builtin-probe.c

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/*
 * builtin-probe.c
 *
 * Builtin probe command: Set up probe events by C expression
 *
 * Written by Masami Hiramatsu <[email protected]>
 *
 * 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 "util/debugfs.h"
#include "util/parse-options.h"
#include "util/probe-finder.h"
#include "util/probe-event.h"

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

/* Session management structure */
static struct {
    bool list_events;
    bool force_add;
    bool show_lines;
    bool show_vars;
    bool show_ext_vars;
    bool show_funcs;
    bool mod_events;
    bool uprobes;
    int nevents;
    struct perf_probe_event events[MAX_PROBES];
    struct strlist *dellist;
    struct line_range line_range;
    const char *target;
    int max_probe_points;
    struct strfilter *filter;
} 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;

    /* 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 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 = ptr;
        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 && 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]);
    }
    params.mod_events = true;
    ret = parse_probe_event(buf);
    free(buf);
    return ret;
}

static int opt_add_probe_event(const struct option *opt __maybe_unused,
                  const char *str, int unset __maybe_unused)
{
    if (str) {
        params.mod_events = true;
        return parse_probe_event(str);
    } else
        return 0;
}

static int opt_del_probe_event(const struct option *opt __maybe_unused,
                   const char *str, int unset __maybe_unused)
{
    if (str) {
        params.mod_events = true;
        if (!params.dellist)
            params.dellist = strlist__new(true, NULL);
        strlist__add(params.dellist, str);
    }
    return 0;
}

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

    if  (str && !params.target) {
        if (!strcmp(opt->long_name, "exec"))
            params.uprobes = true;
#ifdef DWARF_SUPPORT
        else if (!strcmp(opt->long_name, "module"))
            params.uprobes = false;
#endif
        else
            return ret;

        params.target = str;
        ret = 0;
    }

    return ret;
}

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

    if (!str)
        return 0;

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

    params.show_lines = true;
    ret = parse_line_range_desc(str, &params.line_range);
    INIT_LIST_HEAD(&params.line_range.line_list);

    return ret;
}

static int opt_show_vars(const struct option *opt __maybe_unused,
             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.show_vars = true;

    return ret;
}
#endif

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

    if (str) {
        pr_debug2("Set filter: %s\n", str);
        if (params.filter)
            strfilter__delete(params.filter);
        params.filter = strfilter__new(str, &err);
        if (!params.filter) {
            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 -EINVAL;
        }
    }

    return 0;
}

int cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
{
    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",
#ifdef DWARF_SUPPORT
        "perf probe [<options>] --line 'LINEDESC'",
        "perf probe [<options>] --vars 'PROBEPOINT'",
#endif
        NULL
};
    const struct option options[] = {
    OPT_INCR('v', "verbose", &verbose,
            "be more verbose (show parsed arguments, etc)"),
    OPT_BOOLEAN('l', "list", &params.list_events,
            "list up current probe events"),
    OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
        opt_del_probe_event),
    OPT_CALLBACK('a', "add", NULL,
#ifdef DWARF_SUPPORT
        "[EVENT=]FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT"
        " [[NAME=]ARG ...]",
#else
        "[EVENT=]FUNC[+OFF|%return] [[NAME=]ARG ...]",
#endif
        "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 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_BOOLEAN('f', "force", &params.force_add, "forcibly add events"
            " with existing name"),
#ifdef DWARF_SUPPORT
    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", &params.show_ext_vars,
            "Show external variables too (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_CALLBACK('m', "module", NULL, "modname|path",
        "target module name (for online) or path (for offline)",
        opt_set_target),
#endif
    OPT__DRY_RUN(&probe_event_dry_run),
    OPT_INTEGER('\0', "max-probes", &params.max_probe_points,
         "Set how many probe points can be found for a probe."),
    OPT_BOOLEAN('F', "funcs", &params.show_funcs,
            "Show potential probe-able functions."),
    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_END()
    };
    int ret;

    argc = parse_options(argc, argv, options, probe_usage,
                 PARSE_OPT_STOP_AT_NON_OPTION);
    if (argc > 0) {
        if (strcmp(argv[0], "-") == 0) {
            pr_warning("  Error: '-' is not supported.\n");
            usage_with_options(probe_usage, options);
        }
        ret = parse_probe_event_argv(argc, argv);
        if (ret < 0) {
            pr_err("  Error: Parse Error.  (%d)\n", ret);
            return ret;
        }
    }

    if (params.max_probe_points == 0)
        params.max_probe_points = MAX_PROBES;

    if ((!params.nevents && !params.dellist && !params.list_events &&
         !params.show_lines && !params.show_funcs))
        usage_with_options(probe_usage, options);

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

    if (params.list_events) {
        if (params.mod_events) {
            pr_err("  Error: Don't use --list with --add/--del.\n");
            usage_with_options(probe_usage, options);
        }
        if (params.show_lines) {
            pr_err("  Error: Don't use --list with --line.\n");
            usage_with_options(probe_usage, options);
        }
        if (params.show_vars) {
            pr_err(" Error: Don't use --list with --vars.\n");
            usage_with_options(probe_usage, options);
        }
        if (params.show_funcs) {
            pr_err("  Error: Don't use --list with --funcs.\n");
            usage_with_options(probe_usage, options);
        }
        if (params.uprobes) {
            pr_warning("  Error: Don't use --list with --exec.\n");
            usage_with_options(probe_usage, options);
        }
        ret = show_perf_probe_events();
        if (ret < 0)
            pr_err("  Error: Failed to show event list. (%d)\n",
                   ret);
        return ret;
    }
    if (params.show_funcs) {
        if (params.nevents != 0 || params.dellist) {
            pr_err("  Error: Don't use --funcs with"
                   " --add/--del.\n");
            usage_with_options(probe_usage, options);
        }
        if (params.show_lines) {
            pr_err("  Error: Don't use --funcs with --line.\n");
            usage_with_options(probe_usage, options);
        }
        if (params.show_vars) {
            pr_err("  Error: Don't use --funcs with --vars.\n");
            usage_with_options(probe_usage, options);
        }
        if (!params.filter)
            params.filter = strfilter__new(DEFAULT_FUNC_FILTER,
                               NULL);
        ret = show_available_funcs(params.target, params.filter,
                    params.uprobes);
        strfilter__delete(params.filter);
        if (ret < 0)
            pr_err("  Error: Failed to show functions."
                   " (%d)\n", ret);
        return ret;
    }

#ifdef DWARF_SUPPORT
    if (params.show_lines && !params.uprobes) {
        if (params.mod_events) {
            pr_err("  Error: Don't use --line with"
                   " --add/--del.\n");
            usage_with_options(probe_usage, options);
        }
        if (params.show_vars) {
            pr_err(" Error: Don't use --line with --vars.\n");
            usage_with_options(probe_usage, options);
        }

        ret = show_line_range(&params.line_range, params.target);
        if (ret < 0)
            pr_err("  Error: Failed to show lines. (%d)\n", ret);
        return ret;
    }
    if (params.show_vars) {
        if (params.mod_events) {
            pr_err("  Error: Don't use --vars with"
                   " --add/--del.\n");
            usage_with_options(probe_usage, options);
        }
        if (!params.filter)
            params.filter = strfilter__new(DEFAULT_VAR_FILTER,
                               NULL);

        ret = show_available_vars(params.events, params.nevents,
                      params.max_probe_points,
                      params.target,
                      params.filter,
                      params.show_ext_vars);
        strfilter__delete(params.filter);
        if (ret < 0)
            pr_err("  Error: Failed to show vars. (%d)\n", ret);
        return ret;
    }
#endif

    if (params.dellist) {
        ret = del_perf_probe_events(params.dellist);
        strlist__delete(params.dellist);
        if (ret < 0) {
            pr_err("  Error: Failed to delete events. (%d)\n", ret);
            return ret;
        }
    }

    if (params.nevents) {
        ret = add_perf_probe_events(params.events, params.nevents,
                        params.max_probe_points,
                        params.target,
                        params.force_add);
        if (ret < 0) {
            pr_err("  Error: Failed to add events. (%d)\n", ret);
            return ret;
        }
    }
    return 0;
}