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Diffstat (limited to 'src/libstd/sys/unix/android.rs')
| -rw-r--r-- | src/libstd/sys/unix/android.rs | 167 |
1 files changed, 0 insertions, 167 deletions
diff --git a/src/libstd/sys/unix/android.rs b/src/libstd/sys/unix/android.rs deleted file mode 100644 index ea05ee3d7ce..00000000000 --- a/src/libstd/sys/unix/android.rs +++ /dev/null @@ -1,167 +0,0 @@ -//! Android ABI-compatibility module -//! -//! The ABI of Android has changed quite a bit over time, and libstd attempts to -//! be both forwards and backwards compatible as much as possible. We want to -//! always work with the most recent version of Android, but we also want to -//! work with older versions of Android for whenever projects need to. -//! -//! Our current minimum supported Android version is `android-9`, e.g., Android -//! with API level 9. We then in theory want to work on that and all future -//! versions of Android! -//! -//! Some of the detection here is done at runtime via `dlopen` and -//! introspection. Other times no detection is performed at all and we just -//! provide a fallback implementation as some versions of Android we support -//! don't have the function. -//! -//! You'll find more details below about why each compatibility shim is needed. - -#![cfg(target_os = "android")] - -use libc::{c_int, c_void, sighandler_t, size_t, ssize_t}; -use libc::{ftruncate, pread, pwrite}; - -use super::{cvt, cvt_r}; -use crate::io; - -// The `log2` and `log2f` functions apparently appeared in android-18, or at -// least you can see they're not present in the android-17 header [1] and they -// are present in android-18 [2]. -// -// [1]: https://chromium.googlesource.com/android_tools/+/20ee6d20/ndk/platforms -// /android-17/arch-arm/usr/include/math.h -// [2]: https://chromium.googlesource.com/android_tools/+/20ee6d20/ndk/platforms -// /android-18/arch-arm/usr/include/math.h -// -// Note that these shims are likely less precise than directly calling `log2`, -// but hopefully that should be enough for now... -// -// Note that mathematically, for any arbitrary `y`: -// -// log_2(x) = log_y(x) / log_y(2) -// = log_y(x) / (1 / log_2(y)) -// = log_y(x) * log_2(y) -// -// Hence because `ln` (log_e) is available on all Android we just choose `y = e` -// and get: -// -// log_2(x) = ln(x) * log_2(e) - -#[cfg(not(test))] -pub fn log2f32(f: f32) -> f32 { - f.ln() * crate::f32::consts::LOG2_E -} - -#[cfg(not(test))] -pub fn log2f64(f: f64) -> f64 { - f.ln() * crate::f64::consts::LOG2_E -} - -// Back in the day [1] the `signal` function was just an inline wrapper -// around `bsd_signal`, but starting in API level android-20 the `signal` -// symbols was introduced [2]. Finally, in android-21 the API `bsd_signal` was -// removed [3]. -// -// Basically this means that if we want to be binary compatible with multiple -// Android releases (oldest being 9 and newest being 21) then we need to check -// for both symbols and not actually link against either. -// -// [1]: https://chromium.googlesource.com/android_tools/+/20ee6d20/ndk/platforms -// /android-18/arch-arm/usr/include/signal.h -// [2]: https://chromium.googlesource.com/android_tools/+/fbd420/ndk_experimental -// /platforms/android-20/arch-arm -// /usr/include/signal.h -// [3]: https://chromium.googlesource.com/android_tools/+/20ee6d/ndk/platforms -// /android-21/arch-arm/usr/include/signal.h -pub unsafe fn signal(signum: c_int, handler: sighandler_t) -> sighandler_t { - weak!(fn signal(c_int, sighandler_t) -> sighandler_t); - weak!(fn bsd_signal(c_int, sighandler_t) -> sighandler_t); - - let f = signal.get().or_else(|| bsd_signal.get()); - let f = f.expect("neither `signal` nor `bsd_signal` symbols found"); - f(signum, handler) -} - -// The `ftruncate64` symbol apparently appeared in android-12, so we do some -// dynamic detection to see if we can figure out whether `ftruncate64` exists. -// -// If it doesn't we just fall back to `ftruncate`, generating an error for -// too-large values. -#[cfg(target_pointer_width = "32")] -pub fn ftruncate64(fd: c_int, size: u64) -> io::Result<()> { - weak!(fn ftruncate64(c_int, i64) -> c_int); - - unsafe { - match ftruncate64.get() { - Some(f) => cvt_r(|| f(fd, size as i64)).map(drop), - None => { - if size > i32::MAX as u64 { - Err(io::Error::new(io::ErrorKind::InvalidInput, "cannot truncate >2GB")) - } else { - cvt_r(|| ftruncate(fd, size as i32)).map(drop) - } - } - } - } -} - -#[cfg(target_pointer_width = "64")] -pub fn ftruncate64(fd: c_int, size: u64) -> io::Result<()> { - unsafe { cvt_r(|| ftruncate(fd, size as i64)).map(drop) } -} - -#[cfg(target_pointer_width = "32")] -pub unsafe fn cvt_pread64( - fd: c_int, - buf: *mut c_void, - count: size_t, - offset: i64, -) -> io::Result<ssize_t> { - use crate::convert::TryInto; - weak!(fn pread64(c_int, *mut c_void, size_t, i64) -> ssize_t); - pread64.get().map(|f| cvt(f(fd, buf, count, offset))).unwrap_or_else(|| { - if let Ok(o) = offset.try_into() { - cvt(pread(fd, buf, count, o)) - } else { - Err(io::Error::new(io::ErrorKind::InvalidInput, "cannot pread >2GB")) - } - }) -} - -#[cfg(target_pointer_width = "32")] -pub unsafe fn cvt_pwrite64( - fd: c_int, - buf: *const c_void, - count: size_t, - offset: i64, -) -> io::Result<ssize_t> { - use crate::convert::TryInto; - weak!(fn pwrite64(c_int, *const c_void, size_t, i64) -> ssize_t); - pwrite64.get().map(|f| cvt(f(fd, buf, count, offset))).unwrap_or_else(|| { - if let Ok(o) = offset.try_into() { - cvt(pwrite(fd, buf, count, o)) - } else { - Err(io::Error::new(io::ErrorKind::InvalidInput, "cannot pwrite >2GB")) - } - }) -} - -#[cfg(target_pointer_width = "64")] -pub unsafe fn cvt_pread64( - fd: c_int, - buf: *mut c_void, - count: size_t, - offset: i64, -) -> io::Result<ssize_t> { - cvt(pread(fd, buf, count, offset)) -} - -#[cfg(target_pointer_width = "64")] -pub unsafe fn cvt_pwrite64( - fd: c_int, - buf: *const c_void, - count: size_t, - offset: i64, -) -> io::Result<ssize_t> { - cvt(pwrite(fd, buf, count, offset)) -} |