linux/tools/bpf/bpftool/main.c
Andrii Nakryiko c93cc69004 bpftool: add ability to dump BTF types
Add new `btf dump` sub-command to bpftool. It allows to dump
human-readable low-level BTF types representation of BTF types. BTF can
be retrieved from few different sources:
  - from BTF object by ID;
  - from PROG, if it has associated BTF;
  - from MAP, if it has associated BTF data; it's possible to narrow
    down types to either key type, value type, both, or all BTF types;
  - from ELF file (.BTF section).

Output format mostly follows BPF verifier log format with few notable
exceptions:
  - all the type/field/param/etc names are enclosed in single quotes to
    allow easier grepping and to stand out a little bit more;
  - FUNC_PROTO output follows STRUCT/UNION/ENUM format of having one
    line per each argument; this is more uniform and allows easy
    grepping, as opposed to succinct, but inconvenient format that BPF
    verifier log is using.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-25 21:45:14 -07:00

391 lines
7.5 KiB
C

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2017-2018 Netronome Systems, Inc. */
#include <ctype.h>
#include <errno.h>
#include <getopt.h>
#include <linux/bpf.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <bpf.h>
#include "main.h"
#define BATCH_LINE_LEN_MAX 65536
#define BATCH_ARG_NB_MAX 4096
const char *bin_name;
static int last_argc;
static char **last_argv;
static int (*last_do_help)(int argc, char **argv);
json_writer_t *json_wtr;
bool pretty_output;
bool json_output;
bool show_pinned;
bool block_mount;
int bpf_flags;
struct pinned_obj_table prog_table;
struct pinned_obj_table map_table;
static void __noreturn clean_and_exit(int i)
{
if (json_output)
jsonw_destroy(&json_wtr);
exit(i);
}
void usage(void)
{
last_do_help(last_argc - 1, last_argv + 1);
clean_and_exit(-1);
}
static int do_help(int argc, char **argv)
{
if (json_output) {
jsonw_null(json_wtr);
return 0;
}
fprintf(stderr,
"Usage: %s [OPTIONS] OBJECT { COMMAND | help }\n"
" %s batch file FILE\n"
" %s version\n"
"\n"
" OBJECT := { prog | map | cgroup | perf | net | feature | btf }\n"
" " HELP_SPEC_OPTIONS "\n"
"",
bin_name, bin_name, bin_name);
return 0;
}
static int do_version(int argc, char **argv)
{
if (json_output) {
jsonw_start_object(json_wtr);
jsonw_name(json_wtr, "version");
jsonw_printf(json_wtr, "\"%s\"", BPFTOOL_VERSION);
jsonw_end_object(json_wtr);
} else {
printf("%s v%s\n", bin_name, BPFTOOL_VERSION);
}
return 0;
}
int cmd_select(const struct cmd *cmds, int argc, char **argv,
int (*help)(int argc, char **argv))
{
unsigned int i;
last_argc = argc;
last_argv = argv;
last_do_help = help;
if (argc < 1 && cmds[0].func)
return cmds[0].func(argc, argv);
for (i = 0; cmds[i].func; i++)
if (is_prefix(*argv, cmds[i].cmd))
return cmds[i].func(argc - 1, argv + 1);
help(argc - 1, argv + 1);
return -1;
}
bool is_prefix(const char *pfx, const char *str)
{
if (!pfx)
return false;
if (strlen(str) < strlen(pfx))
return false;
return !memcmp(str, pfx, strlen(pfx));
}
void fprint_hex(FILE *f, void *arg, unsigned int n, const char *sep)
{
unsigned char *data = arg;
unsigned int i;
for (i = 0; i < n; i++) {
const char *pfx = "";
if (!i)
/* nothing */;
else if (!(i % 16))
fprintf(f, "\n");
else if (!(i % 8))
fprintf(f, " ");
else
pfx = sep;
fprintf(f, "%s%02hhx", i ? pfx : "", data[i]);
}
}
/* Split command line into argument vector. */
static int make_args(char *line, char *n_argv[], int maxargs, int cmd_nb)
{
static const char ws[] = " \t\r\n";
char *cp = line;
int n_argc = 0;
while (*cp) {
/* Skip leading whitespace. */
cp += strspn(cp, ws);
if (*cp == '\0')
break;
if (n_argc >= (maxargs - 1)) {
p_err("too many arguments to command %d", cmd_nb);
return -1;
}
/* Word begins with quote. */
if (*cp == '\'' || *cp == '"') {
char quote = *cp++;
n_argv[n_argc++] = cp;
/* Find ending quote. */
cp = strchr(cp, quote);
if (!cp) {
p_err("unterminated quoted string in command %d",
cmd_nb);
return -1;
}
} else {
n_argv[n_argc++] = cp;
/* Find end of word. */
cp += strcspn(cp, ws);
if (*cp == '\0')
break;
}
/* Separate words. */
*cp++ = 0;
}
n_argv[n_argc] = NULL;
return n_argc;
}
static int do_batch(int argc, char **argv);
static const struct cmd cmds[] = {
{ "help", do_help },
{ "batch", do_batch },
{ "prog", do_prog },
{ "map", do_map },
{ "cgroup", do_cgroup },
{ "perf", do_perf },
{ "net", do_net },
{ "feature", do_feature },
{ "btf", do_btf },
{ "version", do_version },
{ 0 }
};
static int do_batch(int argc, char **argv)
{
char buf[BATCH_LINE_LEN_MAX], contline[BATCH_LINE_LEN_MAX];
char *n_argv[BATCH_ARG_NB_MAX];
unsigned int lines = 0;
int n_argc;
FILE *fp;
char *cp;
int err;
int i;
if (argc < 2) {
p_err("too few parameters for batch");
return -1;
} else if (!is_prefix(*argv, "file")) {
p_err("expected 'file', got: %s", *argv);
return -1;
} else if (argc > 2) {
p_err("too many parameters for batch");
return -1;
}
NEXT_ARG();
if (!strcmp(*argv, "-"))
fp = stdin;
else
fp = fopen(*argv, "r");
if (!fp) {
p_err("Can't open file (%s): %s", *argv, strerror(errno));
return -1;
}
if (json_output)
jsonw_start_array(json_wtr);
while (fgets(buf, sizeof(buf), fp)) {
cp = strchr(buf, '#');
if (cp)
*cp = '\0';
if (strlen(buf) == sizeof(buf) - 1) {
errno = E2BIG;
break;
}
/* Append continuation lines if any (coming after a line ending
* with '\' in the batch file).
*/
while ((cp = strstr(buf, "\\\n")) != NULL) {
if (!fgets(contline, sizeof(contline), fp) ||
strlen(contline) == 0) {
p_err("missing continuation line on command %d",
lines);
err = -1;
goto err_close;
}
cp = strchr(contline, '#');
if (cp)
*cp = '\0';
if (strlen(buf) + strlen(contline) + 1 > sizeof(buf)) {
p_err("command %d is too long", lines);
err = -1;
goto err_close;
}
buf[strlen(buf) - 2] = '\0';
strcat(buf, contline);
}
n_argc = make_args(buf, n_argv, BATCH_ARG_NB_MAX, lines);
if (!n_argc)
continue;
if (n_argc < 0)
goto err_close;
if (json_output) {
jsonw_start_object(json_wtr);
jsonw_name(json_wtr, "command");
jsonw_start_array(json_wtr);
for (i = 0; i < n_argc; i++)
jsonw_string(json_wtr, n_argv[i]);
jsonw_end_array(json_wtr);
jsonw_name(json_wtr, "output");
}
err = cmd_select(cmds, n_argc, n_argv, do_help);
if (json_output)
jsonw_end_object(json_wtr);
if (err)
goto err_close;
lines++;
}
if (errno && errno != ENOENT) {
p_err("reading batch file failed: %s", strerror(errno));
err = -1;
} else {
if (!json_output)
printf("processed %d commands\n", lines);
err = 0;
}
err_close:
if (fp != stdin)
fclose(fp);
if (json_output)
jsonw_end_array(json_wtr);
return err;
}
int main(int argc, char **argv)
{
static const struct option options[] = {
{ "json", no_argument, NULL, 'j' },
{ "help", no_argument, NULL, 'h' },
{ "pretty", no_argument, NULL, 'p' },
{ "version", no_argument, NULL, 'V' },
{ "bpffs", no_argument, NULL, 'f' },
{ "mapcompat", no_argument, NULL, 'm' },
{ "nomount", no_argument, NULL, 'n' },
{ 0 }
};
int opt, ret;
last_do_help = do_help;
pretty_output = false;
json_output = false;
show_pinned = false;
block_mount = false;
bin_name = argv[0];
hash_init(prog_table.table);
hash_init(map_table.table);
opterr = 0;
while ((opt = getopt_long(argc, argv, "Vhpjfmn",
options, NULL)) >= 0) {
switch (opt) {
case 'V':
return do_version(argc, argv);
case 'h':
return do_help(argc, argv);
case 'p':
pretty_output = true;
/* fall through */
case 'j':
if (!json_output) {
json_wtr = jsonw_new(stdout);
if (!json_wtr) {
p_err("failed to create JSON writer");
return -1;
}
json_output = true;
}
jsonw_pretty(json_wtr, pretty_output);
break;
case 'f':
show_pinned = true;
break;
case 'm':
bpf_flags = MAPS_RELAX_COMPAT;
break;
case 'n':
block_mount = true;
break;
default:
p_err("unrecognized option '%s'", argv[optind - 1]);
if (json_output)
clean_and_exit(-1);
else
usage();
}
}
argc -= optind;
argv += optind;
if (argc < 0)
usage();
ret = cmd_select(cmds, argc, argv, do_help);
if (json_output)
jsonw_destroy(&json_wtr);
if (show_pinned) {
delete_pinned_obj_table(&prog_table);
delete_pinned_obj_table(&map_table);
}
return ret;
}