1 /*
2 * Copyright (c) 2015, 2025, Oracle and/or its affiliates. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * - Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * - Neither the name of Oracle nor the names of its
16 * contributors may be used to endorse or promote products derived
17 * from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
20 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <string.h>
33
34 #include "jimage.hpp"
35
36 #include "imageFile.hpp"
37
38 #include "jni_util.h"
39
40 /*
41 * Declare jimage library specific JNI_Onload entry for static build.
42 */
43 extern "C" {
44 DEF_STATIC_JNI_OnLoad
45 }
46
47 /*
48 * JImageOpen - Given the supplied full path file name, open an image file. This
49 * function will also initialize tables and retrieve meta-data necessary to
50 * satisfy other functions in the API. If the image file has been previously
51 * open, a new open request will share memory and resources used by the previous
52 * open. A call to JImageOpen should be balanced by a call to JImageClose, to
53 * release memory and resources used. If the image file is not found or cannot
54 * be open, then NULL is returned and error will contain a reason for the
55 * failure; a positive value for a system error number, negative for a jimage
56 * specific error (see JImage Error Codes.)
57 *
58 * Ex.
59 * jint error;
60 * JImageFile* jimage = (*JImageOpen)(JAVA_HOME "lib/modules", &error);
61 * if (image == NULL) {
62 * tty->print_cr("JImage failed to open: %d", error);
63 * ...
64 * }
65 * ...
66 */
67 extern "C" JNIEXPORT JImageFile*
68 JIMAGE_Open(const char *name, jint* error) {
69 // TODO - return a meaningful error code
70 *error = 0;
71 ImageFileReader* jfile = ImageFileReader::open(name);
72 return (JImageFile*) jfile;
73 }
74
75 /*
76 * JImageClose - Given the supplied open image file (see JImageOpen), release
77 * memory and resources used by the open file and close the file. If the image
78 * file is shared by other uses, release and close is deferred until the last use
79 * is also closed.
80 *
81 * Ex.
82 * (*JImageClose)(image);
83 */
84 extern "C" JNIEXPORT void
85 JIMAGE_Close(JImageFile* image) {
86 ImageFileReader::close((ImageFileReader*) image);
87 }
88
89 /*
90 * JImageFindResource - Given an open image file (see JImageOpen), a module
91 * name, a version string and the name of a class/resource, return location
92 * information describing the resource and its size. If no resource is found, the
93 * function returns JIMAGE_NOT_FOUND and the value of size is undefined.
94 * The resulting location does/should not have to be released.
95 * All strings are utf-8, zero byte terminated.
96 *
97 * Ex.
98 * jlong size;
99 * JImageLocationRef location = (*JImageFindResource)(image,
100 * "java.base", "java/lang/String.class", is_preview_mode, &size);
101 */
102 extern "C" JNIEXPORT JImageLocationRef
103 JIMAGE_FindResource(JImageFile* image,
104 const char* module_name, const char* name, bool is_preview_mode,
105 jlong* size) {
106 static const char str_modules[] = "modules";
107 static const char str_packages[] = "packages";
108 static const char preview_infix[] = "/META-INF/preview";
109
110 size_t module_name_len = strlen(module_name);
111 size_t name_len = strlen(name);
112 size_t preview_infix_len = strlen(preview_infix);
113
114 // TBD: assert(module_name_len > 0, "module name must be non-empty");
115 assert(name_len > 0 && "resource name must be non-empty");
116
117 // Do not attempt to lookup anything of the form /modules/... or /packages/...
118 if (strncmp(module_name, str_modules, sizeof(str_modules)) == 0
119 || strncmp(module_name, str_packages, sizeof(str_packages)) == 0) {
120 return 0L;
121 }
122 // If the preview mode version of the path string is too long for the buffer,
123 // return not found (even when not in preview mode).
124 if (1 + module_name_len + preview_infix_len + 1 + name_len + 1 > IMAGE_MAX_PATH) {
125 return 0L;
126 }
127
128 // Concatenate to get full path
129 char name_buffer[IMAGE_MAX_PATH];
130 char* path;
131 { // Write the buffer with room to prepend the preview mode infix
132 // at the start (saves copying the trailing name part twice).
133 size_t index = preview_infix_len;
134 name_buffer[index++] = '/';
135 memcpy(&name_buffer[index], module_name, module_name_len);
136 index += module_name_len;
137 name_buffer[index++] = '/';
138 memcpy(&name_buffer[index], name, name_len);
139 index += name_len;
140 name_buffer[index++] = '\0';
141 // Path begins at the leading '/' (not the start of the buffer).
142 path = &name_buffer[preview_infix_len];
143 }
144
145 // find_location_index() returns the data "offset", not an index.
146 const ImageFileReader* image_file = (ImageFileReader*) image;
147 u4 locOffset = image_file->find_location_index(path, (u8*) size);
148 if (locOffset != 0) {
149 ImageLocation loc;
150 loc.set_data(image_file->get_location_offset_data(locOffset));
151
152 u4 flags = loc.get_preview_flags();
153 // No preview flags means "a normal resource, without a preview version".
154 // This is the overwhelmingly common case, with or without preview mode.
155 if (flags == 0) {
156 return locOffset;
157 }
158 // Regardless of preview mode, don't return resources requested directly
159 // via their preview path.
160 if ((flags & ImageLocation::FLAGS_IS_PREVIEW_VERSION) != 0) {
161 return 0L;
162 }
163 // Even if there is a preview version, we might not want to return it.
164 if (!is_preview_mode || (flags & ImageLocation::FLAGS_HAS_PREVIEW_VERSION) == 0) {
165 return locOffset;
166 }
167 } else if (!is_preview_mode) {
168 // No normal resource found, and not in preview mode.
169 return 0L;
170 }
171
172 // We are in preview mode, and the preview version of the resource is needed.
173 // This is either because:
174 // 1. The normal resource was flagged as having a preview version (rare)
175 // 2. This is a preview-only resource (there was no normal resource, very rare)
176 // 3. The requested resource doesn't exist (this should typically not happen)
177 //
178 // Since we only expect requests for resources which exist in jimage files, we
179 // expect this 2nd lookup to succeed (this is contrary to the expectations for
180 // the JRT file system, where non-existent resource lookups are common).
181
182 { // Rewrite the front of the name buffer to make it a preview path.
183 size_t index = 0;
184 name_buffer[index++] = '/';
185 memcpy(&name_buffer[index], module_name, module_name_len);
186 index += module_name_len;
187 memcpy(&name_buffer[index], preview_infix, preview_infix_len);
188 index += preview_infix_len;
189 // Check we copied up to the expected '/' separator.
190 assert(name_buffer[index] == '/' && "bad string concatenation");
191 // The preview path now begins at the start of the buffer.
192 path = &name_buffer[0];
193 }
194 return image_file->find_location_index(path, (u8*) size);
195 }
196
197 /*
198 * JImageGetResource - Given an open image file (see JImageOpen), a resource's
199 * location information (see JImageFindResource), a buffer of appropriate
200 * size and the size, retrieve the bytes associated with the
201 * resource. If the size is less than the resource size then the read is truncated.
202 * If the size is greater than the resource size then the remainder of the buffer
203 * is zero filled. The function will return the actual size of the resource.
204 *
205 * Ex.
206 * jlong size;
207 * JImageLocationRef location = (*JImageFindResource)(image,
208 * "java.base", "9.0", "java/lang/String.class", &size);
209 * char* buffer = new char[size];
210 * (*JImageGetResource)(image, location, buffer, size);
211 */
212 extern "C" JNIEXPORT jlong
213 JIMAGE_GetResource(JImageFile* image, JImageLocationRef location,
214 char* buffer, jlong size) {
215 ((ImageFileReader*) image)->get_resource((u4) location, (u1*) buffer);
216 return size;
217 }
218
219 /*
220 * JImageResourceIterator - Given an open image file (see JImageOpen), a visitor
221 * function and a visitor argument, iterator through each of the image's resources.
222 * The visitor function is called with the image file, the module name, the
223 * package name, the base name, the extension and the visitor argument. The return
224 * value of the visitor function should be true, unless an early iteration exit is
225 * required. All strings are utf-8, zero byte terminated.file.
226 *
227 * Ex.
228 * bool ctw_visitor(JImageFile* jimage, const char* module_name, const char* version,
229 * const char* package, const char* name, const char* extension, void* arg) {
230 * if (strcmp(extension, "class") == 0) {
231 * char path[JIMAGE_MAX_PATH];
232 * Thread* THREAD = Thread::current();
233 * jio_snprintf(path, JIMAGE_MAX_PATH - 1, "/%s/%s", package, name);
234 * ClassLoader::compile_the_world_in(path, (Handle)arg, THREAD);
235 * return !HAS_PENDING_EXCEPTION;
236 * }
237 * return true;
238 * }
239 * (*JImageResourceIterator)(image, ctw_visitor, loader);
240 */
241 extern "C" JNIEXPORT void
242 JIMAGE_ResourceIterator(JImageFile* image,
243 JImageResourceVisitor_t visitor, void* arg) {
244 ImageFileReader* imageFile = (ImageFileReader*) image;
245 u4 nEntries = imageFile->table_length();
246 const ImageStrings strings = imageFile->get_strings();
247 for (u4 i = 0; i < nEntries; i++) {
248 ImageLocation location(imageFile->get_location_data(i));
249
250 u4 moduleOffset = (u4) location.get_attribute(ImageLocation::ATTRIBUTE_MODULE);
251 if (moduleOffset == 0) {
252 continue; // skip non-modules
253 }
254 const char *module = strings.get(moduleOffset);
255 if (strcmp(module, "modules") == 0
256 || strcmp(module, "packages") == 0) {
257 continue; // always skip
258 }
259
260 u4 parentOffset = (u4) location.get_attribute(ImageLocation::ATTRIBUTE_PARENT);
261 const char *parent = strings.get(parentOffset);
262 u4 baseOffset = (u4) location.get_attribute(ImageLocation::ATTRIBUTE_BASE);
263 const char *base = strings.get(baseOffset);
264 u4 extOffset = (u4) location.get_attribute(ImageLocation::ATTRIBUTE_EXTENSION);
265 const char *extension = strings.get(extOffset);
266
267 if (!(*visitor)(image, module, "9", parent, base, extension, arg)) {
268 break;
269 }
270 }
271 }