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 "util/cache.h"
   8 #include "util/config.h"
   9 #include "util/strbuf.h"
  10 #include "builtin.h"
  11 #include <subcmd/exec-cmd.h>
  12 #include "common-cmds.h"
  13 #include <subcmd/parse-options.h>
  14 #include <subcmd/run-command.h>
  15 #include <subcmd/help.h>
  16 #include "util/debug.h"
  17 #include "util/util.h"
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <linux/zalloc.h>
  21 #include <errno.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/types.h>
  26 #include <sys/stat.h>
  27 #include <unistd.h>
  28
  29 static struct man_viewer_list {
  30         struct man_viewer_list *next;
  31         char name[0];
  32 } *man_viewer_list;
  33
  34 static struct man_viewer_info_list {
  35         struct man_viewer_info_list *next;
  36         const char *info;
  37         char name[0];
  38 } *man_viewer_info_list;
  39
  40 enum help_format {
  41         HELP_FORMAT_NONE,
  42         HELP_FORMAT_MAN,
  43         HELP_FORMAT_INFO,
  44         HELP_FORMAT_WEB,
  45 };
  46
  47 static enum help_format parse_help_format(const char *format)
  48 {
  49         if (!strcmp(format, "man"))
  50                 return HELP_FORMAT_MAN;
  51         if (!strcmp(format, "info"))
  52                 return HELP_FORMAT_INFO;
  53         if (!strcmp(format, "web") || !strcmp(format, "html"))
  54                 return HELP_FORMAT_WEB;
  55
  56         pr_err("unrecognized help format '%s'", format);
  57         return HELP_FORMAT_NONE;
  58 }
  59
  60 static const char *get_man_viewer_info(const char *name)
  61 {
  62         struct man_viewer_info_list *viewer;
  63
  64         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next) {
  65                 if (!strcasecmp(name, viewer->name))
  66                         return viewer->info;
  67         }
  68         return NULL;
  69 }
  70
  71 static int check_emacsclient_version(void)
  72 {
  73         struct strbuf buffer = STRBUF_INIT;
  74         struct child_process ec_process;
  75         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  76         int version;
  77         int ret = -1;
  78
  79         /* emacsclient prints its version number on stderr */
  80         memset(&ec_process, 0, sizeof(ec_process));
  81         ec_process.argv = argv_ec;
  82         ec_process.err = -1;
  83         ec_process.stdout_to_stderr = 1;
  84         if (start_command(&ec_process)) {
  85                 fprintf(stderr, "Failed to start emacsclient.\n");
  86                 return -1;
  87         }
  88         if (strbuf_read(&buffer, ec_process.err, 20) < 0) {
  89                 fprintf(stderr, "Failed to read emacsclient version\n");
  90                 goto out;
  91         }
  92         close(ec_process.err);
  93
  94         /*
  95          * Don't bother checking return value, because "emacsclient --version"
  96          * seems to always exits with code 1.
  97          */
  98         finish_command(&ec_process);
  99
 100         if (!strstarts(buffer.buf, "emacsclient")) {
 101                 fprintf(stderr, "Failed to parse emacsclient version.\n");
 102                 goto out;
 103         }
 104
 105         version = atoi(buffer.buf + strlen("emacsclient"));
 106
 107         if (version < 22) {
 108                 fprintf(stderr,
 109                         "emacsclient version '%d' too old (< 22).\n",
 110                         version);
 111         } else
 112                 ret = 0;
 113 out:
 114         strbuf_release(&buffer);
 115         return ret;
 116 }
 117
 118 static void exec_failed(const char *cmd)
 119 {
 120         char sbuf[STRERR_BUFSIZE];
 121         pr_warning("failed to exec '%s': %s", cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
 122 }
 123
 124 static void exec_woman_emacs(const char *path, const char *page)
 125 {
 126         if (!check_emacsclient_version()) {
 127                 /* This works only with emacsclient version >= 22. */
 128                 char *man_page;
 129
 130                 if (!path)
 131                         path = "emacsclient";
 132                 if (asprintf(&man_page, "(woman \"%s\")", page) > 0) {
 133                         execlp(path, "emacsclient", "-e", man_page, NULL);
 134                         free(man_page);
 135                 }
 136                 exec_failed(path);
 137         }
 138 }
 139
 140 static void exec_man_konqueror(const char *path, const char *page)
 141 {
 142         const char *display = getenv("DISPLAY");
 143
 144         if (display && *display) {
 145                 char *man_page;
 146                 const char *filename = "kfmclient";
 147
 148                 /* It's simpler to launch konqueror using kfmclient. */
 149                 if (path) {
 150                         const char *file = strrchr(path, '/');
 151                         if (file && !strcmp(file + 1, "konqueror")) {
 152                                 char *new = strdup(path);
 153                                 char *dest = strrchr(new, '/');
 154
 155                                 /* strlen("konqueror") == strlen("kfmclient") */
 156                                 strcpy(dest + 1, "kfmclient");
 157                                 path = new;
 158                         }
 159                         if (file)
 160                                 filename = file;
 161                 } else
 162                         path = "kfmclient";
 163                 if (asprintf(&man_page, "man:%s(1)", page) > 0) {
 164                         execlp(path, filename, "newTab", man_page, NULL);
 165                         free(man_page);
 166                 }
 167                 exec_failed(path);
 168         }
 169 }
 170
 171 static void exec_man_man(const char *path, const char *page)
 172 {
 173         if (!path)
 174                 path = "man";
 175         execlp(path, "man", page, NULL);
 176         exec_failed(path);
 177 }
 178
 179 static void exec_man_cmd(const char *cmd, const char *page)
 180 {
 181         char *shell_cmd;
 182
 183         if (asprintf(&shell_cmd, "%s %s", cmd, page) > 0) {
 184                 execl("/bin/sh", "sh", "-c", shell_cmd, NULL);
 185                 free(shell_cmd);
 186         }
 187         exec_failed(cmd);
 188 }
 189
 190 static void add_man_viewer(const char *name)
 191 {
 192         struct man_viewer_list **p = &man_viewer_list;
 193         size_t len = strlen(name);
 194
 195         while (*p)
 196                 p = &((*p)->next);
 197         *p = zalloc(sizeof(**p) + len + 1);
 198         strcpy((*p)->name, name);
 199 }
 200
 201 static int supported_man_viewer(const char *name, size_t len)
 202 {
 203         return (!strncasecmp("man", name, len) ||
 204                 !strncasecmp("woman", name, len) ||
 205                 !strncasecmp("konqueror", name, len));
 206 }
 207
 208 static void do_add_man_viewer_info(const char *name,
 209                                    size_t len,
 210                                    const char *value)
 211 {
 212         struct man_viewer_info_list *new = zalloc(sizeof(*new) + len + 1);
 213
 214         strncpy(new->name, name, len);
 215         new->info = strdup(value);
 216         new->next = man_viewer_info_list;
 217         man_viewer_info_list = new;
 218 }
 219
 220 static void unsupported_man_viewer(const char *name, const char *var)
 221 {
 222         pr_warning("'%s': path for unsupported man viewer.\n"
 223                    "Please consider using 'man.<tool>.%s' instead.", name, var);
 224 }
 225
 226 static int add_man_viewer_path(const char *name,
 227                                size_t len,
 228                                const char *value)
 229 {
 230         if (supported_man_viewer(name, len))
 231                 do_add_man_viewer_info(name, len, value);
 232         else
 233                 unsupported_man_viewer(name, "cmd");
 234
 235         return 0;
 236 }
 237
 238 static int add_man_viewer_cmd(const char *name,
 239                               size_t len,
 240                               const char *value)
 241 {
 242         if (supported_man_viewer(name, len))
 243                 unsupported_man_viewer(name, "path");
 244         else
 245                 do_add_man_viewer_info(name, len, value);
 246
 247         return 0;
 248 }
 249
 250 static int add_man_viewer_info(const char *var, const char *value)
 251 {
 252         const char *name = var + 4;
 253         const char *subkey = strrchr(name, '.');
 254
 255         if (!subkey) {
 256                 pr_err("Config with no key for man viewer: %s", name);
 257                 return -1;
 258         }
 259
 260         if (!strcmp(subkey, ".path")) {
 261                 if (!value)
 262                         return config_error_nonbool(var);
 263                 return add_man_viewer_path(name, subkey - name, value);
 264         }
 265         if (!strcmp(subkey, ".cmd")) {
 266                 if (!value)
 267                         return config_error_nonbool(var);
 268                 return add_man_viewer_cmd(name, subkey - name, value);
 269         }
 270
 271         pr_warning("'%s': unsupported man viewer sub key.", subkey);
 272         return 0;
 273 }
 274
 275 static int perf_help_config(const char *var, const char *value, void *cb)
 276 {
 277         enum help_format *help_formatp = cb;
 278
 279         if (!strcmp(var, "help.format")) {
 280                 if (!value)
 281                         return config_error_nonbool(var);
 282                 *help_formatp = parse_help_format(value);
 283                 if (*help_formatp == HELP_FORMAT_NONE)
 284                         return -1;
 285                 return 0;
 286         }
 287         if (!strcmp(var, "man.viewer")) {
 288                 if (!value)
 289                         return config_error_nonbool(var);
 290                 add_man_viewer(value);
 291                 return 0;
 292         }
 293         if (strstarts(var, "man."))
 294                 return add_man_viewer_info(var, value);
 295
 296         return 0;
 297 }
 298
 299 static struct cmdnames main_cmds, other_cmds;
 300
 301 void list_common_cmds_help(void)
 302 {
 303         unsigned int i, longest = 0;
 304
 305         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 306                 if (longest < strlen(common_cmds[i].name))
 307                         longest = strlen(common_cmds[i].name);
 308         }
 309
 310         puts(" The most commonly used perf commands are:");
 311         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 312                 printf("   %-*s   ", longest, common_cmds[i].name);
 313                 puts(common_cmds[i].help);
 314         }
 315 }
 316
 317 static const char *cmd_to_page(const char *perf_cmd)
 318 {
 319         char *s;
 320
 321         if (!perf_cmd)
 322                 return "perf";
 323         else if (strstarts(perf_cmd, "perf"))
 324                 return perf_cmd;
 325
 326         return asprintf(&s, "perf-%s", perf_cmd) < 0 ? NULL : s;
 327 }
 328
 329 static void setup_man_path(void)
 330 {
 331         char *new_path;
 332         const char *old_path = getenv("MANPATH");
 333
 334         /* We should always put ':' after our path. If there is no
 335          * old_path, the ':' at the end will let 'man' to try
 336          * system-wide paths after ours to find the manual page. If
 337          * there is old_path, we need ':' as delimiter. */
 338         if (asprintf(&new_path, "%s:%s", system_path(PERF_MAN_PATH), old_path ?: "") > 0) {
 339                 setenv("MANPATH", new_path, 1);
 340                 free(new_path);
 341         } else {
 342                 pr_err("Unable to setup man path");
 343         }
 344 }
 345
 346 static void exec_viewer(const char *name, const char *page)
 347 {
 348         const char *info = get_man_viewer_info(name);
 349
 350         if (!strcasecmp(name, "man"))
 351                 exec_man_man(info, page);
 352         else if (!strcasecmp(name, "woman"))
 353                 exec_woman_emacs(info, page);
 354         else if (!strcasecmp(name, "konqueror"))
 355                 exec_man_konqueror(info, page);
 356         else if (info)
 357                 exec_man_cmd(info, page);
 358         else
 359                 pr_warning("'%s': unknown man viewer.", name);
 360 }
 361
 362 static int show_man_page(const char *perf_cmd)
 363 {
 364         struct man_viewer_list *viewer;
 365         const char *page = cmd_to_page(perf_cmd);
 366         const char *fallback = getenv("PERF_MAN_VIEWER");
 367
 368         setup_man_path();
 369         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 370                 exec_viewer(viewer->name, page); /* will return when unable */
 371
 372         if (fallback)
 373                 exec_viewer(fallback, page);
 374         exec_viewer("man", page);
 375
 376         pr_err("no man viewer handled the request");
 377         return -1;
 378 }
 379
 380 static int show_info_page(const char *perf_cmd)
 381 {
 382         const char *page = cmd_to_page(perf_cmd);
 383         setenv("INFOPATH", system_path(PERF_INFO_PATH), 1);
 384         execlp("info", "info", "perfman", page, NULL);
 385         return -1;
 386 }
 387
 388 static int get_html_page_path(char **page_path, const char *page)
 389 {
 390         struct stat st;
 391         const char *html_path = system_path(PERF_HTML_PATH);
 392
 393         /* Check that we have a perf documentation directory. */
 394         if (stat(mkpath("%s/perf.html", html_path), &st)
 395             || !S_ISREG(st.st_mode)) {
 396                 pr_err("'%s': not a documentation directory.", html_path);
 397                 return -1;
 398         }
 399
 400         return asprintf(page_path, "%s/%s.html", html_path, page);
 401 }
 402
 403 /*
 404  * If open_html is not defined in a platform-specific way (see for
 405  * example compat/mingw.h), we use the script web--browse to display
 406  * HTML.
 407  */
 408 #ifndef open_html
 409 static void open_html(const char *path)
 410 {
 411         execl_cmd("web--browse", "-c", "help.browser", path, NULL);
 412 }
 413 #endif
 414
 415 static int show_html_page(const char *perf_cmd)
 416 {
 417         const char *page = cmd_to_page(perf_cmd);
 418         char *page_path; /* it leaks but we exec bellow */
 419
 420         if (get_html_page_path(&page_path, page) < 0)
 421                 return -1;
 422
 423         open_html(page_path);
 424
 425         return 0;
 426 }
 427
 428 int cmd_help(int argc, const char **argv)
 429 {
 430         bool show_all = false;
 431         enum help_format help_format = HELP_FORMAT_MAN;
 432         struct option builtin_help_options[] = {
 433         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
 434         OPT_SET_UINT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
 435         OPT_SET_UINT('w', "web", &help_format, "show manual in web browser",
 436                         HELP_FORMAT_WEB),
 437         OPT_SET_UINT('i', "info", &help_format, "show info page",
 438                         HELP_FORMAT_INFO),
 439         OPT_END(),
 440         };
 441         const char * const builtin_help_subcommands[] = {
 442                 "buildid-cache", "buildid-list", "diff", "evlist", "help", "list",
 443                 "record", "report", "bench", "stat", "timechart", "top", "annotate",
 444                 "script", "sched", "kallsyms", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
 445 #ifdef HAVE_LIBELF_SUPPORT
 446                 "probe",
 447 #endif
 448 #if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
 449                 "trace",
 450 #endif
 451         NULL };
 452         const char *builtin_help_usage[] = {
 453                 "perf help [--all] [--man|--web|--info] [command]",
 454                 NULL
 455         };
 456         int rc;
 457
 458         load_command_list("perf-", &main_cmds, &other_cmds);
 459
 460         rc = perf_config(perf_help_config, &help_format);
 461         if (rc)
 462                 return rc;
 463
 464         argc = parse_options_subcommand(argc, argv, builtin_help_options,
 465                         builtin_help_subcommands, builtin_help_usage, 0);
 466
 467         if (show_all) {
 468                 printf("\n Usage: %s\n\n", perf_usage_string);
 469                 list_commands("perf commands", &main_cmds, &other_cmds);
 470                 printf(" %s\n\n", perf_more_info_string);
 471                 return 0;
 472         }
 473
 474         if (!argv[0]) {
 475                 printf("\n usage: %s\n\n", perf_usage_string);
 476                 list_common_cmds_help();
 477                 printf("\n %s\n\n", perf_more_info_string);
 478                 return 0;
 479         }
 480
 481         switch (help_format) {
 482         case HELP_FORMAT_MAN:
 483                 rc = show_man_page(argv[0]);
 484                 break;
 485         case HELP_FORMAT_INFO:
 486                 rc = show_info_page(argv[0]);
 487                 break;
 488         case HELP_FORMAT_WEB:
 489                 rc = show_html_page(argv[0]);
 490                 break;
 491         case HELP_FORMAT_NONE:
 492                 /* fall-through */
 493         default:
 494                 rc = -1;
 495                 break;
 496         }
 497
 498         return rc;
 499 }