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