// 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 "util/quote.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);
                        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);
}

#ifdef _SC_LEVEL1_DCACHE_LINESIZE
#define cache_line_size(cacheline_sizep) *cacheline_sizep = sysconf(_SC_LEVEL1_DCACHE_LINESIZE)
#else
static void cache_line_size(int *cacheline_sizep)
{
        if (sysfs__read_int("devices/system/cpu/cpu0/cache/index0/coherency_line_size", cacheline_sizep))
                pr_debug("cannot determine cache line size");
}
#endif

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

        /* 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);
        cache_line_size(&cacheline_size);

        if (sysctl__read_int("kernel/perf_event_max_stack", &value) == 0)
                sysctl_perf_event_max_stack = value;

        if (sysctl__read_int("kernel/perf_event_max_contexts_per_stack", &value) == 0)
                sysctl_perf_event_max_contexts_per_stack = value;

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

        srandom(time(NULL));

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

        /* get debugfs/tracefs mount point from /proc/mounts */
        tracing_path_mount();

        /*
         * "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;
}