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/debugfs.h>
  26 #include <api/fs/tracefs.h>
  27 #include "probe-event.h"
  28 #include "probe-file.h"
  29 #include "session.h"
  30
  31 #define MAX_CMDLEN 256
  32
  33 static void print_open_warning(int err, bool uprobe)
  34 {
  35         char sbuf[STRERR_BUFSIZE];
  36
  37         if (err == -ENOENT) {
  38                 const char *config;
  39
  40                 if (uprobe)
  41                         config = "CONFIG_UPROBE_EVENTS";
  42                 else
  43                         config = "CONFIG_KPROBE_EVENTS";
  44
  45                 pr_warning("%cprobe_events file does not exist"
  46                            " - please rebuild kernel with %s.\n",
  47                            uprobe ? 'u' : 'k', config);
  48         } else if (err == -ENOTSUP)
  49                 pr_warning("Tracefs or debugfs is not mounted.\n");
  50         else
  51                 pr_warning("Failed to open %cprobe_events: %s\n",
  52                            uprobe ? 'u' : 'k',
  53                            strerror_r(-err, sbuf, sizeof(sbuf)));
  54 }
  55
  56 static void print_both_open_warning(int kerr, int uerr)
  57 {
  58         /* Both kprobes and uprobes are disabled, warn it. */
  59         if (kerr == -ENOTSUP && uerr == -ENOTSUP)
  60                 pr_warning("Tracefs or debugfs is not mounted.\n");
  61         else if (kerr == -ENOENT && uerr == -ENOENT)
  62                 pr_warning("Please rebuild kernel with CONFIG_KPROBE_EVENTS "
  63                            "or/and CONFIG_UPROBE_EVENTS.\n");
  64         else {
  65                 char sbuf[STRERR_BUFSIZE];
  66                 pr_warning("Failed to open kprobe events: %s.\n",
  67                            strerror_r(-kerr, sbuf, sizeof(sbuf)));
  68                 pr_warning("Failed to open uprobe events: %s.\n",
  69                            strerror_r(-uerr, sbuf, sizeof(sbuf)));
  70         }
  71 }
  72
  73 static int open_probe_events(const char *trace_file, bool readwrite)
  74 {
  75         char buf[PATH_MAX];
  76         const char *__debugfs;
  77         const char *tracing_dir = "";
  78         int ret;
  79
  80         __debugfs = tracefs_find_mountpoint();
  81         if (__debugfs == NULL) {
  82                 tracing_dir = "tracing/";
  83
  84                 __debugfs = debugfs_find_mountpoint();
  85                 if (__debugfs == NULL)
  86                         return -ENOTSUP;
  87         }
  88
  89         ret = e_snprintf(buf, PATH_MAX, "%s/%s%s",
  90                          __debugfs, tracing_dir, trace_file);
  91         if (ret >= 0) {
  92                 pr_debug("Opening %s write=%d\n", buf, readwrite);
  93                 if (readwrite && !probe_event_dry_run)
  94                         ret = open(buf, O_RDWR | O_APPEND, 0);
  95                 else
  96                         ret = open(buf, O_RDONLY, 0);
  97
  98                 if (ret < 0)
  99                         ret = -errno;
 100         }
 101         return ret;
 102 }
 103
 104 static int open_kprobe_events(bool readwrite)
 105 {
 106         return open_probe_events("kprobe_events", readwrite);
 107 }
 108
 109 static int open_uprobe_events(bool readwrite)
 110 {
 111         return open_probe_events("uprobe_events", readwrite);
 112 }
 113
 114 int probe_file__open(int flag)
 115 {
 116         int fd;
 117
 118         if (flag & PF_FL_UPROBE)
 119                 fd = open_uprobe_events(flag & PF_FL_RW);
 120         else
 121                 fd = open_kprobe_events(flag & PF_FL_RW);
 122         if (fd < 0)
 123                 print_open_warning(fd, flag & PF_FL_UPROBE);
 124
 125         return fd;
 126 }
 127
 128 int probe_file__open_both(int *kfd, int *ufd, int flag)
 129 {
 130         if (!kfd || !ufd)
 131                 return -EINVAL;
 132
 133         *kfd = open_kprobe_events(flag & PF_FL_RW);
 134         *ufd = open_uprobe_events(flag & PF_FL_RW);
 135         if (*kfd < 0 && *ufd < 0) {
 136                 print_both_open_warning(*kfd, *ufd);
 137                 return *kfd;
 138         }
 139
 140         return 0;
 141 }
 142
 143 /* Get raw string list of current kprobe_events  or uprobe_events */
 144 struct strlist *probe_file__get_rawlist(int fd)
 145 {
 146         int ret, idx;
 147         FILE *fp;
 148         char buf[MAX_CMDLEN];
 149         char *p;
 150         struct strlist *sl;
 151
 152         sl = strlist__new(NULL, NULL);
 153
 154         fp = fdopen(dup(fd), "r");
 155         while (!feof(fp)) {
 156                 p = fgets(buf, MAX_CMDLEN, fp);
 157                 if (!p)
 158                         break;
 159
 160                 idx = strlen(p) - 1;
 161                 if (p[idx] == '\n')
 162                         p[idx] = '\0';
 163                 ret = strlist__add(sl, buf);
 164                 if (ret < 0) {
 165                         pr_debug("strlist__add failed (%d)\n", ret);
 166                         strlist__delete(sl);
 167                         return NULL;
 168                 }
 169         }
 170         fclose(fp);
 171
 172         return sl;
 173 }
 174
 175 static struct strlist *__probe_file__get_namelist(int fd, bool include_group)
 176 {
 177         char buf[128];
 178         struct strlist *sl, *rawlist;
 179         struct str_node *ent;
 180         struct probe_trace_event tev;
 181         int ret = 0;
 182
 183         memset(&tev, 0, sizeof(tev));
 184         rawlist = probe_file__get_rawlist(fd);
 185         if (!rawlist)
 186                 return NULL;
 187         sl = strlist__new(NULL, NULL);
 188         strlist__for_each(ent, rawlist) {
 189                 ret = parse_probe_trace_command(ent->s, &tev);
 190                 if (ret < 0)
 191                         break;
 192                 if (include_group) {
 193                         ret = e_snprintf(buf, 128, "%s:%s", tev.group,
 194                                         tev.event);
 195                         if (ret >= 0)
 196                                 ret = strlist__add(sl, buf);
 197                 } else
 198                         ret = strlist__add(sl, tev.event);
 199                 clear_probe_trace_event(&tev);
 200                 if (ret < 0)
 201                         break;
 202         }
 203         strlist__delete(rawlist);
 204
 205         if (ret < 0) {
 206                 strlist__delete(sl);
 207                 return NULL;
 208         }
 209         return sl;
 210 }
 211
 212 /* Get current perf-probe event names */
 213 struct strlist *probe_file__get_namelist(int fd)
 214 {
 215         return __probe_file__get_namelist(fd, false);
 216 }
 217
 218 int probe_file__add_event(int fd, struct probe_trace_event *tev)
 219 {
 220         int ret = 0;
 221         char *buf = synthesize_probe_trace_command(tev);
 222         char sbuf[STRERR_BUFSIZE];
 223
 224         if (!buf) {
 225                 pr_debug("Failed to synthesize probe trace event.\n");
 226                 return -EINVAL;
 227         }
 228
 229         pr_debug("Writing event: %s\n", buf);
 230         if (!probe_event_dry_run) {
 231                 ret = write(fd, buf, strlen(buf));
 232                 if (ret <= 0) {
 233                         ret = -errno;
 234                         pr_warning("Failed to write event: %s\n",
 235                                    strerror_r(errno, sbuf, sizeof(sbuf)));
 236                 }
 237         }
 238         free(buf);
 239
 240         return ret;
 241 }
 242
 243 static int __del_trace_probe_event(int fd, struct str_node *ent)
 244 {
 245         char *p;
 246         char buf[128];
 247         int ret;
 248
 249         /* Convert from perf-probe event to trace-probe event */
 250         ret = e_snprintf(buf, 128, "-:%s", ent->s);
 251         if (ret < 0)
 252                 goto error;
 253
 254         p = strchr(buf + 2, ':');
 255         if (!p) {
 256                 pr_debug("Internal error: %s should have ':' but not.\n",
 257                          ent->s);
 258                 ret = -ENOTSUP;
 259                 goto error;
 260         }
 261         *p = '/';
 262
 263         pr_debug("Writing event: %s\n", buf);
 264         ret = write(fd, buf, strlen(buf));
 265         if (ret < 0) {
 266                 ret = -errno;
 267                 goto error;
 268         }
 269
 270         pr_info("Removed event: %s\n", ent->s);
 271         return 0;
 272 error:
 273         pr_warning("Failed to delete event: %s\n",
 274                    strerror_r(-ret, buf, sizeof(buf)));
 275         return ret;
 276 }
 277
 278 int probe_file__del_events(int fd, struct strfilter *filter)
 279 {
 280         struct strlist *namelist;
 281         struct str_node *ent;
 282         const char *p;
 283         int ret = -ENOENT;
 284
 285         namelist = __probe_file__get_namelist(fd, true);
 286         if (!namelist)
 287                 return -ENOENT;
 288
 289         strlist__for_each(ent, namelist) {
 290                 p = strchr(ent->s, ':');
 291                 if ((p && strfilter__compare(filter, p + 1)) ||
 292                     strfilter__compare(filter, ent->s)) {
 293                         ret = __del_trace_probe_event(fd, ent);
 294                         if (ret < 0)
 295                                 break;
 296                 }
 297         }
 298         strlist__delete(namelist);
 299
 300         return ret;
 301 }