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         int need_dwarf;
  63         int nr_probe;
  64         struct probe_point probes[MAX_PROBES];
  65         struct strlist *dellist;
  66 } session;
  67
  68 static bool listing;
  69
  70 /* Parse an event definition. Note that any error must die. */
  71 static void parse_probe_event(const char *str)
  72 {
  73         struct probe_point *pp = &session.probes[session.nr_probe];
  74
  75         pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
  76         if (++session.nr_probe == MAX_PROBES)
  77                 die("Too many probes (> %d) are specified.", MAX_PROBES);
  78
  79         /* Parse perf-probe event into probe_point */
  80         session.need_dwarf = parse_perf_probe_event(str, pp);
  81
  82         pr_debug("%d arguments\n", pp->nr_args);
  83 }
  84
  85 static void parse_probe_event_argv(int argc, const char **argv)
  86 {
  87         int i, len;
  88         char *buf;
  89
  90         /* Bind up rest arguments */
  91         len = 0;
  92         for (i = 0; i < argc; i++)
  93                 len += strlen(argv[i]) + 1;
  94         buf = zalloc(len + 1);
  95         if (!buf)
  96                 die("Failed to allocate memory for binding arguments.");
  97         len = 0;
  98         for (i = 0; i < argc; i++)
  99                 len += sprintf(&buf[len], "%s ", argv[i]);
 100         parse_probe_event(buf);
 101         free(buf);
 102 }
 103
 104 static int opt_add_probe_event(const struct option *opt __used,
 105                               const char *str, int unset __used)
 106 {
 107         if (str)
 108                 parse_probe_event(str);
 109         return 0;
 110 }
 111
 112 static int opt_del_probe_event(const struct option *opt __used,
 113                                const char *str, int unset __used)
 114 {
 115         if (str) {
 116                 if (!session.dellist)
 117                         session.dellist = strlist__new(true, NULL);
 118                 strlist__add(session.dellist, str);
 119         }
 120         return 0;
 121 }
 122
 123 #ifndef NO_LIBDWARF
 124 static int open_default_vmlinux(void)
 125 {
 126         struct utsname uts;
 127         char fname[MAX_PATH_LEN];
 128         int fd, ret, i;
 129
 130         ret = uname(&uts);
 131         if (ret) {
 132                 pr_debug("uname() failed.\n");
 133                 return -errno;
 134         }
 135         session.release = uts.release;
 136         for (i = 0; i < NR_SEARCH_PATH; i++) {
 137                 ret = snprintf(fname, MAX_PATH_LEN,
 138                                default_search_path[i], session.release);
 139                 if (ret >= MAX_PATH_LEN || ret < 0) {
 140                         pr_debug("Filename(%d,%s) is too long.\n", i,
 141                                 uts.release);
 142                         errno = E2BIG;
 143                         return -E2BIG;
 144                 }
 145                 pr_debug("try to open %s\n", fname);
 146                 fd = open(fname, O_RDONLY);
 147                 if (fd >= 0)
 148                         break;
 149         }
 150         return fd;
 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         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", &session.vmlinux, "file",
 167                 "vmlinux/module pathname"),
 168 #endif
 169         OPT_BOOLEAN('l', "list", &listing, "list up current probe events"),
 170         OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
 171                 opt_del_probe_event),
 172         OPT_CALLBACK('a', "add", NULL,
 173 #ifdef NO_LIBDWARF
 174                 "FUNC[+OFFS|%return] [ARG ...]",
 175 #else
 176                 "FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
 177 #endif
 178                 "probe point definition, where\n"
 179                 "\t\tGRP:\tGroup name (optional)\n"
 180                 "\t\tNAME:\tEvent name\n"
 181                 "\t\tFUNC:\tFunction name\n"
 182                 "\t\tOFFS:\tOffset from function entry (in byte)\n"
 183                 "\t\t%return:\tPut the probe at function return\n"
 184 #ifdef NO_LIBDWARF
 185                 "\t\tARG:\tProbe argument (only \n"
 186 #else
 187                 "\t\tSRC:\tSource code path\n"
 188                 "\t\tRLN:\tRelative line number from function entry.\n"
 189                 "\t\tALN:\tAbsolute line number in file.\n"
 190                 "\t\tARG:\tProbe argument (local variable name or\n"
 191 #endif
 192                 "\t\t\tkprobe-tracer argument format.)\n",
 193                 opt_add_probe_event),
 194         OPT_END()
 195 };
 196
 197 int cmd_probe(int argc, const char **argv, const char *prefix __used)
 198 {
 199         int i, ret;
 200 #ifndef NO_LIBDWARF
 201         int fd;
 202 #endif
 203         struct probe_point *pp;
 204
 205         argc = parse_options(argc, argv, options, probe_usage,
 206                              PARSE_OPT_STOP_AT_NON_OPTION);
 207         if (argc > 0)
 208                 parse_probe_event_argv(argc, argv);
 209
 210         if ((session.nr_probe == 0 && !session.dellist && !listing))
 211                 usage_with_options(probe_usage, options);
 212
 213         if (listing) {
 214                 if (session.nr_probe != 0 || session.dellist) {
 215                         pr_warning("  Error: Don't use --list with"
 216                                    " --add/--del.\n");
 217                         usage_with_options(probe_usage, options);
 218                 }
 219                 show_perf_probe_events();
 220                 return 0;
 221         }
 222
 223         if (session.dellist) {
 224                 del_trace_kprobe_events(session.dellist);
 225                 strlist__delete(session.dellist);
 226                 if (session.nr_probe == 0)
 227                         return 0;
 228         }
 229
 230         if (session.need_dwarf)
 231 #ifdef NO_LIBDWARF
 232                 die("Debuginfo-analysis is not supported");
 233 #else   /* !NO_LIBDWARF */
 234                 pr_debug("Some probes require debuginfo.\n");
 235
 236         if (session.vmlinux) {
 237                 pr_debug("Try to open %s.", session.vmlinux);
 238                 fd = open(session.vmlinux, O_RDONLY);
 239         } else
 240                 fd = open_default_vmlinux();
 241         if (fd < 0) {
 242                 if (session.need_dwarf)
 243                         die("Could not open debuginfo file.");
 244
 245                 pr_debug("Could not open vmlinux/module file."
 246                          " Try to use symbols.\n");
 247                 goto end_dwarf;
 248         }
 249
 250         /* Searching probe points */
 251         for (i = 0; i < session.nr_probe; i++) {
 252                 pp = &session.probes[i];
 253                 if (pp->found)
 254                         continue;
 255
 256                 lseek(fd, SEEK_SET, 0);
 257                 ret = find_probepoint(fd, pp);
 258                 if (ret < 0) {
 259                         if (session.need_dwarf)
 260                                 die("Could not analyze debuginfo.");
 261
 262                         pr_warning("An error occurred in debuginfo analysis. Try to use symbols.\n");
 263                         break;
 264                 }
 265                 if (ret == 0)   /* No error but failed to find probe point. */
 266                         die("No probe point found.");
 267         }
 268         close(fd);
 269
 270 end_dwarf:
 271 #endif /* !NO_LIBDWARF */
 272
 273         /* Synthesize probes without dwarf */
 274         for (i = 0; i < session.nr_probe; i++) {
 275                 pp = &session.probes[i];
 276                 if (pp->found)  /* This probe is already found. */
 277                         continue;
 278
 279                 ret = synthesize_trace_kprobe_event(pp);
 280                 if (ret == -E2BIG)
 281                         die("probe point definition becomes too long.");
 282                 else if (ret < 0)
 283                         die("Failed to synthesize a probe point.");
 284         }
 285
 286         /* Settng up probe points */
 287         add_trace_kprobe_events(session.probes, session.nr_probe);
 288         return 0;
 289 }
 290