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Subject[PATCH 28/44] bpftool: use bpf_program__get_prog_info_linear() in prog.c:do_dump()
Date
From: Song Liu <songliubraving@fb.com>

This patches uses bpf_program__get_prog_info_linear() to simplify the
logic in prog.c do_dump().

Committer testing:

Before:

# bpftool prog dump xlated id 208 > /tmp/dump.xlated.before
# bpftool prog dump jited id 208 > /tmp/dump.jited.before
# bpftool map dump id 107 > /tmp/map.dump.before

After:

# ~acme/git/perf/tools/bpf/bpftool/bpftool map dump id 107 > /tmp/map.dump.after
# ~acme/git/perf/tools/bpf/bpftool/bpftool prog dump xlated id 208 > /tmp/dump.xlated.after
# ~acme/git/perf/tools/bpf/bpftool/bpftool prog dump jited id 208 > /tmp/dump.jited.after
# diff -u /tmp/dump.xlated.before /tmp/dump.xlated.after
# diff -u /tmp/dump.jited.before /tmp/dump.jited.after
# diff -u /tmp/map.dump.before /tmp/map.dump.after
# ~acme/git/perf/tools/bpf/bpftool/bpftool prog dump xlated id 208
0: (bf) r6 = r1
1: (85) call bpf_get_current_pid_tgid#80800
2: (63) *(u32 *)(r10 -328) = r0
3: (bf) r2 = r10
4: (07) r2 += -328
5: (18) r1 = map[id:107]
7: (85) call __htab_map_lookup_elem#85680
8: (15) if r0 == 0x0 goto pc+1
9: (07) r0 += 56
10: (b7) r7 = 0
11: (55) if r0 != 0x0 goto pc+52
12: (bf) r1 = r10
13: (07) r1 += -328
14: (b7) r2 = 64
15: (bf) r3 = r6
16: (85) call bpf_probe_read#-46848
17: (bf) r2 = r10
18: (07) r2 += -320
19: (18) r1 = map[id:106]
21: (07) r1 += 208
22: (61) r0 = *(u32 *)(r2 +0)
23: (35) if r0 >= 0x200 goto pc+3
24: (67) r0 <<= 3
25: (0f) r0 += r1
26: (05) goto pc+1
27: (b7) r0 = 0
28: (15) if r0 == 0x0 goto pc+35
29: (71) r1 = *(u8 *)(r0 +0)
30: (15) if r1 == 0x0 goto pc+33
31: (b7) r5 = 64
32: (79) r1 = *(u64 *)(r10 -320)
33: (15) if r1 == 0x2 goto pc+2
34: (15) if r1 == 0x101 goto pc+3
35: (55) if r1 != 0x15 goto pc+19
36: (79) r3 = *(u64 *)(r6 +16)
37: (05) goto pc+1
38: (79) r3 = *(u64 *)(r6 +24)
39: (15) if r3 == 0x0 goto pc+15
40: (b7) r1 = 0
41: (63) *(u32 *)(r10 -260) = r1
42: (bf) r1 = r10
43: (07) r1 += -256
44: (b7) r2 = 256
45: (85) call bpf_probe_read_str#-46704
46: (b7) r5 = 328
47: (63) *(u32 *)(r10 -264) = r0
48: (bf) r1 = r0
49: (67) r1 <<= 32
50: (77) r1 >>= 32
51: (25) if r1 > 0xff goto pc+3
52: (07) r0 += 72
53: (57) r0 &= 255
54: (bf) r5 = r0
55: (bf) r4 = r10
56: (07) r4 += -328
57: (bf) r1 = r6
58: (18) r2 = map[id:105]
60: (18) r3 = 0xffffffff
62: (85) call bpf_perf_event_output_tp#-45104
63: (bf) r7 = r0
64: (bf) r0 = r7
65: (95) exit
#

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: kernel-team@fb.com
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Link: http://lkml.kernel.org/r/20190312053051.2690567-4-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/bpf/bpftool/prog.c | 266 +++++++++------------------------------
1 file changed, 59 insertions(+), 207 deletions(-)

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 8ef80d65a474..d2be5a06c339 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -401,41 +401,31 @@ static int do_show(int argc, char **argv)

static int do_dump(int argc, char **argv)
{
- unsigned int finfo_rec_size, linfo_rec_size, jited_linfo_rec_size;
- void *func_info = NULL, *linfo = NULL, *jited_linfo = NULL;
- unsigned int nr_finfo, nr_linfo = 0, nr_jited_linfo = 0;
+ struct bpf_prog_info_linear *info_linear;
struct bpf_prog_linfo *prog_linfo = NULL;
- unsigned long *func_ksyms = NULL;
- struct bpf_prog_info info = {};
- unsigned int *func_lens = NULL;
+ enum {DUMP_JITED, DUMP_XLATED} mode;
const char *disasm_opt = NULL;
- unsigned int nr_func_ksyms;
- unsigned int nr_func_lens;
+ struct bpf_prog_info *info;
struct dump_data dd = {};
- __u32 len = sizeof(info);
+ void *func_info = NULL;
struct btf *btf = NULL;
- unsigned int buf_size;
char *filepath = NULL;
bool opcodes = false;
bool visual = false;
char func_sig[1024];
unsigned char *buf;
bool linum = false;
- __u32 *member_len;
- __u64 *member_ptr;
+ __u32 member_len;
+ __u64 arrays;
ssize_t n;
- int err;
int fd;

if (is_prefix(*argv, "jited")) {
if (disasm_init())
return -1;
-
- member_len = &info.jited_prog_len;
- member_ptr = &info.jited_prog_insns;
+ mode = DUMP_JITED;
} else if (is_prefix(*argv, "xlated")) {
- member_len = &info.xlated_prog_len;
- member_ptr = &info.xlated_prog_insns;
+ mode = DUMP_XLATED;
} else {
p_err("expected 'xlated' or 'jited', got: %s", *argv);
return -1;
@@ -474,175 +464,50 @@ static int do_dump(int argc, char **argv)
return -1;
}

- err = bpf_obj_get_info_by_fd(fd, &info, &len);
- if (err) {
- p_err("can't get prog info: %s", strerror(errno));
- return -1;
- }
-
- if (!*member_len) {
- p_info("no instructions returned");
- close(fd);
- return 0;
- }
+ if (mode == DUMP_JITED)
+ arrays = 1UL << BPF_PROG_INFO_JITED_INSNS;
+ else
+ arrays = 1UL << BPF_PROG_INFO_XLATED_INSNS;

- buf_size = *member_len;
+ arrays |= 1UL << BPF_PROG_INFO_JITED_KSYMS;
+ arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
+ arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
+ arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
+ arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;

- buf = malloc(buf_size);
- if (!buf) {
- p_err("mem alloc failed");
- close(fd);
+ info_linear = bpf_program__get_prog_info_linear(fd, arrays);
+ close(fd);
+ if (IS_ERR_OR_NULL(info_linear)) {
+ p_err("can't get prog info: %s", strerror(errno));
return -1;
}

- nr_func_ksyms = info.nr_jited_ksyms;
- if (nr_func_ksyms) {
- func_ksyms = malloc(nr_func_ksyms * sizeof(__u64));
- if (!func_ksyms) {
- p_err("mem alloc failed");
- close(fd);
- goto err_free;
- }
- }
-
- nr_func_lens = info.nr_jited_func_lens;
- if (nr_func_lens) {
- func_lens = malloc(nr_func_lens * sizeof(__u32));
- if (!func_lens) {
- p_err("mem alloc failed");
- close(fd);
+ info = &info_linear->info;
+ if (mode == DUMP_JITED) {
+ if (info->jited_prog_len == 0) {
+ p_info("no instructions returned");
goto err_free;
}
- }
-
- nr_finfo = info.nr_func_info;
- finfo_rec_size = info.func_info_rec_size;
- if (nr_finfo && finfo_rec_size) {
- func_info = malloc(nr_finfo * finfo_rec_size);
- if (!func_info) {
- p_err("mem alloc failed");
- close(fd);
+ buf = (unsigned char *)(info->jited_prog_insns);
+ member_len = info->jited_prog_len;
+ } else { /* DUMP_XLATED */
+ if (info->xlated_prog_len == 0) {
+ p_err("error retrieving insn dump: kernel.kptr_restrict set?");
goto err_free;
}
+ buf = (unsigned char *)info->xlated_prog_insns;
+ member_len = info->xlated_prog_len;
}

- linfo_rec_size = info.line_info_rec_size;
- if (info.nr_line_info && linfo_rec_size && info.btf_id) {
- nr_linfo = info.nr_line_info;
- linfo = malloc(nr_linfo * linfo_rec_size);
- if (!linfo) {
- p_err("mem alloc failed");
- close(fd);
- goto err_free;
- }
- }
-
- jited_linfo_rec_size = info.jited_line_info_rec_size;
- if (info.nr_jited_line_info &&
- jited_linfo_rec_size &&
- info.nr_jited_ksyms &&
- info.nr_jited_func_lens &&
- info.btf_id) {
- nr_jited_linfo = info.nr_jited_line_info;
- jited_linfo = malloc(nr_jited_linfo * jited_linfo_rec_size);
- if (!jited_linfo) {
- p_err("mem alloc failed");
- close(fd);
- goto err_free;
- }
- }
-
- memset(&info, 0, sizeof(info));
-
- *member_ptr = ptr_to_u64(buf);
- *member_len = buf_size;
- info.jited_ksyms = ptr_to_u64(func_ksyms);
- info.nr_jited_ksyms = nr_func_ksyms;
- info.jited_func_lens = ptr_to_u64(func_lens);
- info.nr_jited_func_lens = nr_func_lens;
- info.nr_func_info = nr_finfo;
- info.func_info_rec_size = finfo_rec_size;
- info.func_info = ptr_to_u64(func_info);
- info.nr_line_info = nr_linfo;
- info.line_info_rec_size = linfo_rec_size;
- info.line_info = ptr_to_u64(linfo);
- info.nr_jited_line_info = nr_jited_linfo;
- info.jited_line_info_rec_size = jited_linfo_rec_size;
- info.jited_line_info = ptr_to_u64(jited_linfo);
-
- err = bpf_obj_get_info_by_fd(fd, &info, &len);
- close(fd);
- if (err) {
- p_err("can't get prog info: %s", strerror(errno));
- goto err_free;
- }
-
- if (*member_len > buf_size) {
- p_err("too many instructions returned");
- goto err_free;
- }
-
- if (info.nr_jited_ksyms > nr_func_ksyms) {
- p_err("too many addresses returned");
- goto err_free;
- }
-
- if (info.nr_jited_func_lens > nr_func_lens) {
- p_err("too many values returned");
- goto err_free;
- }
-
- if (info.nr_func_info != nr_finfo) {
- p_err("incorrect nr_func_info %d vs. expected %d",
- info.nr_func_info, nr_finfo);
- goto err_free;
- }
-
- if (info.func_info_rec_size != finfo_rec_size) {
- p_err("incorrect func_info_rec_size %d vs. expected %d",
- info.func_info_rec_size, finfo_rec_size);
- goto err_free;
- }
-
- if (linfo && info.nr_line_info != nr_linfo) {
- p_err("incorrect nr_line_info %u vs. expected %u",
- info.nr_line_info, nr_linfo);
- goto err_free;
- }
-
- if (info.line_info_rec_size != linfo_rec_size) {
- p_err("incorrect line_info_rec_size %u vs. expected %u",
- info.line_info_rec_size, linfo_rec_size);
- goto err_free;
- }
-
- if (jited_linfo && info.nr_jited_line_info != nr_jited_linfo) {
- p_err("incorrect nr_jited_line_info %u vs. expected %u",
- info.nr_jited_line_info, nr_jited_linfo);
- goto err_free;
- }
-
- if (info.jited_line_info_rec_size != jited_linfo_rec_size) {
- p_err("incorrect jited_line_info_rec_size %u vs. expected %u",
- info.jited_line_info_rec_size, jited_linfo_rec_size);
- goto err_free;
- }
-
- if ((member_len == &info.jited_prog_len &&
- info.jited_prog_insns == 0) ||
- (member_len == &info.xlated_prog_len &&
- info.xlated_prog_insns == 0)) {
- p_err("error retrieving insn dump: kernel.kptr_restrict set?");
- goto err_free;
- }
-
- if (info.btf_id && btf__get_from_id(info.btf_id, &btf)) {
+ if (info->btf_id && btf__get_from_id(info->btf_id, &btf)) {
p_err("failed to get btf");
goto err_free;
}

- if (nr_linfo) {
- prog_linfo = bpf_prog_linfo__new(&info);
+ func_info = (void *)info->func_info;
+
+ if (info->nr_line_info) {
+ prog_linfo = bpf_prog_linfo__new(info);
if (!prog_linfo)
p_info("error in processing bpf_line_info. continue without it.");
}
@@ -655,9 +520,9 @@ static int do_dump(int argc, char **argv)
goto err_free;
}

- n = write(fd, buf, *member_len);
+ n = write(fd, buf, member_len);
close(fd);
- if (n != *member_len) {
+ if (n != member_len) {
p_err("error writing output file: %s",
n < 0 ? strerror(errno) : "short write");
goto err_free;
@@ -665,19 +530,19 @@ static int do_dump(int argc, char **argv)

if (json_output)
jsonw_null(json_wtr);
- } else if (member_len == &info.jited_prog_len) {
+ } else if (mode == DUMP_JITED) {
const char *name = NULL;

- if (info.ifindex) {
- name = ifindex_to_bfd_params(info.ifindex,
- info.netns_dev,
- info.netns_ino,
+ if (info->ifindex) {
+ name = ifindex_to_bfd_params(info->ifindex,
+ info->netns_dev,
+ info->netns_ino,
&disasm_opt);
if (!name)
goto err_free;
}

- if (info.nr_jited_func_lens && info.jited_func_lens) {
+ if (info->nr_jited_func_lens && info->jited_func_lens) {
struct kernel_sym *sym = NULL;
struct bpf_func_info *record;
char sym_name[SYM_MAX_NAME];
@@ -685,17 +550,16 @@ static int do_dump(int argc, char **argv)
__u64 *ksyms = NULL;
__u32 *lens;
__u32 i;
-
- if (info.nr_jited_ksyms) {
+ if (info->nr_jited_ksyms) {
kernel_syms_load(&dd);
- ksyms = (__u64 *) info.jited_ksyms;
+ ksyms = (__u64 *) info->jited_ksyms;
}

if (json_output)
jsonw_start_array(json_wtr);

- lens = (__u32 *) info.jited_func_lens;
- for (i = 0; i < info.nr_jited_func_lens; i++) {
+ lens = (__u32 *) info->jited_func_lens;
+ for (i = 0; i < info->nr_jited_func_lens; i++) {
if (ksyms) {
sym = kernel_syms_search(&dd, ksyms[i]);
if (sym)
@@ -707,7 +571,7 @@ static int do_dump(int argc, char **argv)
}

if (func_info) {
- record = func_info + i * finfo_rec_size;
+ record = func_info + i * info->func_info_rec_size;
btf_dumper_type_only(btf, record->type_id,
func_sig,
sizeof(func_sig));
@@ -744,49 +608,37 @@ static int do_dump(int argc, char **argv)
if (json_output)
jsonw_end_array(json_wtr);
} else {
- disasm_print_insn(buf, *member_len, opcodes, name,
+ disasm_print_insn(buf, member_len, opcodes, name,
disasm_opt, btf, NULL, 0, 0, false);
}
} else if (visual) {
if (json_output)
jsonw_null(json_wtr);
else
- dump_xlated_cfg(buf, *member_len);
+ dump_xlated_cfg(buf, member_len);
} else {
kernel_syms_load(&dd);
- dd.nr_jited_ksyms = info.nr_jited_ksyms;
- dd.jited_ksyms = (__u64 *) info.jited_ksyms;
+ dd.nr_jited_ksyms = info->nr_jited_ksyms;
+ dd.jited_ksyms = (__u64 *) info->jited_ksyms;
dd.btf = btf;
dd.func_info = func_info;
- dd.finfo_rec_size = finfo_rec_size;
+ dd.finfo_rec_size = info->func_info_rec_size;
dd.prog_linfo = prog_linfo;

if (json_output)
- dump_xlated_json(&dd, buf, *member_len, opcodes,
+ dump_xlated_json(&dd, buf, member_len, opcodes,
linum);
else
- dump_xlated_plain(&dd, buf, *member_len, opcodes,
+ dump_xlated_plain(&dd, buf, member_len, opcodes,
linum);
kernel_syms_destroy(&dd);
}

- free(buf);
- free(func_ksyms);
- free(func_lens);
- free(func_info);
- free(linfo);
- free(jited_linfo);
- bpf_prog_linfo__free(prog_linfo);
+ free(info_linear);
return 0;

err_free:
- free(buf);
- free(func_ksyms);
- free(func_lens);
- free(func_info);
- free(linfo);
- free(jited_linfo);
- bpf_prog_linfo__free(prog_linfo);
+ free(info_linear);
return -1;
}

--
2.20.1
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