diff options
Diffstat (limited to 'third_party/rust/nix/src/fcntl.rs')
| -rw-r--r-- | third_party/rust/nix/src/fcntl.rs | 882 |
1 files changed, 882 insertions, 0 deletions
diff --git a/third_party/rust/nix/src/fcntl.rs b/third_party/rust/nix/src/fcntl.rs new file mode 100644 index 0000000000..650828345b --- /dev/null +++ b/third_party/rust/nix/src/fcntl.rs @@ -0,0 +1,882 @@ +use crate::errno::Errno; +use libc::{self, c_char, c_int, c_uint, size_t, ssize_t}; +use std::ffi::OsString; +#[cfg(not(target_os = "redox"))] +use std::os::raw; +use std::os::unix::ffi::OsStringExt; +use std::os::unix::io::RawFd; + +#[cfg(feature = "fs")] +use crate::{sys::stat::Mode, NixPath, Result}; +#[cfg(any(target_os = "android", target_os = "linux"))] +use std::ptr; // For splice and copy_file_range + +#[cfg(any( + target_os = "linux", + target_os = "android", + target_os = "emscripten", + target_os = "fuchsia", + target_os = "wasi", + target_env = "uclibc", + target_os = "freebsd" +))] +#[cfg(feature = "fs")] +pub use self::posix_fadvise::{posix_fadvise, PosixFadviseAdvice}; + +#[cfg(not(target_os = "redox"))] +#[cfg(any(feature = "fs", feature = "process"))] +libc_bitflags! { + #[cfg_attr(docsrs, doc(cfg(any(feature = "fs", feature = "process"))))] + pub struct AtFlags: c_int { + AT_REMOVEDIR; + AT_SYMLINK_FOLLOW; + AT_SYMLINK_NOFOLLOW; + #[cfg(any(target_os = "android", target_os = "linux"))] + AT_NO_AUTOMOUNT; + #[cfg(any(target_os = "android", target_os = "linux"))] + AT_EMPTY_PATH; + #[cfg(any(target_os = "illumos", target_os = "solaris"))] + AT_EACCESS; + } +} + +#[cfg(any(feature = "fs", feature = "term"))] +libc_bitflags!( + /// Configuration options for opened files. + #[cfg_attr(docsrs, doc(cfg(any(feature = "fs", feature = "term"))))] + pub struct OFlag: c_int { + /// Mask for the access mode of the file. + O_ACCMODE; + /// Use alternate I/O semantics. + #[cfg(target_os = "netbsd")] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_ALT_IO; + /// Open the file in append-only mode. + O_APPEND; + /// Generate a signal when input or output becomes possible. + #[cfg(not(any(target_os = "illumos", target_os = "solaris", target_os = "haiku")))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_ASYNC; + /// Closes the file descriptor once an `execve` call is made. + /// + /// Also sets the file offset to the beginning of the file. + O_CLOEXEC; + /// Create the file if it does not exist. + O_CREAT; + /// Try to minimize cache effects of the I/O for this file. + #[cfg(any(target_os = "android", + target_os = "dragonfly", + target_os = "freebsd", + target_os = "linux", + target_os = "netbsd"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_DIRECT; + /// If the specified path isn't a directory, fail. + #[cfg(not(any(target_os = "illumos", target_os = "solaris")))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_DIRECTORY; + /// Implicitly follow each `write()` with an `fdatasync()`. + #[cfg(any(target_os = "android", + target_os = "ios", + target_os = "linux", + target_os = "macos", + target_os = "netbsd", + target_os = "openbsd"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_DSYNC; + /// Error out if a file was not created. + O_EXCL; + /// Open for execute only. + #[cfg(target_os = "freebsd")] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_EXEC; + /// Open with an exclusive file lock. + #[cfg(any(target_os = "dragonfly", + target_os = "freebsd", + target_os = "ios", + target_os = "macos", + target_os = "netbsd", + target_os = "openbsd", + target_os = "redox"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_EXLOCK; + /// Same as `O_SYNC`. + #[cfg(any(target_os = "dragonfly", + target_os = "freebsd", + target_os = "ios", + all(target_os = "linux", not(target_env = "musl")), + target_os = "macos", + target_os = "netbsd", + target_os = "openbsd", + target_os = "redox"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_FSYNC; + /// Allow files whose sizes can't be represented in an `off_t` to be opened. + #[cfg(any(target_os = "android", target_os = "linux"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_LARGEFILE; + /// Do not update the file last access time during `read(2)`s. + #[cfg(any(target_os = "android", target_os = "linux"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_NOATIME; + /// Don't attach the device as the process' controlling terminal. + #[cfg(not(target_os = "redox"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_NOCTTY; + /// Same as `O_NONBLOCK`. + #[cfg(not(any(target_os = "redox", target_os = "haiku")))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_NDELAY; + /// `open()` will fail if the given path is a symbolic link. + O_NOFOLLOW; + /// When possible, open the file in nonblocking mode. + O_NONBLOCK; + /// Don't deliver `SIGPIPE`. + #[cfg(target_os = "netbsd")] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_NOSIGPIPE; + /// Obtain a file descriptor for low-level access. + /// + /// The file itself is not opened and other file operations will fail. + #[cfg(any(target_os = "android", target_os = "linux", target_os = "redox"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_PATH; + /// Only allow reading. + /// + /// This should not be combined with `O_WRONLY` or `O_RDWR`. + O_RDONLY; + /// Allow both reading and writing. + /// + /// This should not be combined with `O_WRONLY` or `O_RDONLY`. + O_RDWR; + /// Similar to `O_DSYNC` but applies to `read`s instead. + #[cfg(any(target_os = "linux", target_os = "netbsd", target_os = "openbsd"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_RSYNC; + /// Skip search permission checks. + #[cfg(target_os = "netbsd")] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_SEARCH; + /// Open with a shared file lock. + #[cfg(any(target_os = "dragonfly", + target_os = "freebsd", + target_os = "ios", + target_os = "macos", + target_os = "netbsd", + target_os = "openbsd", + target_os = "redox"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_SHLOCK; + /// Implicitly follow each `write()` with an `fsync()`. + #[cfg(not(target_os = "redox"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_SYNC; + /// Create an unnamed temporary file. + #[cfg(any(target_os = "android", target_os = "linux"))] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_TMPFILE; + /// Truncate an existing regular file to 0 length if it allows writing. + O_TRUNC; + /// Restore default TTY attributes. + #[cfg(target_os = "freebsd")] + #[cfg_attr(docsrs, doc(cfg(all())))] + O_TTY_INIT; + /// Only allow writing. + /// + /// This should not be combined with `O_RDONLY` or `O_RDWR`. + O_WRONLY; + } +); + +feature! { +#![feature = "fs"] + +// The conversion is not identical on all operating systems. +#[allow(clippy::useless_conversion)] +pub fn open<P: ?Sized + NixPath>(path: &P, oflag: OFlag, mode: Mode) -> Result<RawFd> { + let fd = path.with_nix_path(|cstr| { + unsafe { libc::open(cstr.as_ptr(), oflag.bits(), mode.bits() as c_uint) } + })?; + + Errno::result(fd) +} + +// The conversion is not identical on all operating systems. +#[allow(clippy::useless_conversion)] +#[cfg(not(target_os = "redox"))] +pub fn openat<P: ?Sized + NixPath>( + dirfd: RawFd, + path: &P, + oflag: OFlag, + mode: Mode, +) -> Result<RawFd> { + let fd = path.with_nix_path(|cstr| { + unsafe { libc::openat(dirfd, cstr.as_ptr(), oflag.bits(), mode.bits() as c_uint) } + })?; + Errno::result(fd) +} + +#[cfg(not(target_os = "redox"))] +pub fn renameat<P1: ?Sized + NixPath, P2: ?Sized + NixPath>( + old_dirfd: Option<RawFd>, + old_path: &P1, + new_dirfd: Option<RawFd>, + new_path: &P2, +) -> Result<()> { + let res = old_path.with_nix_path(|old_cstr| { + new_path.with_nix_path(|new_cstr| unsafe { + libc::renameat( + at_rawfd(old_dirfd), + old_cstr.as_ptr(), + at_rawfd(new_dirfd), + new_cstr.as_ptr(), + ) + }) + })??; + Errno::result(res).map(drop) +} +} + +#[cfg(all(target_os = "linux", target_env = "gnu",))] +#[cfg(feature = "fs")] +libc_bitflags! { + #[cfg_attr(docsrs, doc(cfg(feature = "fs")))] + pub struct RenameFlags: u32 { + RENAME_EXCHANGE; + RENAME_NOREPLACE; + RENAME_WHITEOUT; + } +} + +feature! { +#![feature = "fs"] +#[cfg(all( + target_os = "linux", + target_env = "gnu", +))] +pub fn renameat2<P1: ?Sized + NixPath, P2: ?Sized + NixPath>( + old_dirfd: Option<RawFd>, + old_path: &P1, + new_dirfd: Option<RawFd>, + new_path: &P2, + flags: RenameFlags, +) -> Result<()> { + let res = old_path.with_nix_path(|old_cstr| { + new_path.with_nix_path(|new_cstr| unsafe { + libc::renameat2( + at_rawfd(old_dirfd), + old_cstr.as_ptr(), + at_rawfd(new_dirfd), + new_cstr.as_ptr(), + flags.bits(), + ) + }) + })??; + Errno::result(res).map(drop) +} + +fn wrap_readlink_result(mut v: Vec<u8>, len: ssize_t) -> Result<OsString> { + unsafe { v.set_len(len as usize) } + v.shrink_to_fit(); + Ok(OsString::from_vec(v.to_vec())) +} + +fn readlink_maybe_at<P: ?Sized + NixPath>( + dirfd: Option<RawFd>, + path: &P, + v: &mut Vec<u8>, +) -> Result<libc::ssize_t> { + path.with_nix_path(|cstr| unsafe { + match dirfd { + #[cfg(target_os = "redox")] + Some(_) => unreachable!(), + #[cfg(not(target_os = "redox"))] + Some(dirfd) => libc::readlinkat( + dirfd, + cstr.as_ptr(), + v.as_mut_ptr() as *mut c_char, + v.capacity() as size_t, + ), + None => libc::readlink( + cstr.as_ptr(), + v.as_mut_ptr() as *mut c_char, + v.capacity() as size_t, + ), + } + }) +} + +fn inner_readlink<P: ?Sized + NixPath>(dirfd: Option<RawFd>, path: &P) -> Result<OsString> { + let mut v = Vec::with_capacity(libc::PATH_MAX as usize); + // simple case: result is strictly less than `PATH_MAX` + let res = readlink_maybe_at(dirfd, path, &mut v)?; + let len = Errno::result(res)?; + debug_assert!(len >= 0); + if (len as usize) < v.capacity() { + return wrap_readlink_result(v, res); + } + // Uh oh, the result is too long... + // Let's try to ask lstat how many bytes to allocate. + let reported_size = match dirfd { + #[cfg(target_os = "redox")] + Some(_) => unreachable!(), + #[cfg(any(target_os = "android", target_os = "linux"))] + Some(dirfd) => { + let flags = if path.is_empty() { AtFlags::AT_EMPTY_PATH } else { AtFlags::empty() }; + super::sys::stat::fstatat(dirfd, path, flags | AtFlags::AT_SYMLINK_NOFOLLOW) + }, + #[cfg(not(any(target_os = "android", target_os = "linux", target_os = "redox")))] + Some(dirfd) => super::sys::stat::fstatat(dirfd, path, AtFlags::AT_SYMLINK_NOFOLLOW), + None => super::sys::stat::lstat(path) + } + .map(|x| x.st_size) + .unwrap_or(0); + let mut try_size = if reported_size > 0 { + // Note: even if `lstat`'s apparently valid answer turns out to be + // wrong, we will still read the full symlink no matter what. + reported_size as usize + 1 + } else { + // If lstat doesn't cooperate, or reports an error, be a little less + // precise. + (libc::PATH_MAX as usize).max(128) << 1 + }; + loop { + v.reserve_exact(try_size); + let res = readlink_maybe_at(dirfd, path, &mut v)?; + let len = Errno::result(res)?; + debug_assert!(len >= 0); + if (len as usize) < v.capacity() { + break wrap_readlink_result(v, res); + } else { + // Ugh! Still not big enough! + match try_size.checked_shl(1) { + Some(next_size) => try_size = next_size, + // It's absurd that this would happen, but handle it sanely + // anyway. + None => break Err(Errno::ENAMETOOLONG), + } + } + } +} + +pub fn readlink<P: ?Sized + NixPath>(path: &P) -> Result<OsString> { + inner_readlink(None, path) +} + +#[cfg(not(target_os = "redox"))] +pub fn readlinkat<P: ?Sized + NixPath>(dirfd: RawFd, path: &P) -> Result<OsString> { + inner_readlink(Some(dirfd), path) +} + +/// Computes the raw fd consumed by a function of the form `*at`. +#[cfg(not(target_os = "redox"))] +pub(crate) fn at_rawfd(fd: Option<RawFd>) -> raw::c_int { + match fd { + None => libc::AT_FDCWD, + Some(fd) => fd, + } +} +} + +#[cfg(any(target_os = "android", target_os = "linux", target_os = "freebsd"))] +#[cfg(feature = "fs")] +libc_bitflags!( + /// Additional flags for file sealing, which allows for limiting operations on a file. + #[cfg_attr(docsrs, doc(cfg(feature = "fs")))] + pub struct SealFlag: c_int { + /// Prevents further calls to `fcntl()` with `F_ADD_SEALS`. + F_SEAL_SEAL; + /// The file cannot be reduced in size. + F_SEAL_SHRINK; + /// The size of the file cannot be increased. + F_SEAL_GROW; + /// The file contents cannot be modified. + F_SEAL_WRITE; + } +); + +#[cfg(feature = "fs")] +libc_bitflags!( + /// Additional configuration flags for `fcntl`'s `F_SETFD`. + #[cfg_attr(docsrs, doc(cfg(feature = "fs")))] + pub struct FdFlag: c_int { + /// The file descriptor will automatically be closed during a successful `execve(2)`. + FD_CLOEXEC; + } +); + +feature! { +#![feature = "fs"] + +#[cfg(not(target_os = "redox"))] +#[derive(Debug, Eq, Hash, PartialEq)] +#[non_exhaustive] +pub enum FcntlArg<'a> { + F_DUPFD(RawFd), + F_DUPFD_CLOEXEC(RawFd), + F_GETFD, + F_SETFD(FdFlag), // FD_FLAGS + F_GETFL, + F_SETFL(OFlag), // O_NONBLOCK + F_SETLK(&'a libc::flock), + F_SETLKW(&'a libc::flock), + F_GETLK(&'a mut libc::flock), + #[cfg(any(target_os = "linux", target_os = "android"))] + F_OFD_SETLK(&'a libc::flock), + #[cfg(any(target_os = "linux", target_os = "android"))] + F_OFD_SETLKW(&'a libc::flock), + #[cfg(any(target_os = "linux", target_os = "android"))] + F_OFD_GETLK(&'a mut libc::flock), + #[cfg(any(target_os = "android", target_os = "linux", target_os = "freebsd"))] + F_ADD_SEALS(SealFlag), + #[cfg(any(target_os = "android", target_os = "linux", target_os = "freebsd"))] + F_GET_SEALS, + #[cfg(any(target_os = "macos", target_os = "ios"))] + F_FULLFSYNC, + #[cfg(any(target_os = "linux", target_os = "android"))] + F_GETPIPE_SZ, + #[cfg(any(target_os = "linux", target_os = "android"))] + F_SETPIPE_SZ(c_int), + // TODO: Rest of flags +} + +#[cfg(target_os = "redox")] +#[derive(Debug, Clone, Copy, Eq, Hash, PartialEq)] +#[non_exhaustive] +pub enum FcntlArg { + F_DUPFD(RawFd), + F_DUPFD_CLOEXEC(RawFd), + F_GETFD, + F_SETFD(FdFlag), // FD_FLAGS + F_GETFL, + F_SETFL(OFlag), // O_NONBLOCK +} +pub use self::FcntlArg::*; + +// TODO: Figure out how to handle value fcntl returns +pub fn fcntl(fd: RawFd, arg: FcntlArg) -> Result<c_int> { + let res = unsafe { + match arg { + F_DUPFD(rawfd) => libc::fcntl(fd, libc::F_DUPFD, rawfd), + F_DUPFD_CLOEXEC(rawfd) => libc::fcntl(fd, libc::F_DUPFD_CLOEXEC, rawfd), + F_GETFD => libc::fcntl(fd, libc::F_GETFD), + F_SETFD(flag) => libc::fcntl(fd, libc::F_SETFD, flag.bits()), + F_GETFL => libc::fcntl(fd, libc::F_GETFL), + F_SETFL(flag) => libc::fcntl(fd, libc::F_SETFL, flag.bits()), + #[cfg(not(target_os = "redox"))] + F_SETLK(flock) => libc::fcntl(fd, libc::F_SETLK, flock), + #[cfg(not(target_os = "redox"))] + F_SETLKW(flock) => libc::fcntl(fd, libc::F_SETLKW, flock), + #[cfg(not(target_os = "redox"))] + F_GETLK(flock) => libc::fcntl(fd, libc::F_GETLK, flock), + #[cfg(any(target_os = "android", target_os = "linux"))] + F_OFD_SETLK(flock) => libc::fcntl(fd, libc::F_OFD_SETLK, flock), + #[cfg(any(target_os = "android", target_os = "linux"))] + F_OFD_SETLKW(flock) => libc::fcntl(fd, libc::F_OFD_SETLKW, flock), + #[cfg(any(target_os = "android", target_os = "linux"))] + F_OFD_GETLK(flock) => libc::fcntl(fd, libc::F_OFD_GETLK, flock), + #[cfg(any(target_os = "android", target_os = "linux", target_os = "freebsd"))] + F_ADD_SEALS(flag) => libc::fcntl(fd, libc::F_ADD_SEALS, flag.bits()), + #[cfg(any(target_os = "android", target_os = "linux", target_os = "freebsd"))] + F_GET_SEALS => libc::fcntl(fd, libc::F_GET_SEALS), + #[cfg(any(target_os = "macos", target_os = "ios"))] + F_FULLFSYNC => libc::fcntl(fd, libc::F_FULLFSYNC), + #[cfg(any(target_os = "linux", target_os = "android"))] + F_GETPIPE_SZ => libc::fcntl(fd, libc::F_GETPIPE_SZ), + #[cfg(any(target_os = "linux", target_os = "android"))] + F_SETPIPE_SZ(size) => libc::fcntl(fd, libc::F_SETPIPE_SZ, size), + } + }; + + Errno::result(res) +} + +// TODO: convert to libc_enum +#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] +#[non_exhaustive] +pub enum FlockArg { + LockShared, + LockExclusive, + Unlock, + LockSharedNonblock, + LockExclusiveNonblock, + UnlockNonblock, +} + +#[cfg(not(target_os = "redox"))] +pub fn flock(fd: RawFd, arg: FlockArg) -> Result<()> { + use self::FlockArg::*; + + let res = unsafe { + match arg { + LockShared => libc::flock(fd, libc::LOCK_SH), + LockExclusive => libc::flock(fd, libc::LOCK_EX), + Unlock => libc::flock(fd, libc::LOCK_UN), + LockSharedNonblock => libc::flock(fd, libc::LOCK_SH | libc::LOCK_NB), + LockExclusiveNonblock => libc::flock(fd, libc::LOCK_EX | libc::LOCK_NB), + UnlockNonblock => libc::flock(fd, libc::LOCK_UN | libc::LOCK_NB), + } + }; + + Errno::result(res).map(drop) +} +} + +#[cfg(any(target_os = "android", target_os = "linux"))] +#[cfg(feature = "zerocopy")] +libc_bitflags! { + /// Additional flags to `splice` and friends. + #[cfg_attr(docsrs, doc(cfg(feature = "zerocopy")))] + pub struct SpliceFFlags: c_uint { + /// Request that pages be moved instead of copied. + /// + /// Not applicable to `vmsplice`. + SPLICE_F_MOVE; + /// Do not block on I/O. + SPLICE_F_NONBLOCK; + /// Hint that more data will be coming in a subsequent splice. + /// + /// Not applicable to `vmsplice`. + SPLICE_F_MORE; + /// Gift the user pages to the kernel. + /// + /// Not applicable to `splice`. + SPLICE_F_GIFT; + } +} + +feature! { +#![feature = "zerocopy"] + +/// Copy a range of data from one file to another +/// +/// The `copy_file_range` system call performs an in-kernel copy between +/// file descriptors `fd_in` and `fd_out` without the additional cost of +/// transferring data from the kernel to user space and then back into the +/// kernel. It copies up to `len` bytes of data from file descriptor `fd_in` to +/// file descriptor `fd_out`, overwriting any data that exists within the +/// requested range of the target file. +/// +/// If the `off_in` and/or `off_out` arguments are used, the values +/// will be mutated to reflect the new position within the file after +/// copying. If they are not used, the relevant filedescriptors will be seeked +/// to the new position. +/// +/// On successful completion the number of bytes actually copied will be +/// returned. +#[cfg(any(target_os = "android", target_os = "linux"))] +pub fn copy_file_range( + fd_in: RawFd, + off_in: Option<&mut libc::loff_t>, + fd_out: RawFd, + off_out: Option<&mut libc::loff_t>, + len: usize, +) -> Result<usize> { + let off_in = off_in + .map(|offset| offset as *mut libc::loff_t) + .unwrap_or(ptr::null_mut()); + let off_out = off_out + .map(|offset| offset as *mut libc::loff_t) + .unwrap_or(ptr::null_mut()); + + let ret = unsafe { + libc::syscall( + libc::SYS_copy_file_range, + fd_in, + off_in, + fd_out, + off_out, + len, + 0, + ) + }; + Errno::result(ret).map(|r| r as usize) +} + +#[cfg(any(target_os = "linux", target_os = "android"))] +pub fn splice( + fd_in: RawFd, + off_in: Option<&mut libc::loff_t>, + fd_out: RawFd, + off_out: Option<&mut libc::loff_t>, + len: usize, + flags: SpliceFFlags, +) -> Result<usize> { + let off_in = off_in + .map(|offset| offset as *mut libc::loff_t) + .unwrap_or(ptr::null_mut()); + let off_out = off_out + .map(|offset| offset as *mut libc::loff_t) + .unwrap_or(ptr::null_mut()); + + let ret = unsafe { libc::splice(fd_in, off_in, fd_out, off_out, len, flags.bits()) }; + Errno::result(ret).map(|r| r as usize) +} + +#[cfg(any(target_os = "linux", target_os = "android"))] +pub fn tee(fd_in: RawFd, fd_out: RawFd, len: usize, flags: SpliceFFlags) -> Result<usize> { + let ret = unsafe { libc::tee(fd_in, fd_out, len, flags.bits()) }; + Errno::result(ret).map(|r| r as usize) +} + +#[cfg(any(target_os = "linux", target_os = "android"))] +pub fn vmsplice( + fd: RawFd, + iov: &[std::io::IoSlice<'_>], + flags: SpliceFFlags + ) -> Result<usize> +{ + let ret = unsafe { + libc::vmsplice( + fd, + iov.as_ptr() as *const libc::iovec, + iov.len(), + flags.bits(), + ) + }; + Errno::result(ret).map(|r| r as usize) +} +} + +#[cfg(any(target_os = "linux"))] +#[cfg(feature = "fs")] +libc_bitflags!( + /// Mode argument flags for fallocate determining operation performed on a given range. + #[cfg_attr(docsrs, doc(cfg(feature = "fs")))] + pub struct FallocateFlags: c_int { + /// File size is not changed. + /// + /// offset + len can be greater than file size. + FALLOC_FL_KEEP_SIZE; + /// Deallocates space by creating a hole. + /// + /// Must be ORed with FALLOC_FL_KEEP_SIZE. Byte range starts at offset and continues for len bytes. + FALLOC_FL_PUNCH_HOLE; + /// Removes byte range from a file without leaving a hole. + /// + /// Byte range to collapse starts at offset and continues for len bytes. + FALLOC_FL_COLLAPSE_RANGE; + /// Zeroes space in specified byte range. + /// + /// Byte range starts at offset and continues for len bytes. + FALLOC_FL_ZERO_RANGE; + /// Increases file space by inserting a hole within the file size. + /// + /// Does not overwrite existing data. Hole starts at offset and continues for len bytes. + FALLOC_FL_INSERT_RANGE; + /// Shared file data extants are made private to the file. + /// + /// Gaurantees that a subsequent write will not fail due to lack of space. + FALLOC_FL_UNSHARE_RANGE; + } +); + +feature! { +#![feature = "fs"] + +/// Manipulates file space. +/// +/// Allows the caller to directly manipulate the allocated disk space for the +/// file referred to by fd. +#[cfg(any(target_os = "linux"))] +#[cfg(feature = "fs")] +pub fn fallocate( + fd: RawFd, + mode: FallocateFlags, + offset: libc::off_t, + len: libc::off_t, +) -> Result<()> { + let res = unsafe { libc::fallocate(fd, mode.bits(), offset, len) }; + Errno::result(res).map(drop) +} + +/// Argument to [`fspacectl`] describing the range to zero. The first member is +/// the file offset, and the second is the length of the region. +#[cfg(any(target_os = "freebsd"))] +#[derive(Clone, Copy, Debug, Eq, PartialEq)] +pub struct SpacectlRange(pub libc::off_t, pub libc::off_t); + +#[cfg(any(target_os = "freebsd"))] +impl SpacectlRange { + #[inline] + pub fn is_empty(&self) -> bool { + self.1 == 0 + } + + #[inline] + pub fn len(&self) -> libc::off_t { + self.1 + } + + #[inline] + pub fn offset(&self) -> libc::off_t { + self.0 + } +} + +/// Punch holes in a file. +/// +/// `fspacectl` instructs the file system to deallocate a portion of a file. +/// After a successful operation, this region of the file will return all zeroes +/// if read. If the file system supports deallocation, then it may free the +/// underlying storage, too. +/// +/// # Arguments +/// +/// - `fd` - File to operate on +/// - `range.0` - File offset at which to begin deallocation +/// - `range.1` - Length of the region to deallocate +/// +/// # Returns +/// +/// The operation may deallocate less than the entire requested region. On +/// success, it returns the region that still remains to be deallocated. The +/// caller should loop until the returned region is empty. +/// +/// # Example +/// +#[cfg_attr(fbsd14, doc = " ```")] +#[cfg_attr(not(fbsd14), doc = " ```no_run")] +/// # use std::io::Write; +/// # use std::os::unix::fs::FileExt; +/// # use std::os::unix::io::AsRawFd; +/// # use nix::fcntl::*; +/// # use tempfile::tempfile; +/// const INITIAL: &[u8] = b"0123456789abcdef"; +/// let mut f = tempfile().unwrap(); +/// f.write_all(INITIAL).unwrap(); +/// let mut range = SpacectlRange(3, 6); +/// while (!range.is_empty()) { +/// range = fspacectl(f.as_raw_fd(), range).unwrap(); +/// } +/// let mut buf = vec![0; INITIAL.len()]; +/// f.read_exact_at(&mut buf, 0).unwrap(); +/// assert_eq!(buf, b"012\0\0\0\0\0\09abcdef"); +/// ``` +#[cfg(target_os = "freebsd")] +pub fn fspacectl(fd: RawFd, range: SpacectlRange) -> Result<SpacectlRange> { + let mut rqsr = libc::spacectl_range{r_offset: range.0, r_len: range.1}; + let res = unsafe { libc::fspacectl( + fd, + libc::SPACECTL_DEALLOC, // Only one command is supported ATM + &rqsr, + 0, // No flags are currently supported + &mut rqsr + )}; + Errno::result(res).map(|_| SpacectlRange(rqsr.r_offset, rqsr.r_len)) +} + +/// Like [`fspacectl`], but will never return incomplete. +/// +/// # Arguments +/// +/// - `fd` - File to operate on +/// - `offset` - File offset at which to begin deallocation +/// - `len` - Length of the region to deallocate +/// +/// # Returns +/// +/// Returns `()` on success. On failure, the region may or may not be partially +/// deallocated. +/// +/// # Example +/// +#[cfg_attr(fbsd14, doc = " ```")] +#[cfg_attr(not(fbsd14), doc = " ```no_run")] +/// # use std::io::Write; +/// # use std::os::unix::fs::FileExt; +/// # use std::os::unix::io::AsRawFd; +/// # use nix::fcntl::*; +/// # use tempfile::tempfile; +/// const INITIAL: &[u8] = b"0123456789abcdef"; +/// let mut f = tempfile().unwrap(); +/// f.write_all(INITIAL).unwrap(); +/// fspacectl_all(f.as_raw_fd(), 3, 6).unwrap(); +/// let mut buf = vec![0; INITIAL.len()]; +/// f.read_exact_at(&mut buf, 0).unwrap(); +/// assert_eq!(buf, b"012\0\0\0\0\0\09abcdef"); +/// ``` +#[cfg(target_os = "freebsd")] +pub fn fspacectl_all(fd: RawFd, offset: libc::off_t, len: libc::off_t) + -> Result<()> +{ + let mut rqsr = libc::spacectl_range{r_offset: offset, r_len: len}; + while rqsr.r_len > 0 { + let res = unsafe { libc::fspacectl( + fd, + libc::SPACECTL_DEALLOC, // Only one command is supported ATM + &rqsr, + 0, // No flags are currently supported + &mut rqsr + )}; + Errno::result(res)?; + } + Ok(()) +} + +#[cfg(any( + target_os = "linux", + target_os = "android", + target_os = "emscripten", + target_os = "fuchsia", + target_os = "wasi", + target_env = "uclibc", + target_os = "freebsd" +))] +mod posix_fadvise { + use crate::errno::Errno; + use std::os::unix::io::RawFd; + use crate::Result; + + #[cfg(feature = "fs")] + libc_enum! { + #[repr(i32)] + #[non_exhaustive] + #[cfg_attr(docsrs, doc(cfg(feature = "fs")))] + pub enum PosixFadviseAdvice { + POSIX_FADV_NORMAL, + POSIX_FADV_SEQUENTIAL, + POSIX_FADV_RANDOM, + POSIX_FADV_NOREUSE, + POSIX_FADV_WILLNEED, + POSIX_FADV_DONTNEED, + } + } + + feature! { + #![feature = "fs"] + pub fn posix_fadvise( + fd: RawFd, + offset: libc::off_t, + len: libc::off_t, + advice: PosixFadviseAdvice, + ) -> Result<()> { + let res = unsafe { libc::posix_fadvise(fd, offset, len, advice as libc::c_int) }; + + if res == 0 { + Ok(()) + } else { + Err(Errno::from_i32(res)) + } + } + } +} + +#[cfg(any( + target_os = "linux", + target_os = "android", + target_os = "dragonfly", + target_os = "emscripten", + target_os = "fuchsia", + target_os = "wasi", + target_os = "freebsd" +))] +pub fn posix_fallocate(fd: RawFd, offset: libc::off_t, len: libc::off_t) -> Result<()> { + let res = unsafe { libc::posix_fallocate(fd, offset, len) }; + match Errno::result(res) { + Err(err) => Err(err), + Ok(0) => Ok(()), + Ok(errno) => Err(Errno::from_i32(errno)), + } +} +} |