builtin-trace.c

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#include "builtin.h"
#include "util/evlist.h"
#include "util/parse-options.h"
#include "util/thread_map.h"
#include "event-parse.h"

#include <libaudit.h>
#include <stdlib.h>

static struct syscall_fmt {
    const char *name;
    const char *alias;
    bool       errmsg;
    bool       timeout;
} syscall_fmts[] = {
    { .name     = "arch_prctl", .errmsg = true, .alias = "prctl", },
    { .name     = "fstat",      .errmsg = true, .alias = "newfstat", },
    { .name     = "fstatat",    .errmsg = true, .alias = "newfstatat", },
    { .name     = "futex",      .errmsg = true, },
    { .name     = "poll",       .errmsg = true, .timeout = true, },
    { .name     = "ppoll",      .errmsg = true, .timeout = true, },
    { .name     = "read",       .errmsg = true, },
    { .name     = "recvfrom",   .errmsg = true, },
    { .name     = "select",     .errmsg = true, .timeout = true, },
    { .name     = "stat",       .errmsg = true, .alias = "newstat", },
};

static int syscall_fmt__cmp(const void *name, const void *fmtp)
{
    const struct syscall_fmt *fmt = fmtp;
    return strcmp(name, fmt->name);
}

static struct syscall_fmt *syscall_fmt__find(const char *name)
{
    const int nmemb = ARRAY_SIZE(syscall_fmts);
    return bsearch(name, syscall_fmts, nmemb, sizeof(struct syscall_fmt), syscall_fmt__cmp);
}

struct syscall {
    struct event_format *tp_format;
    const char      *name;
    struct syscall_fmt  *fmt;
};

struct trace {
    int         audit_machine;
    struct {
        int     max;
        struct syscall  *table;
    } syscalls;
    struct perf_record_opts opts;
};

static int trace__read_syscall_info(struct trace *trace, int id)
{
    char tp_name[128];
    struct syscall *sc;
    const char *name = audit_syscall_to_name(id, trace->audit_machine);

    if (name == NULL)
        return -1;

    if (id > trace->syscalls.max) {
        struct syscall *nsyscalls = realloc(trace->syscalls.table, (id + 1) * sizeof(*sc));

        if (nsyscalls == NULL)
            return -1;

        if (trace->syscalls.max != -1) {
            memset(nsyscalls + trace->syscalls.max + 1, 0,
                   (id - trace->syscalls.max) * sizeof(*sc));
        } else {
            memset(nsyscalls, 0, (id + 1) * sizeof(*sc));
        }

        trace->syscalls.table = nsyscalls;
        trace->syscalls.max   = id;
    }

    sc = trace->syscalls.table + id;
    sc->name = name;
    sc->fmt  = syscall_fmt__find(sc->name);

    snprintf(tp_name, sizeof(tp_name), "sys_enter_%s", sc->name);
    sc->tp_format = event_format__new("syscalls", tp_name);

    if (sc->tp_format == NULL && sc->fmt && sc->fmt->alias) {
        snprintf(tp_name, sizeof(tp_name), "sys_enter_%s", sc->fmt->alias);
        sc->tp_format = event_format__new("syscalls", tp_name);
    }

    return sc->tp_format != NULL ? 0 : -1;
}

static size_t syscall__fprintf_args(struct syscall *sc, unsigned long *args, FILE *fp)
{
    int i = 0;
    size_t printed = 0;

    if (sc->tp_format != NULL) {
        struct format_field *field;

        for (field = sc->tp_format->format.fields->next; field; field = field->next) {
            printed += fprintf(fp, "%s%s: %ld", printed ? ", " : "",
                       field->name, args[i++]);
        }
    } else {
        while (i < 6) {
            printed += fprintf(fp, "%sarg%d: %ld", printed ? ", " : "", i, args[i]);
            ++i;
        }
    }

    return printed;
}

typedef int (*tracepoint_handler)(struct trace *trace, struct perf_evsel *evsel,
                  struct perf_sample *sample);

static struct syscall *trace__syscall_info(struct trace *trace,
                       struct perf_evsel *evsel,
                       struct perf_sample *sample)
{
    int id = perf_evsel__intval(evsel, sample, "id");

    if (id < 0) {
        printf("Invalid syscall %d id, skipping...\n", id);
        return NULL;
    }

    if ((id > trace->syscalls.max || trace->syscalls.table[id].name == NULL) &&
        trace__read_syscall_info(trace, id))
        goto out_cant_read;

    if ((id > trace->syscalls.max || trace->syscalls.table[id].name == NULL))
        goto out_cant_read;

    return &trace->syscalls.table[id];

out_cant_read:
    printf("Problems reading syscall %d information\n", id);
    return NULL;
}

static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
                struct perf_sample *sample)
{
    void *args;
    struct syscall *sc = trace__syscall_info(trace, evsel, sample);

    if (sc == NULL)
        return -1;

    args = perf_evsel__rawptr(evsel, sample, "args");
    if (args == NULL) {
        printf("Problems reading syscall arguments\n");
        return -1;
    }

    printf("%s(", sc->name);
    syscall__fprintf_args(sc, args, stdout);

    return 0;
}

static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
               struct perf_sample *sample)
{
    int ret;
    struct syscall *sc = trace__syscall_info(trace, evsel, sample);

    if (sc == NULL)
        return -1;

    ret = perf_evsel__intval(evsel, sample, "ret");

    if (ret < 0 && sc->fmt && sc->fmt->errmsg) {
        char bf[256];
        const char *emsg = strerror_r(-ret, bf, sizeof(bf)),
               *e = audit_errno_to_name(-ret);

        printf(") = -1 %s %s", e, emsg);
    } else if (ret == 0 && sc->fmt && sc->fmt->timeout)
        printf(") = 0 Timeout");
    else
        printf(") = %d", ret);

    putchar('\n');
    return 0;
}

static int trace__run(struct trace *trace)
{
    struct perf_evlist *evlist = perf_evlist__new(NULL, NULL);
    struct perf_evsel *evsel;
    int err = -1, i, nr_events = 0, before;

    if (evlist == NULL) {
        printf("Not enough memory to run!\n");
        goto out;
    }

    if (perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_enter", trace__sys_enter) ||
        perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_exit", trace__sys_exit)) {
        printf("Couldn't read the raw_syscalls tracepoints information!\n");
        goto out_delete_evlist;
    }

    err = perf_evlist__create_maps(evlist, &trace->opts.target);
    if (err < 0) {
        printf("Problems parsing the target to trace, check your options!\n");
        goto out_delete_evlist;
    }

    perf_evlist__config_attrs(evlist, &trace->opts);

    err = perf_evlist__open(evlist);
    if (err < 0) {
        printf("Couldn't create the events: %s\n", strerror(errno));
        goto out_delete_evlist;
    }

    err = perf_evlist__mmap(evlist, UINT_MAX, false);
    if (err < 0) {
        printf("Couldn't mmap the events: %s\n", strerror(errno));
        goto out_delete_evlist;
    }

    perf_evlist__enable(evlist);
again:
    before = nr_events;

    for (i = 0; i < evlist->nr_mmaps; i++) {
        union perf_event *event;

        while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
            const u32 type = event->header.type;
            tracepoint_handler handler;
            struct perf_sample sample;

            ++nr_events;

            switch (type) {
            case PERF_RECORD_SAMPLE:
                break;
            case PERF_RECORD_LOST:
                printf("LOST %" PRIu64 " events!\n", event->lost.lost);
                continue;
            default:
                printf("Unexpected %s event, skipping...\n",
                    perf_event__name(type));
                continue;
            }

            err = perf_evlist__parse_sample(evlist, event, &sample);
            if (err) {
                printf("Can't parse sample, err = %d, skipping...\n", err);
                continue;
            }

            evsel = perf_evlist__id2evsel(evlist, sample.id);
            if (evsel == NULL) {
                printf("Unknown tp ID %" PRIu64 ", skipping...\n", sample.id);
                continue;
            }

            if (evlist->threads->map[0] == -1 || evlist->threads->nr > 1)
                printf("%d ", sample.tid);

            if (sample.raw_data == NULL) {
                printf("%s sample with no payload for tid: %d, cpu %d, raw_size=%d, skipping...\n",
                       perf_evsel__name(evsel), sample.tid,
                       sample.cpu, sample.raw_size);
                continue;
            }

            handler = evsel->handler.func;
            handler(trace, evsel, &sample);
        }
    }

    if (nr_events == before)
        poll(evlist->pollfd, evlist->nr_fds, -1);

    goto again;

out_delete_evlist:
    perf_evlist__delete(evlist);
out:
    return err;
}

int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
{
    const char * const trace_usage[] = {
        "perf trace [<options>]",
        NULL
    };
    struct trace trace = {
        .audit_machine = audit_detect_machine(),
        .syscalls = {
            . max = -1,
        },
        .opts = {
            .target = {
                .uid       = UINT_MAX,
                .uses_mmap = true,
            },
            .user_freq     = UINT_MAX,
            .user_interval = ULLONG_MAX,
            .no_delay      = true,
            .mmap_pages    = 1024,
        },
    };
    const struct option trace_options[] = {
    OPT_STRING('p', "pid", &trace.opts.target.pid, "pid",
            "trace events on existing process id"),
    OPT_STRING(0, "tid", &trace.opts.target.tid, "tid",
            "trace events on existing thread id"),
    OPT_BOOLEAN(0, "all-cpus", &trace.opts.target.system_wide,
            "system-wide collection from all CPUs"),
    OPT_STRING(0, "cpu", &trace.opts.target.cpu_list, "cpu",
            "list of cpus to monitor"),
    OPT_BOOLEAN(0, "no-inherit", &trace.opts.no_inherit,
            "child tasks do not inherit counters"),
    OPT_UINTEGER(0, "mmap-pages", &trace.opts.mmap_pages,
             "number of mmap data pages"),
    OPT_STRING(0, "uid", &trace.opts.target.uid_str, "user",
           "user to profile"),
    OPT_END()
    };
    int err;

    argc = parse_options(argc, argv, trace_options, trace_usage, 0);
    if (argc)
        usage_with_options(trace_usage, trace_options);

    err = perf_target__parse_uid(&trace.opts.target);
    if (err) {
        char bf[BUFSIZ];
        perf_target__strerror(&trace.opts.target, err, bf, sizeof(bf));
        printf("%s", bf);
        return err;
    }

    return trace__run(&trace);
}