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