tools/perf/builtin-help.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * builtin-help.c
   4  *
   5  * Builtin help command
   6  */
   7 #include "perf.h"
   8 #include "util/config.h"
   9 #include "builtin.h"
  10 #include <subcmd/exec-cmd.h>
  11 #include "common-cmds.h"
  12 #include <subcmd/parse-options.h>
  13 #include <subcmd/run-command.h>
  14 #include <subcmd/help.h>
  15 #include "util/debug.h"
  16 #include <linux/kernel.h>
  17 #include <errno.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <sys/types.h>
  21 #include <sys/stat.h>
  22 #include <unistd.h>
  23
  24 static struct man_viewer_list {
  25         struct man_viewer_list *next;
  26         char name[0];
  27 } *man_viewer_list;
  28
  29 static struct man_viewer_info_list {
  30         struct man_viewer_info_list *next;
  31         const char *info;
  32         char name[0];
  33 } *man_viewer_info_list;
  34
  35 enum help_format {
  36         HELP_FORMAT_NONE,
  37         HELP_FORMAT_MAN,
  38         HELP_FORMAT_INFO,
  39         HELP_FORMAT_WEB,
  40 };
  41
  42 static enum help_format parse_help_format(const char *format)
  43 {
  44         if (!strcmp(format, "man"))
  45                 return HELP_FORMAT_MAN;
  46         if (!strcmp(format, "info"))
  47                 return HELP_FORMAT_INFO;
  48         if (!strcmp(format, "web") || !strcmp(format, "html"))
  49                 return HELP_FORMAT_WEB;
  50
  51         pr_err("unrecognized help format '%s'", format);
  52         return HELP_FORMAT_NONE;
  53 }
  54
  55 static const char *get_man_viewer_info(const char *name)
  56 {
  57         struct man_viewer_info_list *viewer;
  58
  59         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next) {
  60                 if (!strcasecmp(name, viewer->name))
  61                         return viewer->info;
  62         }
  63         return NULL;
  64 }
  65
  66 static int check_emacsclient_version(void)
  67 {
  68         struct strbuf buffer = STRBUF_INIT;
  69         struct child_process ec_process;
  70         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  71         int version;
  72         int ret = -1;
  73
  74         /* emacsclient prints its version number on stderr */
  75         memset(&ec_process, 0, sizeof(ec_process));
  76         ec_process.argv = argv_ec;
  77         ec_process.err = -1;
  78         ec_process.stdout_to_stderr = 1;
  79         if (start_command(&ec_process)) {
  80                 fprintf(stderr, "Failed to start emacsclient.\n");
  81                 return -1;
  82         }
  83         if (strbuf_read(&buffer, ec_process.err, 20) < 0) {
  84                 fprintf(stderr, "Failed to read emacsclient version\n");
  85                 goto out;
  86         }
  87         close(ec_process.err);
  88
  89         /*
  90          * Don't bother checking return value, because "emacsclient --version"
  91          * seems to always exits with code 1.
  92          */
  93         finish_command(&ec_process);
  94
  95         if (!strstarts(buffer.buf, "emacsclient")) {
  96                 fprintf(stderr, "Failed to parse emacsclient version.\n");
  97                 goto out;
  98         }
  99
 100         version = atoi(buffer.buf + strlen("emacsclient"));
 101
 102         if (version < 22) {
 103                 fprintf(stderr,
 104                         "emacsclient version '%d' too old (< 22).\n",
 105                         version);
 106         } else
 107                 ret = 0;
 108 out:
 109         strbuf_release(&buffer);
 110         return ret;
 111 }
 112
 113 static void exec_failed(const char *cmd)
 114 {
 115         char sbuf[STRERR_BUFSIZE];
 116         pr_warning("failed to exec '%s': %s", cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
 117 }
 118
 119 static void exec_woman_emacs(const char *path, const char *page)
 120 {
 121         if (!check_emacsclient_version()) {
 122                 /* This works only with emacsclient version >= 22. */
 123                 char *man_page;
 124
 125                 if (!path)
 126                         path = "emacsclient";
 127                 if (asprintf(&man_page, "(woman \"%s\")", page) > 0) {
 128                         execlp(path, "emacsclient", "-e", man_page, NULL);
 129                         free(man_page);
 130                 }
 131                 exec_failed(path);
 132         }
 133 }
 134
 135 static void exec_man_konqueror(const char *path, const char *page)
 136 {
 137         const char *display = getenv("DISPLAY");
 138
 139         if (display && *display) {
 140                 char *man_page;
 141                 const char *filename = "kfmclient";
 142
 143                 /* It's simpler to launch konqueror using kfmclient. */
 144                 if (path) {
 145                         const char *file = strrchr(path, '/');
 146                         if (file && !strcmp(file + 1, "konqueror")) {
 147                                 char *new = strdup(path);
 148                                 char *dest = strrchr(new, '/');
 149
 150                                 /* strlen("konqueror") == strlen("kfmclient") */
 151                                 strcpy(dest + 1, "kfmclient");
 152                                 path = new;
 153                         }
 154                         if (file)
 155                                 filename = file;
 156                 } else
 157                         path = "kfmclient";
 158                 if (asprintf(&man_page, "man:%s(1)", page) > 0) {
 159                         execlp(path, filename, "newTab", man_page, NULL);
 160                         free(man_page);
 161                 }
 162                 exec_failed(path);
 163         }
 164 }
 165
 166 static void exec_man_man(const char *path, const char *page)
 167 {
 168         if (!path)
 169                 path = "man";
 170         execlp(path, "man", page, NULL);
 171         exec_failed(path);
 172 }
 173
 174 static void exec_man_cmd(const char *cmd, const char *page)
 175 {
 176         char *shell_cmd;
 177
 178         if (asprintf(&shell_cmd, "%s %s", cmd, page) > 0) {
 179                 execl("/bin/sh", "sh", "-c", shell_cmd, NULL);
 180                 free(shell_cmd);
 181         }
 182         exec_failed(cmd);
 183 }
 184
 185 static void add_man_viewer(const char *name)
 186 {
 187         struct man_viewer_list **p = &man_viewer_list;
 188         size_t len = strlen(name);
 189
 190         while (*p)
 191                 p = &((*p)->next);
 192         *p = zalloc(sizeof(**p) + len + 1);
 193         strcpy((*p)->name, name);
 194 }
 195
 196 static int supported_man_viewer(const char *name, size_t len)
 197 {
 198         return (!strncasecmp("man", name, len) ||
 199                 !strncasecmp("woman", name, len) ||
 200                 !strncasecmp("konqueror", name, len));
 201 }
 202
 203 static void do_add_man_viewer_info(const char *name,
 204                                    size_t len,
 205                                    const char *value)
 206 {
 207         struct man_viewer_info_list *new = zalloc(sizeof(*new) + len + 1);
 208
 209         strncpy(new->name, name, len);
 210         new->info = strdup(value);
 211         new->next = man_viewer_info_list;
 212         man_viewer_info_list = new;
 213 }
 214
 215 static void unsupported_man_viewer(const char *name, const char *var)
 216 {
 217         pr_warning("'%s': path for unsupported man viewer.\n"
 218                    "Please consider using 'man.<tool>.%s' instead.", name, var);
 219 }
 220
 221 static int add_man_viewer_path(const char *name,
 222                                size_t len,
 223                                const char *value)
 224 {
 225         if (supported_man_viewer(name, len))
 226                 do_add_man_viewer_info(name, len, value);
 227         else
 228                 unsupported_man_viewer(name, "cmd");
 229
 230         return 0;
 231 }
 232
 233 static int add_man_viewer_cmd(const char *name,
 234                               size_t len,
 235                               const char *value)
 236 {
 237         if (supported_man_viewer(name, len))
 238                 unsupported_man_viewer(name, "path");
 239         else
 240                 do_add_man_viewer_info(name, len, value);
 241
 242         return 0;
 243 }
 244
 245 static int add_man_viewer_info(const char *var, const char *value)
 246 {
 247         const char *name = var + 4;
 248         const char *subkey = strrchr(name, '.');
 249
 250         if (!subkey) {
 251                 pr_err("Config with no key for man viewer: %s", name);
 252                 return -1;
 253         }
 254
 255         if (!strcmp(subkey, ".path")) {
 256                 if (!value)
 257                         return config_error_nonbool(var);
 258                 return add_man_viewer_path(name, subkey - name, value);
 259         }
 260         if (!strcmp(subkey, ".cmd")) {
 261                 if (!value)
 262                         return config_error_nonbool(var);
 263                 return add_man_viewer_cmd(name, subkey - name, value);
 264         }
 265
 266         pr_warning("'%s': unsupported man viewer sub key.", subkey);
 267         return 0;
 268 }
 269
 270 static int perf_help_config(const char *var, const char *value, void *cb)
 271 {
 272         enum help_format *help_formatp = cb;
 273
 274         if (!strcmp(var, "help.format")) {
 275                 if (!value)
 276                         return config_error_nonbool(var);
 277                 *help_formatp = parse_help_format(value);
 278                 if (*help_formatp == HELP_FORMAT_NONE)
 279                         return -1;
 280                 return 0;
 281         }
 282         if (!strcmp(var, "man.viewer")) {
 283                 if (!value)
 284                         return config_error_nonbool(var);
 285                 add_man_viewer(value);
 286                 return 0;
 287         }
 288         if (strstarts(var, "man."))
 289                 return add_man_viewer_info(var, value);
 290
 291         return 0;
 292 }
 293
 294 static struct cmdnames main_cmds, other_cmds;
 295
 296 void list_common_cmds_help(void)
 297 {
 298         unsigned int i, longest = 0;
 299
 300         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 301                 if (longest < strlen(common_cmds[i].name))
 302                         longest = strlen(common_cmds[i].name);
 303         }
 304
 305         puts(" The most commonly used perf commands are:");
 306         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 307                 printf("   %-*s   ", longest, common_cmds[i].name);
 308                 puts(common_cmds[i].help);
 309         }
 310 }
 311
 312 static const char *cmd_to_page(const char *perf_cmd)
 313 {
 314         char *s;
 315
 316         if (!perf_cmd)
 317                 return "perf";
 318         else if (strstarts(perf_cmd, "perf"))
 319                 return perf_cmd;
 320
 321         return asprintf(&s, "perf-%s", perf_cmd) < 0 ? NULL : s;
 322 }
 323
 324 static void setup_man_path(void)
 325 {
 326         char *new_path;
 327         const char *old_path = getenv("MANPATH");
 328
 329         /* We should always put ':' after our path. If there is no
 330          * old_path, the ':' at the end will let 'man' to try
 331          * system-wide paths after ours to find the manual page. If
 332          * there is old_path, we need ':' as delimiter. */
 333         if (asprintf(&new_path, "%s:%s", system_path(PERF_MAN_PATH), old_path ?: "") > 0) {
 334                 setenv("MANPATH", new_path, 1);
 335                 free(new_path);
 336         } else {
 337                 pr_err("Unable to setup man path");
 338         }
 339 }
 340
 341 static void exec_viewer(const char *name, const char *page)
 342 {
 343         const char *info = get_man_viewer_info(name);
 344
 345         if (!strcasecmp(name, "man"))
 346                 exec_man_man(info, page);
 347         else if (!strcasecmp(name, "woman"))
 348                 exec_woman_emacs(info, page);
 349         else if (!strcasecmp(name, "konqueror"))
 350                 exec_man_konqueror(info, page);
 351         else if (info)
 352                 exec_man_cmd(info, page);
 353         else
 354                 pr_warning("'%s': unknown man viewer.", name);
 355 }
 356
 357 static int show_man_page(const char *perf_cmd)
 358 {
 359         struct man_viewer_list *viewer;
 360         const char *page = cmd_to_page(perf_cmd);
 361         const char *fallback = getenv("PERF_MAN_VIEWER");
 362
 363         setup_man_path();
 364         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 365                 exec_viewer(viewer->name, page); /* will return when unable */
 366
 367         if (fallback)
 368                 exec_viewer(fallback, page);
 369         exec_viewer("man", page);
 370
 371         pr_err("no man viewer handled the request");
 372         return -1;
 373 }
 374
 375 static int show_info_page(const char *perf_cmd)
 376 {
 377         const char *page = cmd_to_page(perf_cmd);
 378         setenv("INFOPATH", system_path(PERF_INFO_PATH), 1);
 379         execlp("info", "info", "perfman", page, NULL);
 380         return -1;
 381 }
 382
 383 static int get_html_page_path(char **page_path, const char *page)
 384 {
 385         struct stat st;
 386         const char *html_path = system_path(PERF_HTML_PATH);
 387
 388         /* Check that we have a perf documentation directory. */
 389         if (stat(mkpath("%s/perf.html", html_path), &st)
 390             || !S_ISREG(st.st_mode)) {
 391                 pr_err("'%s': not a documentation directory.", html_path);
 392                 return -1;
 393         }
 394
 395         return asprintf(page_path, "%s/%s.html", html_path, page);
 396 }
 397
 398 /*
 399  * If open_html is not defined in a platform-specific way (see for
 400  * example compat/mingw.h), we use the script web--browse to display
 401  * HTML.
 402  */
 403 #ifndef open_html
 404 static void open_html(const char *path)
 405 {
 406         execl_cmd("web--browse", "-c", "help.browser", path, NULL);
 407 }
 408 #endif
 409
 410 static int show_html_page(const char *perf_cmd)
 411 {
 412         const char *page = cmd_to_page(perf_cmd);
 413         char *page_path; /* it leaks but we exec bellow */
 414
 415         if (get_html_page_path(&page_path, page) < 0)
 416                 return -1;
 417
 418         open_html(page_path);
 419
 420         return 0;
 421 }
 422
 423 int cmd_help(int argc, const char **argv)
 424 {
 425         bool show_all = false;
 426         enum help_format help_format = HELP_FORMAT_MAN;
 427         struct option builtin_help_options[] = {
 428         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
 429         OPT_SET_UINT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
 430         OPT_SET_UINT('w', "web", &help_format, "show manual in web browser",
 431                         HELP_FORMAT_WEB),
 432         OPT_SET_UINT('i', "info", &help_format, "show info page",
 433                         HELP_FORMAT_INFO),
 434         OPT_END(),
 435         };
 436         const char * const builtin_help_subcommands[] = {
 437                 "buildid-cache", "buildid-list", "diff", "evlist", "help", "list",
 438                 "record", "report", "bench", "stat", "timechart", "top", "annotate",
 439                 "script", "sched", "kallsyms", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
 440 #ifdef HAVE_LIBELF_SUPPORT
 441                 "probe",
 442 #endif
 443 #if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
 444                 "trace",
 445 #endif
 446         NULL };
 447         const char *builtin_help_usage[] = {
 448                 "perf help [--all] [--man|--web|--info] [command]",
 449                 NULL
 450         };
 451         int rc;
 452
 453         load_command_list("perf-", &main_cmds, &other_cmds);
 454
 455         rc = perf_config(perf_help_config, &help_format);
 456         if (rc)
 457                 return rc;
 458
 459         argc = parse_options_subcommand(argc, argv, builtin_help_options,
 460                         builtin_help_subcommands, builtin_help_usage, 0);
 461
 462         if (show_all) {
 463                 printf("\n Usage: %s\n\n", perf_usage_string);
 464                 list_commands("perf commands", &main_cmds, &other_cmds);
 465                 printf(" %s\n\n", perf_more_info_string);
 466                 return 0;
 467         }
 468
 469         if (!argv[0]) {
 470                 printf("\n usage: %s\n\n", perf_usage_string);
 471                 list_common_cmds_help();
 472                 printf("\n %s\n\n", perf_more_info_string);
 473                 return 0;
 474         }
 475
 476         switch (help_format) {
 477         case HELP_FORMAT_MAN:
 478                 rc = show_man_page(argv[0]);
 479                 break;
 480         case HELP_FORMAT_INFO:
 481                 rc = show_info_page(argv[0]);
 482                 break;
 483         case HELP_FORMAT_WEB:
 484                 rc = show_html_page(argv[0]);
 485                 break;
 486         case HELP_FORMAT_NONE:
 487                 /* fall-through */
 488         default:
 489                 rc = -1;
 490                 break;
 491         }
 492
 493         return rc;
 494 }