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 <limits.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/types.h>
  27 #include <sys/stat.h>
  28 #include <unistd.h>
  29
  30 static struct man_viewer_list {
  31         struct man_viewer_list *next;
  32         char name[0];
  33 } *man_viewer_list;
  34
  35 static struct man_viewer_info_list {
  36         struct man_viewer_info_list *next;
  37         const char *info;
  38         char name[0];
  39 } *man_viewer_info_list;
  40
  41 enum help_format {
  42         HELP_FORMAT_NONE,
  43         HELP_FORMAT_MAN,
  44         HELP_FORMAT_INFO,
  45         HELP_FORMAT_WEB,
  46 };
  47
  48 static enum help_format parse_help_format(const char *format)
  49 {
  50         if (!strcmp(format, "man"))
  51                 return HELP_FORMAT_MAN;
  52         if (!strcmp(format, "info"))
  53                 return HELP_FORMAT_INFO;
  54         if (!strcmp(format, "web") || !strcmp(format, "html"))
  55                 return HELP_FORMAT_WEB;
  56
  57         pr_err("unrecognized help format '%s'", format);
  58         return HELP_FORMAT_NONE;
  59 }
  60
  61 static const char *get_man_viewer_info(const char *name)
  62 {
  63         struct man_viewer_info_list *viewer;
  64
  65         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next) {
  66                 if (!strcasecmp(name, viewer->name))
  67                         return viewer->info;
  68         }
  69         return NULL;
  70 }
  71
  72 static int check_emacsclient_version(void)
  73 {
  74         struct strbuf buffer = STRBUF_INIT;
  75         struct child_process ec_process;
  76         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  77         int version;
  78         int ret = -1;
  79
  80         /* emacsclient prints its version number on stderr */
  81         memset(&ec_process, 0, sizeof(ec_process));
  82         ec_process.argv = argv_ec;
  83         ec_process.err = -1;
  84         ec_process.stdout_to_stderr = 1;
  85         if (start_command(&ec_process)) {
  86                 fprintf(stderr, "Failed to start emacsclient.\n");
  87                 return -1;
  88         }
  89         if (strbuf_read(&buffer, ec_process.err, 20) < 0) {
  90                 fprintf(stderr, "Failed to read emacsclient version\n");
  91                 goto out;
  92         }
  93         close(ec_process.err);
  94
  95         /*
  96          * Don't bother checking return value, because "emacsclient --version"
  97          * seems to always exits with code 1.
  98          */
  99         finish_command(&ec_process);
 100
 101         if (!strstarts(buffer.buf, "emacsclient")) {
 102                 fprintf(stderr, "Failed to parse emacsclient version.\n");
 103                 goto out;
 104         }
 105
 106         version = atoi(buffer.buf + strlen("emacsclient"));
 107
 108         if (version < 22) {
 109                 fprintf(stderr,
 110                         "emacsclient version '%d' too old (< 22).\n",
 111                         version);
 112         } else
 113                 ret = 0;
 114 out:
 115         strbuf_release(&buffer);
 116         return ret;
 117 }
 118
 119 static void exec_failed(const char *cmd)
 120 {
 121         char sbuf[STRERR_BUFSIZE];
 122         pr_warning("failed to exec '%s': %s", cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
 123 }
 124
 125 static void exec_woman_emacs(const char *path, const char *page)
 126 {
 127         if (!check_emacsclient_version()) {
 128                 /* This works only with emacsclient version >= 22. */
 129                 char *man_page;
 130
 131                 if (!path)
 132                         path = "emacsclient";
 133                 if (asprintf(&man_page, "(woman \"%s\")", page) > 0) {
 134                         execlp(path, "emacsclient", "-e", man_page, NULL);
 135                         free(man_page);
 136                 }
 137                 exec_failed(path);
 138         }
 139 }
 140
 141 static void exec_man_konqueror(const char *path, const char *page)
 142 {
 143         const char *display = getenv("DISPLAY");
 144
 145         if (display && *display) {
 146                 char *man_page;
 147                 const char *filename = "kfmclient";
 148
 149                 /* It's simpler to launch konqueror using kfmclient. */
 150                 if (path) {
 151                         const char *file = strrchr(path, '/');
 152                         if (file && !strcmp(file + 1, "konqueror")) {
 153                                 char *new = strdup(path);
 154                                 char *dest = strrchr(new, '/');
 155
 156                                 /* strlen("konqueror") == strlen("kfmclient") */
 157                                 strcpy(dest + 1, "kfmclient");
 158                                 path = new;
 159                         }
 160                         if (file)
 161                                 filename = file;
 162                 } else
 163                         path = "kfmclient";
 164                 if (asprintf(&man_page, "man:%s(1)", page) > 0) {
 165                         execlp(path, filename, "newTab", man_page, NULL);
 166                         free(man_page);
 167                 }
 168                 exec_failed(path);
 169         }
 170 }
 171
 172 static void exec_man_man(const char *path, const char *page)
 173 {
 174         if (!path)
 175                 path = "man";
 176         execlp(path, "man", page, NULL);
 177         exec_failed(path);
 178 }
 179
 180 static void exec_man_cmd(const char *cmd, const char *page)
 181 {
 182         char *shell_cmd;
 183
 184         if (asprintf(&shell_cmd, "%s %s", cmd, page) > 0) {
 185                 execl("/bin/sh", "sh", "-c", shell_cmd, NULL);
 186                 free(shell_cmd);
 187         }
 188         exec_failed(cmd);
 189 }
 190
 191 static void add_man_viewer(const char *name)
 192 {
 193         struct man_viewer_list **p = &man_viewer_list;
 194         size_t len = strlen(name);
 195
 196         while (*p)
 197                 p = &((*p)->next);
 198         *p = zalloc(sizeof(**p) + len + 1);
 199         strcpy((*p)->name, name);
 200 }
 201
 202 static int supported_man_viewer(const char *name, size_t len)
 203 {
 204         return (!strncasecmp("man", name, len) ||
 205                 !strncasecmp("woman", name, len) ||
 206                 !strncasecmp("konqueror", name, len));
 207 }
 208
 209 static void do_add_man_viewer_info(const char *name,
 210                                    size_t len,
 211                                    const char *value)
 212 {
 213         struct man_viewer_info_list *new = zalloc(sizeof(*new) + len + 1);
 214
 215         strncpy(new->name, name, len);
 216         new->info = strdup(value);
 217         new->next = man_viewer_info_list;
 218         man_viewer_info_list = new;
 219 }
 220
 221 static void unsupported_man_viewer(const char *name, const char *var)
 222 {
 223         pr_warning("'%s': path for unsupported man viewer.\n"
 224                    "Please consider using 'man.<tool>.%s' instead.", name, var);
 225 }
 226
 227 static int add_man_viewer_path(const char *name,
 228                                size_t len,
 229                                const char *value)
 230 {
 231         if (supported_man_viewer(name, len))
 232                 do_add_man_viewer_info(name, len, value);
 233         else
 234                 unsupported_man_viewer(name, "cmd");
 235
 236         return 0;
 237 }
 238
 239 static int add_man_viewer_cmd(const char *name,
 240                               size_t len,
 241                               const char *value)
 242 {
 243         if (supported_man_viewer(name, len))
 244                 unsupported_man_viewer(name, "path");
 245         else
 246                 do_add_man_viewer_info(name, len, value);
 247
 248         return 0;
 249 }
 250
 251 static int add_man_viewer_info(const char *var, const char *value)
 252 {
 253         const char *name = var + 4;
 254         const char *subkey = strrchr(name, '.');
 255
 256         if (!subkey) {
 257                 pr_err("Config with no key for man viewer: %s", name);
 258                 return -1;
 259         }
 260
 261         if (!strcmp(subkey, ".path")) {
 262                 if (!value)
 263                         return config_error_nonbool(var);
 264                 return add_man_viewer_path(name, subkey - name, value);
 265         }
 266         if (!strcmp(subkey, ".cmd")) {
 267                 if (!value)
 268                         return config_error_nonbool(var);
 269                 return add_man_viewer_cmd(name, subkey - name, value);
 270         }
 271
 272         pr_warning("'%s': unsupported man viewer sub key.", subkey);
 273         return 0;
 274 }
 275
 276 static int perf_help_config(const char *var, const char *value, void *cb)
 277 {
 278         enum help_format *help_formatp = cb;
 279
 280         if (!strcmp(var, "help.format")) {
 281                 if (!value)
 282                         return config_error_nonbool(var);
 283                 *help_formatp = parse_help_format(value);
 284                 if (*help_formatp == HELP_FORMAT_NONE)
 285                         return -1;
 286                 return 0;
 287         }
 288         if (!strcmp(var, "man.viewer")) {
 289                 if (!value)
 290                         return config_error_nonbool(var);
 291                 add_man_viewer(value);
 292                 return 0;
 293         }
 294         if (strstarts(var, "man."))
 295                 return add_man_viewer_info(var, value);
 296
 297         return 0;
 298 }
 299
 300 static struct cmdnames main_cmds, other_cmds;
 301
 302 void list_common_cmds_help(void)
 303 {
 304         unsigned int i, longest = 0;
 305
 306         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 307                 if (longest < strlen(common_cmds[i].name))
 308                         longest = strlen(common_cmds[i].name);
 309         }
 310
 311         puts(" The most commonly used perf commands are:");
 312         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 313                 printf("   %-*s   ", longest, common_cmds[i].name);
 314                 puts(common_cmds[i].help);
 315         }
 316 }
 317
 318 static const char *cmd_to_page(const char *perf_cmd)
 319 {
 320         char *s;
 321
 322         if (!perf_cmd)
 323                 return "perf";
 324         else if (strstarts(perf_cmd, "perf"))
 325                 return perf_cmd;
 326
 327         return asprintf(&s, "perf-%s", perf_cmd) < 0 ? NULL : s;
 328 }
 329
 330 static void setup_man_path(void)
 331 {
 332         char *new_path;
 333         const char *old_path = getenv("MANPATH");
 334
 335         /* We should always put ':' after our path. If there is no
 336          * old_path, the ':' at the end will let 'man' to try
 337          * system-wide paths after ours to find the manual page. If
 338          * there is old_path, we need ':' as delimiter. */
 339         if (asprintf(&new_path, "%s:%s", system_path(PERF_MAN_PATH), old_path ?: "") > 0) {
 340                 setenv("MANPATH", new_path, 1);
 341                 free(new_path);
 342         } else {
 343                 pr_err("Unable to setup man path");
 344         }
 345 }
 346
 347 static void exec_viewer(const char *name, const char *page)
 348 {
 349         const char *info = get_man_viewer_info(name);
 350
 351         if (!strcasecmp(name, "man"))
 352                 exec_man_man(info, page);
 353         else if (!strcasecmp(name, "woman"))
 354                 exec_woman_emacs(info, page);
 355         else if (!strcasecmp(name, "konqueror"))
 356                 exec_man_konqueror(info, page);
 357         else if (info)
 358                 exec_man_cmd(info, page);
 359         else
 360                 pr_warning("'%s': unknown man viewer.", name);
 361 }
 362
 363 static int show_man_page(const char *perf_cmd)
 364 {
 365         struct man_viewer_list *viewer;
 366         const char *page = cmd_to_page(perf_cmd);
 367         const char *fallback = getenv("PERF_MAN_VIEWER");
 368
 369         setup_man_path();
 370         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 371                 exec_viewer(viewer->name, page); /* will return when unable */
 372
 373         if (fallback)
 374                 exec_viewer(fallback, page);
 375         exec_viewer("man", page);
 376
 377         pr_err("no man viewer handled the request");
 378         return -1;
 379 }
 380
 381 static int show_info_page(const char *perf_cmd)
 382 {
 383         const char *page = cmd_to_page(perf_cmd);
 384         setenv("INFOPATH", system_path(PERF_INFO_PATH), 1);
 385         execlp("info", "info", "perfman", page, NULL);
 386         return -1;
 387 }
 388
 389 static int get_html_page_path(char **page_path, const char *page)
 390 {
 391         struct stat st;
 392         const char *html_path = system_path(PERF_HTML_PATH);
 393         char path[PATH_MAX];
 394
 395         /* Check that we have a perf documentation directory. */
 396         if (stat(mkpath(path, sizeof(path), "%s/perf.html", html_path), &st)
 397             || !S_ISREG(st.st_mode)) {
 398                 pr_err("'%s': not a documentation directory.", html_path);
 399                 return -1;
 400         }
 401
 402         return asprintf(page_path, "%s/%s.html", html_path, page);
 403 }
 404
 405 /*
 406  * If open_html is not defined in a platform-specific way (see for
 407  * example compat/mingw.h), we use the script web--browse to display
 408  * HTML.
 409  */
 410 #ifndef open_html
 411 static void open_html(const char *path)
 412 {
 413         execl_cmd("web--browse", "-c", "help.browser", path, NULL);
 414 }
 415 #endif
 416
 417 static int show_html_page(const char *perf_cmd)
 418 {
 419         const char *page = cmd_to_page(perf_cmd);
 420         char *page_path; /* it leaks but we exec below */
 421
 422         if (get_html_page_path(&page_path, page) < 0)
 423                 return -1;
 424
 425         open_html(page_path);
 426
 427         return 0;
 428 }
 429
 430 int cmd_help(int argc, const char **argv)
 431 {
 432         bool show_all = false;
 433         enum help_format help_format = HELP_FORMAT_MAN;
 434         struct option builtin_help_options[] = {
 435         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
 436         OPT_SET_UINT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
 437         OPT_SET_UINT('w', "web", &help_format, "show manual in web browser",
 438                         HELP_FORMAT_WEB),
 439         OPT_SET_UINT('i', "info", &help_format, "show info page",
 440                         HELP_FORMAT_INFO),
 441         OPT_END(),
 442         };
 443         const char * const builtin_help_subcommands[] = {
 444                 "buildid-cache", "buildid-list", "diff", "evlist", "help", "list",
 445                 "record", "report", "bench", "stat", "timechart", "top", "annotate",
 446                 "script", "sched", "kallsyms", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
 447 #ifdef HAVE_LIBELF_SUPPORT
 448                 "probe",
 449 #endif
 450 #if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
 451                 "trace",
 452 #endif
 453         NULL };
 454         const char *builtin_help_usage[] = {
 455                 "perf help [--all] [--man|--web|--info] [command]",
 456                 NULL
 457         };
 458         int rc;
 459
 460         load_command_list("perf-", &main_cmds, &other_cmds);
 461
 462         rc = perf_config(perf_help_config, &help_format);
 463         if (rc)
 464                 return rc;
 465
 466         argc = parse_options_subcommand(argc, argv, builtin_help_options,
 467                         builtin_help_subcommands, builtin_help_usage, 0);
 468
 469         if (show_all) {
 470                 printf("\n Usage: %s\n\n", perf_usage_string);
 471                 list_commands("perf commands", &main_cmds, &other_cmds);
 472                 printf(" %s\n\n", perf_more_info_string);
 473                 return 0;
 474         }
 475
 476         if (!argv[0]) {
 477                 printf("\n usage: %s\n\n", perf_usage_string);
 478                 list_common_cmds_help();
 479                 printf("\n %s\n\n", perf_more_info_string);
 480                 return 0;
 481         }
 482
 483         switch (help_format) {
 484         case HELP_FORMAT_MAN:
 485                 rc = show_man_page(argv[0]);
 486                 break;
 487         case HELP_FORMAT_INFO:
 488                 rc = show_info_page(argv[0]);
 489                 break;
 490         case HELP_FORMAT_WEB:
 491                 rc = show_html_page(argv[0]);
 492                 break;
 493         case HELP_FORMAT_NONE:
 494                 /* fall-through */
 495         default:
 496                 rc = -1;
 497                 break;
 498         }
 499
 500         return rc;
 501 }