1 // SPDX-License-Identifier: GPL-2.0+ 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; 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 } 108 jsonw_end_object(json_wtr); 109 } 110 111 static void print_perf_plain(int pid, int fd, __u32 prog_id, __u32 fd_type, 112 char *buf, __u64 probe_offset, __u64 probe_addr) 113 { 114 printf("pid %d fd %d: prog_id %u ", pid, fd, prog_id); 115 switch (fd_type) { 116 case BPF_FD_TYPE_RAW_TRACEPOINT: 117 printf("raw_tracepoint %s\n", buf); 118 break; 119 case BPF_FD_TYPE_TRACEPOINT: 120 printf("tracepoint %s\n", buf); 121 break; 122 case BPF_FD_TYPE_KPROBE: 123 if (buf[0] != '\0') 124 printf("kprobe func %s offset %llu\n", buf, 125 probe_offset); 126 else 127 printf("kprobe addr %llu\n", probe_addr); 128 break; 129 case BPF_FD_TYPE_KRETPROBE: 130 if (buf[0] != '\0') 131 printf("kretprobe func %s offset %llu\n", buf, 132 probe_offset); 133 else 134 printf("kretprobe addr %llu\n", probe_addr); 135 break; 136 case BPF_FD_TYPE_UPROBE: 137 printf("uprobe filename %s offset %llu\n", buf, probe_offset); 138 break; 139 case BPF_FD_TYPE_URETPROBE: 140 printf("uretprobe filename %s offset %llu\n", buf, 141 probe_offset); 142 break; 143 } 144 } 145 146 static int show_proc(const char *fpath, const struct stat *sb, 147 int tflag, struct FTW *ftwbuf) 148 { 149 __u64 probe_offset, probe_addr; 150 __u32 len, prog_id, fd_type; 151 int err, pid = 0, fd = 0; 152 const char *pch; 153 char buf[4096]; 154 155 /* prefix always /proc */ 156 pch = fpath + 5; 157 if (*pch == '\0') 158 return 0; 159 160 /* pid should be all numbers */ 161 pch++; 162 while (isdigit(*pch)) { 163 pid = pid * 10 + *pch - '0'; 164 pch++; 165 } 166 if (*pch == '\0') 167 return 0; 168 if (*pch != '/') 169 return FTW_SKIP_SUBTREE; 170 171 /* check /proc/<pid>/fd directory */ 172 pch++; 173 if (strncmp(pch, "fd", 2)) 174 return FTW_SKIP_SUBTREE; 175 pch += 2; 176 if (*pch == '\0') 177 return 0; 178 if (*pch != '/') 179 return FTW_SKIP_SUBTREE; 180 181 /* check /proc/<pid>/fd/<fd_num> */ 182 pch++; 183 while (isdigit(*pch)) { 184 fd = fd * 10 + *pch - '0'; 185 pch++; 186 } 187 if (*pch != '\0') 188 return FTW_SKIP_SUBTREE; 189 190 /* query (pid, fd) for potential perf events */ 191 len = sizeof(buf); 192 err = bpf_task_fd_query(pid, fd, 0, buf, &len, &prog_id, &fd_type, 193 &probe_offset, &probe_addr); 194 if (err < 0) 195 return 0; 196 197 if (json_output) 198 print_perf_json(pid, fd, prog_id, fd_type, buf, probe_offset, 199 probe_addr); 200 else 201 print_perf_plain(pid, fd, prog_id, fd_type, buf, probe_offset, 202 probe_addr); 203 204 return 0; 205 } 206 207 static int do_show(int argc, char **argv) 208 { 209 int flags = FTW_ACTIONRETVAL | FTW_PHYS; 210 int err = 0, nopenfd = 16; 211 212 if (!has_perf_query_support()) 213 return -1; 214 215 if (json_output) 216 jsonw_start_array(json_wtr); 217 if (nftw("/proc", show_proc, nopenfd, flags) == -1) { 218 p_err("%s", strerror(errno)); 219 err = -1; 220 } 221 if (json_output) 222 jsonw_end_array(json_wtr); 223 224 return err; 225 } 226 227 static int do_help(int argc, char **argv) 228 { 229 fprintf(stderr, 230 "Usage: %s %s { show | list | help }\n" 231 "", 232 bin_name, argv[-2]); 233 234 return 0; 235 } 236 237 static const struct cmd cmds[] = { 238 { "show", do_show }, 239 { "list", do_show }, 240 { "help", do_help }, 241 { 0 } 242 }; 243 244 int do_perf(int argc, char **argv) 245 { 246 return cmd_select(cmds, argc, argv, do_help); 247 } 248