iterative get_next interface. This prevents efivar(3) from printing 4k of 0's when a variable isn't set. Sponsored by: Netflix
383 lines
9.2 KiB
C
383 lines
9.2 KiB
C
/*-
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* Copyright (c) 2016 Netflix, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <efivar.h>
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#include <sys/efiio.h>
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#include <sys/param.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "libefivar_int.h"
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static int efi_fd = -2;
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#define Z { 0, 0, 0, 0, 0, { 0 } }
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const efi_guid_t efi_guid_empty = Z;
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static struct uuid_table
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{
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const char *uuid_str;
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const char *name;
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efi_guid_t guid;
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} guid_tbl [] =
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{
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{ "00000000-0000-0000-0000-000000000000", "zero", Z },
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{ "093e0fae-a6c4-4f50-9f1b-d41e2b89c19a", "sha512", Z },
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{ "0abba7dc-e516-4167-bbf5-4d9d1c739416", "redhat", Z },
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{ "0b6e5233-a65c-44c9-9407-d9ab83bfc8bd", "sha224", Z },
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{ "126a762d-5758-4fca-8531-201a7f57f850", "lenovo_boot_menu", Z },
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{ "3bd2a492-96c0-4079-b420-fcf98ef103ed", "x509_sha256", Z },
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{ "3c5766e8-269c-4e34-aa14-ed776e85b3b6", "rsa2048", Z },
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{ "3CC24E96-22C7-41D8-8863-8E39DCDCC2CF", "lenovo", Z },
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{ "3f7e615b-0d45-4f80-88dc-26b234958560", "lenovo_diag", Z },
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{ "446dbf63-2502-4cda-bcfa-2465d2b0fe9d", "x509_sha512", Z },
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{ "4aafd29d-68df-49ee-8aa9-347d375665a7", "pkcs7_cert", Z },
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{ "605dab50-e046-4300-abb6-3dd810dd8b23", "shim", Z },
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{ "665d3f60-ad3e-4cad-8e26-db46eee9f1b5", "lenovo_rescue", Z },
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{ "67f8444f-8743-48f1-a328-1eaab8736080", "rsa2048_sha1", Z },
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{ "7076876e-80c2-4ee6-aad2-28b349a6865b", "x509_sha384", Z },
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{ "721c8b66-426c-4e86-8e99-3457c46ab0b9", "lenovo_setup", Z },
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{ "77fa9abd-0359-4d32-bd60-28f4e78f784b", "microsoft", Z },
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{ "7FACC7B6-127F-4E9C-9C5D-080F98994345", "lenovo_2", Z },
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{ "826ca512-cf10-4ac9-b187-be01496631bd", "sha1", Z },
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{ "82988420-7467-4490-9059-feb448dd1963", "lenovo_me_config", Z },
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{ "8be4df61-93ca-11d2-aa0d-00e098032b8c", "global", Z },
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{ "a5c059a1-94e4-4aa7-87b5-ab155c2bf072", "x509_cert", Z },
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{ "a7717414-c616-4977-9420-844712a735bf", "rsa2048_sha256_cert", Z },
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{ "a7d8d9a6-6ab0-4aeb-ad9d-163e59a7a380", "lenovo_diag_splash", Z },
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{ "ade9e48f-9cb8-98e6-31af-b4e6009e2fe3", "redhat_2", Z },
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{ "bc7838d2-0f82-4d60-8316-c068ee79d25b", "lenovo_msg", Z },
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{ "c1c41626-504c-4092-aca9-41f936934328", "sha256", Z },
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{ "c57ad6b7-0515-40a8-9d21-551652854e37", "shell", Z },
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{ "d719b2cb-3d3a-4596-a3bc-dad00e67656f", "security", Z },
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{ "e2b36190-879b-4a3d-ad8d-f2e7bba32784", "rsa2048_sha256", Z },
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{ "ff3e5307-9fd0-48c9-85f1-8ad56c701e01", "sha384", Z },
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{ "f46ee6f4-4785-43a3-923d-7f786c3c8479", "lenovo_startup_interrupt", Z },
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{ "ffffffff-ffff-ffff-ffff-ffffffffffff", "zzignore-this-guid", Z },
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};
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#undef Z
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static void
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efi_guid_tbl_compile(void)
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{
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size_t i;
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uint32_t status;
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for (i = 0; i < nitems(guid_tbl); i++) {
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uuid_from_string(guid_tbl[i].uuid_str, &guid_tbl[i].guid,
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&status);
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/* all f's is a bad version, so ignore that error */
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if (status != uuid_s_ok && status != uuid_s_bad_version)
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fprintf(stderr, "Can't convert %s to a uuid for %s: %d\n",
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guid_tbl[i].uuid_str, guid_tbl[i].name, (int)status);
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}
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}
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static int
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efi_open_dev(void)
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{
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if (efi_fd == -2)
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efi_fd = open("/dev/efi", O_RDWR);
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if (efi_fd < 0)
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efi_fd = -1;
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else
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efi_guid_tbl_compile();
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return (efi_fd);
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}
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static void
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efi_var_reset(struct efi_var_ioc *var)
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{
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var->name = NULL;
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var->namesize = 0;
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memset(&var->vendor, 0, sizeof(var->vendor));
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var->attrib = 0;
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var->data = NULL;
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var->datasize = 0;
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}
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static int
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rv_to_linux_rv(int rv)
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{
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if (rv == 0)
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rv = 1;
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else
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rv = -errno;
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return (rv);
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}
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int
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efi_append_variable(efi_guid_t guid, const char *name,
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uint8_t *data, size_t data_size, uint32_t attributes)
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{
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return efi_set_variable(guid, name, data, data_size,
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attributes | EFI_VARIABLE_APPEND_WRITE, 0);
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}
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int
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efi_del_variable(efi_guid_t guid, const char *name)
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{
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/* data_size of 0 deletes the variable */
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return efi_set_variable(guid, name, NULL, 0, 0, 0);
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}
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int
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efi_get_variable(efi_guid_t guid, const char *name,
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uint8_t **data, size_t *data_size, uint32_t *attributes)
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{
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struct efi_var_ioc var;
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int rv;
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static uint8_t buf[1024*32];
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if (efi_open_dev() == -1)
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return -1;
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efi_var_reset(&var);
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rv = libefi_utf8_to_ucs2(name, &var.name, &var.namesize);
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if (rv != 0)
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goto errout;
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var.vendor = guid;
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var.data = buf;
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var.datasize = sizeof(buf);
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rv = ioctl(efi_fd, EFIIOC_VAR_GET, &var);
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if (data_size != NULL)
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*data_size = var.datasize;
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if (data != NULL)
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*data = buf;
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if (attributes != NULL)
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*attributes = var.attrib;
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errout:
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free(var.name);
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return rv_to_linux_rv(rv);
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}
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int
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efi_get_variable_attributes(efi_guid_t guid, const char *name,
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uint32_t *attributes)
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{
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/* Make sure this construct works -- I think it will fail */
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return efi_get_variable(guid, name, NULL, NULL, attributes);
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}
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int
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efi_get_variable_size(efi_guid_t guid, const char *name,
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size_t *size)
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{
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/* XXX check to make sure this matches the linux value */
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*size = 0;
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return efi_get_variable(guid, name, NULL, size, NULL);
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}
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int
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efi_get_next_variable_name(efi_guid_t **guid, char **name)
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{
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struct efi_var_ioc var;
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int rv;
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static efi_char *buf;
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static size_t buflen = 256 * sizeof(efi_char);
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static efi_guid_t retguid;
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size_t size;
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if (efi_open_dev() == -1)
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return -1;
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if (buf == NULL)
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buf = malloc(buflen);
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again:
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efi_var_reset(&var);
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var.name = buf;
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var.namesize = buflen;
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if (*name == NULL) {
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*buf = 0;
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/* GUID zeroed in var_reset */
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} else {
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rv = libefi_utf8_to_ucs2(*name, &var.name, &size);
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if (rv != 0)
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goto errout;
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var.vendor = **guid;
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}
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rv = ioctl(efi_fd, EFIIOC_VAR_NEXT, &var);
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if (rv == 0 && var.name == NULL) {
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/*
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* oops, too little space. Try again.
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*/
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void *new = realloc(buf, buflen);
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buflen = var.namesize;
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if (new == NULL) {
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rv = -1;
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errno = ENOMEM;
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goto done;
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}
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buf = new;
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goto again;
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}
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if (rv == 0) {
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*name = NULL; /* XXX */
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var.name[var.namesize / sizeof(efi_char)] = 0; /* EFI doesn't NUL terminate */
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rv = libefi_ucs2_to_utf8(var.name, name);
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if (rv != 0)
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goto errout;
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retguid = var.vendor;
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*guid = &retguid;
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}
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errout:
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/* XXX The linux interface expects name to be a static buffer -- fix or leak memory? */
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done:
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if (errno == ENOENT) {
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errno = 0;
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return 0;
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}
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return (rv_to_linux_rv(rv));
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}
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int
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efi_guid_cmp(const efi_guid_t *guid1, const efi_guid_t *guid2)
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{
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uint32_t status;
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return uuid_compare(guid1, guid2, &status);
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}
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int
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efi_guid_is_zero(const efi_guid_t *guid)
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{
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uint32_t status;
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return uuid_is_nil(guid, &status);
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}
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int
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efi_guid_to_name(efi_guid_t *guid, char **name)
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{
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size_t i;
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uint32_t status;
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for (i = 0; i < nitems(guid_tbl); i++) {
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if (uuid_equal(guid, &guid_tbl[i].guid, &status)) {
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*name = strdup(guid_tbl[i].name);
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return (0);
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}
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}
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return (efi_guid_to_str(guid, name));
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}
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int
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efi_guid_to_symbol(efi_guid_t *guid __unused, char **symbol __unused)
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{
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/*
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* Unsure what this is used for, efibootmgr doesn't use it.
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* Leave unimplemented for now.
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*/
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return -1;
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}
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int
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efi_guid_to_str(const efi_guid_t *guid, char **sp)
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{
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uint32_t status;
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/* knows efi_guid_t is a typedef of uuid_t */
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uuid_to_string(guid, sp, &status);
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return (status == uuid_s_ok ? 0 : -1);
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}
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int
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efi_name_to_guid(const char *name, efi_guid_t *guid)
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{
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size_t i;
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for (i = 0; i < nitems(guid_tbl); i++) {
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if (strcmp(name, guid_tbl[i].name) == 0) {
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*guid = guid_tbl[i].guid;
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return (0);
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}
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}
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return (efi_str_to_guid(name, guid));
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}
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int
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efi_set_variable(efi_guid_t guid, const char *name,
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uint8_t *data, size_t data_size, uint32_t attributes, mode_t mode __unused)
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{
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struct efi_var_ioc var;
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int rv;
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if (efi_open_dev() == -1)
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return -1;
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efi_var_reset(&var);
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rv = libefi_utf8_to_ucs2(name, &var.name, &var.namesize);
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if (rv != 0)
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goto errout;
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var.vendor = guid;
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var.data = data;
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var.datasize = data_size;
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var.attrib = attributes;
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rv = ioctl(efi_fd, EFIIOC_VAR_SET, &var);
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errout:
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free(var.name);
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return rv;
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}
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int
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efi_str_to_guid(const char *s, efi_guid_t *guid)
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{
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uint32_t status;
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/* knows efi_guid_t is a typedef of uuid_t */
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uuid_from_string(s, guid, &status);
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return (status == uuid_s_ok ? 0 : -1);
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}
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int
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efi_variables_supported(void)
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{
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return efi_open_dev() != -1;
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}
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