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.h>
17
18 #include "main.h"
19
20 /* 0: undecided, 1: supported, 2: not supported */
21 static int perf_query_supported;
has_perf_query_support(void)22 static 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
57 close_fd:
58 close(fd);
59 out:
60 return perf_query_supported == 1;
61 }
62
print_perf_json(int pid,int fd,__u32 prog_id,__u32 fd_type,char * buf,__u64 probe_offset,__u64 probe_addr)63 static 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
print_perf_plain(int pid,int fd,__u32 prog_id,__u32 fd_type,char * buf,__u64 probe_offset,__u64 probe_addr)113 static 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
show_proc(const char * fpath,const struct stat * sb,int tflag,struct FTW * ftwbuf)150 static 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
do_show(int argc,char ** argv)211 static 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
do_help(int argc,char ** argv)231 static int do_help(int argc, char **argv)
232 {
233 fprintf(stderr,
234 "Usage: %s %s { show | list | help }\n"
235 "",
236 bin_name, argv[-2]);
237
238 return 0;
239 }
240
241 static const struct cmd cmds[] = {
242 { "show", do_show },
243 { "list", do_show },
244 { "help", do_help },
245 { 0 }
246 };
247
do_perf(int argc,char ** argv)248 int do_perf(int argc, char **argv)
249 {
250 return cmd_select(cmds, argc, argv, do_help);
251 }
252
