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 <dirent.h> 15 16 #include <bpf/bpf.h> 17 18 #include "main.h" 19 20 /* 0: undecided, 1: supported, 2: not supported */ 21 static int perf_query_supported; 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 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 } 112 113 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 } 149 150 static int show_proc(void) 151 { 152 struct dirent *proc_de, *pid_fd_de; 153 __u64 probe_offset, probe_addr; 154 __u32 len, prog_id, fd_type; 155 DIR *proc, *pid_fd; 156 int err, pid, fd; 157 const char *pch; 158 char buf[4096]; 159 160 proc = opendir("/proc"); 161 if (!proc) 162 return -1; 163 164 while ((proc_de = readdir(proc))) { 165 pid = 0; 166 pch = proc_de->d_name; 167 168 /* pid should be all numbers */ 169 while (isdigit(*pch)) { 170 pid = pid * 10 + *pch - '0'; 171 pch++; 172 } 173 if (*pch != '\0') 174 continue; 175 176 err = snprintf(buf, sizeof(buf), "/proc/%s/fd", proc_de->d_name); 177 if (err < 0 || err >= (int)sizeof(buf)) 178 continue; 179 180 pid_fd = opendir(buf); 181 if (!pid_fd) 182 continue; 183 184 while ((pid_fd_de = readdir(pid_fd))) { 185 fd = 0; 186 pch = pid_fd_de->d_name; 187 188 /* fd should be all numbers */ 189 while (isdigit(*pch)) { 190 fd = fd * 10 + *pch - '0'; 191 pch++; 192 } 193 if (*pch != '\0') 194 continue; 195 196 /* query (pid, fd) for potential perf events */ 197 len = sizeof(buf); 198 err = bpf_task_fd_query(pid, fd, 0, buf, &len, 199 &prog_id, &fd_type, 200 &probe_offset, &probe_addr); 201 if (err < 0) 202 continue; 203 204 if (json_output) 205 print_perf_json(pid, fd, prog_id, fd_type, buf, 206 probe_offset, probe_addr); 207 else 208 print_perf_plain(pid, fd, prog_id, fd_type, buf, 209 probe_offset, probe_addr); 210 } 211 closedir(pid_fd); 212 } 213 closedir(proc); 214 return 0; 215 } 216 217 static int do_show(int argc, char **argv) 218 { 219 int err; 220 221 if (!has_perf_query_support()) 222 return -1; 223 224 if (json_output) 225 jsonw_start_array(json_wtr); 226 err = show_proc(); 227 if (json_output) 228 jsonw_end_array(json_wtr); 229 230 return err; 231 } 232 233 static int do_help(int argc, char **argv) 234 { 235 fprintf(stderr, 236 "Usage: %1$s %2$s { show | list }\n" 237 " %1$s %2$s help }\n" 238 "\n" 239 " " HELP_SPEC_OPTIONS " }\n" 240 "", 241 bin_name, argv[-2]); 242 243 return 0; 244 } 245 246 static const struct cmd cmds[] = { 247 { "show", do_show }, 248 { "list", do_show }, 249 { "help", do_help }, 250 { 0 } 251 }; 252 253 int do_perf(int argc, char **argv) 254 { 255 return cmd_select(cmds, argc, argv, do_help); 256 } 257