1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "base/os_compat_android.h" 6 7 #include <asm/unistd.h> 8 #include <errno.h> 9 #include <math.h> 10 #include <sys/stat.h> 11 #include <sys/syscall.h> 12 13 #if !defined(__LP64__) 14 #include <time64.h> 15 #endif 16 17 #include "base/rand_util.h" 18 #include "base/strings/string_piece.h" 19 #include "base/strings/stringprintf.h" 20 21 extern "C" { 22 // There is no futimes() avaiable in Bionic, so we provide our own 23 // implementation until it is there. 24 int futimes(int fd, const struct timeval tv[2]) { 25 if (tv == NULL) 26 return syscall(__NR_utimensat, fd, NULL, NULL, 0); 27 28 if (tv[0].tv_usec < 0 || tv[0].tv_usec >= 1000000 || 29 tv[1].tv_usec < 0 || tv[1].tv_usec >= 1000000) { 30 errno = EINVAL; 31 return -1; 32 } 33 34 // Convert timeval to timespec. 35 struct timespec ts[2]; 36 ts[0].tv_sec = tv[0].tv_sec; 37 ts[0].tv_nsec = tv[0].tv_usec * 1000; 38 ts[1].tv_sec = tv[1].tv_sec; 39 ts[1].tv_nsec = tv[1].tv_usec * 1000; 40 return syscall(__NR_utimensat, fd, NULL, ts, 0); 41 } 42 43 #if !defined(__LP64__) 44 // 32-bit Android has only timegm64() and not timegm(). 45 // We replicate the behaviour of timegm() when the result overflows time_t. 46 time_t timegm(struct tm* const t) { 47 // time_t is signed on Android. 48 static const time_t kTimeMax = ~(1L << (sizeof(time_t) * CHAR_BIT - 1)); 49 static const time_t kTimeMin = (1L << (sizeof(time_t) * CHAR_BIT - 1)); 50 time64_t result = timegm64(t); 51 if (result < kTimeMin || result > kTimeMax) 52 return -1; 53 return result; 54 } 55 #endif 56 57 // The following is only needed when building with GCC 4.6 or higher 58 // (i.e. not with Android GCC 4.4.3, nor with Clang). 59 // 60 // GCC is now capable of optimizing successive calls to sin() and cos() into 61 // a single call to sincos(). This means that source code that looks like: 62 // 63 // double c, s; 64 // c = cos(angle); 65 // s = sin(angle); 66 // 67 // Will generate machine code that looks like: 68 // 69 // double c, s; 70 // sincos(angle, &s, &c); 71 // 72 // Unfortunately, sincos() and friends are not part of the Android libm.so 73 // library provided by the NDK for API level 9. When the optimization kicks 74 // in, it makes the final build fail with a puzzling message (puzzling 75 // because 'sincos' doesn't appear anywhere in the sources!). 76 // 77 // To solve this, we provide our own implementation of the sincos() function 78 // and related friends. Note that we must also explicitely tell GCC to disable 79 // optimizations when generating these. Otherwise, the generated machine code 80 // for each function would simply end up calling itself, resulting in a 81 // runtime crash due to stack overflow. 82 // 83 #if defined(__GNUC__) && !defined(__clang__) && \ 84 !defined(ANDROID_SINCOS_PROVIDED) 85 86 // For the record, Clang does not support the 'optimize' attribute. 87 // In the unlikely event that it begins performing this optimization too, 88 // we'll have to find a different way to achieve this. NOTE: Tested with O1 89 // which still performs the optimization. 90 // 91 #define GCC_NO_OPTIMIZE __attribute__((optimize("O0"))) 92 93 GCC_NO_OPTIMIZE 94 void sincos(double angle, double* s, double *c) { 95 *c = cos(angle); 96 *s = sin(angle); 97 } 98 99 GCC_NO_OPTIMIZE 100 void sincosf(float angle, float* s, float* c) { 101 *c = cosf(angle); 102 *s = sinf(angle); 103 } 104 105 #endif // __GNUC__ && !__clang__ 106 107 // An implementation of mkdtemp, since it is not exposed by the NDK 108 // for native API level 9 that we target. 109 // 110 // For any changes in the mkdtemp function, you should manually run the unittest 111 // OsCompatAndroidTest.DISABLED_TestMkdTemp in your local machine to check if it 112 // passes. Please don't enable it, since it creates a directory and may be 113 // source of flakyness. 114 char* mkdtemp(char* path) { 115 if (path == NULL) { 116 errno = EINVAL; 117 return NULL; 118 } 119 120 const int path_len = strlen(path); 121 122 // The last six characters of 'path' must be XXXXXX. 123 const base::StringPiece kSuffix("XXXXXX"); 124 const int kSuffixLen = kSuffix.length(); 125 if (!base::StringPiece(path, path_len).ends_with(kSuffix)) { 126 errno = EINVAL; 127 return NULL; 128 } 129 130 // If the path contains a directory, as in /tmp/foo/XXXXXXXX, make sure 131 // that /tmp/foo exists, otherwise we're going to loop a really long 132 // time for nothing below 133 char* dirsep = strrchr(path, '/'); 134 if (dirsep != NULL) { 135 struct stat st; 136 int ret; 137 138 *dirsep = '\0'; // Terminating directory path temporarily 139 140 ret = stat(path, &st); 141 142 *dirsep = '/'; // Restoring directory separator 143 if (ret < 0) // Directory probably does not exist 144 return NULL; 145 if (!S_ISDIR(st.st_mode)) { // Not a directory 146 errno = ENOTDIR; 147 return NULL; 148 } 149 } 150 151 // Max number of tries using different random suffixes. 152 const int kMaxTries = 100; 153 154 // Now loop until we CAN create a directory by that name or we reach the max 155 // number of tries. 156 for (int i = 0; i < kMaxTries; ++i) { 157 // Fill the suffix XXXXXX with a random string composed of a-z chars. 158 for (int pos = 0; pos < kSuffixLen; ++pos) { 159 char rand_char = static_cast<char>(base::RandInt('a', 'z')); 160 path[path_len - kSuffixLen + pos] = rand_char; 161 } 162 if (mkdir(path, 0700) == 0) { 163 // We just created the directory succesfully. 164 return path; 165 } 166 if (errno != EEXIST) { 167 // The directory doesn't exist, but an error occured 168 return NULL; 169 } 170 } 171 172 // We reached the max number of tries. 173 return NULL; 174 } 175 176 } // extern "C" 177
