diff options
Diffstat (limited to 'otautil/SysUtil.cpp')
| -rw-r--r-- | otautil/SysUtil.cpp | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/otautil/SysUtil.cpp b/otautil/SysUtil.cpp new file mode 100644 index 000000000..2936c5ca4 --- /dev/null +++ b/otautil/SysUtil.cpp @@ -0,0 +1,212 @@ +/* + * Copyright 2006 The Android Open Source Project + * + * System utilities. + */ +#include <assert.h> +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> + +#include <android-base/logging.h> + +#include "SysUtil.h" + +static bool sysMapFD(int fd, MemMapping* pMap) { + assert(pMap != NULL); + + struct stat sb; + if (fstat(fd, &sb) == -1) { + PLOG(ERROR) << "fstat(" << fd << ") failed"; + return false; + } + + void* memPtr = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0); + if (memPtr == MAP_FAILED) { + PLOG(ERROR) << "mmap(" << sb.st_size << ", R, PRIVATE, " << fd << ", 0) failed"; + return false; + } + + pMap->addr = reinterpret_cast<unsigned char*>(memPtr); + pMap->length = sb.st_size; + pMap->range_count = 1; + pMap->ranges = reinterpret_cast<MappedRange*>(malloc(sizeof(MappedRange))); + if (pMap->ranges == NULL) { + PLOG(ERROR) << "malloc failed"; + munmap(memPtr, sb.st_size); + return false; + } + pMap->ranges[0].addr = memPtr; + pMap->ranges[0].length = sb.st_size; + + return true; +} + +static int sysMapBlockFile(FILE* mapf, MemMapping* pMap) +{ + char block_dev[PATH_MAX+1]; + size_t size; + unsigned int blksize; + size_t blocks; + unsigned int range_count; + unsigned int i; + + if (fgets(block_dev, sizeof(block_dev), mapf) == NULL) { + PLOG(ERROR) << "failed to read block device from header"; + return -1; + } + for (i = 0; i < sizeof(block_dev); ++i) { + if (block_dev[i] == '\n') { + block_dev[i] = 0; + break; + } + } + + if (fscanf(mapf, "%zu %u\n%u\n", &size, &blksize, &range_count) != 3) { + LOG(ERROR) << "failed to parse block map header"; + return -1; + } + if (blksize != 0) { + blocks = ((size-1) / blksize) + 1; + } + if (size == 0 || blksize == 0 || blocks > SIZE_MAX / blksize || range_count == 0) { + LOG(ERROR) << "invalid data in block map file: size " << size << ", blksize " << blksize + << ", range_count " << range_count; + return -1; + } + + pMap->range_count = range_count; + pMap->ranges = reinterpret_cast<MappedRange*>(calloc(range_count, sizeof(MappedRange))); + if (pMap->ranges == NULL) { + PLOG(ERROR) << "calloc(" << range_count << ", " << sizeof(MappedRange) << ") failed"; + return -1; + } + + // Reserve enough contiguous address space for the whole file. + unsigned char* reserve = reinterpret_cast<unsigned char*>(mmap64(NULL, blocks * blksize, + PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0)); + if (reserve == MAP_FAILED) { + PLOG(ERROR) << "failed to reserve address space"; + free(pMap->ranges); + return -1; + } + + int fd = open(block_dev, O_RDONLY); + if (fd < 0) { + PLOG(ERROR) << "failed to open block device " << block_dev; + munmap(reserve, blocks * blksize); + free(pMap->ranges); + return -1; + } + + unsigned char* next = reserve; + size_t remaining_size = blocks * blksize; + bool success = true; + for (i = 0; i < range_count; ++i) { + size_t start, end; + if (fscanf(mapf, "%zu %zu\n", &start, &end) != 2) { + LOG(ERROR) << "failed to parse range " << i << " in block map"; + success = false; + break; + } + size_t length = (end - start) * blksize; + if (end <= start || (end - start) > SIZE_MAX / blksize || length > remaining_size) { + LOG(ERROR) << "unexpected range in block map: " << start << " " << end; + success = false; + break; + } + + void* addr = mmap64(next, length, PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, ((off64_t)start)*blksize); + if (addr == MAP_FAILED) { + PLOG(ERROR) << "failed to map block " << i; + success = false; + break; + } + pMap->ranges[i].addr = addr; + pMap->ranges[i].length = length; + + next += length; + remaining_size -= length; + } + if (success && remaining_size != 0) { + LOG(ERROR) << "ranges in block map are invalid: remaining_size = " << remaining_size; + success = false; + } + if (!success) { + close(fd); + munmap(reserve, blocks * blksize); + free(pMap->ranges); + return -1; + } + + close(fd); + pMap->addr = reserve; + pMap->length = size; + + LOG(INFO) << "mmapped " << range_count << " ranges"; + + return 0; +} + +int sysMapFile(const char* fn, MemMapping* pMap) +{ + memset(pMap, 0, sizeof(*pMap)); + + if (fn && fn[0] == '@') { + // A map of blocks + FILE* mapf = fopen(fn+1, "r"); + if (mapf == NULL) { + PLOG(ERROR) << "Unable to open '" << (fn+1) << "'"; + return -1; + } + + if (sysMapBlockFile(mapf, pMap) != 0) { + LOG(ERROR) << "Map of '" << fn << "' failed"; + fclose(mapf); + return -1; + } + + fclose(mapf); + } else { + // This is a regular file. + int fd = open(fn, O_RDONLY); + if (fd == -1) { + PLOG(ERROR) << "Unable to open '" << fn << "'"; + return -1; + } + + if (!sysMapFD(fd, pMap)) { + LOG(ERROR) << "Map of '" << fn << "' failed"; + close(fd); + return -1; + } + + close(fd); + } + return 0; +} + +/* + * Release a memory mapping. + */ +void sysReleaseMap(MemMapping* pMap) +{ + int i; + for (i = 0; i < pMap->range_count; ++i) { + if (munmap(pMap->ranges[i].addr, pMap->ranges[i].length) < 0) { + PLOG(ERROR) << "munmap(" << pMap->ranges[i].addr << ", " << pMap->ranges[i].length + << ") failed"; + } + } + free(pMap->ranges); + pMap->ranges = NULL; + pMap->range_count = 0; +} |