diff --git a/library/std/src/sys/unix/process/process_unix.rs b/library/std/src/sys/unix/process/process_unix.rs index ebdcb5acf22..ceaff596684 100644 --- a/library/std/src/sys/unix/process/process_unix.rs +++ b/library/std/src/sys/unix/process/process_unix.rs @@ -31,6 +31,15 @@ use libc::{c_int, pid_t}; #[cfg(not(any(target_os = "vxworks", target_os = "l4re")))] 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; + } +} + //////////////////////////////////////////////////////////////////////////////// // Command //////////////////////////////////////////////////////////////////////////////// @@ -141,11 +150,31 @@ impl Command { // Attempts to fork the process. If successful, returns Ok((0, -1)) // in the child, and Ok((child_pid, -1)) in the parent. - #[cfg(not(target_os = "linux", target_os = "nto"))] + #[cfg(not(any(target_os = "linux", 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)) } + // On QNX Neutrino, fork can fail with EBADF in case "another thread might have opened + // or closed a file descriptor while the fork() was occurring". + // Documentation says "... or try calling fork() again". This is what we do here. + // See also https://www.qnx.com/developers/docs/7.1/#com.qnx.doc.neutrino.lib_ref/topic/f/fork.html + #[cfg(all(target_os = "nto", target_env = "nto71"))] + 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; + 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; + } else { + return cvt(r).map(|res| (res, -1)); + } + } + } + // Attempts to fork the process. If successful, returns Ok((0, -1)) // in the child, and Ok((child_pid, child_pidfd)) in the parent. #[cfg(target_os = "linux")] @@ -439,6 +468,34 @@ impl Command { } } + // On QNX Neutrino, posix_spawnp can fail with EBADF in case "another thread might have opened + // or closed a file descriptor while the posix_spawn() was occurring". + // Documentation says "... or try calling posix_spawn() again". This is what we do here. + // See also http://www.qnx.com/developers/docs/7.1/#com.qnx.doc.neutrino.lib_ref/topic/p/posix_spawn.html + #[cfg(all(target_os = "nto", target_env = "nto71"))] + unsafe fn retrying_libc_posix_spawnp( + pid: *mut pid_t, + file: *const c_char, + file_actions: *const posix_spawn_file_actions_t, + attrp: *const posix_spawnattr_t, + argv: *const *mut c_char, + envp: *const *mut c_char, + ) -> i32 { + let mut tries_left = MAX_FORKSPAWN_TRIES; + loop { + match libc::posix_spawnp(pid, file, file_actions, attrp, argv, envp) { + libc::EBADF if tries_left > 0 => { + thread::yield_now(); + tries_left -= 1; + continue; + } + r => { + return r; + } + } + } + } + // Solaris, glibc 2.29+, and musl 1.24+ can set a new working directory, // and maybe others will gain this non-POSIX function too. We'll check // for this weak symbol as soon as it's needed, so we can return early @@ -558,7 +615,12 @@ impl Command { // Make sure we synchronize access to the global `environ` resource let _env_lock = sys::os::env_read_lock(); let envp = envp.map(|c| c.as_ptr()).unwrap_or_else(|| *sys::os::environ() as *const _); - cvt_nz(libc::posix_spawnp( + + #[cfg(not(target_os = "nto"))] + let spawn_fn = libc::posix_spawnp; + #[cfg(target_os = "nto")] + let spawn_fn = retrying_libc_posix_spawnp; + cvt_nz(spawn_fn( &mut p.pid, self.get_program_cstr().as_ptr(), file_actions.0.as_ptr(),