1 files changed, 265 insertions, 0 deletions
diff --git a/minzip/SysUtil.c b/minzip/SysUtil.c
new file mode 100644
index 000000000..9c3575b9c
--- /dev/null
+++ b/minzip/SysUtil.c
@@ -0,0 +1,265 @@
+/*
+ * 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>
+
+#define LOG_TAG "sysutil"
+#include "Log.h"
+#include "SysUtil.h"
+
+static int getFileStartAndLength(int fd, loff_t *start_, size_t *length_)
+{
+    loff_t start, end;
+    size_t length;
+
+    assert(start_ != NULL);
+    assert(length_ != NULL);
+
+    // TODO: isn't start always 0 for the single call site? just use fstat instead?
+
+    start = TEMP_FAILURE_RETRY(lseek64(fd, 0L, SEEK_CUR));
+    end = TEMP_FAILURE_RETRY(lseek64(fd, 0L, SEEK_END));
+
+    if (TEMP_FAILURE_RETRY(lseek64(fd, start, SEEK_SET)) == -1 ||
+                start == (loff_t) -1 || end == (loff_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;
+}
+
+/*
+ * Map a file (from fd's current offset) into a private, read-only memory
+ * segment.  The file offset must be a multiple of the page size.
+ *
+ * On success, returns 0 and fills out "pMap".  On failure, returns a nonzero
+ * value and does not disturb "pMap".
+ */
+static bool sysMapFD(int fd, MemMapping* pMap) {
+    loff_t start;
+    size_t length;
+    void* memPtr;
+
+    assert(pMap != NULL);
+
+    if (getFileStartAndLength(fd, &start, &length) < 0)
+        return -1;
+
+#if (PLATFORM_SDK_VERSION >= 21)
+    memPtr = mmap64(NULL, length, PROT_READ, MAP_PRIVATE, fd, start);
+#else
+    // Older versions of Android do not have mmap64 so we will just use mmap instead
+    memPtr = mmap(NULL, length, PROT_READ, MAP_PRIVATE, fd, start);
+#endif
+    if (memPtr == MAP_FAILED) {
+        LOGE("mmap(%d, R, PRIVATE, %d, 0) failed: %s\n", (int) length, fd, strerror(errno));
+        return false;
+    }
+
+    pMap->addr = memPtr;
+    pMap->length = length;
+    pMap->range_count = 1;
+    pMap->ranges = malloc(sizeof(MappedRange));
+    if (pMap->ranges == NULL) {
+        LOGE("malloc failed: %s\n", strerror(errno));
+        munmap(memPtr, length);
+        return false;
+    }
+    pMap->ranges[0].addr = memPtr;
+    pMap->ranges[0].length = length;
+
+    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) {
+        LOGE("failed to read block device from header\n");
+        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) {
+        LOGE("failed to parse block map header\n");
+        return -1;
+    }
+    if (blksize != 0) {
+        blocks = ((size-1) / blksize) + 1;
+    }
+    if (size == 0 || blksize == 0 || blocks > SIZE_MAX / blksize || range_count == 0) {
+        LOGE("invalid data in block map file: size %zu, blksize %u, range_count %u\n",
+             size, blksize, range_count);
+        return -1;
+    }
+
+    pMap->range_count = range_count;
+    pMap->ranges = calloc(range_count, sizeof(MappedRange));
+    if (pMap->ranges == NULL) {
+        LOGE("calloc(%u, %zu) failed: %s\n", range_count, sizeof(MappedRange), strerror(errno));
+        return -1;
+    }
+
+    // Reserve enough contiguous address space for the whole file.
+    unsigned char* reserve;
+#if (PLATFORM_SDK_VERSION >= 21)
+    reserve = mmap64(NULL, blocks * blksize, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
+#else
+    // Older versions of Android do not have mmap64 so we will just use mmap instead
+    reserve = mmap(NULL, blocks * blksize, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
+#endif
+    if (reserve == MAP_FAILED) {
+        LOGE("failed to reserve address space: %s\n", strerror(errno));
+        free(pMap->ranges);
+        return -1;
+    }
+
+    int fd = open(block_dev, O_RDONLY);
+    if (fd < 0) {
+        LOGE("failed to open block device %s: %s\n", block_dev, strerror(errno));
+        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) {
+            LOGE("failed to parse range %d in block map\n", i);
+            success = false;
+            break;
+        }
+        size_t length = (end - start) * blksize;
+        if (end <= start || (end - start) > SIZE_MAX / blksize || length > remaining_size) {
+          LOGE("unexpected range in block map: %zu %zu\n", start, end);
+          success = false;
+          break;
+        }
+#if (PLATFORM_SDK_VERSION >= 21)
+        void* addr = mmap64(next, (end-start)*blksize, PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, ((off64_t)start)*blksize);
+#else
+        // Older versions of Android do not have mmap64 so we will just use mmap instead
+        void* addr = mmap(next, (end-start)*blksize, PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, ((off64_t)start)*blksize);
+#endif
+        if (addr == MAP_FAILED) {
+            LOGE("failed to map block %d: %s\n", i, strerror(errno));
+            success = false;
+            break;
+        }
+        pMap->ranges[i].addr = addr;
+        pMap->ranges[i].length = length;
+
+        next += length;
+        remaining_size -= length;
+    }
+    if (success && remaining_size != 0) {
+      LOGE("ranges in block map are invalid: remaining_size = %zu\n", 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;
+
+    LOGI("mmapped %d ranges\n", range_count);
+
+    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) {
+            LOGE("Unable to open '%s': %s\n", fn+1, strerror(errno));
+            return -1;
+        }
+
+        if (sysMapBlockFile(mapf, pMap) != 0) {
+            LOGE("Map of '%s' failed\n", fn);
+            fclose(mapf);
+            return -1;
+        }
+
+        fclose(mapf);
+    } else {
+        // This is a regular file.
+        int fd = open(fn, O_RDONLY);
+        if (fd == -1) {
+            LOGE("Unable to open '%s': %s\n", fn, strerror(errno));
+            return -1;
+        }
+
+        if (!sysMapFD(fd, pMap)) {
+            LOGE("Map of '%s' failed\n", fn);
+            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) {
+            LOGE("munmap(%p, %d) failed: %s\n",
+                 pMap->ranges[i].addr, (int)pMap->ranges[i].length, strerror(errno));
+        }
+    }
+    free(pMap->ranges);
+    pMap->ranges = NULL;
+    pMap->range_count = 0;
+}