perf.c

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// SPDX-License-Identifier: GPL-2.0
/*
 * perf.c
 *
 * Performance analysis utility.
 *
 * This is the main hub from which the sub-commands (perf stat,
 * perf top, perf record, perf report, etc.) are started.
 */
#include "builtin.h"

#include "util/env.h"
#include <subcmd/exec-cmd.h>
#include "util/config.h"
#include <subcmd/run-command.h>
#include "util/parse-events.h"
#include <subcmd/parse-options.h>
#include "util/bpf-loader.h"
#include "util/debug.h"
#include "util/event.h"
#include <api/fs/fs.h>
#include <api/fs/tracing_path.h>
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <linux/kernel.h>

const char perf_usage_string[] =
    "perf [--version] [--help] [OPTIONS] COMMAND [ARGS]";

const char perf_more_info_string[] =
    "See 'perf help COMMAND' for more information on a specific command.";

static int use_pager = -1;
const char *input_name;

struct cmd_struct {
    const char *cmd;
    int (*fn)(int, const char **);
    int option;
};

static struct cmd_struct commands[] = {
    { "buildid-cache", cmd_buildid_cache, 0 },
    { "buildid-list", cmd_buildid_list, 0 },
    { "config", cmd_config, 0 },
    { "c2c",    cmd_c2c,    0 },
    { "diff",   cmd_diff,   0 },
    { "evlist", cmd_evlist, 0 },
    { "help",   cmd_help,   0 },
    { "kallsyms",   cmd_kallsyms,   0 },
    { "list",   cmd_list,   0 },
    { "record", cmd_record, 0 },
    { "report", cmd_report, 0 },
    { "bench",  cmd_bench,  0 },
    { "stat",   cmd_stat,   0 },
    { "timechart",  cmd_timechart,  0 },
    { "top",    cmd_top,    0 },
    { "annotate",   cmd_annotate,   0 },
    { "version",    cmd_version,    0 },
    { "script", cmd_script, 0 },
    { "sched",  cmd_sched,  0 },
#ifdef HAVE_LIBELF_SUPPORT
    { "probe",  cmd_probe,  0 },
#endif
    { "kmem",   cmd_kmem,   0 },
    { "lock",   cmd_lock,   0 },
    { "kvm",    cmd_kvm,    0 },
    { "test",   cmd_test,   0 },
#if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
    { "trace",  cmd_trace,  0 },
#endif
    { "inject", cmd_inject, 0 },
    { "mem",    cmd_mem,    0 },
    { "data",   cmd_data,   0 },
    { "ftrace", cmd_ftrace, 0 },
};

struct pager_config {
    const char *cmd;
    int val;
};

static int pager_command_config(const char *var, const char *value, void *data)
{
    struct pager_config *c = data;
    if (strstarts(var, "pager.") && !strcmp(var + 6, c->cmd))
        c->val = perf_config_bool(var, value);
    return 0;
}

/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
static int check_pager_config(const char *cmd)
{
    int err;
    struct pager_config c;
    c.cmd = cmd;
    c.val = -1;
    err = perf_config(pager_command_config, &c);
    return err ?: c.val;
}

static int browser_command_config(const char *var, const char *value, void *data)
{
    struct pager_config *c = data;
    if (strstarts(var, "tui.") && !strcmp(var + 4, c->cmd))
        c->val = perf_config_bool(var, value);
    if (strstarts(var, "gtk.") && !strcmp(var + 4, c->cmd))
        c->val = perf_config_bool(var, value) ? 2 : 0;
    return 0;
}

/*
 * returns 0 for "no tui", 1 for "use tui", 2 for "use gtk",
 * and -1 for "not specified"
 */
static int check_browser_config(const char *cmd)
{
    int err;
    struct pager_config c;
    c.cmd = cmd;
    c.val = -1;
    err = perf_config(browser_command_config, &c);
    return err ?: c.val;
}

static void commit_pager_choice(void)
{
    switch (use_pager) {
    case 0:
        setenv(PERF_PAGER_ENVIRONMENT, "cat", 1);
        break;
    case 1:
        /* setup_pager(); */
        break;
    default:
        break;
    }
}

struct option options[] = {
    OPT_ARGUMENT("help", "help"),
    OPT_ARGUMENT("version", "version"),
    OPT_ARGUMENT("exec-path", "exec-path"),
    OPT_ARGUMENT("html-path", "html-path"),
    OPT_ARGUMENT("paginate", "paginate"),
    OPT_ARGUMENT("no-pager", "no-pager"),
    OPT_ARGUMENT("debugfs-dir", "debugfs-dir"),
    OPT_ARGUMENT("buildid-dir", "buildid-dir"),
    OPT_ARGUMENT("list-cmds", "list-cmds"),
    OPT_ARGUMENT("list-opts", "list-opts"),
    OPT_ARGUMENT("debug", "debug"),
    OPT_END()
};

static int handle_options(const char ***argv, int *argc, int *envchanged)
{
    int handled = 0;

    while (*argc > 0) {
        const char *cmd = (*argv)[0];
        if (cmd[0] != '-')
            break;

        /*
         * For legacy reasons, the "version" and "help"
         * commands can be written with "--" prepended
         * to make them look like flags.
         */
        if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
            break;

        /*
         * Shortcut for '-h' and '-v' options to invoke help
         * and version command.
         */
        if (!strcmp(cmd, "-h")) {
            (*argv)[0] = "--help";
            break;
        }

        if (!strcmp(cmd, "-v")) {
            (*argv)[0] = "--version";
            break;
        }

        if (!strcmp(cmd, "-vv")) {
            (*argv)[0] = "version";
            version_verbose = 1;
            break;
        }

        /*
         * Check remaining flags.
         */
        if (strstarts(cmd, CMD_EXEC_PATH)) {
            cmd += strlen(CMD_EXEC_PATH);
            if (*cmd == '=')
                set_argv_exec_path(cmd + 1);
            else {
                puts(get_argv_exec_path());
                exit(0);
            }
        } else if (!strcmp(cmd, "--html-path")) {
            puts(system_path(PERF_HTML_PATH));
            exit(0);
        } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
            use_pager = 1;
        } else if (!strcmp(cmd, "--no-pager")) {
            use_pager = 0;
            if (envchanged)
                *envchanged = 1;
        } else if (!strcmp(cmd, "--debugfs-dir")) {
            if (*argc < 2) {
                fprintf(stderr, "No directory given for --debugfs-dir.\n");
                usage(perf_usage_string);
            }
            tracing_path_set((*argv)[1]);
            if (envchanged)
                *envchanged = 1;
            (*argv)++;
            (*argc)--;
        } else if (!strcmp(cmd, "--buildid-dir")) {
            if (*argc < 2) {
                fprintf(stderr, "No directory given for --buildid-dir.\n");
                usage(perf_usage_string);
            }
            set_buildid_dir((*argv)[1]);
            if (envchanged)
                *envchanged = 1;
            (*argv)++;
            (*argc)--;
        } else if (strstarts(cmd, CMD_DEBUGFS_DIR)) {
            tracing_path_set(cmd + strlen(CMD_DEBUGFS_DIR));
            fprintf(stderr, "dir: %s\n", tracing_path_mount());
            if (envchanged)
                *envchanged = 1;
        } else if (!strcmp(cmd, "--list-cmds")) {
            unsigned int i;

            for (i = 0; i < ARRAY_SIZE(commands); i++) {
                struct cmd_struct *p = commands+i;
                printf("%s ", p->cmd);
            }
            putchar('\n');
            exit(0);
        } else if (!strcmp(cmd, "--list-opts")) {
            unsigned int i;

            for (i = 0; i < ARRAY_SIZE(options)-1; i++) {
                struct option *p = options+i;
                printf("--%s ", p->long_name);
            }
            putchar('\n');
            exit(0);
        } else if (!strcmp(cmd, "--debug")) {
            if (*argc < 2) {
                fprintf(stderr, "No variable specified for --debug.\n");
                usage(perf_usage_string);
            }
            if (perf_debug_option((*argv)[1]))
                usage(perf_usage_string);

            (*argv)++;
            (*argc)--;
        } else {
            fprintf(stderr, "Unknown option: %s\n", cmd);
            usage(perf_usage_string);
        }

        (*argv)++;
        (*argc)--;
        handled++;
    }
    return handled;
}

#define RUN_SETUP   (1<<0)
#define USE_PAGER   (1<<1)

static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
{
    int status;
    struct stat st;
    char sbuf[STRERR_BUFSIZE];

    if (use_browser == -1)
        use_browser = check_browser_config(p->cmd);

    if (use_pager == -1 && p->option & RUN_SETUP)
        use_pager = check_pager_config(p->cmd);
    if (use_pager == -1 && p->option & USE_PAGER)
        use_pager = 1;
    commit_pager_choice();

    perf_env__set_cmdline(&perf_env, argc, argv);
    status = p->fn(argc, argv);
    perf_config__exit();
    exit_browser(status);
    perf_env__exit(&perf_env);
    bpf__clear();

    if (status)
        return status & 0xff;

    /* Somebody closed stdout? */
    if (fstat(fileno(stdout), &st))
        return 0;
    /* Ignore write errors for pipes and sockets.. */
    if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
        return 0;

    status = 1;
    /* Check for ENOSPC and EIO errors.. */
    if (fflush(stdout)) {
        fprintf(stderr, "write failure on standard output: %s",
            str_error_r(errno, sbuf, sizeof(sbuf)));
        goto out;
    }
    if (ferror(stdout)) {
        fprintf(stderr, "unknown write failure on standard output");
        goto out;
    }
    if (fclose(stdout)) {
        fprintf(stderr, "close failed on standard output: %s",
            str_error_r(errno, sbuf, sizeof(sbuf)));
        goto out;
    }
    status = 0;
out:
    return status;
}

static void handle_internal_command(int argc, const char **argv)
{
    const char *cmd = argv[0];
    unsigned int i;

    /* Turn "perf cmd --help" into "perf help cmd" */
    if (argc > 1 && !strcmp(argv[1], "--help")) {
        argv[1] = argv[0];
        argv[0] = cmd = "help";
    }

    for (i = 0; i < ARRAY_SIZE(commands); i++) {
        struct cmd_struct *p = commands+i;
        if (strcmp(p->cmd, cmd))
            continue;
        exit(run_builtin(p, argc, argv));
    }
}

static void execv_dashed_external(const char **argv)
{
    char *cmd;
    const char *tmp;
    int status;

    if (asprintf(&cmd, "perf-%s", argv[0]) < 0)
        goto do_die;

    /*
     * argv[0] must be the perf command, but the argv array
     * belongs to the caller, and may be reused in
     * subsequent loop iterations. Save argv[0] and
     * restore it on error.
     */
    tmp = argv[0];
    argv[0] = cmd;

    /*
     * if we fail because the command is not found, it is
     * OK to return. Otherwise, we just pass along the status code.
     */
    status = run_command_v_opt(argv, 0);
    if (status != -ERR_RUN_COMMAND_EXEC) {
        if (IS_RUN_COMMAND_ERR(status)) {
do_die:
            pr_err("FATAL: unable to run '%s'", argv[0]);
            status = -128;
        }
        exit(-status);
    }
    errno = ENOENT; /* as if we called execvp */

    argv[0] = tmp;
    zfree(&cmd);
}

static int run_argv(int *argcp, const char ***argv)
{
    /* See if it's an internal command */
    handle_internal_command(*argcp, *argv);

    /* .. then try the external ones */
    execv_dashed_external(*argv);
    return 0;
}

static void pthread__block_sigwinch(void)
{
    sigset_t set;

    sigemptyset(&set);
    sigaddset(&set, SIGWINCH);
    pthread_sigmask(SIG_BLOCK, &set, NULL);
}

void pthread__unblock_sigwinch(void)
{
    sigset_t set;

    sigemptyset(&set);
    sigaddset(&set, SIGWINCH);
    pthread_sigmask(SIG_UNBLOCK, &set, NULL);
}

int main(int argc, const char **argv)
{
    int err;
    const char *cmd;
    char sbuf[STRERR_BUFSIZE];

    /* libsubcmd init */
    exec_cmd_init("perf", PREFIX, PERF_EXEC_PATH, EXEC_PATH_ENVIRONMENT);
    pager_init(PERF_PAGER_ENVIRONMENT);

    /* The page_size is placed in util object. */
    page_size = sysconf(_SC_PAGE_SIZE);

    cmd = extract_argv0_path(argv[0]);
    if (!cmd)
        cmd = "perf-help";

    srandom(time(NULL));

    err = perf_config(perf_default_config, NULL);
    if (err)
        return err;
    set_buildid_dir(NULL);

    /*
     * "perf-xxxx" is the same as "perf xxxx", but we obviously:
     *
     *  - cannot take flags in between the "perf" and the "xxxx".
     *  - cannot execute it externally (since it would just do
     *    the same thing over again)
     *
     * So we just directly call the internal command handler. If that one
     * fails to handle this, then maybe we just run a renamed perf binary
     * that contains a dash in its name. To handle this scenario, we just
     * fall through and ignore the "xxxx" part of the command string.
     */
    if (strstarts(cmd, "perf-")) {
        cmd += 5;
        argv[0] = cmd;
        handle_internal_command(argc, argv);
        /*
         * If the command is handled, the above function does not
         * return undo changes and fall through in such a case.
         */
        cmd -= 5;
        argv[0] = cmd;
    }
    if (strstarts(cmd, "trace")) {
#if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
        setup_path();
        argv[0] = "trace";
        return cmd_trace(argc, argv);
#else
        fprintf(stderr,
            "trace command not available: missing audit-libs devel package at build time.\n");
        goto out;
#endif
    }
    /* Look for flags.. */
    argv++;
    argc--;
    handle_options(&argv, &argc, NULL);
    commit_pager_choice();

    if (argc > 0) {
        if (strstarts(argv[0], "--"))
            argv[0] += 2;
    } else {
        /* The user didn't specify a command; give them help */
        printf("\n usage: %s\n\n", perf_usage_string);
        list_common_cmds_help();
        printf("\n %s\n\n", perf_more_info_string);
        goto out;
    }
    cmd = argv[0];

    test_attr__init();

    /*
     * We use PATH to find perf commands, but we prepend some higher
     * precedence paths: the "--exec-path" option, the PERF_EXEC_PATH
     * environment, and the $(perfexecdir) from the Makefile at build
     * time.
     */
    setup_path();
    /*
     * Block SIGWINCH notifications so that the thread that wants it can
     * unblock and get syscalls like select interrupted instead of waiting
     * forever while the signal goes to some other non interested thread.
     */
    pthread__block_sigwinch();

    perf_debug_setup();

    while (1) {
        static int done_help;

        run_argv(&argc, &argv);

        if (errno != ENOENT)
            break;

        if (!done_help) {
            cmd = argv[0] = help_unknown_cmd(cmd);
            done_help = 1;
        } else
            break;
    }

    fprintf(stderr, "Failed to run command '%s': %s\n",
        cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
out:
    return 1;
}