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 } 328