diff options
Diffstat (limited to 'library/std/src/sys/unix/process/process_unix.rs')
| -rw-r--r-- | library/std/src/sys/unix/process/process_unix.rs | 152 |
1 files changed, 128 insertions, 24 deletions
diff --git a/library/std/src/sys/unix/process/process_unix.rs b/library/std/src/sys/unix/process/process_unix.rs index 612d43fe2..0ce93af66 100644 --- a/library/std/src/sys/unix/process/process_unix.rs +++ b/library/std/src/sys/unix/process/process_unix.rs @@ -15,6 +15,8 @@ use crate::sys::weak::raw_syscall; #[cfg(any( target_os = "macos", + target_os = "watchos", + target_os = "tvos", target_os = "freebsd", all(target_os = "linux", target_env = "gnu"), all(target_os = "linux", target_env = "musl"), @@ -28,15 +30,38 @@ use libc::RTP_ID as pid_t; #[cfg(not(target_os = "vxworks"))] use libc::{c_int, pid_t}; -#[cfg(not(any(target_os = "vxworks", target_os = "l4re")))] +#[cfg(not(any( + target_os = "vxworks", + target_os = "l4re", + target_os = "tvos", + target_os = "watchos", +)))] use libc::{gid_t, uid_t}; cfg_if::cfg_if! { if #[cfg(all(target_os = "nto", target_env = "nto71"))] { use crate::thread; use libc::{c_char, posix_spawn_file_actions_t, posix_spawnattr_t}; - // arbitrary number of tries: - const MAX_FORKSPAWN_TRIES: u32 = 4; + use crate::time::Duration; + use crate::sync::LazyLock; + // Get smallest amount of time we can sleep. + // Return a common value if it cannot be determined. + fn get_clock_resolution() -> Duration { + static MIN_DELAY: LazyLock<Duration, fn() -> Duration> = LazyLock::new(|| { + let mut mindelay = libc::timespec { tv_sec: 0, tv_nsec: 0 }; + if unsafe { libc::clock_getres(libc::CLOCK_MONOTONIC, &mut mindelay) } == 0 + { + Duration::from_nanos(mindelay.tv_nsec as u64) + } else { + Duration::from_millis(1) + } + }); + *MIN_DELAY + } + // Arbitrary minimum sleep duration for retrying fork/spawn + const MIN_FORKSPAWN_SLEEP: Duration = Duration::from_nanos(1); + // Maximum duration of sleeping before giving up and returning an error + const MAX_FORKSPAWN_SLEEP: Duration = Duration::from_millis(1000); } } @@ -66,7 +91,6 @@ impl Command { if let Some(ret) = self.posix_spawn(&theirs, envp.as_ref())? { return Ok((ret, ours)); } - let (input, output) = sys::pipe::anon_pipe()?; // Whatever happens after the fork is almost for sure going to touch or @@ -148,9 +172,31 @@ impl Command { crate::sys_common::process::wait_with_output(proc, pipes) } + // WatchOS and TVOS headers mark the `fork`/`exec*` functions with + // `__WATCHOS_PROHIBITED __TVOS_PROHIBITED`, and indicate that the + // `posix_spawn*` functions should be used instead. It isn't entirely clear + // what `PROHIBITED` means here (e.g. if calls to these functions are + // allowed to exist in dead code), but it sounds bad, so we go out of our + // way to avoid that all-together. + #[cfg(any(target_os = "tvos", target_os = "watchos"))] + const ERR_APPLE_TV_WATCH_NO_FORK_EXEC: Error = io::const_io_error!( + ErrorKind::Unsupported, + "`fork`+`exec`-based process spawning is not supported on this target", + ); + + #[cfg(any(target_os = "tvos", target_os = "watchos"))] + unsafe fn do_fork(&mut self) -> Result<(pid_t, pid_t), io::Error> { + return Err(Self::ERR_APPLE_TV_WATCH_NO_FORK_EXEC); + } + // Attempts to fork the process. If successful, returns Ok((0, -1)) // in the child, and Ok((child_pid, -1)) in the parent. - #[cfg(not(any(target_os = "linux", all(target_os = "nto", target_env = "nto71"))))] + #[cfg(not(any( + target_os = "linux", + target_os = "watchos", + target_os = "tvos", + all(target_os = "nto", target_env = "nto71"), + )))] unsafe fn do_fork(&mut self) -> Result<(pid_t, pid_t), io::Error> { cvt(libc::fork()).map(|res| (res, -1)) } @@ -163,12 +209,25 @@ impl Command { unsafe fn do_fork(&mut self) -> Result<(pid_t, pid_t), io::Error> { use crate::sys::os::errno; - let mut tries_left = MAX_FORKSPAWN_TRIES; + let mut delay = MIN_FORKSPAWN_SLEEP; + loop { let r = libc::fork(); - if r == -1 as libc::pid_t && tries_left > 0 && errno() as libc::c_int == libc::EBADF { - thread::yield_now(); - tries_left -= 1; + if r == -1 as libc::pid_t && errno() as libc::c_int == libc::EBADF { + if delay < get_clock_resolution() { + // We cannot sleep this short (it would be longer). + // Yield instead. + thread::yield_now(); + } else if delay < MAX_FORKSPAWN_SLEEP { + thread::sleep(delay); + } else { + return Err(io::const_io_error!( + ErrorKind::WouldBlock, + "forking returned EBADF too often", + )); + } + delay *= 2; + continue; } else { return cvt(r).map(|res| (res, -1)); } @@ -308,6 +367,7 @@ impl Command { // allocation). Instead we just close it manually. This will never // have the drop glue anyway because this code never returns (the // child will either exec() or invoke libc::exit) + #[cfg(not(any(target_os = "tvos", target_os = "watchos")))] unsafe fn do_exec( &mut self, stdio: ChildPipes, @@ -414,8 +474,19 @@ impl Command { Err(io::Error::last_os_error()) } + #[cfg(any(target_os = "tvos", target_os = "watchos"))] + unsafe fn do_exec( + &mut self, + _stdio: ChildPipes, + _maybe_envp: Option<&CStringArray>, + ) -> Result<!, io::Error> { + return Err(Self::ERR_APPLE_TV_WATCH_NO_FORK_EXEC); + } + #[cfg(not(any( target_os = "macos", + target_os = "tvos", + target_os = "watchos", target_os = "freebsd", all(target_os = "linux", target_env = "gnu"), all(target_os = "linux", target_env = "musl"), @@ -433,6 +504,9 @@ impl Command { // directly. #[cfg(any( target_os = "macos", + // FIXME: `target_os = "ios"`? + target_os = "tvos", + target_os = "watchos", target_os = "freebsd", all(target_os = "linux", target_env = "gnu"), all(target_os = "linux", target_env = "musl"), @@ -480,17 +554,28 @@ impl Command { attrp: *const posix_spawnattr_t, argv: *const *mut c_char, envp: *const *mut c_char, - ) -> i32 { - let mut tries_left = MAX_FORKSPAWN_TRIES; + ) -> io::Result<i32> { + let mut delay = MIN_FORKSPAWN_SLEEP; loop { match libc::posix_spawnp(pid, file, file_actions, attrp, argv, envp) { - libc::EBADF if tries_left > 0 => { - thread::yield_now(); - tries_left -= 1; + libc::EBADF => { + if delay < get_clock_resolution() { + // We cannot sleep this short (it would be longer). + // Yield instead. + thread::yield_now(); + } else if delay < MAX_FORKSPAWN_SLEEP { + thread::sleep(delay); + } else { + return Err(io::const_io_error!( + ErrorKind::WouldBlock, + "posix_spawnp returned EBADF too often", + )); + } + delay *= 2; continue; } r => { - return r; + return Ok(r); } } } @@ -508,7 +593,7 @@ impl Command { } let addchdir = match self.get_cwd() { Some(cwd) => { - if cfg!(target_os = "macos") { + if cfg!(any(target_os = "macos", target_os = "tvos", target_os = "watchos")) { // There is a bug in macOS where a relative executable // path like "../myprogram" will cause `posix_spawn` to // successfully launch the program, but erroneously return @@ -620,14 +705,20 @@ impl Command { let spawn_fn = libc::posix_spawnp; #[cfg(target_os = "nto")] let spawn_fn = retrying_libc_posix_spawnp; - cvt_nz(spawn_fn( + + let spawn_res = spawn_fn( &mut p.pid, self.get_program_cstr().as_ptr(), file_actions.0.as_ptr(), attrs.0.as_ptr(), self.get_argv().as_ptr() as *const _, envp as *const _, - ))?; + ); + + #[cfg(target_os = "nto")] + let spawn_res = spawn_res?; + + cvt_nz(spawn_res)?; Ok(Some(p)) } } @@ -671,12 +762,9 @@ impl Process { pub fn kill(&mut self) -> io::Result<()> { // If we've already waited on this process then the pid can be recycled // and used for another process, and we probably shouldn't be killing - // random processes, so just return an error. + // random processes, so return Ok because the process has exited already. if self.status.is_some() { - Err(io::const_io_error!( - ErrorKind::InvalidInput, - "invalid argument: can't kill an exited process", - )) + Ok(()) } else { cvt(unsafe { libc::kill(self.pid, libc::SIGKILL) }).map(drop) } @@ -788,31 +876,47 @@ fn signal_string(signal: i32) -> &'static str { libc::SIGILL => " (SIGILL)", libc::SIGTRAP => " (SIGTRAP)", libc::SIGABRT => " (SIGABRT)", + #[cfg(not(target_os = "l4re"))] libc::SIGBUS => " (SIGBUS)", libc::SIGFPE => " (SIGFPE)", libc::SIGKILL => " (SIGKILL)", + #[cfg(not(target_os = "l4re"))] libc::SIGUSR1 => " (SIGUSR1)", libc::SIGSEGV => " (SIGSEGV)", + #[cfg(not(target_os = "l4re"))] libc::SIGUSR2 => " (SIGUSR2)", libc::SIGPIPE => " (SIGPIPE)", libc::SIGALRM => " (SIGALRM)", libc::SIGTERM => " (SIGTERM)", + #[cfg(not(target_os = "l4re"))] libc::SIGCHLD => " (SIGCHLD)", + #[cfg(not(target_os = "l4re"))] libc::SIGCONT => " (SIGCONT)", + #[cfg(not(target_os = "l4re"))] libc::SIGSTOP => " (SIGSTOP)", + #[cfg(not(target_os = "l4re"))] libc::SIGTSTP => " (SIGTSTP)", + #[cfg(not(target_os = "l4re"))] libc::SIGTTIN => " (SIGTTIN)", + #[cfg(not(target_os = "l4re"))] libc::SIGTTOU => " (SIGTTOU)", + #[cfg(not(target_os = "l4re"))] libc::SIGURG => " (SIGURG)", + #[cfg(not(target_os = "l4re"))] libc::SIGXCPU => " (SIGXCPU)", + #[cfg(not(target_os = "l4re"))] libc::SIGXFSZ => " (SIGXFSZ)", + #[cfg(not(target_os = "l4re"))] libc::SIGVTALRM => " (SIGVTALRM)", + #[cfg(not(target_os = "l4re"))] libc::SIGPROF => " (SIGPROF)", + #[cfg(not(target_os = "l4re"))] libc::SIGWINCH => " (SIGWINCH)", - #[cfg(not(target_os = "haiku"))] + #[cfg(not(any(target_os = "haiku", target_os = "l4re")))] libc::SIGIO => " (SIGIO)", #[cfg(target_os = "haiku")] libc::SIGPOLL => " (SIGPOLL)", + #[cfg(not(target_os = "l4re"))] libc::SIGSYS => " (SIGSYS)", // For information on Linux signals, run `man 7 signal` #[cfg(all( |