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