1 /*
2 * Copyright (C) 2019 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 <procinfo/process_map.h>
18
19 #include <fcntl.h>
20 #include <string.h>
21 #include <unistd.h>
22
23 #include <procinfo/process.h>
24
25 namespace android {
26 namespace procinfo {
27
ReadMapFileAsyncSafe(const char * map_file,void * buffer,size_t buffer_size,const std::function<void (uint64_t,uint64_t,uint16_t,uint64_t,ino_t,const char *)> & callback)28 bool ReadMapFileAsyncSafe(const char* map_file, void* buffer, size_t buffer_size,
29 const std::function<void(uint64_t, uint64_t, uint16_t, uint64_t, ino_t,
30 const char*)>& callback) {
31 if (buffer == nullptr || buffer_size == 0) {
32 return false;
33 }
34
35 int fd = open(map_file, O_RDONLY | O_CLOEXEC);
36 if (fd == -1) {
37 return false;
38 }
39
40 char* char_buffer = reinterpret_cast<char*>(buffer);
41 size_t start = 0;
42 size_t read_bytes = 0;
43 char* line = nullptr;
44 bool read_complete = false;
45 while (true) {
46 ssize_t bytes =
47 TEMP_FAILURE_RETRY(read(fd, char_buffer + read_bytes, buffer_size - read_bytes - 1));
48 if (bytes <= 0) {
49 if (read_bytes == 0) {
50 close(fd);
51 return bytes == 0;
52 }
53 // Treat the last piece of data as the last line.
54 char_buffer[start + read_bytes] = '\n';
55 bytes = 1;
56 read_complete = true;
57 }
58 read_bytes += bytes;
59
60 while (read_bytes > 0) {
61 char* newline = reinterpret_cast<char*>(memchr(&char_buffer[start], '\n', read_bytes));
62 if (newline == nullptr) {
63 break;
64 }
65 *newline = '\0';
66 line = &char_buffer[start];
67 start = newline - char_buffer + 1;
68 read_bytes -= newline - line + 1;
69
70 // Ignore the return code, errors are okay.
71 ReadMapFileContent(line, callback);
72 }
73
74 if (read_complete) {
75 close(fd);
76 return true;
77 }
78
79 if (start == 0 && read_bytes == buffer_size - 1) {
80 // The buffer provided is too small to contain this line, give up
81 // and indicate failure.
82 close(fd);
83 return false;
84 }
85
86 // Copy any leftover data to the front of the buffer.
87 if (start > 0) {
88 if (read_bytes > 0) {
89 memmove(char_buffer, &char_buffer[start], read_bytes);
90 }
91 start = 0;
92 }
93 }
94 }
95
96 } /* namespace procinfo */
97 } /* namespace android */
98