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 <limits.h> 10 #include <math.h> 11 #include <sys/stat.h> 12 #include <sys/syscall.h> 13 14 #if !defined(__LP64__) 15 #include <time64.h> 16 #endif 17 18 #include "base/rand_util.h" 19 #include "base/strings/string_piece.h" 20 #include "base/strings/stringprintf.h" 21 22 extern "C" { 23 // There is no futimes() avaiable in Bionic, so we provide our own 24 // implementation until it is there. 25 int futimes(int fd, const struct timeval tv[2]) { 26 if (tv == NULL) 27 return syscall(__NR_utimensat, fd, NULL, NULL, 0); 28 29 if (tv[0].tv_usec < 0 || tv[0].tv_usec >= 1000000 || 30 tv[1].tv_usec < 0 || tv[1].tv_usec >= 1000000) { 31 errno = EINVAL; 32 return -1; 33 } 34 35 // Convert timeval to timespec. 36 struct timespec ts[2]; 37 ts[0].tv_sec = tv[0].tv_sec; 38 ts[0].tv_nsec = tv[0].tv_usec * 1000; 39 ts[1].tv_sec = tv[1].tv_sec; 40 ts[1].tv_nsec = tv[1].tv_usec * 1000; 41 return syscall(__NR_utimensat, fd, NULL, ts, 0); 42 } 43 44 #if !defined(__LP64__) 45 // 32-bit Android has only timegm64() and not timegm(). 46 // We replicate the behaviour of timegm() when the result overflows time_t. 47 time_t timegm(struct tm* const t) { 48 // time_t is signed on Android. 49 static const time_t kTimeMax = ~(1L << (sizeof(time_t) * CHAR_BIT - 1)); 50 static const time_t kTimeMin = (1L << (sizeof(time_t) * CHAR_BIT - 1)); 51 time64_t result = timegm64(t); 52 if (result < kTimeMin || result > kTimeMax) 53 return -1; 54 return result; 55 } 56 #endif 57 58 // The following is only needed when building with GCC 4.6 or higher 59 // (i.e. not with Android GCC 4.4.3, nor with Clang). 60 // 61 // GCC is now capable of optimizing successive calls to sin() and cos() into 62 // a single call to sincos(). This means that source code that looks like: 63 // 64 // double c, s; 65 // c = cos(angle); 66 // s = sin(angle); 67 // 68 // Will generate machine code that looks like: 69 // 70 // double c, s; 71 // sincos(angle, &s, &c); 72 // 73 // Unfortunately, sincos() and friends are not part of the Android libm.so 74 // library provided by the NDK for API level 9. When the optimization kicks 75 // in, it makes the final build fail with a puzzling message (puzzling 76 // because 'sincos' doesn't appear anywhere in the sources!). 77 // 78 // To solve this, we provide our own implementation of the sincos() function 79 // and related friends. Note that we must also explicitely tell GCC to disable 80 // optimizations when generating these. Otherwise, the generated machine code 81 // for each function would simply end up calling itself, resulting in a 82 // runtime crash due to stack overflow. 83 // 84 #if defined(__GNUC__) && !defined(__clang__) && \ 85 !defined(ANDROID_SINCOS_PROVIDED) 86 87 // For the record, Clang does not support the 'optimize' attribute. 88 // In the unlikely event that it begins performing this optimization too, 89 // we'll have to find a different way to achieve this. NOTE: Tested with O1 90 // which still performs the optimization. 91 // 92 #define GCC_NO_OPTIMIZE __attribute__((optimize("O0"))) 93 94 GCC_NO_OPTIMIZE 95 void sincos(double angle, double* s, double *c) { 96 *c = cos(angle); 97 *s = sin(angle); 98 } 99 100 GCC_NO_OPTIMIZE 101 void sincosf(float angle, float* s, float* c) { 102 *c = cosf(angle); 103 *s = sinf(angle); 104 } 105 106 #endif // __GNUC__ && !__clang__ 107 108 // An implementation of mkdtemp, since it is not exposed by the NDK 109 // for native API level 9 that we target. 110 // 111 // For any changes in the mkdtemp function, you should manually run the unittest 112 // OsCompatAndroidTest.DISABLED_TestMkdTemp in your local machine to check if it 113 // passes. Please don't enable it, since it creates a directory and may be 114 // source of flakyness. 115 char* mkdtemp(char* path) { 116 if (path == NULL) { 117 errno = EINVAL; 118 return NULL; 119 } 120 121 const int path_len = strlen(path); 122 123 // The last six characters of 'path' must be XXXXXX. 124 const base::StringPiece kSuffix("XXXXXX"); 125 const int kSuffixLen = kSuffix.length(); 126 if (!base::StringPiece(path, path_len).ends_with(kSuffix)) { 127 errno = EINVAL; 128 return NULL; 129 } 130 131 // If the path contains a directory, as in /tmp/foo/XXXXXXXX, make sure 132 // that /tmp/foo exists, otherwise we're going to loop a really long 133 // time for nothing below 134 char* dirsep = strrchr(path, '/'); 135 if (dirsep != NULL) { 136 struct stat st; 137 int ret; 138 139 *dirsep = '\0'; // Terminating directory path temporarily 140 141 ret = stat(path, &st); 142 143 *dirsep = '/'; // Restoring directory separator 144 if (ret < 0) // Directory probably does not exist 145 return NULL; 146 if (!S_ISDIR(st.st_mode)) { // Not a directory 147 errno = ENOTDIR; 148 return NULL; 149 } 150 } 151 152 // Max number of tries using different random suffixes. 153 const int kMaxTries = 100; 154 155 // Now loop until we CAN create a directory by that name or we reach the max 156 // number of tries. 157 for (int i = 0; i < kMaxTries; ++i) { 158 // Fill the suffix XXXXXX with a random string composed of a-z chars. 159 for (int pos = 0; pos < kSuffixLen; ++pos) { 160 char rand_char = static_cast<char>(base::RandInt('a', 'z')); 161 path[path_len - kSuffixLen + pos] = rand_char; 162 } 163 if (mkdir(path, 0700) == 0) { 164 // We just created the directory succesfully. 165 return path; 166 } 167 if (errno != EEXIST) { 168 // The directory doesn't exist, but an error occured 169 return NULL; 170 } 171 } 172 173 // We reached the max number of tries. 174 return NULL; 175 } 176 177 } // extern "C" 178
