Commit 034565da authored by Daniel Borkmann's avatar Daniel Borkmann

Merge branch 'bpf-bpftool-cleanups'

Quentin Monnet says:

====================
This series contains several minor fixes for bpftool source and
documentation.

The first patches focus on documentation: addition of an option in the page
for "bpftool prog", clean up and update of the same page, and addition of
an example of prog array map manipulation in "bpftool map" page.

The last two fix warnings susceptible to appear when libbfd is not present
(patch 4), or with additional warning flags passed to the compiler (last
patch).
====================
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parents bab89add c101189b
......@@ -170,6 +170,61 @@ The following three commands are equivalent:
| **# bpftool map pin id 10 /sys/fs/bpf/map**
| **# bpftool map del pinned /sys/fs/bpf/map key 13 00 07 00**
Note that map update can also be used in order to change the program references
hold by a program array map. This can be used, for example, to change the
programs used for tail-call jumps at runtime, without having to reload the
entry-point program. Below is an example for this use case: we load a program
defining a prog array map, and with a main function that contains a tail call
to other programs that can be used either to "process" packets or to "debug"
processing. Note that the prog array map MUST be pinned into the BPF virtual
file system for the map update to work successfully, as kernel flushes prog
array maps when they have no more references from user space (and the update
would be lost as soon as bpftool exits).
|
| **# bpftool prog loadall tail_calls.o /sys/fs/bpf/foo type xdp**
| **# bpftool prog --bpffs**
::
545: xdp name main_func tag 674b4b5597193dc3 gpl
loaded_at 2018-12-12T15:02:58+0000 uid 0
xlated 240B jited 257B memlock 4096B map_ids 294
pinned /sys/fs/bpf/foo/xdp
546: xdp name bpf_func_process tag e369a529024751fc gpl
loaded_at 2018-12-12T15:02:58+0000 uid 0
xlated 200B jited 164B memlock 4096B
pinned /sys/fs/bpf/foo/process
547: xdp name bpf_func_debug tag 0b597868bc7f0976 gpl
loaded_at 2018-12-12T15:02:58+0000 uid 0
xlated 200B jited 164B memlock 4096B
pinned /sys/fs/bpf/foo/debug
**# bpftool map**
::
294: prog_array name jmp_table flags 0x0
key 4B value 4B max_entries 1 memlock 4096B
owner_prog_type xdp owner jited
|
| **# bpftool map pin id 294 /sys/fs/bpf/bar**
| **# bpftool map dump pinned /sys/fs/bpf/bar**
::
Found 0 elements
|
| **# bpftool map update pinned /sys/fs/bpf/bar key 0 0 0 0 value pinned /sys/fs/bpf/foo/debug**
| **# bpftool map dump pinned /sys/fs/bpf/bar**
::
key: 00 00 00 00 value: 22 02 00 00
Found 1 element
SEE ALSO
========
**bpf**\ (2),
......
......@@ -158,26 +158,29 @@ OPTIONS
When showing BPF programs, show file names of pinned
programs.
-m, --mapcompat
Allow loading maps with unknown map definitions.
EXAMPLES
========
**# bpftool prog show**
::
10: xdp name some_prog tag 005a3d2123620c8b gpl
loaded_at Sep 29/20:11 uid 0
loaded_at 2017-09-29T20:11:00+0000 uid 0
xlated 528B jited 370B memlock 4096B map_ids 10
**# bpftool --json --pretty prog show**
::
{
"programs": [{
[{
"id": 10,
"type": "xdp",
"tag": "005a3d2123620c8b",
"gpl_compatible": true,
"loaded_at": "Sep 29/20:11",
"loaded_at": 1506715860,
"uid": 0,
"bytes_xlated": 528,
"jited": true,
......@@ -187,54 +190,62 @@ EXAMPLES
]
}
]
}
|
| **# bpftool prog dump xlated id 10 file /tmp/t**
| **# ls -l /tmp/t**
| -rw------- 1 root root 560 Jul 22 01:42 /tmp/t
**# bpftool prog dum jited tag 005a3d2123620c8b**
::
-rw------- 1 root root 560 Jul 22 01:42 /tmp/t
**# bpftool prog dump jited tag 005a3d2123620c8b**
::
push %rbp
mov %rsp,%rbp
sub $0x228,%rsp
sub $0x28,%rbp
mov %rbx,0x0(%rbp)
0: push %rbp
1: mov %rsp,%rbp
2: sub $0x228,%rsp
3: sub $0x28,%rbp
4: mov %rbx,0x0(%rbp)
|
| **# mount -t bpf none /sys/fs/bpf/**
| **# bpftool prog pin id 10 /sys/fs/bpf/prog**
| **# bpftool prog load ./my_prog.o /sys/fs/bpf/prog2**
| **# ls -l /sys/fs/bpf/**
| -rw------- 1 root root 0 Jul 22 01:43 prog
| -rw------- 1 root root 0 Jul 22 01:44 prog2
**# bpftool prog dum jited pinned /sys/fs/bpf/prog opcodes**
::
-rw------- 1 root root 0 Jul 22 01:43 prog
-rw------- 1 root root 0 Jul 22 01:44 prog2
**# bpftool prog dump jited pinned /sys/fs/bpf/prog opcodes**
::
push %rbp
0: push %rbp
55
mov %rsp,%rbp
1: mov %rsp,%rbp
48 89 e5
sub $0x228,%rsp
4: sub $0x228,%rsp
48 81 ec 28 02 00 00
sub $0x28,%rbp
b: sub $0x28,%rbp
48 83 ed 28
mov %rbx,0x0(%rbp)
f: mov %rbx,0x0(%rbp)
48 89 5d 00
|
| **# bpftool prog load xdp1_kern.o /sys/fs/bpf/xdp1 type xdp map name rxcnt id 7**
| **# bpftool prog show pinned /sys/fs/bpf/xdp1**
| 9: xdp name xdp_prog1 tag 539ec6ce11b52f98 gpl
| loaded_at 2018-06-25T16:17:31-0700 uid 0
| xlated 488B jited 336B memlock 4096B map_ids 7
| **# rm /sys/fs/bpf/xdp1**
|
::
9: xdp name xdp_prog1 tag 539ec6ce11b52f98 gpl
loaded_at 2018-06-25T16:17:31-0700 uid 0
xlated 488B jited 336B memlock 4096B map_ids 7
**# rm /sys/fs/bpf/xdp1**
SEE ALSO
========
......
......@@ -28,7 +28,7 @@
#define BPF_FS_MAGIC 0xcafe4a11
#endif
void p_err(const char *fmt, ...)
void __printf(1, 2) p_err(const char *fmt, ...)
{
va_list ap;
......@@ -46,7 +46,7 @@ void p_err(const char *fmt, ...)
va_end(ap);
}
void p_info(const char *fmt, ...)
void __printf(1, 2) p_info(const char *fmt, ...)
{
va_list ap;
......
......@@ -20,6 +20,7 @@
#include <malloc.h>
#include <inttypes.h>
#include <stdint.h>
#include <linux/compiler.h>
#include "json_writer.h"
......@@ -157,7 +158,8 @@ void jsonw_name(json_writer_t *self, const char *name)
putc(' ', self->out);
}
void jsonw_vprintf_enquote(json_writer_t *self, const char *fmt, va_list ap)
void __printf(2, 0)
jsonw_vprintf_enquote(json_writer_t *self, const char *fmt, va_list ap)
{
jsonw_eor(self);
putc('"', self->out);
......@@ -165,7 +167,7 @@ void jsonw_vprintf_enquote(json_writer_t *self, const char *fmt, va_list ap)
putc('"', self->out);
}
void jsonw_printf(json_writer_t *self, const char *fmt, ...)
void __printf(2, 3) jsonw_printf(json_writer_t *self, const char *fmt, ...)
{
va_list ap;
......
......@@ -147,8 +147,8 @@ int prog_parse_fd(int *argc, char ***argv);
int map_parse_fd(int *argc, char ***argv);
int map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len);
#ifdef HAVE_LIBBFD_SUPPORT
struct bpf_prog_linfo;
#ifdef HAVE_LIBBFD_SUPPORT
void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
const char *arch, const char *disassembler_options,
const struct btf *btf,
......
......@@ -32,7 +32,7 @@ static const char * const attach_type_strings[] = {
[__MAX_BPF_ATTACH_TYPE] = NULL,
};
enum bpf_attach_type parse_attach_type(const char *str)
static enum bpf_attach_type parse_attach_type(const char *str)
{
enum bpf_attach_type type;
......@@ -798,7 +798,7 @@ struct map_replace {
char *name;
};
int map_replace_compar(const void *p1, const void *p2)
static int map_replace_compar(const void *p1, const void *p2)
{
const struct map_replace *a = p1, *b = p2;
......
......@@ -81,7 +81,7 @@ struct kernel_sym *kernel_syms_search(struct dump_data *dd,
sizeof(*dd->sym_mapping), kernel_syms_cmp) : NULL;
}
static void print_insn(void *private_data, const char *fmt, ...)
static void __printf(2, 3) print_insn(void *private_data, const char *fmt, ...)
{
va_list args;
......@@ -90,7 +90,7 @@ static void print_insn(void *private_data, const char *fmt, ...)
va_end(args);
}
static void
static void __printf(2, 3)
print_insn_for_graph(void *private_data, const char *fmt, ...)
{
char buf[64], *p;
......@@ -121,7 +121,8 @@ print_insn_for_graph(void *private_data, const char *fmt, ...)
printf("%s", buf);
}
static void print_insn_json(void *private_data, const char *fmt, ...)
static void __printf(2, 3)
print_insn_json(void *private_data, const char *fmt, ...)
{
unsigned int l = strlen(fmt);
char chomped_fmt[l];
......
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