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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 | // SPDX-License-Identifier: GPL-2.0+ /* * File interface for UEFI variables * * Copyright (c) 2020, Heinrich Schuchardt */ #define LOG_CATEGORY LOGC_EFI #include <charset.h> #include <fs.h> #include <log.h> #include <malloc.h> #include <mapmem.h> #include <efi_loader.h> #include <efi_variable.h> #define PART_STR_LEN 10 /** * efi_set_blk_dev_to_system_partition() - select EFI system partition * * Set the EFI system partition as current block device. * * Return: status code */ static efi_status_t __maybe_unused efi_set_blk_dev_to_system_partition(void) { char part_str[PART_STR_LEN]; int r; if (efi_system_partition.uclass_id == UCLASS_INVALID) return EFI_DEVICE_ERROR; snprintf(part_str, PART_STR_LEN, "%x:%x", efi_system_partition.devnum, efi_system_partition.part); r = fs_set_blk_dev(blk_get_uclass_name(efi_system_partition.uclass_id), part_str, FS_TYPE_ANY); if (r) return EFI_DEVICE_ERROR; return EFI_SUCCESS; } /** * efi_var_to_storage() - save non-volatile variables as file * * File ubootefi.var is created on the EFI system partion. * * Return: status code */ efi_status_t efi_var_to_storage(void) { efi_status_t ret; struct efi_var_file *buf; loff_t len; loff_t actlen; int r; static bool once; ret = efi_var_collect(&buf, &len, EFI_VARIABLE_NON_VOLATILE); if (ret != EFI_SUCCESS) goto error; ret = efi_set_blk_dev_to_system_partition(); if (ret != EFI_SUCCESS) { if (!once) { log_warning("Cannot persist EFI variables without system partition\n"); once = true; } goto out; } once = false; r = fs_write(EFI_VAR_FILE_NAME, map_to_sysmem(buf), 0, len, &actlen); if (r || len != actlen) ret = EFI_DEVICE_ERROR; error: if (ret != EFI_SUCCESS) log_err("Failed to persist EFI variables\n"); out: free(buf); return ret; } /** * efi_var_from_storage() - read variables from file * * File ubootefi.var is read from the EFI system partitions and the variables * stored in the file are created. * * On first boot the file ubootefi.var does not exist yet. This is why we must * return EFI_SUCCESS in this case. * * If the variable file is corrupted, e.g. incorrect CRC32, we do not want to * stop the boot process. We deliberately return EFI_SUCCESS in this case, too. * * Return: status code */ efi_status_t efi_var_from_storage(void) { struct efi_var_file *buf; loff_t len; efi_status_t ret; int r; buf = calloc(1, EFI_VAR_BUF_SIZE); if (!buf) { log_err("Out of memory\n"); return EFI_OUT_OF_RESOURCES; } ret = efi_set_blk_dev_to_system_partition(); if (ret != EFI_SUCCESS) goto error; r = fs_read(EFI_VAR_FILE_NAME, map_to_sysmem(buf), 0, EFI_VAR_BUF_SIZE, &len); if (r || len < sizeof(struct efi_var_file)) { log_info("No EFI variables loaded\n"); goto error; } if (buf->length != len || efi_var_restore(buf, false) != EFI_SUCCESS) log_err("Invalid EFI variables file\n"); error: free(buf); return EFI_SUCCESS; } |