1 /* 2 * builtin-probe.c 3 * 4 * Builtin probe command: Set up probe events by C expression 5 * 6 * Written by Masami Hiramatsu <mhiramat@redhat.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 21 * 22 */ 23 #define _GNU_SOURCE 24 #include <sys/utsname.h> 25 #include <sys/types.h> 26 #include <sys/stat.h> 27 #include <fcntl.h> 28 #include <errno.h> 29 #include <stdio.h> 30 #include <unistd.h> 31 #include <stdlib.h> 32 #include <string.h> 33 34 #undef _GNU_SOURCE 35 #include "perf.h" 36 #include "builtin.h" 37 #include "util/util.h" 38 #include "util/strlist.h" 39 #include "util/event.h" 40 #include "util/debug.h" 41 #include "util/debugfs.h" 42 #include "util/symbol.h" 43 #include "util/thread.h" 44 #include "util/session.h" 45 #include "util/parse-options.h" 46 #include "util/parse-events.h" /* For debugfs_path */ 47 #include "util/probe-finder.h" 48 #include "util/probe-event.h" 49 50 #define MAX_PATH_LEN 256 51 #define MAX_PROBES 128 52 53 /* Session management structure */ 54 static struct { 55 bool need_dwarf; 56 bool list_events; 57 bool force_add; 58 int nr_probe; 59 struct probe_point probes[MAX_PROBES]; 60 struct strlist *dellist; 61 struct perf_session *psession; 62 struct map *kmap; 63 } session; 64 65 66 /* Parse an event definition. Note that any error must die. */ 67 static void parse_probe_event(const char *str) 68 { 69 struct probe_point *pp = &session.probes[session.nr_probe]; 70 71 pr_debug("probe-definition(%d): %s\n", session.nr_probe, str); 72 if (++session.nr_probe == MAX_PROBES) 73 die("Too many probes (> %d) are specified.", MAX_PROBES); 74 75 /* Parse perf-probe event into probe_point */ 76 parse_perf_probe_event(str, pp, &session.need_dwarf); 77 78 pr_debug("%d arguments\n", pp->nr_args); 79 } 80 81 static void parse_probe_event_argv(int argc, const char **argv) 82 { 83 int i, len; 84 char *buf; 85 86 /* Bind up rest arguments */ 87 len = 0; 88 for (i = 0; i < argc; i++) 89 len += strlen(argv[i]) + 1; 90 buf = zalloc(len + 1); 91 if (!buf) 92 die("Failed to allocate memory for binding arguments."); 93 len = 0; 94 for (i = 0; i < argc; i++) 95 len += sprintf(&buf[len], "%s ", argv[i]); 96 parse_probe_event(buf); 97 free(buf); 98 } 99 100 static int opt_add_probe_event(const struct option *opt __used, 101 const char *str, int unset __used) 102 { 103 if (str) 104 parse_probe_event(str); 105 return 0; 106 } 107 108 static int opt_del_probe_event(const struct option *opt __used, 109 const char *str, int unset __used) 110 { 111 if (str) { 112 if (!session.dellist) 113 session.dellist = strlist__new(true, NULL); 114 strlist__add(session.dellist, str); 115 } 116 return 0; 117 } 118 119 /* Currently just checking function name from symbol map */ 120 static void evaluate_probe_point(struct probe_point *pp) 121 { 122 struct symbol *sym; 123 sym = map__find_symbol_by_name(session.kmap, pp->function, 124 session.psession, NULL); 125 if (!sym) 126 die("Kernel symbol \'%s\' not found - probe not added.", 127 pp->function); 128 } 129 130 #ifndef NO_LIBDWARF 131 static int open_vmlinux(void) 132 { 133 if (map__load(session.kmap, session.psession, NULL) < 0) { 134 pr_debug("Failed to load kernel map.\n"); 135 return -EINVAL; 136 } 137 pr_debug("Try to open %s\n", session.kmap->dso->long_name); 138 return open(session.kmap->dso->long_name, O_RDONLY); 139 } 140 #endif 141 142 static const char * const probe_usage[] = { 143 "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]", 144 "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]", 145 "perf probe [<options>] --del '[GROUP:]EVENT' ...", 146 "perf probe --list", 147 NULL 148 }; 149 150 static const struct option options[] = { 151 OPT_BOOLEAN('v', "verbose", &verbose, 152 "be more verbose (show parsed arguments, etc)"), 153 #ifndef NO_LIBDWARF 154 OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name, 155 "file", "vmlinux pathname"), 156 #endif 157 OPT_BOOLEAN('l', "list", &session.list_events, 158 "list up current probe events"), 159 OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.", 160 opt_del_probe_event), 161 OPT_CALLBACK('a', "add", NULL, 162 #ifdef NO_LIBDWARF 163 "[EVENT=]FUNC[+OFFS|%return] [ARG ...]", 164 #else 165 "[EVENT=]FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]", 166 #endif 167 "probe point definition, where\n" 168 "\t\tGROUP:\tGroup name (optional)\n" 169 "\t\tEVENT:\tEvent name\n" 170 "\t\tFUNC:\tFunction name\n" 171 "\t\tOFFS:\tOffset from function entry (in byte)\n" 172 "\t\t%return:\tPut the probe at function return\n" 173 #ifdef NO_LIBDWARF 174 "\t\tARG:\tProbe argument (only \n" 175 #else 176 "\t\tSRC:\tSource code path\n" 177 "\t\tRLN:\tRelative line number from function entry.\n" 178 "\t\tALN:\tAbsolute line number in file.\n" 179 "\t\tARG:\tProbe argument (local variable name or\n" 180 #endif 181 "\t\t\tkprobe-tracer argument format.)\n", 182 opt_add_probe_event), 183 OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events" 184 " with existing name"), 185 OPT_END() 186 }; 187 188 int cmd_probe(int argc, const char **argv, const char *prefix __used) 189 { 190 int i, ret; 191 #ifndef NO_LIBDWARF 192 int fd; 193 #endif 194 struct probe_point *pp; 195 196 argc = parse_options(argc, argv, options, probe_usage, 197 PARSE_OPT_STOP_AT_NON_OPTION); 198 if (argc > 0) { 199 if (strcmp(argv[0], "-") == 0) { 200 pr_warning(" Error: '-' is not supported.\n"); 201 usage_with_options(probe_usage, options); 202 } 203 parse_probe_event_argv(argc, argv); 204 } 205 206 if ((!session.nr_probe && !session.dellist && !session.list_events)) 207 usage_with_options(probe_usage, options); 208 209 if (debugfs_valid_mountpoint(debugfs_path) < 0) 210 die("Failed to find debugfs path."); 211 212 if (session.list_events) { 213 if (session.nr_probe != 0 || session.dellist) { 214 pr_warning(" Error: Don't use --list with" 215 " --add/--del.\n"); 216 usage_with_options(probe_usage, options); 217 } 218 show_perf_probe_events(); 219 return 0; 220 } 221 222 if (session.dellist) { 223 del_trace_kprobe_events(session.dellist); 224 strlist__delete(session.dellist); 225 if (session.nr_probe == 0) 226 return 0; 227 } 228 229 /* Initialize symbol maps for vmlinux */ 230 symbol_conf.sort_by_name = true; 231 if (symbol_conf.vmlinux_name == NULL) 232 symbol_conf.try_vmlinux_path = true; 233 if (symbol__init() < 0) 234 die("Failed to init symbol map."); 235 session.psession = perf_session__new(NULL, O_WRONLY, false); 236 if (session.psession == NULL) 237 die("Failed to init perf_session."); 238 session.kmap = map_groups__find_by_name(&session.psession->kmaps, 239 MAP__FUNCTION, 240 "[kernel.kallsyms]"); 241 if (!session.kmap) 242 die("Could not find kernel map.\n"); 243 244 if (session.need_dwarf) 245 #ifdef NO_LIBDWARF 246 die("Debuginfo-analysis is not supported"); 247 #else /* !NO_LIBDWARF */ 248 pr_debug("Some probes require debuginfo.\n"); 249 250 fd = open_vmlinux(); 251 if (fd < 0) { 252 if (session.need_dwarf) 253 die("Could not open debuginfo file."); 254 255 pr_debug("Could not open vmlinux/module file." 256 " Try to use symbols.\n"); 257 goto end_dwarf; 258 } 259 260 /* Searching probe points */ 261 for (i = 0; i < session.nr_probe; i++) { 262 pp = &session.probes[i]; 263 if (pp->found) 264 continue; 265 266 lseek(fd, SEEK_SET, 0); 267 ret = find_probepoint(fd, pp); 268 if (ret > 0) 269 continue; 270 if (ret == 0) { /* No error but failed to find probe point. */ 271 synthesize_perf_probe_point(pp); 272 die("Probe point '%s' not found. - probe not added.", 273 pp->probes[0]); 274 } 275 /* Error path */ 276 if (session.need_dwarf) { 277 if (ret == -ENOENT) 278 pr_warning("No dwarf info found in the vmlinux - please rebuild with CONFIG_DEBUG_INFO=y.\n"); 279 die("Could not analyze debuginfo."); 280 } 281 pr_debug("An error occurred in debuginfo analysis." 282 " Try to use symbols.\n"); 283 break; 284 } 285 close(fd); 286 287 end_dwarf: 288 #endif /* !NO_LIBDWARF */ 289 290 /* Synthesize probes without dwarf */ 291 for (i = 0; i < session.nr_probe; i++) { 292 pp = &session.probes[i]; 293 if (pp->found) /* This probe is already found. */ 294 continue; 295 296 evaluate_probe_point(pp); 297 ret = synthesize_trace_kprobe_event(pp); 298 if (ret == -E2BIG) 299 die("probe point definition becomes too long."); 300 else if (ret < 0) 301 die("Failed to synthesize a probe point."); 302 } 303 304 /* Settng up probe points */ 305 add_trace_kprobe_events(session.probes, session.nr_probe, 306 session.force_add); 307 return 0; 308 } 309 310