LXR qemu/tests/plugin/syscall.c

   1/*
   2 * Copyright (C) 2020, Matthias Weckbecker <matthias@weckbecker.name>
   3 *
   4 * License: GNU GPL, version 2 or later.
   5 *   See the COPYING file in the top-level directory.
   6 */
   7#include <inttypes.h>
   8#include <assert.h>
   9#include <stdlib.h>
  10#include <string.h>
  11#include <unistd.h>
  12#include <stdio.h>
  13#include <glib.h>
  14
  15#include <qemu-plugin.h>
  16
  17QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
  18
  19typedef struct {
  20    int64_t num;
  21    int64_t calls;
  22    int64_t errors;
  23} SyscallStats;
  24
  25static GMutex lock;
  26static GHashTable *statistics;
  27
  28static SyscallStats *get_or_create_entry(int64_t num)
  29{
  30    SyscallStats *entry =
  31        (SyscallStats *) g_hash_table_lookup(statistics, GINT_TO_POINTER(num));
  32
  33    if (!entry) {
  34        entry = g_new0(SyscallStats, 1);
  35        entry->num = num;
  36        g_hash_table_insert(statistics, GINT_TO_POINTER(num), (gpointer) entry);
  37    }
  38
  39    return entry;
  40}
  41
  42static void vcpu_syscall(qemu_plugin_id_t id, unsigned int vcpu_index,
  43                         int64_t num, uint64_t a1, uint64_t a2,
  44                         uint64_t a3, uint64_t a4, uint64_t a5,
  45                         uint64_t a6, uint64_t a7, uint64_t a8)
  46{
  47    if (statistics) {
  48        SyscallStats *entry;
  49        g_mutex_lock(&lock);
  50        entry = get_or_create_entry(num);
  51        entry->calls++;
  52        g_mutex_unlock(&lock);
  53    } else {
  54        g_autofree gchar *out = g_strdup_printf("syscall #%" PRIi64 "\n", num);
  55        qemu_plugin_outs(out);
  56    }
  57}
  58
  59static void vcpu_syscall_ret(qemu_plugin_id_t id, unsigned int vcpu_idx,
  60                             int64_t num, int64_t ret)
  61{
  62    if (statistics) {
  63        SyscallStats *entry;
  64
  65        g_mutex_lock(&lock);
  66        /* Should always return an existent entry. */
  67        entry = get_or_create_entry(num);
  68        if (ret < 0) {
  69            entry->errors++;
  70        }
  71        g_mutex_unlock(&lock);
  72    } else {
  73        g_autofree gchar *out;
  74        out = g_strdup_printf("syscall #%" PRIi64 " returned -> %" PRIi64 "\n",
  75                num, ret);
  76        qemu_plugin_outs(out);
  77    }
  78}
  79
  80static void print_entry(gpointer val, gpointer user_data)
  81{
  82    g_autofree gchar *out;
  83    SyscallStats *entry = (SyscallStats *) val;
  84    int64_t syscall_num = entry->num;
  85    out = g_strdup_printf(
  86        "%-13" PRIi64 "%-6" PRIi64 " %" PRIi64 "\n",
  87        syscall_num, entry->calls, entry->errors);
  88    qemu_plugin_outs(out);
  89}
  90
  91static gint comp_func(gconstpointer ea, gconstpointer eb)
  92{
  93    SyscallStats *ent_a = (SyscallStats *) ea;
  94    SyscallStats *ent_b = (SyscallStats *) eb;
  95
  96    return ent_a->calls > ent_b->calls ? -1 : 1;
  97}
  98
  99/* ************************************************************************* */
 100static void plugin_exit(qemu_plugin_id_t id, void *p)
 101{
 102    if (!statistics) {
 103        return;
 104    }
 105
 106    g_mutex_lock(&lock);
 107    GList *entries = g_hash_table_get_values(statistics);
 108    entries = g_list_sort(entries, comp_func);
 109    qemu_plugin_outs("syscall no.  calls  errors\n");
 110
 111    g_list_foreach(entries, print_entry, NULL);
 112
 113    g_list_free(entries);
 114    g_hash_table_destroy(statistics);
 115    g_mutex_unlock(&lock);
 116}
 117
 118QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
 119                                           const qemu_info_t *info,
 120                                           int argc, char **argv)
 121{
 122    if (argc == 0) {
 123        statistics = g_hash_table_new_full(NULL, g_direct_equal, NULL, g_free);
 124    } else {
 125        for (int i = 0; i < argc; i++) {
 126            if (g_strcmp0(argv[i], "print") != 0) {
 127                fprintf(stderr, "unsupported argument: %s\n", argv[i]);
 128                return -1;
 129            }
 130        }
 131    }
 132
 133    qemu_plugin_register_vcpu_syscall_cb(id, vcpu_syscall);
 134    qemu_plugin_register_vcpu_syscall_ret_cb(id, vcpu_syscall_ret);
 135    qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
 136    return 0;
 137}
 138