1 /*
2 * Copyright (C) 2015 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 #include "linker_utils.h"
18 #include "linker_debug.h"
19
normalize_path(const char * path,std::string * normalized_path)20 bool normalize_path(const char* path, std::string* normalized_path) {
21 // Input should be an absolute path
22 if (path[0] != '/') {
23 PRINT("normalize_path - invalid input: \"%s\", the input path should be absolute", path);
24 return false;
25 }
26
27 const size_t len = strlen(path) + 1;
28 char buf[len];
29
30 const char* in_ptr = path;
31 char* out_ptr = buf;
32
33 while (*in_ptr != 0) {
34 if (*in_ptr == '/') {
35 char c1 = in_ptr[1];
36 if (c1 == '.') {
37 char c2 = in_ptr[2];
38 if (c2 == '/') {
39 in_ptr += 2;
40 continue;
41 } else if (c2 == '.' && (in_ptr[3] == '/' || in_ptr[3] == 0)) {
42 in_ptr += 3;
43 while (out_ptr > buf && *--out_ptr != '/') {
44 }
45 if (in_ptr[0] == 0) {
46 // retain '/'
47 out_ptr++;
48 }
49 continue;
50 }
51 } else if (c1 == '/') {
52 ++in_ptr;
53 continue;
54 }
55 }
56 *out_ptr++ = *in_ptr++;
57 }
58
59 *out_ptr = 0;
60 *normalized_path = buf;
61 return true;
62 }
63
file_is_in_dir(const std::string & file,const std::string & dir)64 bool file_is_in_dir(const std::string& file, const std::string& dir) {
65 const char* needle = dir.c_str();
66 const char* haystack = file.c_str();
67 size_t needle_len = strlen(needle);
68
69 return strncmp(haystack, needle, needle_len) == 0 &&
70 haystack[needle_len] == '/' &&
71 strchr(haystack + needle_len + 1, '/') == nullptr;
72 }
73
file_is_under_dir(const std::string & file,const std::string & dir)74 bool file_is_under_dir(const std::string& file, const std::string& dir) {
75 const char* needle = dir.c_str();
76 const char* haystack = file.c_str();
77 size_t needle_len = strlen(needle);
78
79 return strncmp(haystack, needle, needle_len) == 0 &&
80 haystack[needle_len] == '/';
81 }
82
83 const char* const kZipFileSeparator = "!/";
84
parse_zip_path(const char * input_path,std::string * zip_path,std::string * entry_path)85 bool parse_zip_path(const char* input_path, std::string* zip_path, std::string* entry_path) {
86 std::string normalized_path;
87 if (!normalize_path(input_path, &normalized_path)) {
88 return false;
89 }
90
91 const char* const path = normalized_path.c_str();
92 TRACE("Trying zip file open from path \"%s\" -> normalized \"%s\"", input_path, path);
93
94 // Treat an '!/' separator inside a path as the separator between the name
95 // of the zip file on disk and the subdirectory to search within it.
96 // For example, if path is "foo.zip!/bar/bas/x.so", then we search for
97 // "bar/bas/x.so" within "foo.zip".
98 const char* const separator = strstr(path, kZipFileSeparator);
99 if (separator == nullptr) {
100 return false;
101 }
102
103 char buf[512];
104 if (strlcpy(buf, path, sizeof(buf)) >= sizeof(buf)) {
105 PRINT("Warning: ignoring very long library path: %s", path);
106 return false;
107 }
108
109 buf[separator - path] = '\0';
110
111 *zip_path = buf;
112 *entry_path = &buf[separator - path + 2];
113
114 return true;
115 }
116
117 constexpr off64_t kPageMask = ~static_cast<off64_t>(PAGE_SIZE-1);
118
page_start(off64_t offset)119 off64_t page_start(off64_t offset) {
120 return offset & kPageMask;
121 }
122
safe_add(off64_t * out,off64_t a,size_t b)123 bool safe_add(off64_t* out, off64_t a, size_t b) {
124 CHECK(a >= 0);
125 if (static_cast<uint64_t>(INT64_MAX - a) < b) {
126 return false;
127 }
128
129 *out = a + b;
130 return true;
131 }
132
page_offset(off64_t offset)133 size_t page_offset(off64_t offset) {
134 return static_cast<size_t>(offset & (PAGE_SIZE-1));
135 }
136
137