/* 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 */ // For TWRP purposes, we'll be opting for version 3 of the GPL #include #include #include #include #include #include #include #include #include #include #include #include "gpt.h" #include "gptcrc32.h" #define BLKGETLASTSECT _IO(0x12,108) /* get last sector of block device */ #define BLKGETSIZE _IO(0x12,96) /* return device size */ #define BLKSSZGET _IO(0x12,104) /* get block device sector size */ #define BLKGETSIZE64 _IOR(0x12,114,uint64_t) /* return device size in bytes (u64 *arg) */ struct blkdev_ioctl_param { unsigned int block; size_t content_length; char * block_contents; }; static inline int efi_guidcmp(efi_guid_t left, efi_guid_t right) { return memcmp(&left, &right, sizeof (efi_guid_t)); } 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; } /** * 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 (gptcrc32(buf, len, ~0L) ^ ~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].os_type == EFI_PMBR_OSTYPE_EFI_GPT) { found = 1; break; } } return (signature && found); } /** * kernel_has_blkgetsize64() * * Returns: 0 on false, 1 on true * True means kernel is 2.4.x, x>=18, or * is 2.5.x, x>4, or * is > 2.5 */ static int kernel_has_blkgetsize64(void) { int major=0, minor=0, patch=0, parsed; int rc; struct utsname u; memset(&u, 0, sizeof(u)); rc = uname(&u); if (rc) return 0; parsed = sscanf(u.release, "%d.%d.%d", &major, &minor, &patch); if (parsed < 3) return 0; if (major > 2) return 1; if (major == 2 && minor > 5) return 1; if (major == 2 && minor == 5 && patch >= 4) return 1; if (major == 2 && minor == 4 && patch >= 18) return 1; return 0; } /************************************************************ * _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) { unsigned long sectors=0; uint64_t bytes=0; int rc; if (kernel_has_blkgetsize64()) { rc = ioctl(filedes, BLKGETSIZE64, &bytes); if (!rc) return bytes / get_sector_size(filedes); } rc = ioctl(filedes, BLKGETSIZE, §ors); if (rc) return 0; return sectors; } /************************************************************ * 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 - 1; } static ssize_t read_lastoddsector(int fd, uint64_t lba __unused, 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; ssize_t bytesread; void *aligned; void *unaligned; if (bytes % sector_size) return EINVAL; unaligned = malloc(bytes+sector_size-1); aligned = (void *) (((unsigned long)unaligned + sector_size - 1) & ~(unsigned long)(sector_size-1)); memset(aligned, 0, bytes); lseek(fd, offset, SEEK_SET); bytesread = read(fd, aligned, bytes); memcpy(buffer, aligned, bytesread); free(unaligned); /* 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 && !(last_lba(fd) & 1) && lba == last_lba(fd)) { 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; } 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)) { fprintf(stderr, "GPT:Primary header LBA != Alt. header alternate_lba\n"); fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n", __le64_to_cpu(pgpt->my_lba), __le64_to_cpu(agpt->alternate_lba)); error_found++; } if (__le64_to_cpu(pgpt->alternate_lba) != __le64_to_cpu(agpt->my_lba)) { fprintf(stderr, "GPT:Primary header alternate_lba != Alt. header my_lba\n"); fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n", __le64_to_cpu(pgpt->alternate_lba), __le64_to_cpu(agpt->my_lba)); error_found++; } if (__le64_to_cpu(pgpt->first_usable_lba) != __le64_to_cpu(agpt->first_usable_lba)) { fprintf(stderr, "GPT:first_usable_lbas don't match.\n"); fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n", __le64_to_cpu(pgpt->first_usable_lba), __le64_to_cpu(agpt->first_usable_lba)); error_found++; } if (__le64_to_cpu(pgpt->last_usable_lba) != __le64_to_cpu(agpt->last_usable_lba)) { fprintf(stderr, "GPT:last_usable_lbas don't match.\n"); fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n", __le64_to_cpu(pgpt->last_usable_lba), __le64_to_cpu(agpt->last_usable_lba)); error_found++; } if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) { fprintf(stderr, "GPT:disk_guids don't match.\n"); error_found++; } if (__le32_to_cpu(pgpt->num_partition_entries) != __le32_to_cpu(agpt->num_partition_entries)) { 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)); error_found++; } if (__le32_to_cpu(pgpt->sizeof_partition_entry) != __le32_to_cpu(agpt->sizeof_partition_entry)) { 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)); error_found++; } if (__le32_to_cpu(pgpt->partition_entry_array_crc32) != __le32_to_cpu(agpt->partition_entry_array_crc32)) { 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)); error_found++; } if (__le64_to_cpu(pgpt->alternate_lba) != lastlba) { fprintf(stderr, "GPT:Primary header thinks Alt. header is not at the end of the disk.\n"); fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n", __le64_to_cpu(pgpt->alternate_lba), lastlba); error_found++; } if (__le64_to_cpu(agpt->my_lba) != lastlba) { fprintf(stderr, "GPT:Alternate GPT header not at the end of the disk.\n"); fprintf(stderr, "GPT:0x%" PRIx64 " != 0x%" PRIx64 "\n", __le64_to_cpu(agpt->my_lba), lastlba); error_found++; } 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) { 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; lastlba = last_lba(fd); 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) { 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) { 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)) { *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)) { *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; } void guid_to_ascii(const char *guid, char *s) { uint32_t p1; uint16_t p2; uint16_t p3; unsigned char p4[8]; memcpy(&p1, guid + 0, 4); memcpy(&p2, guid + 4, 2); memcpy(&p3, guid + 6, 2); memcpy(p4, guid + 8, 8); sprintf(s, "%08x%04x%04x%02x%02x%02x%02x%02x%02x%02x%02x", p1, p2, p3, p4[0], p4[1], p4[2], p4[3], p4[4], p4[5], p4[6], p4[7]); } /************************************************************ * gpt_disk_get_partition_info() * Requires: * - open file descriptor fd * - start, size, signature, mbr_type, signature_type * Modifies: all these * Returns: * 0 on success * non-zero on failure * ************************************************************/ int gpt_disk_get_partition_info(int fd, uint32_t num, char *type, char *part) { gpt_header *gpt = NULL; gpt_entry *ptes = NULL, *p; if (!find_valid_gpt(fd, &gpt, &ptes)) return 1; if (num > 0 && num <= __le32_to_cpu(gpt->num_partition_entries)) { p = &ptes[num - 1]; guid_to_ascii((char*)&p->partition_type_guid, type); guid_to_ascii((char*)&p->unique_partition_guid, part); } else { fprintf (stderr,"partition %d is not valid\n", num); return 1; } return 0; } /* * Overrides for Emacs so that we follow Linus's tabbing style. * Emacs will notice this stuff at the end of the file and automatically * adjust the settings for this buffer only. This must remain at the end * of the file. * --------------------------------------------------------------------------- * Local variables: * c-indent-level: 4 * c-brace-imaginary-offset: 0 * c-brace-offset: -4 * c-argdecl-indent: 4 * c-label-offset: -4 * c-continued-statement-offset: 4 * c-continued-brace-offset: 0 * indent-tabs-mode: nil * tab-width: 8 * End: */