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