bpftool: use bpf_program__get_prog_info_linear() in prog.c:do_dump()

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>

1 files 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;
 }