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
35 static const char* kCacheDirectoryName = "dalvik-cache";
36 static 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 */
dexOptGenerateCacheFileName(const char * fileName,const char * subFileName)47 char* 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 ALOGE("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 ALOGV("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 */
dexOptCreateEmptyHeader(int fd)120 int 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 ALOGE("opt header write failed: %s", strerror(errno));
139 return errno;
140 }
141
142 return 0;
143 }
144