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-rw-r--r--libdex/SysUtil.c408
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diff --git a/libdex/SysUtil.c b/libdex/SysUtil.c
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+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * System utilities.
+ */
+#include "DexFile.h"
+#include "SysUtil.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#ifdef HAVE_POSIX_FILEMAP
+# include <sys/mman.h>
+#endif
+#include <limits.h>
+#include <errno.h>
+
+#include <JNIHelp.h> // TEMP_FAILURE_RETRY may or may not be in unistd
+
+
+/*
+ * Create an anonymous shared memory segment large enough to hold "length"
+ * bytes. The actual segment may be larger because mmap() operates on
+ * page boundaries (usually 4K).
+ */
+static void* sysCreateAnonShmem(size_t length)
+{
+#ifdef HAVE_POSIX_FILEMAP
+ void* ptr;
+
+ ptr = mmap(NULL, length, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_ANON, -1, 0);
+ if (ptr == MAP_FAILED) {
+ LOGW("mmap(%d, RW, SHARED|ANON) failed: %s\n", (int) length,
+ strerror(errno));
+ return NULL;
+ }
+
+ return ptr;
+#else
+ LOGE("sysCreateAnonShmem not implemented.\n");
+ return NULL;
+#endif
+}
+
+/*
+ * Create a private anonymous storage area.
+ */
+int sysCreatePrivateMap(size_t length, MemMapping* pMap)
+{
+ void* memPtr;
+
+ memPtr = sysCreateAnonShmem(length);
+ if (memPtr == NULL)
+ return -1;
+
+ pMap->addr = pMap->baseAddr = memPtr;
+ pMap->length = pMap->baseLength = length;
+ return 0;
+}
+
+/*
+ * Determine the current offset and remaining length of the open file.
+ */
+static int getFileStartAndLength(int fd, off_t *start_, size_t *length_)
+{
+ off_t start, end;
+ size_t length;
+
+ assert(start_ != NULL);
+ assert(length_ != NULL);
+
+ start = lseek(fd, 0L, SEEK_CUR);
+ end = lseek(fd, 0L, SEEK_END);
+ (void) lseek(fd, start, SEEK_SET);
+
+ if (start == (off_t) -1 || end == (off_t) -1) {
+ LOGE("could not determine length of file\n");
+ return -1;
+ }
+
+ length = end - start;
+ if (length == 0) {
+ LOGE("file is empty\n");
+ return -1;
+ }
+
+ *start_ = start;
+ *length_ = length;
+
+ return 0;
+}
+
+/*
+ * Pull the contents of a file into an new shared memory segment. We grab
+ * everything from fd's current offset on.
+ *
+ * We need to know the length ahead of time so we can allocate a segment
+ * of sufficient size.
+ */
+int sysLoadFileInShmem(int fd, MemMapping* pMap)
+{
+#ifdef HAVE_POSIX_FILEMAP
+ off_t start;
+ size_t length, actual;
+ void* memPtr;
+
+ assert(pMap != NULL);
+
+ if (getFileStartAndLength(fd, &start, &length) < 0)
+ return -1;
+
+ memPtr = sysCreateAnonShmem(length);
+ if (memPtr == NULL)
+ return -1;
+
+ actual = read(fd, memPtr, length);
+ if (actual != length) {
+ LOGE("only read %d of %d bytes\n", (int) actual, (int) length);
+ sysReleaseShmem(pMap);
+ return -1;
+ }
+
+ pMap->baseAddr = pMap->addr = memPtr;
+ pMap->baseLength = pMap->length = length;
+
+ return 0;
+#else
+ LOGE("sysLoadFileInShmem not implemented.\n");
+ return -1;
+#endif
+}
+
+#ifndef HAVE_POSIX_FILEMAP
+int sysFakeMapFile(int fd, MemMapping* pMap)
+{
+ /* No MMAP, just fake it by copying the bits.
+ For Win32 we could use MapViewOfFile if really necessary
+ (see libs/utils/FileMap.cpp).
+ */
+ off_t start;
+ size_t length;
+ void* memPtr;
+
+ assert(pMap != NULL);
+
+ if (getFileStartAndLength(fd, &start, &length) < 0)
+ return -1;
+
+ memPtr = malloc(length);
+ if (read(fd, memPtr, length) < 0) {
+ LOGW("read(fd=%d, start=%d, length=%d) failed: %s\n", (int) length,
+ fd, (int) start, strerror(errno));
+ return -1;
+ }
+
+ pMap->baseAddr = pMap->addr = memPtr;
+ pMap->baseLength = pMap->length = length;
+
+ return 0;
+}
+#endif
+
+/*
+ * Map a file (from fd's current offset) into a shared, read-only memory
+ * segment. The file offset must be a multiple of the system page size.
+ *
+ * On success, returns 0 and fills out "pMap". On failure, returns a nonzero
+ * value and does not disturb "pMap".
+ */
+int sysMapFileInShmemReadOnly(int fd, MemMapping* pMap)
+{
+#ifdef HAVE_POSIX_FILEMAP
+ off_t start;
+ size_t length;
+ void* memPtr;
+
+ assert(pMap != NULL);
+
+ if (getFileStartAndLength(fd, &start, &length) < 0)
+ return -1;
+
+ memPtr = mmap(NULL, length, PROT_READ, MAP_FILE | MAP_SHARED, fd, start);
+ if (memPtr == MAP_FAILED) {
+ LOGW("mmap(%d, RO, FILE|SHARED, %d, %d) failed: %s\n", (int) length,
+ fd, (int) start, strerror(errno));
+ return -1;
+ }
+
+ pMap->baseAddr = pMap->addr = memPtr;
+ pMap->baseLength = pMap->length = length;
+
+ return 0;
+#else
+ return sysFakeMapFile(fd, pMap);
+#endif
+}
+
+/*
+ * Map a file (from fd's current offset) into a private, read-write memory
+ * segment that will be marked read-only (a/k/a "writable read-only"). The
+ * file offset must be a multiple of the system page size.
+ *
+ * In some cases the mapping will be fully writable (e.g. for files on
+ * FAT filesystems).
+ *
+ * On success, returns 0 and fills out "pMap". On failure, returns a nonzero
+ * value and does not disturb "pMap".
+ */
+int sysMapFileInShmemWritableReadOnly(int fd, MemMapping* pMap)
+{
+#ifdef HAVE_POSIX_FILEMAP
+ off_t start;
+ size_t length;
+ void* memPtr;
+
+ assert(pMap != NULL);
+
+ if (getFileStartAndLength(fd, &start, &length) < 0)
+ return -1;
+
+ memPtr = mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_FILE | MAP_PRIVATE,
+ fd, start);
+ if (memPtr == MAP_FAILED) {
+ LOGW("mmap(%d, R/W, FILE|PRIVATE, %d, %d) failed: %s\n", (int) length,
+ fd, (int) start, strerror(errno));
+ return -1;
+ }
+ if (mprotect(memPtr, length, PROT_READ) < 0) {
+ /* this fails with EACCESS on FAT filesystems, e.g. /sdcard */
+ int err = errno;
+ LOGV("mprotect(%p, %d, PROT_READ) failed: %s\n",
+ memPtr, length, strerror(err));
+ LOGD("mprotect(RO) failed (%d), file will remain read-write\n", err);
+ }
+
+ pMap->baseAddr = pMap->addr = memPtr;
+ pMap->baseLength = pMap->length = length;
+
+ return 0;
+#else
+ return sysFakeMapFile(fd, pMap);
+#endif
+}
+
+/*
+ * Map part of a file into a shared, read-only memory segment. The "start"
+ * offset is absolute, not relative.
+ *
+ * On success, returns 0 and fills out "pMap". On failure, returns a nonzero
+ * value and does not disturb "pMap".
+ */
+int sysMapFileSegmentInShmem(int fd, off_t start, size_t length,
+ MemMapping* pMap)
+{
+#ifdef HAVE_POSIX_FILEMAP
+ size_t actualLength;
+ off_t actualStart;
+ int adjust;
+ void* memPtr;
+
+ assert(pMap != NULL);
+
+ /* adjust to be page-aligned */
+ adjust = start % SYSTEM_PAGE_SIZE;
+ actualStart = start - adjust;
+ actualLength = length + adjust;
+
+ memPtr = mmap(NULL, actualLength, PROT_READ, MAP_FILE | MAP_SHARED,
+ fd, actualStart);
+ if (memPtr == MAP_FAILED) {
+ LOGW("mmap(%d, R, FILE|SHARED, %d, %d) failed: %s\n",
+ (int) actualLength, fd, (int) actualStart, strerror(errno));
+ return -1;
+ }
+
+ pMap->baseAddr = memPtr;
+ pMap->baseLength = actualLength;
+ pMap->addr = (char*)memPtr + adjust;
+ pMap->length = length;
+
+ LOGVV("mmap seg (st=%d ln=%d): bp=%p bl=%d ad=%p ln=%d\n",
+ (int) start, (int) length,
+ pMap->baseAddr, (int) pMap->baseLength,
+ pMap->addr, (int) pMap->length);
+
+ return 0;
+#else
+ LOGE("sysMapFileSegmentInShmem not implemented.\n");
+ return -1;
+#endif
+}
+
+/*
+ * Change the access rights on one or more pages to read-only or read-write.
+ *
+ * Returns 0 on success.
+ */
+int sysChangeMapAccess(void* addr, size_t length, int wantReadWrite,
+ MemMapping* pMap)
+{
+#ifdef HAVE_POSIX_FILEMAP
+ /*
+ * Verify that "addr" is part of this mapping file.
+ */
+ if (addr < pMap->baseAddr ||
+ (u1*)addr >= (u1*)pMap->baseAddr + pMap->baseLength)
+ {
+ LOGE("Attempted to change %p; map is %p - %p\n",
+ addr, pMap->baseAddr, (u1*)pMap->baseAddr + pMap->baseLength);
+ return -1;
+ }
+
+ /*
+ * Align "addr" to a page boundary and adjust "length" appropriately.
+ * (The address must be page-aligned, the length doesn't need to be,
+ * but we do need to ensure we cover the same range.)
+ */
+ u1* alignAddr = (u1*) ((int) addr & ~(SYSTEM_PAGE_SIZE-1));
+ size_t alignLength = length + ((u1*) addr - alignAddr);
+
+ //LOGI("%p/%zd --> %p/%zd\n", addr, length, alignAddr, alignLength);
+ int prot = wantReadWrite ? (PROT_READ|PROT_WRITE) : (PROT_READ);
+ if (mprotect(alignAddr, alignLength, prot) != 0) {
+ int err = errno;
+ LOGV("mprotect (%p,%zd,%d) failed: %s\n",
+ alignAddr, alignLength, prot, strerror(errno));
+ return (errno != 0) ? errno : -1;
+ }
+#endif
+
+ /* for "fake" mapping, no need to do anything */
+ return 0;
+}
+
+/*
+ * Release a memory mapping.
+ */
+void sysReleaseShmem(MemMapping* pMap)
+{
+#ifdef HAVE_POSIX_FILEMAP
+ if (pMap->baseAddr == NULL && pMap->baseLength == 0)
+ return;
+
+ if (munmap(pMap->baseAddr, pMap->baseLength) < 0) {
+ LOGW("munmap(%p, %d) failed: %s\n",
+ pMap->baseAddr, (int)pMap->baseLength, strerror(errno));
+ } else {
+ LOGV("munmap(%p, %d) succeeded\n", pMap->baseAddr, pMap->baseLength);
+ pMap->baseAddr = NULL;
+ pMap->baseLength = 0;
+ }
+#else
+ /* Free the bits allocated by sysMapFileInShmem. */
+ if (pMap->baseAddr != NULL) {
+ free(pMap->baseAddr);
+ pMap->baseAddr = NULL;
+ }
+ pMap->baseLength = 0;
+#endif
+}
+
+/*
+ * Make a copy of a MemMapping.
+ */
+void sysCopyMap(MemMapping* dst, const MemMapping* src)
+{
+ memcpy(dst, src, sizeof(MemMapping));
+}
+
+/*
+ * Write until all bytes have been written.
+ *
+ * Returns 0 on success, or an errno value on failure.
+ */
+int sysWriteFully(int fd, const void* buf, size_t count, const char* logMsg)
+{
+ while (count != 0) {
+ ssize_t actual = TEMP_FAILURE_RETRY(write(fd, buf, count));
+ if (actual < 0) {
+ int err = errno;
+ LOGE("%s: write failed: %s\n", logMsg, strerror(err));
+ return err;
+ } else if (actual != (ssize_t) count) {
+ LOGD("%s: partial write (will retry): (%d of %zd)\n",
+ logMsg, (int) actual, count);
+ buf = (const void*) (((const u1*) buf) + actual);
+ }
+ count -= actual;
+ }
+
+ return 0;
+}