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/parse-options.h"
  42 #include "util/parse-events.h"  /* For debugfs_path */
  43 #include "util/probe-finder.h"
  44 #include "util/probe-event.h"
  45
  46 /* Default vmlinux search paths */
  47 #define NR_SEARCH_PATH 4
  48 const char *default_search_path[NR_SEARCH_PATH] = {
  49 "/lib/modules/%s/build/vmlinux",                /* Custom build kernel */
  50 "/usr/lib/debug/lib/modules/%s/vmlinux",        /* Red Hat debuginfo */
  51 "/boot/vmlinux-debug-%s",                       /* Ubuntu */
  52 "./vmlinux",                                    /* CWD */
  53 };
  54
  55 #define MAX_PATH_LEN 256
  56 #define MAX_PROBES 128
  57
  58 /* Session management structure */
  59 static struct {
  60         char *vmlinux;
  61         char *release;
  62         bool need_dwarf;
  63         bool list_events;
  64         bool force_add;
  65         int nr_probe;
  66         struct probe_point probes[MAX_PROBES];
  67         struct strlist *dellist;
  68 } session;
  69
  70
  71 /* Parse an event definition. Note that any error must die. */
  72 static void parse_probe_event(const char *str)
  73 {
  74         struct probe_point *pp = &session.probes[session.nr_probe];
  75
  76         pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
  77         if (++session.nr_probe == MAX_PROBES)
  78                 die("Too many probes (> %d) are specified.", MAX_PROBES);
  79
  80         /* Parse perf-probe event into probe_point */
  81         parse_perf_probe_event(str, pp, &session.need_dwarf);
  82
  83         pr_debug("%d arguments\n", pp->nr_args);
  84 }
  85
  86 static void parse_probe_event_argv(int argc, const char **argv)
  87 {
  88         int i, len;
  89         char *buf;
  90
  91         /* Bind up rest arguments */
  92         len = 0;
  93         for (i = 0; i < argc; i++)
  94                 len += strlen(argv[i]) + 1;
  95         buf = zalloc(len + 1);
  96         if (!buf)
  97                 die("Failed to allocate memory for binding arguments.");
  98         len = 0;
  99         for (i = 0; i < argc; i++)
 100                 len += sprintf(&buf[len], "%s ", argv[i]);
 101         parse_probe_event(buf);
 102         free(buf);
 103 }
 104
 105 static int opt_add_probe_event(const struct option *opt __used,
 106                               const char *str, int unset __used)
 107 {
 108         if (str)
 109                 parse_probe_event(str);
 110         return 0;
 111 }
 112
 113 static int opt_del_probe_event(const struct option *opt __used,
 114                                const char *str, int unset __used)
 115 {
 116         if (str) {
 117                 if (!session.dellist)
 118                         session.dellist = strlist__new(true, NULL);
 119                 strlist__add(session.dellist, str);
 120         }
 121         return 0;
 122 }
 123
 124 #ifndef NO_LIBDWARF
 125 static int open_default_vmlinux(void)
 126 {
 127         struct utsname uts;
 128         char fname[MAX_PATH_LEN];
 129         int fd, ret, i;
 130
 131         ret = uname(&uts);
 132         if (ret) {
 133                 pr_debug("uname() failed.\n");
 134                 return -errno;
 135         }
 136         session.release = uts.release;
 137         for (i = 0; i < NR_SEARCH_PATH; i++) {
 138                 ret = snprintf(fname, MAX_PATH_LEN,
 139                                default_search_path[i], session.release);
 140                 if (ret >= MAX_PATH_LEN || ret < 0) {
 141                         pr_debug("Filename(%d,%s) is too long.\n", i,
 142                                 uts.release);
 143                         errno = E2BIG;
 144                         return -E2BIG;
 145                 }
 146                 pr_debug("try to open %s\n", fname);
 147                 fd = open(fname, O_RDONLY);
 148                 if (fd >= 0)
 149                         break;
 150         }
 151         return fd;
 152 }
 153 #endif
 154
 155 static const char * const probe_usage[] = {
 156         "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
 157         "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
 158         "perf probe [<options>] --del '[GROUP:]EVENT' ...",
 159         "perf probe --list",
 160         NULL
 161 };
 162
 163 static const struct option options[] = {
 164         OPT_BOOLEAN('v', "verbose", &verbose,
 165                     "be more verbose (show parsed arguments, etc)"),
 166 #ifndef NO_LIBDWARF
 167         OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
 168                 "vmlinux/module pathname"),
 169 #endif
 170         OPT_BOOLEAN('l', "list", &session.list_events,
 171                     "list up current probe events"),
 172         OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
 173                 opt_del_probe_event),
 174         OPT_CALLBACK('a', "add", NULL,
 175 #ifdef NO_LIBDWARF
 176                 "[EVENT=]FUNC[+OFFS|%return] [ARG ...]",
 177 #else
 178                 "[EVENT=]FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [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\tOFFS:\tOffset from function entry (in byte)\n"
 185                 "\t\t%return:\tPut the probe at function return\n"
 186 #ifdef NO_LIBDWARF
 187                 "\t\tARG:\tProbe argument (only \n"
 188 #else
 189                 "\t\tSRC:\tSource code path\n"
 190                 "\t\tRLN:\tRelative line number from function entry.\n"
 191                 "\t\tALN:\tAbsolute line number in file.\n"
 192                 "\t\tARG:\tProbe argument (local variable name or\n"
 193 #endif
 194                 "\t\t\tkprobe-tracer argument format.)\n",
 195                 opt_add_probe_event),
 196         OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events"
 197                     " with existing name"),
 198         OPT_END()
 199 };
 200
 201 int cmd_probe(int argc, const char **argv, const char *prefix __used)
 202 {
 203         int i, ret;
 204 #ifndef NO_LIBDWARF
 205         int fd;
 206 #endif
 207         struct probe_point *pp;
 208
 209         argc = parse_options(argc, argv, options, probe_usage,
 210                              PARSE_OPT_STOP_AT_NON_OPTION);
 211         if (argc > 0) {
 212                 if (strcmp(argv[0], "-") == 0) {
 213                         pr_warning("  Error: '-' is not supported.\n");
 214                         usage_with_options(probe_usage, options);
 215                 }
 216                 parse_probe_event_argv(argc, argv);
 217         }
 218
 219         if ((!session.nr_probe && !session.dellist && !session.list_events))
 220                 usage_with_options(probe_usage, options);
 221
 222         if (session.list_events) {
 223                 if (session.nr_probe != 0 || session.dellist) {
 224                         pr_warning("  Error: Don't use --list with"
 225                                    " --add/--del.\n");
 226                         usage_with_options(probe_usage, options);
 227                 }
 228                 show_perf_probe_events();
 229                 return 0;
 230         }
 231
 232         if (session.dellist) {
 233                 del_trace_kprobe_events(session.dellist);
 234                 strlist__delete(session.dellist);
 235                 if (session.nr_probe == 0)
 236                         return 0;
 237         }
 238
 239         if (session.need_dwarf)
 240 #ifdef NO_LIBDWARF
 241                 die("Debuginfo-analysis is not supported");
 242 #else   /* !NO_LIBDWARF */
 243                 pr_debug("Some probes require debuginfo.\n");
 244
 245         if (session.vmlinux) {
 246                 pr_debug("Try to open %s.", session.vmlinux);
 247                 fd = open(session.vmlinux, O_RDONLY);
 248         } else
 249                 fd = open_default_vmlinux();
 250         if (fd < 0) {
 251                 if (session.need_dwarf)
 252                         die("Could not open debuginfo file.");
 253
 254                 pr_debug("Could not open vmlinux/module file."
 255                          " Try to use symbols.\n");
 256                 goto end_dwarf;
 257         }
 258
 259         /* Searching probe points */
 260         for (i = 0; i < session.nr_probe; i++) {
 261                 pp = &session.probes[i];
 262                 if (pp->found)
 263                         continue;
 264
 265                 lseek(fd, SEEK_SET, 0);
 266                 ret = find_probepoint(fd, pp);
 267                 if (ret > 0)
 268                         continue;
 269                 if (ret == 0)   /* No error but failed to find probe point. */
 270                         die("No probe point found.");
 271                 /* Error path */
 272                 if (session.need_dwarf) {
 273                         if (ret == -ENOENT)
 274                                 pr_warning("No dwarf info found in the vmlinux - please rebuild with CONFIG_DEBUG_INFO=y.\n");
 275                         die("Could not analyze debuginfo.");
 276                 }
 277                 pr_debug("An error occurred in debuginfo analysis."
 278                          " Try to use symbols.\n");
 279                 break;
 280         }
 281         close(fd);
 282
 283 end_dwarf:
 284 #endif /* !NO_LIBDWARF */
 285
 286         /* Synthesize probes without dwarf */
 287         for (i = 0; i < session.nr_probe; i++) {
 288                 pp = &session.probes[i];
 289                 if (pp->found)  /* This probe is already found. */
 290                         continue;
 291
 292                 ret = synthesize_trace_kprobe_event(pp);
 293                 if (ret == -E2BIG)
 294                         die("probe point definition becomes too long.");
 295                 else if (ret < 0)
 296                         die("Failed to synthesize a probe point.");
 297         }
 298
 299         /* Settng up probe points */
 300         add_trace_kprobe_events(session.probes, session.nr_probe,
 301                                 session.force_add);
 302         return 0;
 303 }
 304