linux-stable/tools/bpf/bpftool/perf.c
Quentin Monnet c07ba629df tools: bpftool: Update and synchronise option list in doc and help msg
All bpftool commands support the options for JSON output and debug from
libbpf. In addition, some commands support additional options
corresponding to specific use cases.

The list of options described in the man pages for the different
commands are not always accurate. The messages for interactive help are
mostly limited to HELP_SPEC_OPTIONS, and are even less representative of
the actual set of options supported for the commands.

Let's update the lists:

- HELP_SPEC_OPTIONS is modified to contain the "default" options (JSON
  and debug), and to be extensible (no ending curly bracket).
- All commands use HELP_SPEC_OPTIONS in their help message, and then
  complete the list with their specific options.
- The lists of options in the man pages are updated.
- The formatting of the list for bpftool.rst is adjusted to match
  formatting for the other man pages. This is for consistency, and also
  because it will be helpful in a future patch to automatically check
  that the files are synchronised.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210730215435.7095-5-quentin@isovalent.com
2021-07-30 15:40:27 -07:00

254 lines
5.8 KiB
C

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
// Copyright (C) 2018 Facebook
// Author: Yonghong Song <yhs@fb.com>
#define _GNU_SOURCE
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <ftw.h>
#include <bpf/bpf.h>
#include "main.h"
/* 0: undecided, 1: supported, 2: not supported */
static int perf_query_supported;
static bool has_perf_query_support(void)
{
__u64 probe_offset, probe_addr;
__u32 len, prog_id, fd_type;
char buf[256];
int fd;
if (perf_query_supported)
goto out;
fd = open("/", O_RDONLY);
if (fd < 0) {
p_err("perf_query_support: cannot open directory \"/\" (%s)",
strerror(errno));
goto out;
}
/* the following query will fail as no bpf attachment,
* the expected errno is ENOTSUPP
*/
errno = 0;
len = sizeof(buf);
bpf_task_fd_query(getpid(), fd, 0, buf, &len, &prog_id,
&fd_type, &probe_offset, &probe_addr);
if (errno == 524 /* ENOTSUPP */) {
perf_query_supported = 1;
goto close_fd;
}
perf_query_supported = 2;
p_err("perf_query_support: %s", strerror(errno));
fprintf(stderr,
"HINT: non root or kernel doesn't support TASK_FD_QUERY\n");
close_fd:
close(fd);
out:
return perf_query_supported == 1;
}
static void print_perf_json(int pid, int fd, __u32 prog_id, __u32 fd_type,
char *buf, __u64 probe_offset, __u64 probe_addr)
{
jsonw_start_object(json_wtr);
jsonw_int_field(json_wtr, "pid", pid);
jsonw_int_field(json_wtr, "fd", fd);
jsonw_uint_field(json_wtr, "prog_id", prog_id);
switch (fd_type) {
case BPF_FD_TYPE_RAW_TRACEPOINT:
jsonw_string_field(json_wtr, "fd_type", "raw_tracepoint");
jsonw_string_field(json_wtr, "tracepoint", buf);
break;
case BPF_FD_TYPE_TRACEPOINT:
jsonw_string_field(json_wtr, "fd_type", "tracepoint");
jsonw_string_field(json_wtr, "tracepoint", buf);
break;
case BPF_FD_TYPE_KPROBE:
jsonw_string_field(json_wtr, "fd_type", "kprobe");
if (buf[0] != '\0') {
jsonw_string_field(json_wtr, "func", buf);
jsonw_lluint_field(json_wtr, "offset", probe_offset);
} else {
jsonw_lluint_field(json_wtr, "addr", probe_addr);
}
break;
case BPF_FD_TYPE_KRETPROBE:
jsonw_string_field(json_wtr, "fd_type", "kretprobe");
if (buf[0] != '\0') {
jsonw_string_field(json_wtr, "func", buf);
jsonw_lluint_field(json_wtr, "offset", probe_offset);
} else {
jsonw_lluint_field(json_wtr, "addr", probe_addr);
}
break;
case BPF_FD_TYPE_UPROBE:
jsonw_string_field(json_wtr, "fd_type", "uprobe");
jsonw_string_field(json_wtr, "filename", buf);
jsonw_lluint_field(json_wtr, "offset", probe_offset);
break;
case BPF_FD_TYPE_URETPROBE:
jsonw_string_field(json_wtr, "fd_type", "uretprobe");
jsonw_string_field(json_wtr, "filename", buf);
jsonw_lluint_field(json_wtr, "offset", probe_offset);
break;
default:
break;
}
jsonw_end_object(json_wtr);
}
static void print_perf_plain(int pid, int fd, __u32 prog_id, __u32 fd_type,
char *buf, __u64 probe_offset, __u64 probe_addr)
{
printf("pid %d fd %d: prog_id %u ", pid, fd, prog_id);
switch (fd_type) {
case BPF_FD_TYPE_RAW_TRACEPOINT:
printf("raw_tracepoint %s\n", buf);
break;
case BPF_FD_TYPE_TRACEPOINT:
printf("tracepoint %s\n", buf);
break;
case BPF_FD_TYPE_KPROBE:
if (buf[0] != '\0')
printf("kprobe func %s offset %llu\n", buf,
probe_offset);
else
printf("kprobe addr %llu\n", probe_addr);
break;
case BPF_FD_TYPE_KRETPROBE:
if (buf[0] != '\0')
printf("kretprobe func %s offset %llu\n", buf,
probe_offset);
else
printf("kretprobe addr %llu\n", probe_addr);
break;
case BPF_FD_TYPE_UPROBE:
printf("uprobe filename %s offset %llu\n", buf, probe_offset);
break;
case BPF_FD_TYPE_URETPROBE:
printf("uretprobe filename %s offset %llu\n", buf,
probe_offset);
break;
default:
break;
}
}
static int show_proc(const char *fpath, const struct stat *sb,
int tflag, struct FTW *ftwbuf)
{
__u64 probe_offset, probe_addr;
__u32 len, prog_id, fd_type;
int err, pid = 0, fd = 0;
const char *pch;
char buf[4096];
/* prefix always /proc */
pch = fpath + 5;
if (*pch == '\0')
return 0;
/* pid should be all numbers */
pch++;
while (isdigit(*pch)) {
pid = pid * 10 + *pch - '0';
pch++;
}
if (*pch == '\0')
return 0;
if (*pch != '/')
return FTW_SKIP_SUBTREE;
/* check /proc/<pid>/fd directory */
pch++;
if (strncmp(pch, "fd", 2))
return FTW_SKIP_SUBTREE;
pch += 2;
if (*pch == '\0')
return 0;
if (*pch != '/')
return FTW_SKIP_SUBTREE;
/* check /proc/<pid>/fd/<fd_num> */
pch++;
while (isdigit(*pch)) {
fd = fd * 10 + *pch - '0';
pch++;
}
if (*pch != '\0')
return FTW_SKIP_SUBTREE;
/* query (pid, fd) for potential perf events */
len = sizeof(buf);
err = bpf_task_fd_query(pid, fd, 0, buf, &len, &prog_id, &fd_type,
&probe_offset, &probe_addr);
if (err < 0)
return 0;
if (json_output)
print_perf_json(pid, fd, prog_id, fd_type, buf, probe_offset,
probe_addr);
else
print_perf_plain(pid, fd, prog_id, fd_type, buf, probe_offset,
probe_addr);
return 0;
}
static int do_show(int argc, char **argv)
{
int flags = FTW_ACTIONRETVAL | FTW_PHYS;
int err = 0, nopenfd = 16;
if (!has_perf_query_support())
return -1;
if (json_output)
jsonw_start_array(json_wtr);
if (nftw("/proc", show_proc, nopenfd, flags) == -1) {
p_err("%s", strerror(errno));
err = -1;
}
if (json_output)
jsonw_end_array(json_wtr);
return err;
}
static int do_help(int argc, char **argv)
{
fprintf(stderr,
"Usage: %1$s %2$s { show | list }\n"
" %1$s %2$s help }\n"
"\n"
" " HELP_SPEC_OPTIONS " }\n"
"",
bin_name, argv[-2]);
return 0;
}
static const struct cmd cmds[] = {
{ "show", do_show },
{ "list", do_show },
{ "help", do_help },
{ 0 }
};
int do_perf(int argc, char **argv)
{
return cmd_select(cmds, argc, argv, do_help);
}