Update V8 to version 4.6.52.
[chromium-blink-merge.git] / base / os_compat_android.cc
blobb2756b2b2264dd44a35afb30c9ddfa4e21f8594a
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.
5 #include "base/os_compat_android.h"
7 #include <asm/unistd.h>
8 #include <errno.h>
9 #include <math.h>
10 #include <sys/stat.h>
11 #include <sys/syscall.h>
13 #if !defined(__LP64__)
14 #include <time64.h>
15 #endif
17 #include "base/rand_util.h"
18 #include "base/strings/string_piece.h"
19 #include "base/strings/stringprintf.h"
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);
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;
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);
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;
55 #endif
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).
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:
63 // double c, s;
64 // c = cos(angle);
65 // s = sin(angle);
67 // Will generate machine code that looks like:
69 // double c, s;
70 // sincos(angle, &s, &c);
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!).
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.
83 #if defined(__GNUC__) && !defined(__clang__) && \
84 !defined(ANDROID_SINCOS_PROVIDED)
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.
91 #define GCC_NO_OPTIMIZE __attribute__((optimize("O0")))
93 GCC_NO_OPTIMIZE
94 void sincos(double angle, double* s, double *c) {
95 *c = cos(angle);
96 *s = sin(angle);
99 GCC_NO_OPTIMIZE
100 void sincosf(float angle, float* s, float* c) {
101 *c = cosf(angle);
102 *s = sinf(angle);
105 #endif // __GNUC__ && !__clang__
107 // An implementation of mkdtemp, since it is not exposed by the NDK
108 // for native API level 9 that we target.
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;
120 const int path_len = strlen(path);
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;
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;
138 *dirsep = '\0'; // Terminating directory path temporarily
140 ret = stat(path, &st);
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;
151 // Max number of tries using different random suffixes.
152 const int kMaxTries = 100;
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;
162 if (mkdir(path, 0700) == 0) {
163 // We just created the directory succesfully.
164 return path;
166 if (errno != EEXIST) {
167 // The directory doesn't exist, but an error occured
168 return NULL;
172 // We reached the max number of tries.
173 return NULL;
176 } // extern "C"