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Fix error checking in posix_spawn implementation of Command #77717

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Merged
merged 2 commits into from
Oct 10, 2020
Merged

Fix error checking in posix_spawn implementation of Command #77717

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5faf25b
Check for non-zero return value from posix_spawn functions
tmiasko Oct 8, 2020
6cd5506
Check for errors returned from posix_spawn*_init functions
tmiasko Oct 8, 2020
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42 changes: 24 additions & 18 deletions library/std/src/sys/unix/process/process_unix.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -319,79 +319,85 @@ impl Command {

let mut p = Process { pid: 0, status: None };

struct PosixSpawnFileActions(MaybeUninit<libc::posix_spawn_file_actions_t>);
struct PosixSpawnFileActions<'a>(&'a mut MaybeUninit<libc::posix_spawn_file_actions_t>);

impl Drop for PosixSpawnFileActions {
impl Drop for PosixSpawnFileActions<'_> {
fn drop(&mut self) {
unsafe {
libc::posix_spawn_file_actions_destroy(self.0.as_mut_ptr());
}
}
}

struct PosixSpawnattr(MaybeUninit<libc::posix_spawnattr_t>);
struct PosixSpawnattr<'a>(&'a mut MaybeUninit<libc::posix_spawnattr_t>);

impl Drop for PosixSpawnattr {
impl Drop for PosixSpawnattr<'_> {
fn drop(&mut self) {
unsafe {
libc::posix_spawnattr_destroy(self.0.as_mut_ptr());
}
}
}

fn cvt_nz(error: libc::c_int) -> io::Result<()> {
if error == 0 { Ok(()) } else { Err(io::Error::from_raw_os_error(error)) }
}

unsafe {
let mut file_actions = PosixSpawnFileActions(MaybeUninit::uninit());
let mut attrs = PosixSpawnattr(MaybeUninit::uninit());
let mut attrs = MaybeUninit::uninit();
cvt_nz(libc::posix_spawnattr_init(attrs.as_mut_ptr()))?;
let attrs = PosixSpawnattr(&mut attrs);

libc::posix_spawnattr_init(attrs.0.as_mut_ptr());
libc::posix_spawn_file_actions_init(file_actions.0.as_mut_ptr());
let mut file_actions = MaybeUninit::uninit();
cvt_nz(libc::posix_spawn_file_actions_init(file_actions.as_mut_ptr()))?;
let file_actions = PosixSpawnFileActions(&mut file_actions);

if let Some(fd) = stdio.stdin.fd() {
cvt(libc::posix_spawn_file_actions_adddup2(
cvt_nz(libc::posix_spawn_file_actions_adddup2(
file_actions.0.as_mut_ptr(),
fd,
libc::STDIN_FILENO,
))?;
}
if let Some(fd) = stdio.stdout.fd() {
cvt(libc::posix_spawn_file_actions_adddup2(
cvt_nz(libc::posix_spawn_file_actions_adddup2(
file_actions.0.as_mut_ptr(),
fd,
libc::STDOUT_FILENO,
))?;
}
if let Some(fd) = stdio.stderr.fd() {
cvt(libc::posix_spawn_file_actions_adddup2(
cvt_nz(libc::posix_spawn_file_actions_adddup2(
file_actions.0.as_mut_ptr(),
fd,
libc::STDERR_FILENO,
))?;
}
if let Some((f, cwd)) = addchdir {
cvt(f(file_actions.0.as_mut_ptr(), cwd.as_ptr()))?;
cvt_nz(f(file_actions.0.as_mut_ptr(), cwd.as_ptr()))?;
}

let mut set = MaybeUninit::<libc::sigset_t>::uninit();
cvt(sigemptyset(set.as_mut_ptr()))?;
cvt(libc::posix_spawnattr_setsigmask(attrs.0.as_mut_ptr(), set.as_ptr()))?;
cvt_nz(libc::posix_spawnattr_setsigmask(attrs.0.as_mut_ptr(), set.as_ptr()))?;
cvt(sigaddset(set.as_mut_ptr(), libc::SIGPIPE))?;
cvt(libc::posix_spawnattr_setsigdefault(attrs.0.as_mut_ptr(), set.as_ptr()))?;
cvt_nz(libc::posix_spawnattr_setsigdefault(attrs.0.as_mut_ptr(), set.as_ptr()))?;

let flags = libc::POSIX_SPAWN_SETSIGDEF | libc::POSIX_SPAWN_SETSIGMASK;
cvt(libc::posix_spawnattr_setflags(attrs.0.as_mut_ptr(), flags as _))?;
cvt_nz(libc::posix_spawnattr_setflags(attrs.0.as_mut_ptr(), flags as _))?;

// Make sure we synchronize access to the global `environ` resource
let _env_lock = sys::os::env_lock();
let envp = envp.map(|c| c.as_ptr()).unwrap_or_else(|| *sys::os::environ() as *const _);
let ret = libc::posix_spawnp(
cvt_nz(libc::posix_spawnp(
&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 _,
);
if ret == 0 { Ok(Some(p)) } else { Err(io::Error::from_raw_os_error(ret)) }
))?;
Ok(Some(p))
}
}
}
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