linux/tools/perf/builtin-help.c
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   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
  23static struct man_viewer_list {
  24        struct man_viewer_list *next;
  25        char name[0];
  26} *man_viewer_list;
  27
  28static 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
  34enum help_format {
  35        HELP_FORMAT_NONE,
  36        HELP_FORMAT_MAN,
  37        HELP_FORMAT_INFO,
  38        HELP_FORMAT_WEB,
  39};
  40
  41static 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
  54static 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
  65static 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;
 107out:
 108        strbuf_release(&buffer);
 109        return ret;
 110}
 111
 112static 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
 118static 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
 134static 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
 165static 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
 173static 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
 184static 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        strncpy((*p)->name, name, len);
 193}
 194
 195static 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
 202static 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
 214static 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
 220static 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
 232static 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
 244static 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
 269static 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
 293static struct cmdnames main_cmds, other_cmds;
 294
 295void 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
 311static 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
 323static 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
 340static 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
 356static 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
 374static 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
 382static 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
 403static void open_html(const char *path)
 404{
 405        execl_cmd("web--browse", "-c", "help.browser", path, NULL);
 406}
 407#endif
 408
 409static 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
 422int 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}
 494