1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
  2// Copyright (C) 2018 Facebook
  3// Author: Yonghong Song <yhs@fb.com>
  4
  5#define _GNU_SOURCE
  6#include <ctype.h>
  7#include <errno.h>
  8#include <fcntl.h>
  9#include <stdlib.h>
 10#include <string.h>
 11#include <sys/stat.h>
 12#include <sys/types.h>
 13#include <unistd.h>
 14#include <ftw.h>
 15
 16#include <bpf/bpf.h>
 17
 18#include "main.h"
 19
 20/* 0: undecided, 1: supported, 2: not supported */
 21static int perf_query_supported;
 22static bool has_perf_query_support(void)
 23{
 24	__u64 probe_offset, probe_addr;
 25	__u32 len, prog_id, fd_type;
 26	char buf[256];
 27	int fd;
 28
 29	if (perf_query_supported)
 30		goto out;
 31
 32	fd = open("/", O_RDONLY);
 33	if (fd < 0) {
 34		p_err("perf_query_support: cannot open directory \"/\" (%s)",
 35		      strerror(errno));
 36		goto out;
 37	}
 38
 39	/* the following query will fail as no bpf attachment,
 40	 * the expected errno is ENOTSUPP
 41	 */
 42	errno = 0;
 43	len = sizeof(buf);
 44	bpf_task_fd_query(getpid(), fd, 0, buf, &len, &prog_id,
 45			  &fd_type, &probe_offset, &probe_addr);
 46
 47	if (errno == 524 /* ENOTSUPP */) {
 48		perf_query_supported = 1;
 49		goto close_fd;
 50	}
 51
 52	perf_query_supported = 2;
 53	p_err("perf_query_support: %s", strerror(errno));
 54	fprintf(stderr,
 55		"HINT: non root or kernel doesn't support TASK_FD_QUERY\n");
 56
 57close_fd:
 58	close(fd);
 59out:
 60	return perf_query_supported == 1;
 61}
 62
 63static void print_perf_json(int pid, int fd, __u32 prog_id, __u32 fd_type,
 64			    char *buf, __u64 probe_offset, __u64 probe_addr)
 65{
 66	jsonw_start_object(json_wtr);
 67	jsonw_int_field(json_wtr, "pid", pid);
 68	jsonw_int_field(json_wtr, "fd", fd);
 69	jsonw_uint_field(json_wtr, "prog_id", prog_id);
 70	switch (fd_type) {
 71	case BPF_FD_TYPE_RAW_TRACEPOINT:
 72		jsonw_string_field(json_wtr, "fd_type", "raw_tracepoint");
 73		jsonw_string_field(json_wtr, "tracepoint", buf);
 74		break;
 75	case BPF_FD_TYPE_TRACEPOINT:
 76		jsonw_string_field(json_wtr, "fd_type", "tracepoint");
 77		jsonw_string_field(json_wtr, "tracepoint", buf);
 78		break;
 79	case BPF_FD_TYPE_KPROBE:
 80		jsonw_string_field(json_wtr, "fd_type", "kprobe");
 81		if (buf[0] != '\0') {
 82			jsonw_string_field(json_wtr, "func", buf);
 83			jsonw_lluint_field(json_wtr, "offset", probe_offset);
 84		} else {
 85			jsonw_lluint_field(json_wtr, "addr", probe_addr);
 86		}
 87		break;
 88	case BPF_FD_TYPE_KRETPROBE:
 89		jsonw_string_field(json_wtr, "fd_type", "kretprobe");
 90		if (buf[0] != '\0') {
 91			jsonw_string_field(json_wtr, "func", buf);
 92			jsonw_lluint_field(json_wtr, "offset", probe_offset);
 93		} else {
 94			jsonw_lluint_field(json_wtr, "addr", probe_addr);
 95		}
 96		break;
 97	case BPF_FD_TYPE_UPROBE:
 98		jsonw_string_field(json_wtr, "fd_type", "uprobe");
 99		jsonw_string_field(json_wtr, "filename", buf);
100		jsonw_lluint_field(json_wtr, "offset", probe_offset);
101		break;
102	case BPF_FD_TYPE_URETPROBE:
103		jsonw_string_field(json_wtr, "fd_type", "uretprobe");
104		jsonw_string_field(json_wtr, "filename", buf);
105		jsonw_lluint_field(json_wtr, "offset", probe_offset);
106		break;
107	default:
108		break;
109	}
110	jsonw_end_object(json_wtr);
111}
112
113static void print_perf_plain(int pid, int fd, __u32 prog_id, __u32 fd_type,
114			     char *buf, __u64 probe_offset, __u64 probe_addr)
115{
116	printf("pid %d  fd %d: prog_id %u  ", pid, fd, prog_id);
117	switch (fd_type) {
118	case BPF_FD_TYPE_RAW_TRACEPOINT:
119		printf("raw_tracepoint  %s\n", buf);
120		break;
121	case BPF_FD_TYPE_TRACEPOINT:
122		printf("tracepoint  %s\n", buf);
123		break;
124	case BPF_FD_TYPE_KPROBE:
125		if (buf[0] != '\0')
126			printf("kprobe  func %s  offset %llu\n", buf,
127			       probe_offset);
128		else
129			printf("kprobe  addr %llu\n", probe_addr);
130		break;
131	case BPF_FD_TYPE_KRETPROBE:
132		if (buf[0] != '\0')
133			printf("kretprobe  func %s  offset %llu\n", buf,
134			       probe_offset);
135		else
136			printf("kretprobe  addr %llu\n", probe_addr);
137		break;
138	case BPF_FD_TYPE_UPROBE:
139		printf("uprobe  filename %s  offset %llu\n", buf, probe_offset);
140		break;
141	case BPF_FD_TYPE_URETPROBE:
142		printf("uretprobe  filename %s  offset %llu\n", buf,
143		       probe_offset);
144		break;
145	default:
146		break;
147	}
148}
149
150static int show_proc(const char *fpath, const struct stat *sb,
151		     int tflag, struct FTW *ftwbuf)
152{
153	__u64 probe_offset, probe_addr;
154	__u32 len, prog_id, fd_type;
155	int err, pid = 0, fd = 0;
156	const char *pch;
157	char buf[4096];
158
159	/* prefix always /proc */
160	pch = fpath + 5;
161	if (*pch == '\0')
162		return 0;
163
164	/* pid should be all numbers */
165	pch++;
166	while (isdigit(*pch)) {
167		pid = pid * 10 + *pch - '0';
168		pch++;
169	}
170	if (*pch == '\0')
171		return 0;
172	if (*pch != '/')
173		return FTW_SKIP_SUBTREE;
174
175	/* check /proc/<pid>/fd directory */
176	pch++;
177	if (strncmp(pch, "fd", 2))
178		return FTW_SKIP_SUBTREE;
179	pch += 2;
180	if (*pch == '\0')
181		return 0;
182	if (*pch != '/')
183		return FTW_SKIP_SUBTREE;
184
185	/* check /proc/<pid>/fd/<fd_num> */
186	pch++;
187	while (isdigit(*pch)) {
188		fd = fd * 10 + *pch - '0';
189		pch++;
190	}
191	if (*pch != '\0')
192		return FTW_SKIP_SUBTREE;
193
194	/* query (pid, fd) for potential perf events */
195	len = sizeof(buf);
196	err = bpf_task_fd_query(pid, fd, 0, buf, &len, &prog_id, &fd_type,
197				&probe_offset, &probe_addr);
198	if (err < 0)
199		return 0;
200
201	if (json_output)
202		print_perf_json(pid, fd, prog_id, fd_type, buf, probe_offset,
203				probe_addr);
204	else
205		print_perf_plain(pid, fd, prog_id, fd_type, buf, probe_offset,
206				 probe_addr);
207
208	return 0;
209}
210
211static int do_show(int argc, char **argv)
212{
213	int flags = FTW_ACTIONRETVAL | FTW_PHYS;
214	int err = 0, nopenfd = 16;
215
216	if (!has_perf_query_support())
217		return -1;
218
219	if (json_output)
220		jsonw_start_array(json_wtr);
221	if (nftw("/proc", show_proc, nopenfd, flags) == -1) {
222		p_err("%s", strerror(errno));
223		err = -1;
224	}
225	if (json_output)
226		jsonw_end_array(json_wtr);
227
228	return err;
229}
230
231static int do_help(int argc, char **argv)
232{
233	fprintf(stderr,
234		"Usage: %1$s %2$s { show | list | help }\n"
235		"",
236		bin_name, argv[-2]);
237
238	return 0;
239}
240
241static const struct cmd cmds[] = {
242	{ "show",	do_show },
243	{ "list",	do_show },
244	{ "help",	do_help },
245	{ 0 }
246};
247
248int do_perf(int argc, char **argv)
249{
250	return cmd_select(cmds, argc, argv, do_help);
251}