/* gpt.[ch] Copyright (C) 2000-2001 Dell Computer Corporation EFI GUID Partition Table handling Per Intel EFI Specification v1.02 http://developer.intel.com/technology/efi/efi.htm This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #define _FILE_OFFSET_BITS 64 #include "gpt.h" #include #include #include #include #include #include #include #include #include #include #include #include #include "crc32.h" #if BYTE_ORDER == LITTLE_ENDIAN # define __le16_to_cpu(x) (x) # define __le32_to_cpu(x) (x) # define __le64_to_cpu(x) (x) # define __cpu_to_le32(x) (x) #elif BYTE_ORDER == BIG_ENDIAN # define __le16_to_cpu(x) bswap_16(x) # define __le32_to_cpu(x) bswap_32(x) # define __le64_to_cpu(x) bswap_64(x) # define __cpu_to_le32(x) bswap_32(x) #endif #ifndef BLKGETLASTSECT #define BLKGETLASTSECT _IO(0x12,108) /* get last sector of block device */ #endif #ifndef BLKGETSIZE #define BLKGETSIZE _IO(0x12,96) /* return device size */ #endif #ifndef BLKSSZGET #define BLKSSZGET _IO(0x12,104) /* get block device sector size */ #endif #ifndef BLKGETSIZE64 #define BLKGETSIZE64 _IOR(0x12,114,sizeof(uint64_t)) /* return device size in bytes (u64 *arg) */ #endif struct blkdev_ioctl_param { unsigned int block; size_t content_length; char * block_contents; }; /** * efi_crc32() - EFI version of crc32 function * @buf: buffer to calculate crc32 of * @len - length of buf * * Description: Returns EFI-style CRC32 value for @buf * * This function uses the little endian Ethernet polynomial * but seeds the function with ~0, and xor's with ~0 at the end. * Note, the EFI Specification, v1.02, has a reference to * Dr. Dobbs Journal, May 1994 (actually it's in May 1992). */ static inline uint32_t efi_crc32(const void *buf, unsigned long len) { return (crc32(~0L, buf, len) ^ ~0L); } /** * is_pmbr_valid(): test Protective MBR for validity * @mbr: pointer to a legacy mbr structure * * Description: Returns 1 if PMBR is valid, 0 otherwise. * Validity depends on two things: * 1) MSDOS signature is in the last two bytes of the MBR * 2) One partition of type 0xEE is found */ static int is_pmbr_valid(legacy_mbr *mbr) { int i, found = 0, signature = 0; if (!mbr) return 0; signature = (__le16_to_cpu(mbr->signature) == MSDOS_MBR_SIGNATURE); for (i = 0; signature && i < 4; i++) { if (mbr->partition[i].sys_type == EFI_PMBR_OSTYPE_EFI_GPT) { found = 1; break; } } return (signature && found); } /************************************************************ * get_sector_size * Requires: * - filedes is an open file descriptor, suitable for reading * Modifies: nothing * Returns: * sector size, or 512. ************************************************************/ static int get_sector_size(int filedes) { int rc, sector_size = 512; rc = ioctl(filedes, BLKSSZGET, §or_size); if (rc) sector_size = 512; return sector_size; } /************************************************************ * _get_num_sectors * Requires: * - filedes is an open file descriptor, suitable for reading * Modifies: nothing * Returns: * Last LBA value on success * 0 on error * * Try getting BLKGETSIZE64 and BLKSSZGET first, * then BLKGETSIZE if necessary. * Kernels 2.4.15-2.4.18 and 2.5.0-2.5.3 have a broken BLKGETSIZE64 * which returns the number of 512-byte sectors, not the size of * the disk in bytes. Fixed in kernels 2.4.18-pre8 and 2.5.4-pre3. ************************************************************/ static uint64_t _get_num_sectors(int filedes) { int rc; uint64_t bytes=0; rc = ioctl(filedes, BLKGETSIZE64, &bytes); if (!rc) return bytes / get_sector_size(filedes); return 0; } /************************************************************ * last_lba(): return number of last logical block of device * * @fd * * Description: returns Last LBA value on success, 0 on error. * Notes: The value st_blocks gives the size of the file * in 512-byte blocks, which is OK if * EFI_BLOCK_SIZE_SHIFT == 9. ************************************************************/ static uint64_t last_lba(int filedes) { int rc; uint64_t sectors = 0; struct stat s; memset(&s, 0, sizeof (s)); rc = fstat(filedes, &s); if (rc == -1) { fprintf(stderr, "last_lba() could not stat: %s\n", strerror(errno)); return 0; } if (S_ISBLK(s.st_mode)) { sectors = _get_num_sectors(filedes); } else { fprintf(stderr, "last_lba(): I don't know how to handle files with mode %x\n", s.st_mode); sectors = 1; } return sectors ? sectors - 1 : 0; } static ssize_t read_lastoddsector(int fd, uint64_t lba, void *buffer, size_t count) { int rc; struct blkdev_ioctl_param ioctl_param; if (!buffer) return 0; ioctl_param.block = 0; /* read the last sector */ ioctl_param.content_length = count; ioctl_param.block_contents = buffer; rc = ioctl(fd, BLKGETLASTSECT, &ioctl_param); if (rc == -1) perror("read failed"); return !rc; } static ssize_t read_lba(int fd, uint64_t lba, void *buffer, size_t bytes) { int sector_size = get_sector_size(fd); off_t offset = lba * sector_size; uint64_t lastlba; ssize_t bytesread; lseek(fd, offset, SEEK_SET); bytesread = read(fd, buffer, bytes); lastlba = last_lba(fd); if (!lastlba) return bytesread; /* Kludge. This is necessary to read/write the last block of an odd-sized disk, until Linux 2.5.x kernel fixes. This is only used by gpt.c, and only to read one sector, so we don't have to be fancy. */ if (!bytesread && !(lastlba & 1) && lba == lastlba) { bytesread = read_lastoddsector(fd, lba, buffer, bytes); } return bytesread; } /** * alloc_read_gpt_entries(): reads partition entries from disk * @fd is an open file descriptor to the whole disk * @gpt is a buffer into which the GPT will be put * Description: Returns ptes on success, NULL on error. * Allocates space for PTEs based on information found in @gpt. * Notes: remember to free pte when you're done! */ static gpt_entry * alloc_read_gpt_entries(int fd, gpt_header * gpt) { gpt_entry *pte; size_t count = __le32_to_cpu(gpt->num_partition_entries) * __le32_to_cpu(gpt->sizeof_partition_entry); if (!count) return NULL; pte = (gpt_entry *)malloc(count); if (!pte) return NULL; memset(pte, 0, count); if (!read_lba(fd, __le64_to_cpu(gpt->partition_entry_lba), pte, count)) { free(pte); return NULL; } return pte; } /** * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk * @fd is an open file descriptor to the whole disk * @lba is the Logical Block Address of the partition table * * Description: returns GPT header on success, NULL on error. Allocates * and fills a GPT header starting at @ from @bdev. * Note: remember to free gpt when finished with it. */ static gpt_header * alloc_read_gpt_header(int fd, uint64_t lba) { gpt_header *gpt; gpt = (gpt_header *) malloc(sizeof (gpt_header)); if (!gpt) return NULL; memset(gpt, 0, sizeof (*gpt)); if (!read_lba(fd, lba, gpt, sizeof (gpt_header))) { free(gpt); return NULL; } return gpt; } /** * is_gpt_valid() - tests one GPT header and PTEs for validity * @fd is an open file descriptor to the whole disk * @lba is the logical block address of the GPT header to test * @gpt is a GPT header ptr, filled on return. * @ptes is a PTEs ptr, filled on return. * * Description: returns 1 if valid, 0 on error. * If valid, returns pointers to newly allocated GPT header and PTEs. */ static int is_gpt_valid(int fd, uint64_t lba, gpt_header ** gpt, gpt_entry ** ptes) { int rc = 0; /* default to not valid */ uint32_t crc, origcrc; if (!gpt || !ptes) return 0; if (!(*gpt = alloc_read_gpt_header(fd, lba))) return 0; /* Check the GUID Partition Table signature */ if (__le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) { /* printf("GUID Partition Table Header signature is wrong: %" PRIx64" != %" PRIx64 "\n", __le64_to_cpu((*gpt)->signature), GUID_PT_HEADER_SIGNATURE); */ free(*gpt); *gpt = NULL; return rc; } /* Check the GUID Partition Table Header CRC */ origcrc = __le32_to_cpu((*gpt)->header_crc32); (*gpt)->header_crc32 = 0; crc = efi_crc32(*gpt, __le32_to_cpu((*gpt)->header_size)); if (crc != origcrc) { // printf( "GPTH CRC check failed, %x != %x.\n", origcrc, crc); (*gpt)->header_crc32 = __cpu_to_le32(origcrc); free(*gpt); *gpt = NULL; return 0; } (*gpt)->header_crc32 = __cpu_to_le32(origcrc); /* Check that the my_lba entry points to the LBA * that contains the GPT we read */ if (__le64_to_cpu((*gpt)->my_lba) != lba) { /* printf( "my_lba % PRIx64 "x != lba %"PRIx64 "x.\n", __le64_to_cpu((*gpt)->my_lba), lba); */ free(*gpt); *gpt = NULL; return 0; } /* Check that sizeof_partition_entry has the correct value */ if (__le32_to_cpu((*gpt)->sizeof_partition_entry) != sizeof(gpt_entry)) { // printf("GUID partition entry size check failed.\n"); free(*gpt); *gpt = NULL; return 0; } if (!(*ptes = alloc_read_gpt_entries(fd, *gpt))) { free(*gpt); *gpt = NULL; return 0; } /* Check the GUID Partition Entry Array CRC */ crc = efi_crc32(*ptes, __le32_to_cpu((*gpt)->num_partition_entries) * __le32_to_cpu((*gpt)->sizeof_partition_entry)); if (crc != __le32_to_cpu((*gpt)->partition_entry_array_crc32)) { // printf("GUID Partitition Entry Array CRC check failed.\n"); free(*gpt); *gpt = NULL; free(*ptes); *ptes = NULL; return 0; } /* We're done, all's well */ return 1; } /** * compare_gpts() - Search disk for valid GPT headers and PTEs * @pgpt is the primary GPT header * @agpt is the alternate GPT header * @lastlba is the last LBA number * Description: Returns nothing. Sanity checks pgpt and agpt fields * and prints warnings on discrepancies. * */ static void compare_gpts(gpt_header *pgpt, gpt_header *agpt, uint64_t lastlba) { int error_found = 0; if (!pgpt || !agpt) return; if (__le64_to_cpu(pgpt->my_lba) != __le64_to_cpu(agpt->alternate_lba)) { error_found++; fprintf(stderr, "GPT:Primary header LBA != Alt. header alternate_lba\n"); #ifdef DEBUG fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n", __le64_to_cpu(pgpt->my_lba), __le64_to_cpu(agpt->alternate_lba)); #endif } if (__le64_to_cpu(pgpt->alternate_lba) != __le64_to_cpu(agpt->my_lba)) { error_found++; fprintf(stderr, "GPT:Primary header alternate_lba != Alt. header my_lba\n"); #ifdef DEBUG fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n", __le64_to_cpu(pgpt->alternate_lba), __le64_to_cpu(agpt->my_lba)); #endif } if (__le64_to_cpu(pgpt->first_usable_lba) != __le64_to_cpu(agpt->first_usable_lba)) { error_found++; fprintf(stderr, "GPT:first_usable_lbas don't match.\n"); #ifdef DEBUG fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n", __le64_to_cpu(pgpt->first_usable_lba), __le64_to_cpu(agpt->first_usable_lba)); #endif } if (__le64_to_cpu(pgpt->last_usable_lba) != __le64_to_cpu(agpt->last_usable_lba)) { error_found++; fprintf(stderr, "GPT:last_usable_lbas don't match.\n"); #ifdef DEBUG fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n", __le64_to_cpu(pgpt->last_usable_lba), __le64_to_cpu(agpt->last_usable_lba)); #endif } if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) { error_found++; fprintf(stderr, "GPT:disk_guids don't match.\n"); } if (__le32_to_cpu(pgpt->num_partition_entries) != __le32_to_cpu(agpt->num_partition_entries)) { error_found++; fprintf(stderr, "GPT:num_partition_entries don't match: " "0x%x != 0x%x\n", __le32_to_cpu(pgpt->num_partition_entries), __le32_to_cpu(agpt->num_partition_entries)); } if (__le32_to_cpu(pgpt->sizeof_partition_entry) != __le32_to_cpu(agpt->sizeof_partition_entry)) { error_found++; fprintf(stderr, "GPT:sizeof_partition_entry values don't match: " "0x%x != 0x%x\n", __le32_to_cpu(pgpt->sizeof_partition_entry), __le32_to_cpu(agpt->sizeof_partition_entry)); } if (__le32_to_cpu(pgpt->partition_entry_array_crc32) != __le32_to_cpu(agpt->partition_entry_array_crc32)) { error_found++; fprintf(stderr, "GPT:partition_entry_array_crc32 values don't match: " "0x%x != 0x%x\n", __le32_to_cpu(pgpt->partition_entry_array_crc32), __le32_to_cpu(agpt->partition_entry_array_crc32)); } if (__le64_to_cpu(pgpt->alternate_lba) != lastlba) { error_found++; fprintf(stderr, "GPT:Primary header thinks Alt. header is not at the end of the disk.\n"); #ifdef DEBUG fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n", __le64_to_cpu(pgpt->alternate_lba), lastlba); #endif } if (__le64_to_cpu(agpt->my_lba) != lastlba) { error_found++; fprintf(stderr, "GPT:Alternate GPT header not at the end of the disk.\n"); #ifdef DEBUG fprintf(stderr, "GPT:%" PRIx64 " != %" PRIx64 "\n", __le64_to_cpu(agpt->my_lba), lastlba); #endif } if (error_found) fprintf(stderr, "GPT: Use GNU Parted to correct GPT errors.\n"); return; } /** * find_valid_gpt() - Search disk for valid GPT headers and PTEs * @fd is an open file descriptor to the whole disk * @gpt is a GPT header ptr, filled on return. * @ptes is a PTEs ptr, filled on return. * Description: Returns 1 if valid, 0 on error. * If valid, returns pointers to newly allocated GPT header and PTEs. * Validity depends on finding either the Primary GPT header and PTEs valid, * or the Alternate GPT header and PTEs valid, and the PMBR valid. */ static int find_valid_gpt(int fd, gpt_header ** gpt, gpt_entry ** ptes) { extern int force_gpt; int good_pgpt = 0, good_agpt = 0, good_pmbr = 0; gpt_header *pgpt = NULL, *agpt = NULL; gpt_entry *pptes = NULL, *aptes = NULL; legacy_mbr *legacymbr = NULL; uint64_t lastlba; if (!gpt || !ptes) return 0; if (!(lastlba = last_lba(fd))) return 0; good_pgpt = is_gpt_valid(fd, GPT_PRIMARY_PARTITION_TABLE_LBA, &pgpt, &pptes); if (good_pgpt) { good_agpt = is_gpt_valid(fd, __le64_to_cpu(pgpt->alternate_lba), &agpt, &aptes); if (!good_agpt) { good_agpt = is_gpt_valid(fd, lastlba, &agpt, &aptes); } } else { good_agpt = is_gpt_valid(fd, lastlba, &agpt, &aptes); } /* The obviously unsuccessful case */ if (!good_pgpt && !good_agpt) { goto fail; } /* This will be added to the EFI Spec. per Intel after v1.02. */ legacymbr = malloc(sizeof (*legacymbr)); if (legacymbr) { memset(legacymbr, 0, sizeof (*legacymbr)); read_lba(fd, 0, (uint8_t *) legacymbr, sizeof (*legacymbr)); good_pmbr = is_pmbr_valid(legacymbr); free(legacymbr); legacymbr=NULL; } /* Failure due to bad PMBR */ if ((good_pgpt || good_agpt) && !good_pmbr && !force_gpt) { fprintf(stderr, " Warning: Disk has a valid GPT signature " "but invalid PMBR.\n" " Assuming this disk is *not* a GPT disk anymore.\n" " Use gpt kernel option to override. " "Use GNU Parted to correct disk.\n"); goto fail; } /* Would fail due to bad PMBR, but force GPT anyhow */ if ((good_pgpt || good_agpt) && !good_pmbr && force_gpt) { fprintf(stderr, " Warning: Disk has a valid GPT signature but " "invalid PMBR.\n" " Use GNU Parted to correct disk.\n" " gpt option taken, disk treated as GPT.\n"); } compare_gpts(pgpt, agpt, lastlba); /* The good cases */ if (good_pgpt && (good_pmbr || force_gpt)) { *gpt = pgpt; *ptes = pptes; if (agpt) { free(agpt); agpt = NULL; } if (aptes) { free(aptes); aptes = NULL; } if (!good_agpt) { fprintf(stderr, "Alternate GPT is invalid, " "using primary GPT.\n"); } return 1; } else if (good_agpt && (good_pmbr || force_gpt)) { *gpt = agpt; *ptes = aptes; if (pgpt) { free(pgpt); pgpt = NULL; } if (pptes) { free(pptes); pptes = NULL; } fprintf(stderr, "Primary GPT is invalid, using alternate GPT.\n"); return 1; } fail: if (pgpt) { free(pgpt); pgpt=NULL; } if (agpt) { free(agpt); agpt=NULL; } if (pptes) { free(pptes); pptes=NULL; } if (aptes) { free(aptes); aptes=NULL; } *gpt = NULL; *ptes = NULL; return 0; } /** * read_gpt_pt() * @fd * @all - slice with start/size of whole disk * * 0 if this isn't our partition table * number of partitions if successful * */ int read_gpt_pt (int fd, struct slice all, struct slice *sp, int ns) { gpt_header *gpt = NULL; gpt_entry *ptes = NULL; uint32_t i; int n = 0; int last_used_index=-1; if (!find_valid_gpt (fd, &gpt, &ptes) || !gpt || !ptes) { if (gpt) free (gpt); if (ptes) free (ptes); return 0; } for (i = 0; i < __le32_to_cpu(gpt->num_partition_entries) && i < ns; i++) { if (!efi_guidcmp (NULL_GUID, ptes[i].partition_type_guid)) { sp[n].start = 0; sp[n].size = 0; n++; } else { sp[n].start = __le64_to_cpu(ptes[i].starting_lba); sp[n].size = __le64_to_cpu(ptes[i].ending_lba) - __le64_to_cpu(ptes[i].starting_lba) + 1; last_used_index=n; n++; } } free (ptes); free (gpt); return last_used_index+1; }