OptInvocation.cpp revision 6f9edbe7d3a83f7741c4d56f9f5be1414ecabc9f 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/*
18 * Utility functions for dealing with optimized dex files.
19 */
20
21#include "vm/DalvikVersion.h"
22
23#include <stdint.h>
24#include <stdlib.h>
25#include <unistd.h>
26#include <fcntl.h>
27#include <string.h>
28#include <sys/stat.h>
29#include <sys/file.h>
30#include <errno.h>
31
32#include "OptInvocation.h"
33#include "DexFile.h"
34
35static const char* kCacheDirectoryName = "dalvik-cache";
36static const char* kClassesDex = "classes.dex";
37
38/*
39 * Given the filename of a .jar or .dex file, construct the DEX file cache
40 * name.
41 *
42 * For a Jar, "subFileName" is the name of the entry (usually "classes.dex").
43 * For a DEX, it may be NULL.
44 *
45 * Returns a newly-allocated string, or NULL on failure.
46 */
47char* dexOptGenerateCacheFileName(const char* fileName, const char* subFileName)
48{
49    char nameBuf[512];
50    char absoluteFile[sizeof(nameBuf)];
51    const size_t kBufLen = sizeof(nameBuf) - 1;
52    const char* dataRoot;
53    char* cp;
54
55    /*
56     * Get the absolute path of the Jar or DEX file.
57     */
58    absoluteFile[0] = '\0';
59    if (fileName[0] != '/') {
60        /*
61         * Generate the absolute path.  This doesn't do everything it
62         * should, e.g. if filename is "./out/whatever" it doesn't crunch
63         * the leading "./" out, but it'll do.
64         */
65        if (getcwd(absoluteFile, kBufLen) == NULL) {
66            LOGE("Can't get CWD while opening jar file");
67            return NULL;
68        }
69        strncat(absoluteFile, "/", kBufLen);
70    }
71    strncat(absoluteFile, fileName, kBufLen);
72
73    /*
74     * Append the name of the Jar file entry, if any.  This is not currently
75     * required, but will be if we start putting more than one DEX file
76     * in a Jar.
77     */
78    if (subFileName != NULL) {
79        strncat(absoluteFile, "/", kBufLen);
80        strncat(absoluteFile, subFileName, kBufLen);
81    }
82
83    /* Turn the path into a flat filename by replacing
84     * any slashes after the first one with '@' characters.
85     */
86    cp = absoluteFile + 1;
87    while (*cp != '\0') {
88        if (*cp == '/') {
89            *cp = '@';
90        }
91        cp++;
92    }
93
94    /* Build the name of the cache directory.
95     */
96    dataRoot = getenv("ANDROID_DATA");
97    if (dataRoot == NULL)
98        dataRoot = "/data";
99    snprintf(nameBuf, kBufLen, "%s/%s", dataRoot, kCacheDirectoryName);
100
101    /* Tack on the file name for the actual cache file path.
102     */
103    strncat(nameBuf, absoluteFile, kBufLen);
104
105    LOGV("Cache file for '%s' '%s' is '%s'", fileName, subFileName, nameBuf);
106    return strdup(nameBuf);
107}
108
109/*
110 * Create a skeletal "opt" header in a new file.  Most of the fields are
111 * initialized to garbage, but we fill in "dexOffset" so others can
112 * see how large the header is.
113 *
114 * "fd" must be positioned at the start of the file.  On return, it will
115 * be positioned just past the header, and the place where the DEX data
116 * should go.
117 *
118 * Returns 0 on success, errno on failure.
119 */
120int dexOptCreateEmptyHeader(int fd)
121{
122    DexOptHeader optHdr;
123    ssize_t actual;
124
125    assert(lseek(fd, 0, SEEK_CUR) == 0);
126
127    /*
128     * The data is only expected to be readable on the current system, so
129     * we just write the structure.  We do need the file offset to be 64-bit
130     * aligned to fulfill a DEX requirement.
131     */
132    assert((sizeof(optHdr) & 0x07) == 0);
133    memset(&optHdr, 0xff, sizeof(optHdr));
134    optHdr.dexOffset = sizeof(optHdr);
135    actual = write(fd, &optHdr, sizeof(optHdr));
136    if (actual != sizeof(optHdr)) {
137        int err = errno ? errno : -1;
138        LOGE("opt header write failed: %s", strerror(errno));
139        return errno;
140    }
141
142    return 0;
143}
144