1 // Copyright 2014 The Android Open Source Project
2 //
3 // This software is licensed under the terms of the GNU General Public
4 // License version 2, as published by the Free Software Foundation, and
5 // may be copied, distributed, and modified under those terms.
6 //
7 // This program is distributed in the hope that it will be useful,
8 // but WITHOUT ANY WARRANTY; without even the implied warranty of
9 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 // GNU General Public License for more details.
11
12 #include "android/kernel/kernel_utils.h"
13
14 #include "android/base/Log.h"
15 #include "android/base/files/ScopedStdioFile.h"
16 #include "android/base/String.h"
17 #include "android/kernel/kernel_utils_testing.h"
18 #include "android/utils/path.h"
19
20 #include <stdint.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <strings.h>
25
26 #define DEBUG_KERNEL 0
27
28 #define KERNEL_LOG LOG_IF(INFO, DEBUG_KERNEL)
29 #define KERNEL_PLOG PLOG_IF(INFO, DEBUG_KERNEL)
30 #define KERNEL_ERROR LOG_IF(ERROR, DEBUG_KERNEL)
31 #define KERNEL_PERROR PLOG_IF(ERROR, DEBUG_KERNEL)
32
33 using android::base::String;
34
35 namespace {
36
37 #ifndef _WIN32
38 // Helper class to perform launch a command through popen() and call
39 // pclose() on destruction.
40 class ScopedPopenFile {
41 public:
ScopedPopenFile(const char * command)42 ScopedPopenFile(const char* command) {
43 mFile = ::popen(command, "r");
44 }
45
get() const46 FILE* get() const { return mFile; }
47
~ScopedPopenFile()48 ~ScopedPopenFile() {
49 if (mFile) {
50 ::pclose(mFile);
51 }
52 }
53
54 private:
55 FILE* mFile;
56 };
57 #endif // !_WIN32
58
getFileDescription(void * opaque,const char * filePath,String * text)59 bool getFileDescription(void* opaque, const char* filePath, String* text) {
60 if (!filePath) {
61 KERNEL_ERROR << "NULL path parameter";
62 return false;
63 }
64
65 if (!path_exists(filePath)) {
66 KERNEL_ERROR << "Kernel file doesn't exist: " << filePath;
67 return false;
68 }
69
70 #ifdef _WIN32
71 // TODO(digit): Better/portable detection based on libmagic or something.
72 KERNEL_ERROR << "Can't detect kernel version on Windows!";
73 return false;
74 #else
75 // NOTE: Use /usr/bin/file instead of 'file' because the latter can
76 // be broken in certain environments (e.g. some versions of MacPorts).
77 String command("/usr/bin/file ");
78 command += filePath;
79
80 ScopedPopenFile file(command.c_str());
81 if (!file.get()) {
82 KERNEL_PERROR << "Could not launch command: " << command.c_str();
83 return false;
84 }
85
86 String result;
87 const size_t kReserveSize = 256U;
88 result.resize(kReserveSize);
89
90 int ret = ::fread(&result[0], 1, kReserveSize, file.get());
91 if (ret < static_cast<int>(kReserveSize) && ferror(file.get())) {
92 KERNEL_ERROR << "Could not read file command output!?";
93 return false;
94 }
95 result.resize(ret);
96 text->assign(result);
97 return true;
98 #endif
99 }
100
101 android::kernel::GetFileDescriptionFunction* sGetFileDescription =
102 getFileDescription;
103
104 void* sGetFileDescriptionOpaque = NULL;
105
106 } // namespace
107
108 namespace android {
109 namespace kernel {
110
setFileDescriptionFunction(GetFileDescriptionFunction * file_func,void * file_opaque)111 void setFileDescriptionFunction(GetFileDescriptionFunction* file_func,
112 void* file_opaque) {
113 sGetFileDescription = file_func ? file_func : &getFileDescription;
114 sGetFileDescriptionOpaque = file_func ? file_opaque : NULL;
115 }
116
117 } // namespace kernel
118 } // namespace android
119
android_pathProbeKernelType(const char * kernelPath,KernelType * ktype)120 bool android_pathProbeKernelType(const char* kernelPath, KernelType* ktype) {
121 String description;
122
123 if (!sGetFileDescription(sGetFileDescriptionOpaque,
124 kernelPath,
125 &description)) {
126 return false;
127 }
128 const char* bzImage = ::strstr(description.c_str(), "bzImage");
129 if (!bzImage) {
130 KERNEL_ERROR << "Not a compressed Linux kernel image!";
131 return false;
132 }
133 const char* version = ::strstr(bzImage, "version ");
134 if (!version) {
135 KERNEL_ERROR << "Could not determine version!";
136 return false;
137 }
138 version += ::strlen("version ");
139 KERNEL_LOG << "Found kernel version " << version;
140
141 char* end;
142 unsigned long major = ::strtoul(version, &end, 10);
143 if (end == version || *end != '.') {
144 KERNEL_ERROR << "Could not find kernel major version!";
145 return false;
146 }
147 KERNEL_LOG << "Kernel major version: " << major;
148 if (major > 3) {
149 *ktype = KERNEL_TYPE_3_10_OR_ABOVE;
150 } else if (major < 3) {
151 *ktype = KERNEL_TYPE_LEGACY;
152 } else /* major == 3 */ {
153 version = end + 1;
154 unsigned long minor = ::strtoul(version, &end, 10);
155 if (end == version) {
156 KERNEL_ERROR << "Could not find kernel minor version!";
157 return false;
158 }
159 KERNEL_LOG << "Kernel minor version: " << minor;
160
161 *ktype = (minor >= 10)
162 ? KERNEL_TYPE_3_10_OR_ABOVE : KERNEL_TYPE_LEGACY;
163 }
164 return true;
165 }
166
android_kernelSerialDevicePrefix(KernelType ktype)167 const char* android_kernelSerialDevicePrefix(KernelType ktype) {
168 switch (ktype) {
169 case KERNEL_TYPE_LEGACY: return "ttyS";
170 case KERNEL_TYPE_3_10_OR_ABOVE: return "ttyGF";
171 default: return "";
172 }
173 }
174