builtin-probe.c

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/*
 * builtin-probe.c
 *
 * Builtin probe command: Set up probe events by C expression
 *
 * Written by Masami Hiramatsu <mhiramat@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */
#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 "perf.h"
#include "builtin.h"
#include "util/util.h"
#include "util/strlist.h"
#include "util/strfilter.h"
#include "util/symbol.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"

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

/* Session management structure */
static struct {
    int command;    /* Command short_name */
    bool list_events;
    bool uprobes;
    bool quiet;
    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: %s\n", str,
                   strerror(errno));
            return ret;
        }
        nsip = nsinfo__new(ns_pid);
        if (nsip && nsip->need_setns)
            params.nsi = nsinfo__get(nsip);
        nsinfo__put(nsip);

        ret = 0;
    }

    return ret;
}


/* Command option callbacks */

#ifdef HAVE_DWARF_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)
{
    return line_range__init(&params.line_range);
}

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);
    free(params.target);
    strfilter__delete(params.filter);
    nsinfo__put(params.nsi);
    memset(&params, 0, sizeof(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 */
        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];

            /* 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) {
        /* 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);
    }

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;
    }

    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;
    }

    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_DWARF_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_DWARF_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", &params.quiet,
            "be quiet (do not show any 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_DWARF_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_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_DWARF_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_DWARF=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 (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';
    }

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

    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_DWARF_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':
    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) {
            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;
}