/*
 * 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/string.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.";

static int use_pager = -1;
struct pager_config {
        const char *cmd;
        int val;
};

static char debugfs_mntpt[MAXPATHLEN];

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

static void set_debugfs_path(void)
{
        char *path;

        path = getenv(PERF_DEBUGFS_ENVIRONMENT);
        snprintf(debugfs_path, MAXPATHLEN, "%s/%s", path ?: debugfs_mntpt,
                 "tracing/events");
}

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, "--exec-path")) {
                        cmd += 11;
                        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, "--perf-dir=")) {
                        setenv(PERF_DIR_ENVIRONMENT, cmd + 10, 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, "--work-tree=")) {
                        setenv(PERF_WORK_TREE_ENVIRONMENT, cmd + 12, 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);
                        }
                        strncpy(debugfs_mntpt, (*argv)[1], MAXPATHLEN);
                        debugfs_mntpt[MAXPATHLEN - 1] = '\0';
                        if (envchanged)
                                *envchanged = 1;
                        (*argv)++;
                        (*argc)--;
                } else if (!prefixcmp(cmd, "--debugfs-dir=")) {
                        strncpy(debugfs_mntpt, cmd + 14, MAXPATHLEN);
                        debugfs_mntpt[MAXPATHLEN - 1] = '\0';
                        if (envchanged)
                                *envchanged = 1;
                } 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)

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

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_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();
        set_debugfs_path();

        status = p->fn(argc, argv, prefix);
        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];
        static struct cmd_struct commands[] = {
                { "help", cmd_help, 0 },
                { "list", cmd_list, 0 },
                { "record", cmd_record, 0 },
                { "report", cmd_report, 0 },
                { "stat", cmd_stat, 0 },
                { "timechart", cmd_timechart, 0 },
                { "top", cmd_top, 0 },
                { "annotate", cmd_annotate, 0 },
                { "version", cmd_version, 0 },
                { "trace", cmd_trace, 0 },
                { "sched", cmd_sched, 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;
}

/* mini /proc/mounts parser: searching for "^blah /mount/point debugfs" */
static void get_debugfs_mntpt(void)
{
        FILE *file;
        char fs_type[100];
        char debugfs[MAXPATHLEN];

        /*
         * try the standard location
         */
        if (valid_debugfs_mount("/sys/kernel/debug/") == 0) {
                strcpy(debugfs_mntpt, "/sys/kernel/debug/");
                return;
        }

        /*
         * try the sane location
         */
        if (valid_debugfs_mount("/debug/") == 0) {
                strcpy(debugfs_mntpt, "/debug/");
                return;
        }

        /*
         * give up and parse /proc/mounts
         */
        file = fopen("/proc/mounts", "r");
        if (file == NULL)
                return;

        while (fscanf(file, "%*s %"
                      STR(MAXPATHLEN)
                      "s %99s %*s %*d %*d\n",
                      debugfs, fs_type) == 2) {
                if (strcmp(fs_type, "debugfs") == 0)
                        break;
        }
        fclose(file);
        if (strcmp(fs_type, "debugfs") == 0) {
                strncpy(debugfs_mntpt, debugfs, MAXPATHLEN);
                debugfs_mntpt[MAXPATHLEN - 1] = '\0';
        }
}

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 */
        get_debugfs_mntpt();
        /*
         * "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_debugfs_path();
        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
         * precidence paths: the "--exec-path" option, the PERF_EXEC_PATH
         * environment, and the $(perfexecdir) from the Makefile at build
         * time.
         */
        setup_path();

        while (1) {
                static int done_help = 0;
                static int was_alias = 0;

                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;
}