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- // Copyright (c) 2012 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include "base/os_compat_android.h"
- #include <asm/unistd.h>
- #include <errno.h>
- #include <limits.h>
- #include <math.h>
- #include <sys/stat.h>
- #include <sys/syscall.h>
- #include <unistd.h>
- #include "base/strings/string_util.h"
- #if !defined(__LP64__)
- #include <time64.h>
- #endif
- #include "base/files/file.h"
- #include "base/numerics/safe_conversions.h"
- #include "base/rand_util.h"
- #include "base/strings/string_piece.h"
- extern "C" {
- // There is no futimes() avaiable in Bionic, so we provide our own
- // implementation until it is there.
- int futimes(int fd, const struct timeval tv[2]) {
- if (tv == nullptr)
- return base::checked_cast<int>(syscall(__NR_utimensat, fd, NULL, NULL, 0));
- if (tv[0].tv_usec < 0 || tv[0].tv_usec >= 1000000 ||
- tv[1].tv_usec < 0 || tv[1].tv_usec >= 1000000) {
- errno = EINVAL;
- return -1;
- }
- // Convert timeval to timespec.
- struct timespec ts[2];
- ts[0].tv_sec = tv[0].tv_sec;
- ts[0].tv_nsec = tv[0].tv_usec * 1000;
- ts[1].tv_sec = tv[1].tv_sec;
- ts[1].tv_nsec = tv[1].tv_usec * 1000;
- return base::checked_cast<int>(syscall(__NR_utimensat, fd, NULL, ts, 0));
- }
- #if !defined(__LP64__)
- // 32-bit Android has only timegm64() and not timegm().
- // We replicate the behaviour of timegm() when the result overflows time_t.
- time_t timegm(struct tm* const t) {
- // time_t is signed on Android.
- static const time_t kTimeMax = ~(1L << (sizeof(time_t) * CHAR_BIT - 1));
- static const time_t kTimeMin = (1L << (sizeof(time_t) * CHAR_BIT - 1));
- time64_t result = timegm64(t);
- if (result < kTimeMin || result > kTimeMax)
- return -1;
- return static_cast<time_t>(result);
- }
- #endif
- // The following is only needed when building with GCC 4.6 or higher
- // (i.e. not with Android GCC 4.4.3, nor with Clang).
- //
- // GCC is now capable of optimizing successive calls to sin() and cos() into
- // a single call to sincos(). This means that source code that looks like:
- //
- // double c, s;
- // c = cos(angle);
- // s = sin(angle);
- //
- // Will generate machine code that looks like:
- //
- // double c, s;
- // sincos(angle, &s, &c);
- //
- // Unfortunately, sincos() and friends are not part of the Android libm.so
- // library provided by the NDK for API level 9. When the optimization kicks
- // in, it makes the final build fail with a puzzling message (puzzling
- // because 'sincos' doesn't appear anywhere in the sources!).
- //
- // To solve this, we provide our own implementation of the sincos() function
- // and related friends. Note that we must also explicitely tell GCC to disable
- // optimizations when generating these. Otherwise, the generated machine code
- // for each function would simply end up calling itself, resulting in a
- // runtime crash due to stack overflow.
- //
- #if defined(__GNUC__) && !defined(__clang__) && \
- !defined(ANDROID_SINCOS_PROVIDED)
- // For the record, Clang does not support the 'optimize' attribute.
- // In the unlikely event that it begins performing this optimization too,
- // we'll have to find a different way to achieve this. NOTE: Tested with O1
- // which still performs the optimization.
- //
- #define GCC_NO_OPTIMIZE __attribute__((optimize("O0")))
- GCC_NO_OPTIMIZE
- void sincos(double angle, double* s, double *c) {
- *c = cos(angle);
- *s = sin(angle);
- }
- GCC_NO_OPTIMIZE
- void sincosf(float angle, float* s, float* c) {
- *c = cosf(angle);
- *s = sinf(angle);
- }
- #endif // __GNUC__ && !__clang__
- // An implementation of mkdtemp, since it is not exposed by the NDK
- // for native API level 9 that we target.
- //
- // For any changes in the mkdtemp function, you should manually run the unittest
- // OsCompatAndroidTest.DISABLED_TestMkdTemp in your local machine to check if it
- // passes. Please don't enable it, since it creates a directory and may be
- // source of flakyness.
- char* mkdtemp(char* path) {
- if (!path) {
- errno = EINVAL;
- return nullptr;
- }
- const size_t path_len = strlen(path);
- // The last six characters of 'path' must be XXXXXX.
- const base::StringPiece kSuffix("XXXXXX");
- const size_t kSuffixLen = kSuffix.length();
- if (!base::EndsWith(base::StringPiece(path, path_len), kSuffix)) {
- errno = EINVAL;
- return nullptr;
- }
- // If the path contains a directory, as in /tmp/foo/XXXXXXXX, make sure
- // that /tmp/foo exists, otherwise we're going to loop a really long
- // time for nothing below
- char* dirsep = strrchr(path, '/');
- if (dirsep) {
- *dirsep = '\0'; // Terminating directory path temporarily
- base::stat_wrapper_t st;
- int ret = base::File::Stat(path, &st);
- *dirsep = '/'; // Restoring directory separator
- if (ret < 0) // Directory probably does not exist
- return nullptr;
- if (!S_ISDIR(st.st_mode)) { // Not a directory
- errno = ENOTDIR;
- return nullptr;
- }
- }
- // Max number of tries using different random suffixes.
- const int kMaxTries = 100;
- // Now loop until we CAN create a directory by that name or we reach the max
- // number of tries.
- for (int i = 0; i < kMaxTries; ++i) {
- // Fill the suffix XXXXXX with a random string composed of a-z chars.
- for (size_t pos = 0; pos < kSuffixLen; ++pos) {
- char rand_char = static_cast<char>(base::RandInt('a', 'z'));
- path[path_len - kSuffixLen + pos] = rand_char;
- }
- if (mkdir(path, 0700) == 0) {
- // We just created the directory succesfully.
- return path;
- }
- if (errno != EEXIST) {
- // The directory doesn't exist, but an error occured
- return nullptr;
- }
- }
- // We reached the max number of tries.
- return nullptr;
- }
- } // extern "C"
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