1 /*
2 * Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_CLASSFILE_SHAREDPATHSMISCINFO_HPP
26 #define SHARE_VM_CLASSFILE_SHAREDPATHSMISCINFO_HPP
27
28 #include "classfile/classLoader.hpp"
29 #include "runtime/os.hpp"
30
31 class outputStream;
32
33 // During dumping time, when processing class paths, we build up the dump-time
34 // classpath. The JAR files that exist are stored in the list ClassLoader::_first_append_entry.
35 // However, we need to store other "misc" information for run-time checking, such as
36 //
37 // + The values of Arguments::get_sysclasspath() used during dumping.
38 //
39 // + The meta-index file(s) used during dumping (incl modification time and size)
40 //
41 // + The class path elements specified during dumping but did not exist --
42 // these elements must also be specified at run time, and they also must not
43 // exist at run time.
44 //
45 // These misc items are stored in a linear buffer in SharedPathsMiscInfo.
46 // The storage format is stream oriented to minimize its size.
47 //
48 // When writing the information to the archive file, SharedPathsMiscInfo is stored in
49 // the archive file header. At run-time, this information is used only during initialization
50 // (accessed using read() instead of mmap()), and is deallocated afterwards to save space.
51 //
52 // The SharedPathsMiscInfo class is used for both creating the the information (during
53 // dumping time) and validation (at run time). Different constructors are used in the
54 // two situations. See below.
55
56 class SharedPathsMiscInfo : public CHeapObj<mtClass> {
57 protected:
58 char* _buf_start;
59 char* _cur_ptr;
60 char* _end_ptr;
61 int _buf_size;
62 bool _allocated; // was _buf_start allocated by me?
63 void ensure_size(size_t needed_bytes);
64 void add_path(const char* path, int type);
65
66 void write(const void* ptr, size_t size);
67 bool read(void* ptr, size_t size);
68
69 protected:
70 static bool fail(const char* msg, const char* name = NULL);
71 virtual bool check(jint type, const char* path);
72
73 public:
74 enum {
75 INITIAL_BUF_SIZE = 128
76 };
77 // This constructor is used when creating the misc information (during dump)
78 SharedPathsMiscInfo() {
79 _buf_size = INITIAL_BUF_SIZE;
80 _cur_ptr = _buf_start = NEW_C_HEAP_ARRAY(char, _buf_size, mtClass);
81 _allocated = true;
82 }
83 // This constructor is used when validating the misc info (during run time)
84 SharedPathsMiscInfo(char *buff, int size) {
85 _cur_ptr = _buf_start = buff;
86 _end_ptr = _buf_start + size;
87 _buf_size = size;
88 _allocated = false;
89 }
90 ~SharedPathsMiscInfo() {
91 if (_allocated) {
92 FREE_C_HEAP_ARRAY(char, _buf_start);
93 }
94 }
95 int get_used_bytes() {
96 return _cur_ptr - _buf_start;
97 }
98 void* buffer() {
99 return _buf_start;
100 }
101
102 // writing --
103
104 // The path must not exist at run-time
105 void add_nonexist_path(const char* path) {
106 add_path(path, NON_EXIST);
107 }
108
109 // The path must exist, and must contain exactly <num_entries> files/dirs
110 void add_boot_classpath(const char* path) {
111 add_path(path, BOOT);
112 }
113 int write_jint(jint num) {
114 write(&num, sizeof(num));
115 return 0;
116 }
117 void write_time(time_t t) {
118 write(&t, sizeof(t));
119 }
120 void write_long(long l) {
121 write(&l, sizeof(l));
122 }
123
124 bool dump_to_file(int fd) {
125 int n = get_used_bytes();
126 return (os::write(fd, _buf_start, n) == (size_t)n);
127 }
128
129 // reading --
130
131 enum {
132 BOOT = 1,
133 NON_EXIST = 2
134 };
135
136 virtual const char* type_name(int type) {
137 switch (type) {
138 case BOOT: return "BOOT";
139 case NON_EXIST: return "NON_EXIST";
140 default: ShouldNotReachHere(); return "?";
141 }
142 }
143
144 virtual void print_path(outputStream* os, int type, const char* path);
145
146 bool check();
147 bool read_jint(jint *ptr) {
148 return read(ptr, sizeof(jint));
149 }
150 bool read_long(long *ptr) {
151 return read(ptr, sizeof(long));
152 }
153 bool read_time(time_t *ptr) {
154 return read(ptr, sizeof(time_t));
155 }
156 };
157
158 #endif // SHARE_VM_CLASSFILE_SHAREDPATHSMISCINFO_HPP