// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * builtin-probe.c
 *
 * Builtin probe command: Set up probe events by C expression
 *
 * Written by Masami Hiramatsu <mhiramat@redhat.com>
 */
#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

#include "builtin.h"
#include "namespaces.h"
#include "util/build-id.h"
#include "util/strlist.h"
#include "util/strfilter.h"
#include "util/symbol.h"
#include "util/symbol_conf.h"
#include "util/debug.h"
#include <subcmd/parse-options.h>
#include "util/probe-finder.h"
#include "util/probe-event.h"
#include "util/probe-file.h"
#include <linux/string.h>
#include <linux/zalloc.h>

#define DEFAULT_VAR_FILTER "!__k???tab_* & !__crc_*"
#define DEFAULT_FUNC_FILTER "!_* & !*@plt"
#define DEFAULT_LIST_FILTER "*"

/* Session management structure */
static struct {
        int command;    /* Command short_name */
        bool list_events;
        bool uprobes;
        bool target_used;
        int nevents;
        struct perf_probe_event events[MAX_PROBES];
        struct line_range line_range;
        char *target;
        struct strfilter *filter;
        struct nsinfo *nsi;
} *params;

/* Parse an event definition. Note that any error must die. */
static int parse_probe_event(const char *str)
{
        struct perf_probe_event *pev = &params->events[params->nevents];
        int ret;

        pr_debug("probe-definition(%d): %s\n", params->nevents, str);
        if (++params->nevents == MAX_PROBES) {
                pr_err("Too many probes (> %d) were specified.", MAX_PROBES);
                return -1;
        }

        pev->uprobes = params->uprobes;
        if (params->target) {
                pev->target = strdup(params->target);
                if (!pev->target)
                        return -ENOMEM;
                params->target_used = true;
        }

        pev->nsi = nsinfo__get(params->nsi);

        /* Parse a perf-probe command into event */
        ret = parse_perf_probe_command(str, pev);
        pr_debug("%d arguments\n", pev->nargs);

        return ret;
}

static int params_add_filter(const char *str)
{
        const char *err = NULL;
        int ret = 0;

        pr_debug2("Add filter: %s\n", str);
        if (!params->filter) {
                params->filter = strfilter__new(str, &err);
                if (!params->filter)
                        ret = err ? -EINVAL : -ENOMEM;
        } else
                ret = strfilter__or(params->filter, str, &err);

        if (ret == -EINVAL) {
                pr_err("Filter parse error at %td.\n", err - str + 1);
                pr_err("Source: \"%s\"\n", str);
                pr_err("         %*c\n", (int)(err - str + 1), '^');
        }

        return ret;
}

static int set_target(const char *ptr)
{
        int found = 0;
        const char *buf;

        /*
         * The first argument after options can be an absolute path
         * to an executable / library or kernel module.
         *
         * TODO: Support relative path, and $PATH, $LD_LIBRARY_PATH,
         * short module name.
         */
        if (!params->target && ptr && *ptr == '/') {
                params->target = strdup(ptr);
                if (!params->target)
                        return -ENOMEM;
                params->target_used = false;

                found = 1;
                buf = ptr + (strlen(ptr) - 3);

                if (strcmp(buf, ".ko"))
                        params->uprobes = true;

        }

        return found;
}

static int parse_probe_event_argv(int argc, const char **argv)
{
        int i, len, ret, found_target;
        char *buf;

        found_target = set_target(argv[0]);
        if (found_target < 0)
                return found_target;

        if (found_target && argc == 1)
                return 0;

        /* Bind up rest arguments */
        len = 0;
        for (i = 0; i < argc; i++) {
                if (i == 0 && found_target)
                        continue;

                len += strlen(argv[i]) + 1;
        }
        buf = zalloc(len + 1);
        if (buf == NULL)
                return -ENOMEM;
        len = 0;
        for (i = 0; i < argc; i++) {
                if (i == 0 && found_target)
                        continue;

                len += sprintf(&buf[len], "%s ", argv[i]);
        }
        ret = parse_probe_event(buf);
        free(buf);
        return ret;
}

static int opt_set_target(const struct option *opt, const char *str,
                        int unset __maybe_unused)
{
        int ret = -ENOENT;
        char *tmp;

        if  (str) {
                if (!strcmp(opt->long_name, "exec"))
                        params->uprobes = true;
                else if (!strcmp(opt->long_name, "module"))
                        params->uprobes = false;
                else
                        return ret;

                /* Expand given path to absolute path, except for modulename */
                if (params->uprobes || strchr(str, '/')) {
                        tmp = nsinfo__realpath(str, params->nsi);
                        if (!tmp) {
                                pr_warning("Failed to get the absolute path of %s: %m\n", str);
                                return ret;
                        }
                } else {
                        tmp = strdup(str);
                        if (!tmp)
                                return -ENOMEM;
                }
                free(params->target);
                params->target = tmp;
                params->target_used = false;
                ret = 0;
        }

        return ret;
}

static int opt_set_target_ns(const struct option *opt __maybe_unused,
                             const char *str, int unset __maybe_unused)
{
        int ret = -ENOENT;
        pid_t ns_pid;
        struct nsinfo *nsip;

        if (str) {
                errno = 0;
                ns_pid = (pid_t)strtol(str, NULL, 10);
                if (errno != 0) {
                        ret = -errno;
                        pr_warning("Failed to parse %s as a pid: %m\n", str);
                        return ret;
                }
                nsip = nsinfo__new(ns_pid);
                if (nsip && nsinfo__need_setns(nsip))
                        params->nsi = nsinfo__get(nsip);
                nsinfo__put(nsip);

                ret = 0;
        }

        return ret;
}


/* Command option callbacks */

#ifdef HAVE_LIBDW_SUPPORT
static int opt_show_lines(const struct option *opt,
                          const char *str, int unset __maybe_unused)
{
        int ret = 0;

        if (!str)
                return 0;

        if (params->command == 'L') {
                pr_warning("Warning: more than one --line options are"
                           " detected. Only the first one is valid.\n");
                return 0;
        }

        params->command = opt->short_name;
        ret = parse_line_range_desc(str, &params->line_range);

        return ret;
}

static int opt_show_vars(const struct option *opt,
                         const char *str, int unset __maybe_unused)
{
        struct perf_probe_event *pev = &params->events[params->nevents];
        int ret;

        if (!str)
                return 0;

        ret = parse_probe_event(str);
        if (!ret && pev->nargs != 0) {
                pr_err("  Error: '--vars' doesn't accept arguments.\n");
                return -EINVAL;
        }
        params->command = opt->short_name;

        return ret;
}
#else
# define opt_show_lines NULL
# define opt_show_vars NULL
#endif
static int opt_add_probe_event(const struct option *opt,
                              const char *str, int unset __maybe_unused)
{
        if (str) {
                params->command = opt->short_name;
                return parse_probe_event(str);
        }

        return 0;
}

static int opt_set_filter_with_command(const struct option *opt,
                                       const char *str, int unset)
{
        if (!unset)
                params->command = opt->short_name;

        if (str)
                return params_add_filter(str);

        return 0;
}

static int opt_set_filter(const struct option *opt __maybe_unused,
                          const char *str, int unset __maybe_unused)
{
        if (str)
                return params_add_filter(str);

        return 0;
}

static int init_params(void)
{
        int ret;

        params = calloc(1, sizeof(*params));
        if (!params)
                return -ENOMEM;

        ret = line_range__init(&params->line_range);
        if (ret)
                zfree(&params);
        return ret;
}

static void cleanup_params(void)
{
        int i;

        for (i = 0; i < params->nevents; i++)
                clear_perf_probe_event(params->events + i);
        line_range__clear(&params->line_range);
        zfree(&params->target);
        strfilter__delete(params->filter);
        nsinfo__put(params->nsi);
        zfree(&params);
}

static void pr_err_with_code(const char *msg, int err)
{
        char sbuf[STRERR_BUFSIZE];

        pr_err("%s", msg);
        pr_debug(" Reason: %s (Code: %d)",
                 str_error_r(-err, sbuf, sizeof(sbuf)), err);
        pr_err("\n");
}

static int perf_add_probe_events(struct perf_probe_event *pevs, int npevs)
{
        int ret;
        int i, k;
        const char *event = NULL, *group = NULL;

        ret = init_probe_symbol_maps(pevs->uprobes);
        if (ret < 0)
                return ret;

        ret = convert_perf_probe_events(pevs, npevs);
        if (ret < 0)
                goto out_cleanup;

        if (params->command == 'D') {   /* it shows definition */
                if (probe_conf.bootconfig)
                        ret = show_bootconfig_events(pevs, npevs);
                else
                        ret = show_probe_trace_events(pevs, npevs);
                goto out_cleanup;
        }

        ret = apply_perf_probe_events(pevs, npevs);
        if (ret < 0)
                goto out_cleanup;

        for (i = k = 0; i < npevs; i++)
                k += pevs[i].ntevs;

        pr_info("Added new event%s\n", (k > 1) ? "s:" : ":");
        for (i = 0; i < npevs; i++) {
                struct perf_probe_event *pev = &pevs[i];

                for (k = 0; k < pev->ntevs; k++) {
                        struct probe_trace_event *tev = &pev->tevs[k];
                        /* Skipped events have no event name */
                        if (!tev->event)
                                continue;

                        /* We use tev's name for showing new events */
                        show_perf_probe_event(tev->group, tev->event, pev,
                                              tev->point.module, false);

                        /* Save the last valid name */
                        event = tev->event;
                        group = tev->group;
                }
        }

        /* Note that it is possible to skip all events because of blacklist */
        if (event) {
#ifndef HAVE_LIBTRACEEVENT
                pr_info("\nperf is not linked with libtraceevent, to use the new probe you can use tracefs:\n\n");
                pr_info("\tcd /sys/kernel/tracing/\n");
                pr_info("\techo 1 > events/%s/%s/enable\n", group, event);
                pr_info("\techo 1 > tracing_on\n");
                pr_info("\tcat trace_pipe\n");
                pr_info("\tBefore removing the probe, echo 0 > events/%s/%s/enable\n", group, event);
#else
                /* Show how to use the event. */
                pr_info("\nYou can now use it in all perf tools, such as:\n\n");
                pr_info("\tperf record -e %s:%s -aR sleep 1\n\n", group, event);
#endif
        }

out_cleanup:
        cleanup_perf_probe_events(pevs, npevs);
        exit_probe_symbol_maps();
        return ret;
}

static int del_perf_probe_caches(struct strfilter *filter)
{
        struct probe_cache *cache;
        struct strlist *bidlist;
        struct str_node *nd;
        int ret;

        bidlist = build_id_cache__list_all(false);
        if (!bidlist) {
                ret = -errno;
                pr_debug("Failed to get buildids: %d\n", ret);
                return ret ?: -ENOMEM;
        }

        strlist__for_each_entry(nd, bidlist) {
                cache = probe_cache__new(nd->s, NULL);
                if (!cache)
                        continue;
                if (probe_cache__filter_purge(cache, filter) < 0 ||
                    probe_cache__commit(cache) < 0)
                        pr_warning("Failed to remove entries for %s\n", nd->s);
                probe_cache__delete(cache);
        }
        return 0;
}

static int perf_del_probe_events(struct strfilter *filter)
{
        int ret, ret2, ufd = -1, kfd = -1;
        char *str = strfilter__string(filter);
        struct strlist *klist = NULL, *ulist = NULL;
        struct str_node *ent;

        if (!str)
                return -EINVAL;

        pr_debug("Delete filter: \'%s\'\n", str);

        if (probe_conf.cache)
                return del_perf_probe_caches(filter);

        /* Get current event names */
        ret = probe_file__open_both(&kfd, &ufd, PF_FL_RW);
        if (ret < 0)
                goto out;

        klist = strlist__new(NULL, NULL);
        ulist = strlist__new(NULL, NULL);
        if (!klist || !ulist) {
                ret = -ENOMEM;
                goto out;
        }

        ret = probe_file__get_events(kfd, filter, klist);
        if (ret == 0) {
                strlist__for_each_entry(ent, klist)
                        pr_info("Removed event: %s\n", ent->s);

                ret = probe_file__del_strlist(kfd, klist);
                if (ret < 0)
                        goto error;
        } else if (ret == -ENOMEM)
                goto error;

        ret2 = probe_file__get_events(ufd, filter, ulist);
        if (ret2 == 0) {
                strlist__for_each_entry(ent, ulist)
                        pr_info("Removed event: %s\n", ent->s);

                ret2 = probe_file__del_strlist(ufd, ulist);
                if (ret2 < 0)
                        goto error;
        } else if (ret2 == -ENOMEM)
                goto error;

        if (ret == -ENOENT && ret2 == -ENOENT)
                pr_warning("\"%s\" does not hit any event.\n", str);
        else
                ret = 0;

error:
        if (kfd >= 0)
                close(kfd);
        if (ufd >= 0)
                close(ufd);
out:
        strlist__delete(klist);
        strlist__delete(ulist);
        free(str);

        return ret;
}

#ifdef HAVE_LIBDW_SUPPORT
#define PROBEDEF_STR    \
        "[EVENT=]FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT [[NAME=]ARG ...]"
#else
#define PROBEDEF_STR    "[EVENT=]FUNC[+OFF|%return] [[NAME=]ARG ...]"
#endif


static int
__cmd_probe(int argc, const char **argv)
{
        const char * const probe_usage[] = {
                "perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
                "perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
                "perf probe [<options>] --del '[GROUP:]EVENT' ...",
                "perf probe --list [GROUP:]EVENT ...",
#ifdef HAVE_LIBDW_SUPPORT
                "perf probe [<options>] --line 'LINEDESC'",
                "perf probe [<options>] --vars 'PROBEPOINT'",
#endif
                "perf probe [<options>] --funcs",
                NULL
        };
        struct option options[] = {
        OPT_INCR('v', "verbose", &verbose,
                    "be more verbose (show parsed arguments, etc)"),
        OPT_BOOLEAN('q', "quiet", &quiet,
                    "be quiet (do not show any warnings or messages)"),
        OPT_CALLBACK_DEFAULT('l', "list", NULL, "[GROUP:]EVENT",
                             "list up probe events",
                             opt_set_filter_with_command, DEFAULT_LIST_FILTER),
        OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
                     opt_set_filter_with_command),
        OPT_CALLBACK('a', "add", NULL, PROBEDEF_STR,
                "probe point definition, where\n"
                "\t\tGROUP:\tGroup name (optional)\n"
                "\t\tEVENT:\tEvent name\n"
                "\t\tFUNC:\tFunction name\n"
                "\t\tOFF:\tOffset from function entry (in byte)\n"
                "\t\t%return:\tPut the probe at function return\n"
#ifdef HAVE_LIBDW_SUPPORT
                "\t\tSRC:\tSource code path\n"
                "\t\tRL:\tRelative line number from function entry.\n"
                "\t\tAL:\tAbsolute line number in file.\n"
                "\t\tPT:\tLazy expression of line code.\n"
                "\t\tARG:\tProbe argument (local variable name or\n"
                "\t\t\tkprobe-tracer argument format.)\n",
#else
                "\t\tARG:\tProbe argument (kprobe-tracer argument format.)\n",
#endif
                opt_add_probe_event),
        OPT_CALLBACK('D', "definition", NULL, PROBEDEF_STR,
                "Show trace event definition of given traceevent for k/uprobe_events.",
                opt_add_probe_event),
        OPT_BOOLEAN('f', "force", &probe_conf.force_add, "forcibly add events"
                    " with existing name"),
        OPT_CALLBACK('L', "line", NULL,
                     "FUNC[:RLN[+NUM|-RLN2]]|SRC:ALN[+NUM|-ALN2]",
                     "Show source code lines.", opt_show_lines),
        OPT_CALLBACK('V', "vars", NULL,
                     "FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT",
                     "Show accessible variables on PROBEDEF", opt_show_vars),
        OPT_BOOLEAN('\0', "externs", &probe_conf.show_ext_vars,
                    "Show external variables too (with --vars only)"),
        OPT_BOOLEAN('\0', "range", &probe_conf.show_location_range,
                "Show variables location range in scope (with --vars only)"),
        OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
                   "file", "vmlinux pathname"),
        OPT_STRING('s', "source", &symbol_conf.source_prefix,
                   "directory", "path to kernel source"),
        OPT_BOOLEAN('\0', "no-inlines", &probe_conf.no_inlines,
                "Don't search inlined functions"),
        OPT__DRY_RUN(&probe_event_dry_run),
        OPT_INTEGER('\0', "max-probes", &probe_conf.max_probes,
                 "Set how many probe points can be found for a probe."),
        OPT_CALLBACK_DEFAULT('F', "funcs", NULL, "[FILTER]",
                             "Show potential probe-able functions.",
                             opt_set_filter_with_command, DEFAULT_FUNC_FILTER),
        OPT_CALLBACK('\0', "filter", NULL,
                     "[!]FILTER", "Set a filter (with --vars/funcs only)\n"
                     "\t\t\t(default: \"" DEFAULT_VAR_FILTER "\" for --vars,\n"
                     "\t\t\t \"" DEFAULT_FUNC_FILTER "\" for --funcs)",
                     opt_set_filter),
        OPT_CALLBACK('x', "exec", NULL, "executable|path",
                        "target executable name or path", opt_set_target),
        OPT_CALLBACK('m', "module", NULL, "modname|path",
                "target module name (for online) or path (for offline)",
                opt_set_target),
        OPT_BOOLEAN(0, "demangle", &symbol_conf.demangle,
                    "Enable symbol demangling"),
        OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel,
                    "Enable kernel symbol demangling"),
        OPT_BOOLEAN(0, "cache", &probe_conf.cache, "Manipulate probe cache"),
        OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
                   "Look for files with symbols relative to this directory"),
        OPT_CALLBACK(0, "target-ns", NULL, "pid",
                     "target pid for namespace contexts", opt_set_target_ns),
        OPT_BOOLEAN(0, "bootconfig", &probe_conf.bootconfig,
                    "Output probe definition with bootconfig format"),
        OPT_END()
        };
        int ret;

        set_option_flag(options, 'a', "add", PARSE_OPT_EXCLUSIVE);
        set_option_flag(options, 'd', "del", PARSE_OPT_EXCLUSIVE);
        set_option_flag(options, 'D', "definition", PARSE_OPT_EXCLUSIVE);
        set_option_flag(options, 'l', "list", PARSE_OPT_EXCLUSIVE);
#ifdef HAVE_LIBDW_SUPPORT
        set_option_flag(options, 'L', "line", PARSE_OPT_EXCLUSIVE);
        set_option_flag(options, 'V', "vars", PARSE_OPT_EXCLUSIVE);
#else
# define set_nobuild(s, l, c) set_option_nobuild(options, s, l, "NO_LIBDW=1", c)
        set_nobuild('L', "line", false);
        set_nobuild('V', "vars", false);
        set_nobuild('\0', "externs", false);
        set_nobuild('\0', "range", false);
        set_nobuild('k', "vmlinux", true);
        set_nobuild('s', "source", true);
        set_nobuild('\0', "no-inlines", true);
# undef set_nobuild
#endif
        set_option_flag(options, 'F', "funcs", PARSE_OPT_EXCLUSIVE);

        argc = parse_options(argc, argv, options, probe_usage,
                             PARSE_OPT_STOP_AT_NON_OPTION);

        if (quiet) {
                if (verbose != 0) {
                        pr_err("  Error: -v and -q are exclusive.\n");
                        return -EINVAL;
                }
                verbose = -1;
        }

        if (argc > 0) {
                if (strcmp(argv[0], "-") == 0) {
                        usage_with_options_msg(probe_usage, options,
                                "'-' is not supported.\n");
                }
                if (params->command && params->command != 'a') {
                        usage_with_options_msg(probe_usage, options,
                                "another command except --add is set.\n");
                }
                ret = parse_probe_event_argv(argc, argv);
                if (ret < 0) {
                        pr_err_with_code("  Error: Command Parse Error.", ret);
                        return ret;
                }
                params->command = 'a';
        }

        ret = symbol__validate_sym_arguments();
        if (ret)
                return ret;

        if (probe_conf.max_probes == 0)
                probe_conf.max_probes = MAX_PROBES;

        /*
         * Only consider the user's kernel image path if given.
         */
        symbol_conf.try_vmlinux_path = (symbol_conf.vmlinux_name == NULL);

        /*
         * Except for --list, --del and --add, other command doesn't depend
         * nor change running kernel. So if user gives offline vmlinux,
         * ignore its buildid.
         */
        if (!strchr("lda", params->command) && symbol_conf.vmlinux_name)
                symbol_conf.ignore_vmlinux_buildid = true;

        switch (params->command) {
        case 'l':
                if (params->uprobes) {
                        pr_err("  Error: Don't use --list with --exec.\n");
                        parse_options_usage(probe_usage, options, "l", true);
                        parse_options_usage(NULL, options, "x", true);
                        return -EINVAL;
                }
                ret = show_perf_probe_events(params->filter);
                if (ret < 0)
                        pr_err_with_code("  Error: Failed to show event list.", ret);
                return ret;
        case 'F':
                ret = show_available_funcs(params->target, params->nsi,
                                           params->filter, params->uprobes);
                if (ret < 0)
                        pr_err_with_code("  Error: Failed to show functions.", ret);
                return ret;
#ifdef HAVE_LIBDW_SUPPORT
        case 'L':
                ret = show_line_range(&params->line_range, params->target,
                                      params->nsi, params->uprobes);
                if (ret < 0)
                        pr_err_with_code("  Error: Failed to show lines.", ret);
                return ret;
        case 'V':
                if (!params->filter)
                        params->filter = strfilter__new(DEFAULT_VAR_FILTER,
                                                       NULL);

                ret = show_available_vars(params->events, params->nevents,
                                          params->filter);
                if (ret < 0)
                        pr_err_with_code("  Error: Failed to show vars.", ret);
                return ret;
#endif
        case 'd':
                ret = perf_del_probe_events(params->filter);
                if (ret < 0) {
                        pr_err_with_code("  Error: Failed to delete events.", ret);
                        return ret;
                }
                break;
        case 'D':
                if (probe_conf.bootconfig && params->uprobes) {
                        pr_err("  Error: --bootconfig doesn't support uprobes.\n");
                        return -EINVAL;
                }
                fallthrough;
        case 'a':

                /* Ensure the last given target is used */
                if (params->target && !params->target_used) {
                        pr_err("  Error: -x/-m must follow the probe definitions.\n");
                        parse_options_usage(probe_usage, options, "m", true);
                        parse_options_usage(NULL, options, "x", true);
                        return -EINVAL;
                }

                ret = perf_add_probe_events(params->events, params->nevents);
                if (ret < 0) {

                        /*
                         * When perf_add_probe_events() fails it calls
                         * cleanup_perf_probe_events(pevs, npevs), i.e.
                         * cleanup_perf_probe_events(params->events, params->nevents), which
                         * will call clear_perf_probe_event(), so set nevents to zero
                         * to avoid cleanup_params() to call clear_perf_probe_event() again
                         * on the same pevs.
                         */
                        params->nevents = 0;
                        pr_err_with_code("  Error: Failed to add events.", ret);
                        return ret;
                }
                break;
        default:
                usage_with_options(probe_usage, options);
        }
        return 0;
}

int cmd_probe(int argc, const char **argv)
{
        int ret;

        ret = init_params();
        if (!ret) {
                ret = __cmd_probe(argc, argv);
                cleanup_params();
        }

        return ret < 0 ? ret : 0;
}