linux_dsm_epyc7002/tools/bpf/bpftool/main.c
Quentin Monnet 33221307c3 tools: bpftool: add an option to prevent auto-mount of bpffs, tracefs
In order to make life easier for users, bpftool automatically attempts
to mount the BPF virtual file system, if it is not mounted already,
before trying to pin objects in it. Similarly, it attempts to mount
tracefs if necessary before trying to dump the trace pipe to the
console.

While mounting file systems on-the-fly can improve user experience, some
administrators might prefer to avoid that. Let's add an option to block
these mount attempts. Note that it does not prevent automatic mounting
of tracefs by debugfs for the "bpftool prog tracelog" command.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-12-18 14:47:17 +01:00

389 lines
7.4 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 }\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 },
{ "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;
}