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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <unistd.h>
#include "alloc-util.h"
#include "bus-util.h"
#include "capability-util.h"
#include "fileio.h"
#include "kmod-setup.h"
#include "macro.h"
#include "recurse-dir.h"
#include "string-util.h"
#include "strv.h"
#include "virt.h"
#if HAVE_KMOD
#include "module-util.h"
static void systemd_kmod_log(
void *data,
int priority,
const char *file, int line,
const char *fn,
const char *format,
va_list args) {
/* library logging is enabled at debug only */
DISABLE_WARNING_FORMAT_NONLITERAL;
log_internalv(LOG_DEBUG, 0, file, line, fn, format, args);
REENABLE_WARNING;
}
static int match_modalias_recurse_dir_cb(
RecurseDirEvent event,
const char *path,
int dir_fd,
int inode_fd,
const struct dirent *de,
const struct statx *sx,
void *userdata) {
_cleanup_free_ char *alias = NULL;
char **modaliases = ASSERT_PTR(userdata);
int r;
if (event != RECURSE_DIR_ENTRY)
return RECURSE_DIR_CONTINUE;
if (de->d_type != DT_REG)
return RECURSE_DIR_CONTINUE;
if (!streq(de->d_name, "modalias"))
return RECURSE_DIR_CONTINUE;
r = read_one_line_file(path, &alias);
if (r < 0) {
log_debug_errno(r, "Failed to read %s, ignoring: %m", path);
return RECURSE_DIR_LEAVE_DIRECTORY;
}
if (startswith_strv(alias, modaliases))
return 1;
return RECURSE_DIR_LEAVE_DIRECTORY;
}
static bool has_virtio_feature(const char *name, char **modaliases) {
int r;
/* Directory traversal might be slow, hence let's do a cheap check first if it's even worth it */
if (detect_vm() == VIRTUALIZATION_NONE)
return false;
r = recurse_dir_at(
AT_FDCWD,
"/sys/devices/pci0000:00",
/* statx_mask= */ 0,
/* n_depth_max= */ 3,
RECURSE_DIR_ENSURE_TYPE,
match_modalias_recurse_dir_cb,
modaliases);
if (r < 0)
log_debug_errno(r, "Failed to determine whether host has %s device, ignoring: %m", name);
return r > 0;
}
static bool has_virtio_rng(void) {
return has_virtio_feature("virtio-rng", STRV_MAKE("pci:v00001AF4d00001005", "pci:v00001AF4d00001044"));
}
static bool has_virtiofs(void) {
return has_virtio_feature("virtiofs", STRV_MAKE("virtio:d0000001Av"));
}
static bool has_virtio_pci(void) {
return has_virtio_feature("virtio-pci", STRV_MAKE("pci:v00001AF4d"));
}
static bool in_qemu(void) {
return IN_SET(detect_vm(), VIRTUALIZATION_KVM, VIRTUALIZATION_QEMU);
}
#endif
int kmod_setup(void) {
#if HAVE_KMOD
static const struct {
const char *module;
const char *path;
bool warn_if_unavailable:1;
bool warn_if_module:1;
bool (*condition_fn)(void);
} kmod_table[] = {
/* This one we need to load explicitly, since auto-loading on use doesn't work
* before udev created the ghost device nodes, and we need it earlier than that. */
{ "autofs4", "/sys/class/misc/autofs", true, false, NULL },
/* This one we need to load explicitly, since auto-loading of IPv6 is not done when
* we try to configure ::1 on the loopback device. */
{ "ipv6", "/sys/module/ipv6", false, true, NULL },
/* This should never be a module */
{ "unix", "/proc/net/unix", true, true, NULL },
#if HAVE_LIBIPTC
/* netfilter is needed by networkd, nspawn among others, and cannot be autoloaded */
{ "ip_tables", "/proc/net/ip_tables_names", false, false, NULL },
#endif
/* virtio_rng would be loaded by udev later, but real entropy might be needed very early */
{ "virtio_rng", NULL, false, false, has_virtio_rng },
/* We can't wait for specific virtiofs tags to show up as device nodes so we have to load the
* virtiofs and virtio_pci modules early to make sure the virtiofs tags are found when
* sysroot.mount is started.
*
* TODO: Remove these again once https://gitlab.com/virtio-fs/virtiofsd/-/issues/128 is
* resolved and the kernel fix is widely available. */
{ "virtiofs", "/sys/module/virtiofs", false, false, has_virtiofs },
{ "virtio_pci", "/sys/module/virtio_pci", false, false, has_virtio_pci },
/* qemu_fw_cfg would be loaded by udev later, but we want to import credentials from it super early */
{ "qemu_fw_cfg", "/sys/firmware/qemu_fw_cfg", false, false, in_qemu },
/* dmi-sysfs is needed to import credentials from it super early */
{ "dmi-sysfs", "/sys/firmware/dmi/entries", false, false, NULL },
};
_cleanup_(kmod_unrefp) struct kmod_ctx *ctx = NULL;
unsigned i;
if (have_effective_cap(CAP_SYS_MODULE) == 0)
return 0;
for (i = 0; i < ELEMENTSOF(kmod_table); i++) {
if (kmod_table[i].path && access(kmod_table[i].path, F_OK) >= 0)
continue;
if (kmod_table[i].condition_fn && !kmod_table[i].condition_fn())
continue;
if (kmod_table[i].warn_if_module)
log_debug("Your kernel apparently lacks built-in %s support. Might be "
"a good idea to compile it in. We'll now try to work around "
"this by loading the module...", kmod_table[i].module);
if (!ctx) {
ctx = kmod_new(NULL, NULL);
if (!ctx)
return log_oom();
kmod_set_log_fn(ctx, systemd_kmod_log, NULL);
kmod_load_resources(ctx);
}
(void) module_load_and_warn(ctx, kmod_table[i].module, kmod_table[i].warn_if_unavailable);
}
#endif
return 0;
}
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