 0, sizeof(*obj_node));
+ obj_node->id = pinned_info.id;
+ obj_node->path = strdup(fpath);
+ hash_add(build_fn_table->table, &obj_node->hash, obj_node->id);
+
+out_close:
+ close(fd);
+out_ret:
+ return err;
+}
+
+int build_pinned_obj_table(struct pinned_obj_table *tab,
+ enum bpf_obj_type type)
+{
+ struct mntent *mntent = NULL;
FILE *mntfile = NULL;
- FTSENT *ftse = NULL;
- FTS *fts = NULL;
- int fd, err;
+ int flags = FTW_PHYS;
+ int nopenfd = 16;
mntfile = setmntent("/proc/mounts", "r");
if (!mntfile)
return -1;
+ build_fn_table = tab;
+ build_fn_type = type;
+
while ((mntent = getmntent(mntfile))) {
- char *path[] = { mntent->mnt_dir, NULL };
+ char *path = mntent->mnt_dir;
if (strncmp(mntent->mnt_type, "bpf", 3) != 0)
continue;
-
- fts = fts_open(path, 0, NULL);
- if (!fts)
- continue;
-
- while ((ftse = fts_read(fts))) {
- if (!(ftse->fts_info & FTS_F))
- continue;
- fd = open_obj_pinned(ftse->fts_path, true);
- if (fd < 0)
- continue;
-
- objtype = get_fd_type(fd);
- if (objtype != type) {
- close(fd);
- continue;
- }
- memset(&pinned_info, 0, sizeof(pinned_info));
- err = bpf_obj_get_info_by_fd(fd, &pinned_info, &len);
- if (err) {
- close(fd);
- continue;
- }
-
- obj_node = malloc(sizeof(*obj_node));
- if (!obj_node) {
- close(fd);
- fts_close(fts);
- fclose(mntfile);
- return -1;
- }
-
- memset(obj_node, 0, sizeof(*obj_node));
- obj_node->id = pinned_info.id;
- obj_node->path = strdup(ftse->fts_path);
- hash_add(tab->table, &obj_node->hash, obj_node->id);
-
- close(fd);
- }
- fts_close(fts);
+ if (nftw(path, do_build_table_cb, nopenfd, flags) == -1)
+ break;
}
fclose(mntfile);
return 0;
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 78d34e860713..e3a79b5a9960 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -152,8 +152,8 @@ int cmd_select(const struct cmd *cmds, int argc, char **argv,
int get_fd_type(int fd);
const char *get_fd_type_name(enum bpf_obj_type type);
char *get_fdinfo(int fd, const char *key);
-int open_obj_pinned(char *path, bool quiet);
-int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type);
+int open_obj_pinned(const char *path, bool quiet);
+int open_obj_pinned_any(const char *path, enum bpf_obj_type exp_type);
int mount_bpffs_for_pin(const char *name);
int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(int *, char ***));
int do_pin_fd(int fd, const char *name);
--
2.17.1
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