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   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 #define MAX_PROBES 128
  51
  52 /* Session management structure */
  53 static struct {
  54         bool need_dwarf;
  55         bool list_events;
  56         bool force_add;
  57         bool show_lines;
  58         int nr_probe;
  59         struct probe_point probes[MAX_PROBES];
  60         struct strlist *dellist;
  61         struct map_groups kmap_groups;
  62         struct map *kmaps[MAP__NR_TYPES];
  63         struct line_range line_range;
  64 } session;
  65
  66
  67 /* Parse an event definition. Note that any error must die. */
  68 static void parse_probe_event(const char *str)
  69 {
  70         struct probe_point *pp = &session.probes[session.nr_probe];
  71
  72         pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
  73         if (++session.nr_probe == MAX_PROBES)
  74                 die("Too many probes (> %d) are specified.", MAX_PROBES);
  75
  76         /* Parse perf-probe event into probe_point */
  77         parse_perf_probe_event(str, pp, &session.need_dwarf);
  78
  79         pr_debug("%d arguments\n", pp->nr_args);
  80 }
  81
  82 static void parse_probe_event_argv(int argc, const char **argv)
  83 {
  84         int i, len;
  85         char *buf;
  86
  87         /* Bind up rest arguments */
  88         len = 0;
  89         for (i = 0; i < argc; i++)
  90                 len += strlen(argv[i]) + 1;
  91         buf = zalloc(len + 1);
  92         if (!buf)
  93                 die("Failed to allocate memory for binding arguments.");
  94         len = 0;
  95         for (i = 0; i < argc; i++)
  96                 len += sprintf(&buf[len], "%s ", argv[i]);
  97         parse_probe_event(buf);
  98         free(buf);
  99 }
 100
 101 static int opt_add_probe_event(const struct option *opt __used,
 102                               const char *str, int unset __used)
 103 {
 104         if (str)
 105                 parse_probe_event(str);
 106         return 0;
 107 }
 108
 109 static int opt_del_probe_event(const struct option *opt __used,
 110                                const char *str, int unset __used)
 111 {
 112         if (str) {
 113                 if (!session.dellist)
 114                         session.dellist = strlist__new(true, NULL);
 115                 strlist__add(session.dellist, str);
 116         }
 117         return 0;
 118 }
 119
 120 /* Currently just checking function name from symbol map */
 121 static void evaluate_probe_point(struct probe_point *pp)
 122 {
 123         struct symbol *sym;
 124         sym = map__find_symbol_by_name(session.kmaps[MAP__FUNCTION],
 125                                        pp->function, NULL);
 126         if (!sym)
 127                 die("Kernel symbol \'%s\' not found - probe not added.",
 128                     pp->function);
 129 }
 130
 131 #ifndef NO_LIBDWARF
 132 static int open_vmlinux(void)
 133 {
 134         if (map__load(session.kmaps[MAP__FUNCTION], NULL) < 0) {
 135                 pr_debug("Failed to load kernel map.\n");
 136                 return -EINVAL;
 137         }
 138         pr_debug("Try to open %s\n",
 139                  session.kmaps[MAP__FUNCTION]->dso->long_name);
 140         return open(session.kmaps[MAP__FUNCTION]->dso->long_name, O_RDONLY);
 141 }
 142
 143 static int opt_show_lines(const struct option *opt __used,
 144                           const char *str, int unset __used)
 145 {
 146         if (str)
 147                 parse_line_range_desc(str, &session.line_range);
 148         INIT_LIST_HEAD(&session.line_range.line_list);
 149         session.show_lines = true;
 150         return 0;
 151 }
 152 #endif
 153
 154 static const char * const probe_usage[] = {
 155         "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
 156         "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
 157         "perf probe [<options>] --del '[GROUP:]EVENT' ...",
 158         "perf probe --list",
 159 #ifndef NO_LIBDWARF
 160         "perf probe --line 'LINEDESC'",
 161 #endif
 162         NULL
 163 };
 164
 165 static const struct option options[] = {
 166         OPT_BOOLEAN('v', "verbose", &verbose,
 167                     "be more verbose (show parsed arguments, etc)"),
 168 #ifndef NO_LIBDWARF
 169         OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
 170                    "file", "vmlinux pathname"),
 171 #endif
 172         OPT_BOOLEAN('l', "list", &session.list_events,
 173                     "list up current probe events"),
 174         OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
 175                 opt_del_probe_event),
 176         OPT_CALLBACK('a', "add", NULL,
 177 #ifdef NO_LIBDWARF
 178                 "[EVENT=]FUNC[+OFFS|%return] [ARG ...]",
 179 #else
 180                 "[EVENT=]FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [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\tOFFS:\tOffset from function entry (in byte)\n"
 187                 "\t\t%return:\tPut the probe at function return\n"
 188 #ifdef NO_LIBDWARF
 189                 "\t\tARG:\tProbe argument (only \n"
 190 #else
 191                 "\t\tSRC:\tSource code path\n"
 192                 "\t\tRLN:\tRelative line number from function entry.\n"
 193                 "\t\tALN:\tAbsolute line number in file.\n"
 194                 "\t\tARG:\tProbe argument (local variable name or\n"
 195 #endif
 196                 "\t\t\tkprobe-tracer argument format.)\n",
 197                 opt_add_probe_event),
 198         OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events"
 199                     " with existing name"),
 200 #ifndef NO_LIBDWARF
 201         OPT_CALLBACK('L', "line", NULL,
 202                      "FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]",
 203                      "Show source code lines.", opt_show_lines),
 204 #endif
 205         OPT_END()
 206 };
 207
 208 /* Initialize symbol maps for vmlinux */
 209 static void init_vmlinux(void)
 210 {
 211         symbol_conf.sort_by_name = true;
 212         if (symbol_conf.vmlinux_name == NULL)
 213                 symbol_conf.try_vmlinux_path = true;
 214         else
 215                 pr_debug("Use vmlinux: %s\n", symbol_conf.vmlinux_name);
 216         if (symbol__init() < 0)
 217                 die("Failed to init symbol map.");
 218
 219         map_groups__init(&session.kmap_groups);
 220         if (map_groups__create_kernel_maps(&session.kmap_groups,
 221                                            session.kmaps) < 0)
 222                 die("Failed to create kernel maps.");
 223 }
 224
 225 int cmd_probe(int argc, const char **argv, const char *prefix __used)
 226 {
 227         int i, ret;
 228 #ifndef NO_LIBDWARF
 229         int fd;
 230 #endif
 231         struct probe_point *pp;
 232
 233         argc = parse_options(argc, argv, options, probe_usage,
 234                              PARSE_OPT_STOP_AT_NON_OPTION);
 235         if (argc > 0) {
 236                 if (strcmp(argv[0], "-") == 0) {
 237                         pr_warning("  Error: '-' is not supported.\n");
 238                         usage_with_options(probe_usage, options);
 239                 }
 240                 parse_probe_event_argv(argc, argv);
 241         }
 242
 243         if ((!session.nr_probe && !session.dellist && !session.list_events &&
 244              !session.show_lines))
 245                 usage_with_options(probe_usage, options);
 246
 247         if (debugfs_valid_mountpoint(debugfs_path) < 0)
 248                 die("Failed to find debugfs path.");
 249
 250         if (session.list_events) {
 251                 if (session.nr_probe != 0 || session.dellist) {
 252                         pr_warning("  Error: Don't use --list with"
 253                                    " --add/--del.\n");
 254                         usage_with_options(probe_usage, options);
 255                 }
 256                 if (session.show_lines) {
 257                         pr_warning("  Error: Don't use --list with --line.\n");
 258                         usage_with_options(probe_usage, options);
 259                 }
 260                 show_perf_probe_events();
 261                 return 0;
 262         }
 263
 264 #ifndef NO_LIBDWARF
 265         if (session.show_lines) {
 266                 if (session.nr_probe != 0 || session.dellist) {
 267                         pr_warning("  Error: Don't use --line with"
 268                                    " --add/--del.\n");
 269                         usage_with_options(probe_usage, options);
 270                 }
 271                 init_vmlinux();
 272                 fd = open_vmlinux();
 273                 if (fd < 0)
 274                         die("Could not open debuginfo file.");
 275                 ret = find_line_range(fd, &session.line_range);
 276                 if (ret <= 0)
 277                         die("Source line is not found.\n");
 278                 close(fd);
 279                 show_line_range(&session.line_range);
 280                 return 0;
 281         }
 282 #endif
 283
 284         if (session.dellist) {
 285                 del_trace_kprobe_events(session.dellist);
 286                 strlist__delete(session.dellist);
 287                 if (session.nr_probe == 0)
 288                         return 0;
 289         }
 290
 291         /* Add probes */
 292         init_vmlinux();
 293
 294         if (session.need_dwarf)
 295 #ifdef NO_LIBDWARF
 296                 die("Debuginfo-analysis is not supported");
 297 #else   /* !NO_LIBDWARF */
 298                 pr_debug("Some probes require debuginfo.\n");
 299
 300         fd = open_vmlinux();
 301         if (fd < 0) {
 302                 if (session.need_dwarf)
 303                         die("Could not open debuginfo file.");
 304
 305                 pr_debug("Could not open vmlinux/module file."
 306                          " Try to use symbols.\n");
 307                 goto end_dwarf;
 308         }
 309
 310         /* Searching probe points */
 311         for (i = 0; i < session.nr_probe; i++) {
 312                 pp = &session.probes[i];
 313                 if (pp->found)
 314                         continue;
 315
 316                 lseek(fd, SEEK_SET, 0);
 317                 ret = find_probe_point(fd, pp);
 318                 if (ret > 0)
 319                         continue;
 320                 if (ret == 0) { /* No error but failed to find probe point. */
 321                         synthesize_perf_probe_point(pp);
 322                         die("Probe point '%s' not found. - probe not added.",
 323                             pp->probes[0]);
 324                 }
 325                 /* Error path */
 326                 if (session.need_dwarf) {
 327                         if (ret == -ENOENT)
 328                                 pr_warning("No dwarf info found in the vmlinux - please rebuild with CONFIG_DEBUG_INFO=y.\n");
 329                         die("Could not analyze debuginfo.");
 330                 }
 331                 pr_debug("An error occurred in debuginfo analysis."
 332                          " Try to use symbols.\n");
 333                 break;
 334         }
 335         close(fd);
 336
 337 end_dwarf:
 338 #endif /* !NO_LIBDWARF */
 339
 340         /* Synthesize probes without dwarf */
 341         for (i = 0; i < session.nr_probe; i++) {
 342                 pp = &session.probes[i];
 343                 if (pp->found)  /* This probe is already found. */
 344                         continue;
 345
 346                 evaluate_probe_point(pp);
 347                 ret = synthesize_trace_kprobe_event(pp);
 348                 if (ret == -E2BIG)
 349                         die("probe point definition becomes too long.");
 350                 else if (ret < 0)
 351                         die("Failed to synthesize a probe point.");
 352         }
 353
 354         /* Settng up probe points */
 355         add_trace_kprobe_events(session.probes, session.nr_probe,
 356                                 session.force_add);
 357         return 0;
 358 }
 359