perf.c

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/*
 * 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/exec_cmd.h"
#include "util/cache.h"
#include "util/quote.h"
#include "util/run-command.h"
#include "util/parse-events.h"
#include "util/debugfs.h"
#include <pthread.h>

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

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

int use_browser = -1;
static int use_pager = -1;

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

static struct cmd_struct commands[] = {
    { "buildid-cache", cmd_buildid_cache, 0 },
    { "buildid-list", cmd_buildid_list, 0 },
    { "diff",   cmd_diff,   0 },
    { "evlist", cmd_evlist, 0 },
    { "help",   cmd_help,   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 LIBELF_SUPPORT
    { "probe",  cmd_probe,  0 },
#endif
    { "kmem",   cmd_kmem,   0 },
    { "lock",   cmd_lock,   0 },
    { "kvm",    cmd_kvm,    0 },
    { "test",   cmd_test,   0 },
#ifdef LIBAUDIT_SUPPORT
    { "trace",  cmd_trace,  0 },
#endif
    { "inject", cmd_inject, 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 (!prefixcmp(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" */
int check_pager_config(const char *cmd)
{
    struct pager_config c;
    c.cmd = cmd;
    c.val = -1;
    perf_config(pager_command_config, &c);
    return c.val;
}

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

/* returns 0 for "no tui", 1 for "use tui", and -1 for "not specified" */
static int check_tui_config(const char *cmd)
{
    struct pager_config c;
    c.cmd = cmd;
    c.val = -1;
    perf_config(tui_command_config, &c);
    return c.val;
}

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

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;

        /*
         * Check remaining flags.
         */
        if (!prefixcmp(cmd, CMD_EXEC_PATH)) {
            cmd += strlen(CMD_EXEC_PATH);
            if (*cmd == '=')
                perf_set_argv_exec_path(cmd + 1);
            else {
                puts(perf_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, "--perf-dir")) {
            if (*argc < 2) {
                fprintf(stderr, "No directory given for --perf-dir.\n");
                usage(perf_usage_string);
            }
            setenv(PERF_DIR_ENVIRONMENT, (*argv)[1], 1);
            if (envchanged)
                *envchanged = 1;
            (*argv)++;
            (*argc)--;
            handled++;
        } else if (!prefixcmp(cmd, CMD_PERF_DIR)) {
            setenv(PERF_DIR_ENVIRONMENT, cmd + strlen(CMD_PERF_DIR), 1);
            if (envchanged)
                *envchanged = 1;
        } else if (!strcmp(cmd, "--work-tree")) {
            if (*argc < 2) {
                fprintf(stderr, "No directory given for --work-tree.\n");
                usage(perf_usage_string);
            }
            setenv(PERF_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
            if (envchanged)
                *envchanged = 1;
            (*argv)++;
            (*argc)--;
        } else if (!prefixcmp(cmd, CMD_WORK_TREE)) {
            setenv(PERF_WORK_TREE_ENVIRONMENT, cmd + strlen(CMD_WORK_TREE), 1);
            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);
            }
            debugfs_set_path((*argv)[1]);
            if (envchanged)
                *envchanged = 1;
            (*argv)++;
            (*argc)--;
        } else if (!prefixcmp(cmd, CMD_DEBUGFS_DIR)) {
            debugfs_set_path(cmd + strlen(CMD_DEBUGFS_DIR));
            fprintf(stderr, "dir: %s\n", debugfs_mountpoint);
            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);
            }
            exit(0);
        } else {
            fprintf(stderr, "Unknown option: %s\n", cmd);
            usage(perf_usage_string);
        }

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

static int handle_alias(int *argcp, const char ***argv)
{
    int envchanged = 0, ret = 0, saved_errno = errno;
    int count, option_count;
    const char **new_argv;
    const char *alias_command;
    char *alias_string;

    alias_command = (*argv)[0];
    alias_string = alias_lookup(alias_command);
    if (alias_string) {
        if (alias_string[0] == '!') {
            if (*argcp > 1) {
                struct strbuf buf;

                strbuf_init(&buf, PATH_MAX);
                strbuf_addstr(&buf, alias_string);
                sq_quote_argv(&buf, (*argv) + 1, PATH_MAX);
                free(alias_string);
                alias_string = buf.buf;
            }
            ret = system(alias_string + 1);
            if (ret >= 0 && WIFEXITED(ret) &&
                WEXITSTATUS(ret) != 127)
                exit(WEXITSTATUS(ret));
            die("Failed to run '%s' when expanding alias '%s'",
                alias_string + 1, alias_command);
        }
        count = split_cmdline(alias_string, &new_argv);
        if (count < 0)
            die("Bad alias.%s string", alias_command);
        option_count = handle_options(&new_argv, &count, &envchanged);
        if (envchanged)
            die("alias '%s' changes environment variables\n"
                 "You can use '!perf' in the alias to do this.",
                 alias_command);
        memmove(new_argv - option_count, new_argv,
                count * sizeof(char *));
        new_argv -= option_count;

        if (count < 1)
            die("empty alias for %s", alias_command);

        if (!strcmp(alias_command, new_argv[0]))
            die("recursive alias: %s", alias_command);

        new_argv = realloc(new_argv, sizeof(char *) *
                    (count + *argcp + 1));
        /* insert after command name */
        memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
        new_argv[count + *argcp] = NULL;

        *argv = new_argv;
        *argcp += count - 1;

        ret = 1;
    }

    errno = saved_errno;

    return ret;
}

const char perf_version_string[] = PERF_VERSION;

#define RUN_SETUP   (1<<0)
#define USE_PAGER   (1<<1)
/*
 * require working tree to be present -- anything uses this needs
 * RUN_SETUP for reading from the configuration file.
 */
#define NEED_WORK_TREE  (1<<2)

static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
{
    int status;
    struct stat st;
    const char *prefix;

    prefix = NULL;
    if (p->option & RUN_SETUP)
        prefix = NULL; /* setup_perf_directory(); */

    if (use_browser == -1)
        use_browser = check_tui_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();

    status = p->fn(argc, argv, prefix);
    exit_browser(status);

    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;

    /* Check for ENOSPC and EIO errors.. */
    if (fflush(stdout))
        die("write failure on standard output: %s", strerror(errno));
    if (ferror(stdout))
        die("unknown write failure on standard output");
    if (fclose(stdout))
        die("close failed on standard output: %s", strerror(errno));
    return 0;
}

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

    if (sizeof(ext) > 1) {
        i = strlen(argv[0]) - strlen(ext);
        if (i > 0 && !strcmp(argv[0] + i, ext)) {
            char *argv0 = strdup(argv[0]);
            argv[0] = cmd = argv0;
            argv0[i] = '\0';
        }
    }

    /* 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)
{
    struct strbuf cmd = STRBUF_INIT;
    const char *tmp;
    int status;

    strbuf_addf(&cmd, "perf-%s", argv[0]);

    /*
     * 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.buf;

    /*
     * 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))
            die("unable to run '%s'", argv[0]);
        exit(-status);
    }
    errno = ENOENT; /* as if we called execvp */

    argv[0] = tmp;

    strbuf_release(&cmd);
}

static int run_argv(int *argcp, const char ***argv)
{
    int done_alias = 0;

    while (1) {
        /* See if it's an internal command */
        handle_internal_command(*argcp, *argv);

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

        /* It could be an alias -- this works around the insanity
         * of overriding "perf log" with "perf show" by having
         * alias.log = show
         */
        if (done_alias || !handle_alias(argcp, argv))
            break;
        done_alias = 1;
    }

    return done_alias;
}

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)
{
    const char *cmd;

    cmd = perf_extract_argv0_path(argv[0]);
    if (!cmd)
        cmd = "perf-help";
    /* get debugfs mount point from /proc/mounts */
    debugfs_mount(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, and
     * die if that one cannot handle it.
     */
    if (!prefixcmp(cmd, "perf-")) {
        cmd += 5;
        argv[0] = cmd;
        handle_internal_command(argc, argv);
        die("cannot handle %s internally", cmd);
    }

    /* Look for flags.. */
    argv++;
    argc--;
    handle_options(&argv, &argc, NULL);
    commit_pager_choice();
    set_buildid_dir();

    if (argc > 0) {
        if (!prefixcmp(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);
        exit(1);
    }
    cmd = argv[0];

    /*
     * 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();

    while (1) {
        static int done_help;
        static int was_alias;

        was_alias = run_argv(&argc, &argv);
        if (errno != ENOENT)
            break;

        if (was_alias) {
            fprintf(stderr, "Expansion of alias '%s' failed; "
                "'%s' is not a perf-command\n",
                cmd, argv[0]);
            exit(1);
        }
        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, strerror(errno));

    return 1;
}