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v261
src/boot/initrd.c
262 строки
10 KB
Daan De Meyer
tree-wide: standardize header names across src/fundamental, src/basic and src/shared
21 май 2026, 04:33
21 май 2026, 04:33
74d392e
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/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include "efi-log.h" #include "initrd.h" #include "iovec-util.h" #include "proto/device-path.h" #include "proto/load-file.h" #include "util.h" #define LINUX_INITRD_MEDIA_GUID \ GUID_DEF(0x5568e427, 0x68fc, 0x4f3d, 0xac, 0x74, 0xca, 0x55, 0x52, 0x31, 0xcc, 0x68) /* extend LoadFileProtocol */ struct initrd_loader { EFI_LOAD_FILE_PROTOCOL load_file; struct iovec data; }; /* static structure for LINUX_INITRD_MEDIA device path see https://github.com/torvalds/linux/blob/v5.13/drivers/firmware/efi/libstub/efi-stub-helper.c */ static const struct { VENDOR_DEVICE_PATH vendor; EFI_DEVICE_PATH end; } _packed_ efi_initrd_device_path = { .vendor = { .Header = { .Type = MEDIA_DEVICE_PATH, .SubType = MEDIA_VENDOR_DP, .Length = sizeof(efi_initrd_device_path.vendor), }, .Guid = LINUX_INITRD_MEDIA_GUID }, .end = { .Type = END_DEVICE_PATH_TYPE, .SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE, .Length = sizeof(efi_initrd_device_path.end), } }; static EFIAPI EFI_STATUS initrd_load_file( EFI_LOAD_FILE_PROTOCOL *this, EFI_DEVICE_PATH *file_path, bool boot_policy, size_t *buffer_size, void *buffer) { struct initrd_loader *loader; if (!this || !buffer_size || !file_path) return EFI_INVALID_PARAMETER; if (boot_policy) return EFI_UNSUPPORTED; loader = (struct initrd_loader *) this; if (!iovec_is_set(&loader->data)) return EFI_NOT_FOUND; if (!buffer || *buffer_size < loader->data.iov_len) { *buffer_size = loader->data.iov_len; return EFI_BUFFER_TOO_SMALL; } memcpy(buffer, loader->data.iov_base, loader->data.iov_len); *buffer_size = loader->data.iov_len; return EFI_SUCCESS; } EFI_STATUS initrd_register( const struct iovec *initrd, EFI_HANDLE *ret_initrd_handle) { EFI_STATUS err; assert(ret_initrd_handle); /* If no initrd is specified we'll not install any. This avoids registration of the protocol for that * case, leaving it open for something else. */ if (!iovec_is_set(initrd)) return EFI_SUCCESS; /* We want to override the LINUX_INITRD_MEDIA device, let's hence first unregister any existing * one. We don't really expect multiple of these to be registered, but who knows? Let's kill all we * can find. */ for (unsigned attempt = 0;; attempt++) { if (attempt >= 16) return log_debug_status(EFI_DEVICE_ERROR, "Unable to free LINUX_INITRD_MEDIA device path after %u attempts, giving up.", attempt); EFI_DEVICE_PATH *dp = (EFI_DEVICE_PATH *) &efi_initrd_device_path; EFI_HANDLE handle = NULL; err = BS->LocateDevicePath(MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL), &dp, &handle); if (err == EFI_NOT_FOUND) /* Yay! All gone */ break; if (err != EFI_SUCCESS) return log_debug_status(err, "Failed to locate LINUX_INITRD_MEDIA device: %m"); /* Get the *actually* installed pointer for the device path */ err = BS->HandleProtocol(handle, MAKE_GUID_PTR(EFI_DEVICE_PATH_PROTOCOL), (void**) &dp); if (err != EFI_SUCCESS) return log_debug_status(err, "Failed to acquire DevicePath protocol on LINUX_INITRD_MEDIA device: %m"); /* Take away the device path protocol */ err = BS->UninstallMultipleProtocolInterfaces( handle, MAKE_GUID_PTR(EFI_DEVICE_PATH_PROTOCOL), dp, /* sentinel= */ NULL); if (err != EFI_SUCCESS) return log_debug_status(err, "Unable to release DevicePath protocol from old handle: %m"); /* NB: we leave the handle around (and thus leave the LoadFile2 protocol installed), because * the owner might be unhappy if we destroy it for them. It will no longer have the device * path we want to take possession of on it though. The assumption here is that whoever * registered the device path is OK with the device path being taken away, even if it might * not be OK with the handle being invalidated as a whole. */ log_debug("Successfully unregistered previous LINUX_INITRD_MEDIA device."); } _cleanup_free_ struct initrd_loader *loader = xnew(struct initrd_loader, 1); *loader = (struct initrd_loader) { .load_file.LoadFile = initrd_load_file, .data = *initrd, }; /* create a new handle and register the LoadFile2 protocol with the InitrdMediaPath on it */ err = BS->InstallMultipleProtocolInterfaces( ret_initrd_handle, MAKE_GUID_PTR(EFI_DEVICE_PATH_PROTOCOL), &efi_initrd_device_path, MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL), loader, /* sentinel= */ NULL); if (err != EFI_SUCCESS) return log_debug_status(err, "Failed to install new initrd device: %m"); log_debug("Installed new initrd of size %zu.", loader->data.iov_len); TAKE_PTR(loader); return EFI_SUCCESS; } EFI_STATUS initrd_unregister(EFI_HANDLE initrd_handle) { struct initrd_loader *loader; EFI_STATUS err; if (!initrd_handle) return EFI_SUCCESS; /* Get the LoadFile2 protocol that we allocated earlier */ err = BS->HandleProtocol(initrd_handle, MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL), (void **) &loader); if (err != EFI_SUCCESS) return log_debug_status(err, "Failed to acquire LoadFile2 protocol on our own initrd handle: %m"); /* We uninstall the DevicePath and the LoadFile2 protocol in separate steps. That's because we want * to gracefully handle the former (because it's OK if something else takes over the device path), * but be strict on the latter, because that's genuinely ours */ (void) BS->UninstallMultipleProtocolInterfaces( initrd_handle, MAKE_GUID_PTR(EFI_DEVICE_PATH_PROTOCOL), &efi_initrd_device_path, /* sentinel= */ NULL); /* This second call will also invalidate the handle, because it should be the last protocol on the handle */ err = BS->UninstallMultipleProtocolInterfaces( initrd_handle, MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL), loader, /* sentinel= */ NULL); if (err != EFI_SUCCESS) return log_debug_status(err, "Failed to uninstall LoadFile2 protocol from our own initrd handle: %m"); free(loader); return EFI_SUCCESS; } EFI_STATUS initrd_read_previous(struct iovec *ret_initrd) { EFI_STATUS err; /* If there's already an initrd registered, read it out, so that we can incorporate it in ours */ assert(ret_initrd); /* Get from the device path to the handle */ EFI_DEVICE_PATH *dp = (EFI_DEVICE_PATH *) &efi_initrd_device_path; EFI_HANDLE handle; err = BS->LocateDevicePath(MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL), &dp, &handle); if (err != EFI_SUCCESS) return err; /* Get from the handle to the protocol */ EFI_LOAD_FILE2_PROTOCOL *protocol = NULL; err = BS->HandleProtocol(handle, MAKE_GUID_PTR(EFI_LOAD_FILE2_PROTOCOL), (void**) &protocol); if (err != EFI_SUCCESS) return err; size_t size = 0; err = protocol->LoadFile(protocol, dp, /* bootPolicy= */ false, &size, /* Buffer= */ NULL); if (err == EFI_SUCCESS) /* Success? Kinda unexpected given we set Buffer to NULL, but it probably * means, that the file is zero-sized, let's treat it as such. */ size = 0; else if (err != EFI_BUFFER_TOO_SMALL) return err; if (size == 0) return EFI_NOT_FOUND; /* Treat empty initrds like missing ones */ _cleanup_free_ void *data = xmalloc(size); err = protocol->LoadFile(protocol, dp, /* bootPolicy= */ false, &size, data); if (err != EFI_SUCCESS) return err; *ret_initrd = (struct iovec) { .iov_base = TAKE_PTR(data), .iov_len = size, }; return EFI_SUCCESS; } EFI_STATUS combine_initrds( const struct iovec initrds[], size_t n_initrds, Pages *ret_initrd_pages, size_t *ret_initrd_size) { size_t n = 0; /* Combine initrds by concatenation in memory */ assert(initrds || n_initrds == 0); assert(ret_initrd_pages); assert(ret_initrd_size); FOREACH_ARRAY(i, initrds, n_initrds) { /* some initrds (the ones from UKI sections) need padding, pad all to be safe */ size_t initrd_size = ALIGN4(i->iov_len); if (n > SIZE_MAX - initrd_size) return EFI_OUT_OF_RESOURCES; n += initrd_size; } _cleanup_pages_ Pages pages = xmalloc_initrd_pages(n); uint8_t *p = PHYSICAL_ADDRESS_TO_POINTER(pages.addr); FOREACH_ARRAY(i, initrds, n_initrds) { size_t pad; p = mempcpy(p, i->iov_base, i->iov_len); pad = ALIGN4(i->iov_len) - i->iov_len; if (pad == 0) continue; memzero(p, pad); p += pad; } assert(PHYSICAL_ADDRESS_TO_POINTER(pages.addr + n) == p); *ret_initrd_pages = TAKE_STRUCT(pages); *ret_initrd_size = n; return EFI_SUCCESS; }