tools/perf/builtin-probe.c

   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/parse-options.h"
  45 #include "util/parse-events.h"  /* For debugfs_path */
  46 #include "util/probe-finder.h"
  47 #include "util/probe-event.h"
  48
  49 #define MAX_PATH_LEN 256
  50
  51 /* Session management structure */
  52 static struct {
  53         bool need_dwarf;
  54         bool list_events;
  55         bool force_add;
  56         bool show_lines;
  57         int nr_probe;
  58         struct probe_point probes[MAX_PROBES];
  59         struct strlist *dellist;
  60         struct map_groups kmap_groups;
  61         struct map *kmaps[MAP__NR_TYPES];
  62         struct line_range line_range;
  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.kmaps[MAP__FUNCTION],
 124                                        pp->function, NULL);
 125         if (!sym)
 126                 die("Kernel symbol \'%s\' not found - probe not added.",
 127                     pp->function);
 128 }
 129
 130 #ifndef NO_DWARF_SUPPORT
 131 static int open_vmlinux(void)
 132 {
 133         if (map__load(session.kmaps[MAP__FUNCTION], NULL) < 0) {
 134                 pr_debug("Failed to load kernel map.\n");
 135                 return -EINVAL;
 136         }
 137         pr_debug("Try to open %s\n",
 138                  session.kmaps[MAP__FUNCTION]->dso->long_name);
 139         return open(session.kmaps[MAP__FUNCTION]->dso->long_name, O_RDONLY);
 140 }
 141
 142 static int opt_show_lines(const struct option *opt __used,
 143                           const char *str, int unset __used)
 144 {
 145         if (str)
 146                 parse_line_range_desc(str, &session.line_range);
 147         INIT_LIST_HEAD(&session.line_range.line_list);
 148         session.show_lines = true;
 149         return 0;
 150 }
 151 #endif
 152
 153 static const char * const probe_usage[] = {
 154         "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
 155         "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
 156         "perf probe [<options>] --del '[GROUP:]EVENT' ...",
 157         "perf probe --list",
 158 #ifndef NO_DWARF_SUPPORT
 159         "perf probe --line 'LINEDESC'",
 160 #endif
 161         NULL
 162 };
 163
 164 static const struct option options[] = {
 165         OPT_INCR('v', "verbose", &verbose,
 166                     "be more verbose (show parsed arguments, etc)"),
 167 #ifndef NO_DWARF_SUPPORT
 168         OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
 169                    "file", "vmlinux pathname"),
 170 #endif
 171         OPT_BOOLEAN('l', "list", &session.list_events,
 172                     "list up current probe events"),
 173         OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
 174                 opt_del_probe_event),
 175         OPT_CALLBACK('a', "add", NULL,
 176 #ifdef NO_DWARF_SUPPORT
 177                 "[EVENT=]FUNC[+OFF|%return] [ARG ...]",
 178 #else
 179                 "[EVENT=]FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT"
 180                 " [ARG ...]",
 181 #endif
 182                 "probe point definition, where\n"
 183                 "\t\tGROUP:\tGroup name (optional)\n"
 184                 "\t\tEVENT:\tEvent name\n"
 185                 "\t\tFUNC:\tFunction name\n"
 186                 "\t\tOFF:\tOffset from function entry (in byte)\n"
 187                 "\t\t%return:\tPut the probe at function return\n"
 188 #ifdef NO_DWARF_SUPPORT
 189                 "\t\tARG:\tProbe argument (only \n"
 190 #else
 191                 "\t\tSRC:\tSource code path\n"
 192                 "\t\tRL:\tRelative line number from function entry.\n"
 193                 "\t\tAL:\tAbsolute line number in file.\n"
 194                 "\t\tPT:\tLazy expression of line code.\n"
 195                 "\t\tARG:\tProbe argument (local variable name or\n"
 196 #endif
 197                 "\t\t\tkprobe-tracer argument format.)\n",
 198                 opt_add_probe_event),
 199         OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events"
 200                     " with existing name"),
 201 #ifndef NO_DWARF_SUPPORT
 202         OPT_CALLBACK('L', "line", NULL,
 203                      "FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]",
 204                      "Show source code lines.", opt_show_lines),
 205 #endif
 206         OPT_END()
 207 };
 208
 209 /* Initialize symbol maps for vmlinux */
 210 static void init_vmlinux(void)
 211 {
 212         symbol_conf.sort_by_name = true;
 213         if (symbol_conf.vmlinux_name == NULL)
 214                 symbol_conf.try_vmlinux_path = true;
 215         else
 216                 pr_debug("Use vmlinux: %s\n", symbol_conf.vmlinux_name);
 217         if (symbol__init() < 0)
 218                 die("Failed to init symbol map.");
 219
 220         map_groups__init(&session.kmap_groups);
 221         if (map_groups__create_kernel_maps(&session.kmap_groups,
 222                                            session.kmaps) < 0)
 223                 die("Failed to create kernel maps.");
 224 }
 225
 226 int cmd_probe(int argc, const char **argv, const char *prefix __used)
 227 {
 228         int i, ret;
 229 #ifndef NO_DWARF_SUPPORT
 230         int fd;
 231 #endif
 232         struct probe_point *pp;
 233
 234         argc = parse_options(argc, argv, options, probe_usage,
 235                              PARSE_OPT_STOP_AT_NON_OPTION);
 236         if (argc > 0) {
 237                 if (strcmp(argv[0], "-") == 0) {
 238                         pr_warning("  Error: '-' is not supported.\n");
 239                         usage_with_options(probe_usage, options);
 240                 }
 241                 parse_probe_event_argv(argc, argv);
 242         }
 243
 244         if ((!session.nr_probe && !session.dellist && !session.list_events &&
 245              !session.show_lines))
 246                 usage_with_options(probe_usage, options);
 247
 248         if (debugfs_valid_mountpoint(debugfs_path) < 0)
 249                 die("Failed to find debugfs path.");
 250
 251         if (session.list_events) {
 252                 if (session.nr_probe != 0 || session.dellist) {
 253                         pr_warning("  Error: Don't use --list with"
 254                                    " --add/--del.\n");
 255                         usage_with_options(probe_usage, options);
 256                 }
 257                 if (session.show_lines) {
 258                         pr_warning("  Error: Don't use --list with --line.\n");
 259                         usage_with_options(probe_usage, options);
 260                 }
 261                 show_perf_probe_events();
 262                 return 0;
 263         }
 264
 265 #ifndef NO_DWARF_SUPPORT
 266         if (session.show_lines) {
 267                 if (session.nr_probe != 0 || session.dellist) {
 268                         pr_warning("  Error: Don't use --line with"
 269                                    " --add/--del.\n");
 270                         usage_with_options(probe_usage, options);
 271                 }
 272                 init_vmlinux();
 273                 fd = open_vmlinux();
 274                 if (fd < 0)
 275                         die("Could not open debuginfo file.");
 276                 ret = find_line_range(fd, &session.line_range);
 277                 if (ret <= 0)
 278                         die("Source line is not found.\n");
 279                 close(fd);
 280                 show_line_range(&session.line_range);
 281                 return 0;
 282         }
 283 #endif
 284
 285         if (session.dellist) {
 286                 del_trace_kprobe_events(session.dellist);
 287                 strlist__delete(session.dellist);
 288                 if (session.nr_probe == 0)
 289                         return 0;
 290         }
 291
 292         /* Add probes */
 293         init_vmlinux();
 294
 295         if (session.need_dwarf)
 296 #ifdef NO_DWARF_SUPPORT
 297                 die("Debuginfo-analysis is not supported");
 298 #else   /* !NO_DWARF_SUPPORT */
 299                 pr_debug("Some probes require debuginfo.\n");
 300
 301         fd = open_vmlinux();
 302         if (fd < 0) {
 303                 if (session.need_dwarf)
 304                         die("Could not open debuginfo file.");
 305
 306                 pr_debug("Could not open vmlinux/module file."
 307                          " Try to use symbols.\n");
 308                 goto end_dwarf;
 309         }
 310
 311         /* Searching probe points */
 312         for (i = 0; i < session.nr_probe; i++) {
 313                 pp = &session.probes[i];
 314                 if (pp->found)
 315                         continue;
 316
 317                 lseek(fd, SEEK_SET, 0);
 318                 ret = find_probe_point(fd, pp);
 319                 if (ret > 0)
 320                         continue;
 321                 if (ret == 0) { /* No error but failed to find probe point. */
 322                         synthesize_perf_probe_point(pp);
 323                         die("Probe point '%s' not found. - probe not added.",
 324                             pp->probes[0]);
 325                 }
 326                 /* Error path */
 327                 if (session.need_dwarf) {
 328                         if (ret == -ENOENT)
 329                                 pr_warning("No dwarf info found in the vmlinux - please rebuild with CONFIG_DEBUG_INFO=y.\n");
 330                         die("Could not analyze debuginfo.");
 331                 }
 332                 pr_debug("An error occurred in debuginfo analysis."
 333                          " Try to use symbols.\n");
 334                 break;
 335         }
 336         close(fd);
 337
 338 end_dwarf:
 339 #endif /* !NO_DWARF_SUPPORT */
 340
 341         /* Synthesize probes without dwarf */
 342         for (i = 0; i < session.nr_probe; i++) {
 343                 pp = &session.probes[i];
 344                 if (pp->found)  /* This probe is already found. */
 345                         continue;
 346
 347                 evaluate_probe_point(pp);
 348                 ret = synthesize_trace_kprobe_event(pp);
 349                 if (ret == -E2BIG)
 350                         die("probe point definition becomes too long.");
 351                 else if (ret < 0)
 352                         die("Failed to synthesize a probe point.");
 353         }
 354
 355         /* Settng up probe points */
 356         add_trace_kprobe_events(session.probes, session.nr_probe,
 357                                 session.force_add);
 358         return 0;
 359 }
 360