kernel/tools/perf/util/probe-file.c

   1 /*
   2  * probe-file.c : operate ftrace k/uprobe events files
   3  *
   4  * Written by Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17 #include "util.h"
  18 #include "event.h"
  19 #include "strlist.h"
  20 #include "debug.h"
  21 #include "cache.h"
  22 #include "color.h"
  23 #include "symbol.h"
  24 #include "thread.h"
  25 #include <api/fs/tracing_path.h>
  26 #include "probe-event.h"
  27 #include "probe-file.h"
  28 #include "session.h"
  29
  30 #define MAX_CMDLEN 256
  31
  32 static void print_open_warning(int err, bool uprobe)
  33 {
  34         char sbuf[STRERR_BUFSIZE];
  35
  36         if (err == -ENOENT) {
  37                 const char *config;
  38
  39                 if (uprobe)
  40                         config = "CONFIG_UPROBE_EVENTS";
  41                 else
  42                         config = "CONFIG_KPROBE_EVENTS";
  43
  44                 pr_warning("%cprobe_events file does not exist"
  45                            " - please rebuild kernel with %s.\n",
  46                            uprobe ? 'u' : 'k', config);
  47         } else if (err == -ENOTSUP)
  48                 pr_warning("Tracefs or debugfs is not mounted.\n");
  49         else
  50                 pr_warning("Failed to open %cprobe_events: %s\n",
  51                            uprobe ? 'u' : 'k',
  52                            strerror_r(-err, sbuf, sizeof(sbuf)));
  53 }
  54
  55 static void print_both_open_warning(int kerr, int uerr)
  56 {
  57         /* Both kprobes and uprobes are disabled, warn it. */
  58         if (kerr == -ENOTSUP && uerr == -ENOTSUP)
  59                 pr_warning("Tracefs or debugfs is not mounted.\n");
  60         else if (kerr == -ENOENT && uerr == -ENOENT)
  61                 pr_warning("Please rebuild kernel with CONFIG_KPROBE_EVENTS "
  62                            "or/and CONFIG_UPROBE_EVENTS.\n");
  63         else {
  64                 char sbuf[STRERR_BUFSIZE];
  65                 pr_warning("Failed to open kprobe events: %s.\n",
  66                            strerror_r(-kerr, sbuf, sizeof(sbuf)));
  67                 pr_warning("Failed to open uprobe events: %s.\n",
  68                            strerror_r(-uerr, sbuf, sizeof(sbuf)));
  69         }
  70 }
  71
  72 static int open_probe_events(const char *trace_file, bool readwrite)
  73 {
  74         char buf[PATH_MAX];
  75         const char *tracing_dir = "";
  76         int ret;
  77
  78         ret = e_snprintf(buf, PATH_MAX, "%s/%s%s",
  79                          tracing_path, tracing_dir, trace_file);
  80         if (ret >= 0) {
  81                 pr_debug("Opening %s write=%d\n", buf, readwrite);
  82                 if (readwrite && !probe_event_dry_run)
  83                         ret = open(buf, O_RDWR | O_APPEND, 0);
  84                 else
  85                         ret = open(buf, O_RDONLY, 0);
  86
  87                 if (ret < 0)
  88                         ret = -errno;
  89         }
  90         return ret;
  91 }
  92
  93 static int open_kprobe_events(bool readwrite)
  94 {
  95         return open_probe_events("kprobe_events", readwrite);
  96 }
  97
  98 static int open_uprobe_events(bool readwrite)
  99 {
 100         return open_probe_events("uprobe_events", readwrite);
 101 }
 102
 103 int probe_file__open(int flag)
 104 {
 105         int fd;
 106
 107         if (flag & PF_FL_UPROBE)
 108                 fd = open_uprobe_events(flag & PF_FL_RW);
 109         else
 110                 fd = open_kprobe_events(flag & PF_FL_RW);
 111         if (fd < 0)
 112                 print_open_warning(fd, flag & PF_FL_UPROBE);
 113
 114         return fd;
 115 }
 116
 117 int probe_file__open_both(int *kfd, int *ufd, int flag)
 118 {
 119         if (!kfd || !ufd)
 120                 return -EINVAL;
 121
 122         *kfd = open_kprobe_events(flag & PF_FL_RW);
 123         *ufd = open_uprobe_events(flag & PF_FL_RW);
 124         if (*kfd < 0 && *ufd < 0) {
 125                 print_both_open_warning(*kfd, *ufd);
 126                 return *kfd;
 127         }
 128
 129         return 0;
 130 }
 131
 132 /* Get raw string list of current kprobe_events  or uprobe_events */
 133 struct strlist *probe_file__get_rawlist(int fd)
 134 {
 135         int ret, idx;
 136         FILE *fp;
 137         char buf[MAX_CMDLEN];
 138         char *p;
 139         struct strlist *sl;
 140
 141         if (fd < 0)
 142                 return NULL;
 143
 144         sl = strlist__new(NULL, NULL);
 145
 146         fp = fdopen(dup(fd), "r");
 147         while (!feof(fp)) {
 148                 p = fgets(buf, MAX_CMDLEN, fp);
 149                 if (!p)
 150                         break;
 151
 152                 idx = strlen(p) - 1;
 153                 if (p[idx] == '\n')
 154                         p[idx] = '\0';
 155                 ret = strlist__add(sl, buf);
 156                 if (ret < 0) {
 157                         pr_debug("strlist__add failed (%d)\n", ret);
 158                         strlist__delete(sl);
 159                         return NULL;
 160                 }
 161         }
 162         fclose(fp);
 163
 164         return sl;
 165 }
 166
 167 static struct strlist *__probe_file__get_namelist(int fd, bool include_group)
 168 {
 169         char buf[128];
 170         struct strlist *sl, *rawlist;
 171         struct str_node *ent;
 172         struct probe_trace_event tev;
 173         int ret = 0;
 174
 175         memset(&tev, 0, sizeof(tev));
 176         rawlist = probe_file__get_rawlist(fd);
 177         if (!rawlist)
 178                 return NULL;
 179         sl = strlist__new(NULL, NULL);
 180         strlist__for_each(ent, rawlist) {
 181                 ret = parse_probe_trace_command(ent->s, &tev);
 182                 if (ret < 0)
 183                         break;
 184                 if (include_group) {
 185                         ret = e_snprintf(buf, 128, "%s:%s", tev.group,
 186                                         tev.event);
 187                         if (ret >= 0)
 188                                 ret = strlist__add(sl, buf);
 189                 } else
 190                         ret = strlist__add(sl, tev.event);
 191                 clear_probe_trace_event(&tev);
 192                 if (ret < 0)
 193                         break;
 194         }
 195         strlist__delete(rawlist);
 196
 197         if (ret < 0) {
 198                 strlist__delete(sl);
 199                 return NULL;
 200         }
 201         return sl;
 202 }
 203
 204 /* Get current perf-probe event names */
 205 struct strlist *probe_file__get_namelist(int fd)
 206 {
 207         return __probe_file__get_namelist(fd, false);
 208 }
 209
 210 int probe_file__add_event(int fd, struct probe_trace_event *tev)
 211 {
 212         int ret = 0;
 213         char *buf = synthesize_probe_trace_command(tev);
 214         char sbuf[STRERR_BUFSIZE];
 215
 216         if (!buf) {
 217                 pr_debug("Failed to synthesize probe trace event.\n");
 218                 return -EINVAL;
 219         }
 220
 221         pr_debug("Writing event: %s\n", buf);
 222         if (!probe_event_dry_run) {
 223                 ret = write(fd, buf, strlen(buf));
 224                 if (ret <= 0) {
 225                         ret = -errno;
 226                         pr_warning("Failed to write event: %s\n",
 227                                    strerror_r(errno, sbuf, sizeof(sbuf)));
 228                 }
 229         }
 230         free(buf);
 231
 232         return ret;
 233 }
 234
 235 static int __del_trace_probe_event(int fd, struct str_node *ent)
 236 {
 237         char *p;
 238         char buf[128];
 239         int ret;
 240
 241         /* Convert from perf-probe event to trace-probe event */
 242         ret = e_snprintf(buf, 128, "-:%s", ent->s);
 243         if (ret < 0)
 244                 goto error;
 245
 246         p = strchr(buf + 2, ':');
 247         if (!p) {
 248                 pr_debug("Internal error: %s should have ':' but not.\n",
 249                          ent->s);
 250                 ret = -ENOTSUP;
 251                 goto error;
 252         }
 253         *p = '/';
 254
 255         pr_debug("Writing event: %s\n", buf);
 256         ret = write(fd, buf, strlen(buf));
 257         if (ret < 0) {
 258                 ret = -errno;
 259                 goto error;
 260         }
 261
 262         return 0;
 263 error:
 264         pr_warning("Failed to delete event: %s\n",
 265                    strerror_r(-ret, buf, sizeof(buf)));
 266         return ret;
 267 }
 268
 269 int probe_file__get_events(int fd, struct strfilter *filter,
 270                            struct strlist *plist)
 271 {
 272         struct strlist *namelist;
 273         struct str_node *ent;
 274         const char *p;
 275         int ret = -ENOENT;
 276
 277         if (!plist)
 278                 return -EINVAL;
 279
 280         namelist = __probe_file__get_namelist(fd, true);
 281         if (!namelist)
 282                 return -ENOENT;
 283
 284         strlist__for_each(ent, namelist) {
 285                 p = strchr(ent->s, ':');
 286                 if ((p && strfilter__compare(filter, p + 1)) ||
 287                     strfilter__compare(filter, ent->s)) {
 288                         strlist__add(plist, ent->s);
 289                         ret = 0;
 290                 }
 291         }
 292         strlist__delete(namelist);
 293
 294         return ret;
 295 }
 296
 297 int probe_file__del_strlist(int fd, struct strlist *namelist)
 298 {
 299         int ret = 0;
 300         struct str_node *ent;
 301
 302         strlist__for_each(ent, namelist) {
 303                 ret = __del_trace_probe_event(fd, ent);
 304                 if (ret < 0)
 305                         break;
 306         }
 307         return ret;
 308 }
 309
 310 int probe_file__del_events(int fd, struct strfilter *filter)
 311 {
 312         struct strlist *namelist;
 313         int ret;
 314
 315         namelist = strlist__new(NULL, NULL);
 316         if (!namelist)
 317                 return -ENOMEM;
 318
 319         ret = probe_file__get_events(fd, filter, namelist);
 320         if (ret < 0)
 321                 return ret;
 322
 323         ret = probe_file__del_strlist(fd, namelist);
 324         strlist__delete(namelist);
 325
 326         return ret;
 327 }