1 files changed, 66 insertions, 96 deletions

diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 7317438ecd9e..1b8ec91899e6 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -8,8 +8,8 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
-#include <gelf.h>
 #include <bpf.h>
+#include <libbpf.h>
 #include <linux/btf.h>
 
 #include "btf.h"
@@ -340,109 +340,40 @@ static int dump_btf_raw(const struct btf *btf,
         return 0;
 }
 
-static bool check_btf_endianness(GElf_Ehdr *ehdr)
+static void __printf(2, 0) btf_dump_printf(void *ctx,
+                                           const char *fmt, va_list args)
 {
-        static unsigned int const endian = 1;
-
-        switch (ehdr->e_ident[EI_DATA]) {
-        case ELFDATA2LSB:
-                return *(unsigned char const *)&endian == 1;
-        case ELFDATA2MSB:
-                return *(unsigned char const *)&endian == 0;
-        default:
-                return 0;
-        }
+        vfprintf(stdout, fmt, args);
 }
 
-static int btf_load_from_elf(const char *path, struct btf **btf)
+static int dump_btf_c(const struct btf *btf,
+                      __u32 *root_type_ids, int root_type_cnt)
 {
-        int err = -1, fd = -1, idx = 0;
-        Elf_Data *btf_data = NULL;
-        Elf_Scn *scn = NULL;
-        Elf *elf = NULL;
-        GElf_Ehdr ehdr;
-
-        if (elf_version(EV_CURRENT) == EV_NONE) {
-                p_err("failed to init libelf for %s", path);
-                return -1;
-        }
-
-        fd = open(path, O_RDONLY);
-        if (fd < 0) {
-                p_err("failed to open %s: %s", path, strerror(errno));
-                return -1;
-        }
-
-        elf = elf_begin(fd, ELF_C_READ, NULL);
-        if (!elf) {
-                p_err("failed to open %s as ELF file", path);
-                goto done;
-        }
-        if (!gelf_getehdr(elf, &ehdr)) {
-                p_err("failed to get EHDR from %s", path);
-                goto done;
-        }
-        if (!check_btf_endianness(&ehdr)) {
-                p_err("non-native ELF endianness is not supported");
-                goto done;
-        }
-        if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) {
-                p_err("failed to get e_shstrndx from %s\n", path);
-                goto done;
-        }
+        struct btf_dump *d;
+        int err = 0, i;
 
-        while ((scn = elf_nextscn(elf, scn)) != NULL) {
-                GElf_Shdr sh;
-                char *name;
+        d = btf_dump__new(btf, NULL, NULL, btf_dump_printf);
+        if (IS_ERR(d))
+                return PTR_ERR(d);
 
-                idx++;
-                if (gelf_getshdr(scn, &sh) != &sh) {
-                        p_err("failed to get section(%d) header from %s",
-                              idx, path);
-                        goto done;
-                }
-                name = elf_strptr(elf, ehdr.e_shstrndx, sh.sh_name);
-                if (!name) {
-                        p_err("failed to get section(%d) name from %s",
-                              idx, path);
-                        goto done;
-                }
-                if (strcmp(name, BTF_ELF_SEC) == 0) {
-                        btf_data = elf_getdata(scn, 0);
-                        if (!btf_data) {
-                                p_err("failed to get section(%d, %s) data from %s",
-                                      idx, name, path);
+        if (root_type_cnt) {
+                for (i = 0; i < root_type_cnt; i++) {
+                        err = btf_dump__dump_type(d, root_type_ids[i]);
+                        if (err)
                                 goto done;
-                        }
-                        break;
                 }
-        }
-
-        if (!btf_data) {
-                p_err("%s ELF section not found in %s", BTF_ELF_SEC, path);
-                goto done;
-        }
+        } else {
+                int cnt = btf__get_nr_types(btf);
 
-        *btf = btf__new(btf_data->d_buf, btf_data->d_size);
-        if (IS_ERR(*btf)) {
-                err = PTR_ERR(*btf);
-                *btf = NULL;
-                p_err("failed to load BTF data from %s: %s",
-                      path, strerror(err));
-                goto done;
+                for (i = 1; i <= cnt; i++) {
+                        err = btf_dump__dump_type(d, i);
+                        if (err)
+                                goto done;
+                }
         }
 
-        err = 0;
 done:
-        if (err) {
-                if (*btf) {
-                        btf__free(*btf);
-                        *btf = NULL;
-                }
-        }
-        if (elf)
-                elf_end(elf);
-        close(fd);
+        btf_dump__free(d);
         return err;
 }
 
@@ -451,6 +382,7 @@ static int do_dump(int argc, char **argv)
         struct btf *btf = NULL;
         __u32 root_type_ids[2];
         int root_type_cnt = 0;
+        bool dump_c = false;
         __u32 btf_id = -1;
         const char *src;
         int fd = -1;
@@ -522,9 +454,14 @@ static int do_dump(int argc, char **argv)
                 }
                 NEXT_ARG();
         } else if (is_prefix(src, "file")) {
-                err = btf_load_from_elf(*argv, &btf);
-                if (err)
+                btf = btf__parse_elf(*argv, NULL);
+                if (IS_ERR(btf)) {
+                        err = PTR_ERR(btf);
+                        btf = NULL;
+                        p_err("failed to load BTF from %s: %s", 
+                              *argv, strerror(err));
                         goto done;
+                }
                 NEXT_ARG();
         } else {
                 err = -1;
@@ -532,6 +469,29 @@ static int do_dump(int argc, char **argv)
                 goto done;
         }
 
+        while (argc) {
+                if (is_prefix(*argv, "format")) {
+                        NEXT_ARG();
+                        if (argc < 1) {
+                                p_err("expecting value for 'format' option\n");
+                                goto done;
+                        }
+                        if (strcmp(*argv, "c") == 0) {
+                                dump_c = true;
+                        } else if (strcmp(*argv, "raw") == 0) {
+                                dump_c = false;
+                        } else {
+                                p_err("unrecognized format specifier: '%s', possible values: raw, c",
+                                      *argv);
+                                goto done;
+                        }
+                        NEXT_ARG();
+                } else {
+                        p_err("unrecognized option: '%s'", *argv);
+                        goto done;
+                }
+        }
+
         if (!btf) {
                 err = btf__get_from_id(btf_id, &btf);
                 if (err) {
@@ -545,7 +505,16 @@ static int do_dump(int argc, char **argv)
                 }
         }
 
-        dump_btf_raw(btf, root_type_ids, root_type_cnt);
+        if (dump_c) {
+                if (json_output) {
+                        p_err("JSON output for C-syntax dump is not supported");
+                        err = -ENOTSUP;
+                        goto done;
+                }
+                err = dump_btf_c(btf, root_type_ids, root_type_cnt);
+        } else {
+                err = dump_btf_raw(btf, root_type_ids, root_type_cnt);
+        }
 
 done:
         close(fd);
@@ -561,10 +530,11 @@ static int do_help(int argc, char **argv)
         }
 
         fprintf(stderr,
-                "Usage: %s btf dump BTF_SRC\n"
+                "Usage: %s btf dump BTF_SRC [format FORMAT]\n"
                 "       %s btf help\n"
                 "\n"
                 "       BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
+                "       FORMAT  := { raw | c }\n"
                 "       " HELP_SPEC_MAP "\n"
                 "       " HELP_SPEC_PROGRAM "\n"
                 "       " HELP_SPEC_OPTIONS "\n"