cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

module.c (9195B)

      1/*
      2 * QEMU Module Infrastructure
      3 *
      4 * Copyright IBM, Corp. 2009
      5 *
      6 * Authors:
      7 *  Anthony Liguori   <aliguori@us.ibm.com>
      8 *
      9 * This work is licensed under the terms of the GNU GPL, version 2.  See
     10 * the COPYING file in the top-level directory.
     11 *
     12 * Contributions after 2012-01-13 are licensed under the terms of the
     13 * GNU GPL, version 2 or (at your option) any later version.
     14 */
     15
     16#include "qemu/osdep.h"
     17#ifdef CONFIG_MODULES
     18#include <gmodule.h>
     19#endif
     20#include "qemu/queue.h"
     21#include "qemu/module.h"
     22#include "qemu/cutils.h"
     23#include "qemu/config-file.h"
     24#ifdef CONFIG_MODULE_UPGRADES
     25#include "qemu-version.h"
     26#endif
     27#include "trace.h"
     28
     29typedef struct ModuleEntry
     30{
     31    void (*init)(void);
     32    QTAILQ_ENTRY(ModuleEntry) node;
     33    module_init_type type;
     34} ModuleEntry;
     35
     36typedef QTAILQ_HEAD(, ModuleEntry) ModuleTypeList;
     37
     38static ModuleTypeList init_type_list[MODULE_INIT_MAX];
     39static bool modules_init_done[MODULE_INIT_MAX];
     40
     41static ModuleTypeList dso_init_list;
     42
     43static void init_lists(void)
     44{
     45    static int inited;
     46    int i;
     47
     48    if (inited) {
     49        return;
     50    }
     51
     52    for (i = 0; i < MODULE_INIT_MAX; i++) {
     53        QTAILQ_INIT(&init_type_list[i]);
     54    }
     55
     56    QTAILQ_INIT(&dso_init_list);
     57
     58    inited = 1;
     59}
     60
     61
     62static ModuleTypeList *find_type(module_init_type type)
     63{
     64    init_lists();
     65
     66    return &init_type_list[type];
     67}
     68
     69void register_module_init(void (*fn)(void), module_init_type type)
     70{
     71    ModuleEntry *e;
     72    ModuleTypeList *l;
     73
     74    e = g_malloc0(sizeof(*e));
     75    e->init = fn;
     76    e->type = type;
     77
     78    l = find_type(type);
     79
     80    QTAILQ_INSERT_TAIL(l, e, node);
     81}
     82
     83void register_dso_module_init(void (*fn)(void), module_init_type type)
     84{
     85    ModuleEntry *e;
     86
     87    init_lists();
     88
     89    e = g_malloc0(sizeof(*e));
     90    e->init = fn;
     91    e->type = type;
     92
     93    QTAILQ_INSERT_TAIL(&dso_init_list, e, node);
     94}
     95
     96void module_call_init(module_init_type type)
     97{
     98    ModuleTypeList *l;
     99    ModuleEntry *e;
    100
    101    if (modules_init_done[type]) {
    102        return;
    103    }
    104
    105    l = find_type(type);
    106
    107    QTAILQ_FOREACH(e, l, node) {
    108        e->init();
    109    }
    110
    111    modules_init_done[type] = true;
    112}
    113
    114#ifdef CONFIG_MODULES
    115
    116static const QemuModinfo module_info_stub[] = { {
    117    /* end of list */
    118} };
    119static const QemuModinfo *module_info = module_info_stub;
    120static const char *module_arch;
    121
    122void module_init_info(const QemuModinfo *info)
    123{
    124    module_info = info;
    125}
    126
    127void module_allow_arch(const char *arch)
    128{
    129    module_arch = arch;
    130}
    131
    132static bool module_check_arch(const QemuModinfo *modinfo)
    133{
    134    if (modinfo->arch) {
    135        if (!module_arch) {
    136            /* no arch set -> ignore all */
    137            return false;
    138        }
    139        if (strcmp(module_arch, modinfo->arch) != 0) {
    140            /* mismatch */
    141            return false;
    142        }
    143    }
    144    return true;
    145}
    146
    147static int module_load_file(const char *fname, bool mayfail, bool export_symbols)
    148{
    149    GModule *g_module;
    150    void (*sym)(void);
    151    const char *dsosuf = CONFIG_HOST_DSOSUF;
    152    int len = strlen(fname);
    153    int suf_len = strlen(dsosuf);
    154    ModuleEntry *e, *next;
    155    int ret, flags;
    156
    157    if (len <= suf_len || strcmp(&fname[len - suf_len], dsosuf)) {
    158        /* wrong suffix */
    159        ret = -EINVAL;
    160        goto out;
    161    }
    162    if (access(fname, F_OK)) {
    163        ret = -ENOENT;
    164        goto out;
    165    }
    166
    167    assert(QTAILQ_EMPTY(&dso_init_list));
    168
    169    flags = 0;
    170    if (!export_symbols) {
    171        flags |= G_MODULE_BIND_LOCAL;
    172    }
    173    g_module = g_module_open(fname, flags);
    174    if (!g_module) {
    175        if (!mayfail) {
    176            fprintf(stderr, "Failed to open module: %s\n",
    177                    g_module_error());
    178        }
    179        ret = -EINVAL;
    180        goto out;
    181    }
    182    if (!g_module_symbol(g_module, DSO_STAMP_FUN_STR, (gpointer *)&sym)) {
    183        fprintf(stderr, "Failed to initialize module: %s\n",
    184                fname);
    185        /* Print some info if this is a QEMU module (but from different build),
    186         * this will make debugging user problems easier. */
    187        if (g_module_symbol(g_module, "qemu_module_dummy", (gpointer *)&sym)) {
    188            fprintf(stderr,
    189                    "Note: only modules from the same build can be loaded.\n");
    190        }
    191        g_module_close(g_module);
    192        ret = -EINVAL;
    193    } else {
    194        QTAILQ_FOREACH(e, &dso_init_list, node) {
    195            e->init();
    196            register_module_init(e->init, e->type);
    197        }
    198        ret = 0;
    199    }
    200
    201    trace_module_load_module(fname);
    202    QTAILQ_FOREACH_SAFE(e, &dso_init_list, node, next) {
    203        QTAILQ_REMOVE(&dso_init_list, e, node);
    204        g_free(e);
    205    }
    206out:
    207    return ret;
    208}
    209#endif
    210
    211bool module_load_one(const char *prefix, const char *lib_name, bool mayfail)
    212{
    213    bool success = false;
    214
    215#ifdef CONFIG_MODULES
    216    char *fname = NULL;
    217#ifdef CONFIG_MODULE_UPGRADES
    218    char *version_dir;
    219#endif
    220    const char *search_dir;
    221    char *dirs[5];
    222    char *module_name;
    223    int i = 0, n_dirs = 0;
    224    int ret;
    225    bool export_symbols = false;
    226    static GHashTable *loaded_modules;
    227    const QemuModinfo *modinfo;
    228    const char **sl;
    229
    230    if (!g_module_supported()) {
    231        fprintf(stderr, "Module is not supported by system.\n");
    232        return false;
    233    }
    234
    235    if (!loaded_modules) {
    236        loaded_modules = g_hash_table_new(g_str_hash, g_str_equal);
    237    }
    238
    239    module_name = g_strdup_printf("%s%s", prefix, lib_name);
    240
    241    if (g_hash_table_contains(loaded_modules, module_name)) {
    242        g_free(module_name);
    243        return true;
    244    }
    245    g_hash_table_add(loaded_modules, module_name);
    246
    247    for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
    248        if (modinfo->arch) {
    249            if (strcmp(modinfo->name, module_name) == 0) {
    250                if (!module_check_arch(modinfo)) {
    251                    return false;
    252                }
    253            }
    254        }
    255        if (modinfo->deps) {
    256            if (strcmp(modinfo->name, module_name) == 0) {
    257                /* we depend on other module(s) */
    258                for (sl = modinfo->deps; *sl != NULL; sl++) {
    259                    module_load_one("", *sl, false);
    260                }
    261            } else {
    262                for (sl = modinfo->deps; *sl != NULL; sl++) {
    263                    if (strcmp(module_name, *sl) == 0) {
    264                        /* another module depends on us */
    265                        export_symbols = true;
    266                    }
    267                }
    268            }
    269        }
    270    }
    271
    272    search_dir = getenv("QEMU_MODULE_DIR");
    273    if (search_dir != NULL) {
    274        dirs[n_dirs++] = g_strdup_printf("%s", search_dir);
    275    }
    276    dirs[n_dirs++] = get_relocated_path(CONFIG_QEMU_MODDIR);
    277    dirs[n_dirs++] = g_strdup(qemu_get_exec_dir());
    278
    279#ifdef CONFIG_MODULE_UPGRADES
    280    version_dir = g_strcanon(g_strdup(QEMU_PKGVERSION),
    281                             G_CSET_A_2_Z G_CSET_a_2_z G_CSET_DIGITS "+-.~",
    282                             '_');
    283    dirs[n_dirs++] = g_strdup_printf("/var/run/qemu/%s", version_dir);
    284#endif
    285
    286    assert(n_dirs <= ARRAY_SIZE(dirs));
    287
    288    for (i = 0; i < n_dirs; i++) {
    289        fname = g_strdup_printf("%s/%s%s",
    290                dirs[i], module_name, CONFIG_HOST_DSOSUF);
    291        ret = module_load_file(fname, mayfail, export_symbols);
    292        g_free(fname);
    293        fname = NULL;
    294        /* Try loading until loaded a module file */
    295        if (!ret) {
    296            success = true;
    297            break;
    298        }
    299    }
    300
    301    if (!success) {
    302        g_hash_table_remove(loaded_modules, module_name);
    303        g_free(module_name);
    304    }
    305
    306    for (i = 0; i < n_dirs; i++) {
    307        g_free(dirs[i]);
    308    }
    309
    310#endif
    311    return success;
    312}
    313
    314#ifdef CONFIG_MODULES
    315
    316static bool module_loaded_qom_all;
    317
    318void module_load_qom_one(const char *type)
    319{
    320    const QemuModinfo *modinfo;
    321    const char **sl;
    322
    323    if (!type) {
    324        return;
    325    }
    326
    327    trace_module_lookup_object_type(type);
    328    for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
    329        if (!modinfo->objs) {
    330            continue;
    331        }
    332        if (!module_check_arch(modinfo)) {
    333            continue;
    334        }
    335        for (sl = modinfo->objs; *sl != NULL; sl++) {
    336            if (strcmp(type, *sl) == 0) {
    337                module_load_one("", modinfo->name, false);
    338            }
    339        }
    340    }
    341}
    342
    343void module_load_qom_all(void)
    344{
    345    const QemuModinfo *modinfo;
    346
    347    if (module_loaded_qom_all) {
    348        return;
    349    }
    350
    351    for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
    352        if (!modinfo->objs) {
    353            continue;
    354        }
    355        if (!module_check_arch(modinfo)) {
    356            continue;
    357        }
    358        module_load_one("", modinfo->name, false);
    359    }
    360    module_loaded_qom_all = true;
    361}
    362
    363void qemu_load_module_for_opts(const char *group)
    364{
    365    const QemuModinfo *modinfo;
    366    const char **sl;
    367
    368    for (modinfo = module_info; modinfo->name != NULL; modinfo++) {
    369        if (!modinfo->opts) {
    370            continue;
    371        }
    372        for (sl = modinfo->opts; *sl != NULL; sl++) {
    373            if (strcmp(group, *sl) == 0) {
    374                module_load_one("", modinfo->name, false);
    375            }
    376        }
    377    }
    378}
    379
    380#else
    381
    382void module_allow_arch(const char *arch) {}
    383void qemu_load_module_for_opts(const char *group) {}
    384void module_load_qom_one(const char *type) {}
    385void module_load_qom_all(void) {}
    386
    387#endif