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/*
* 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;
}
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