commit 75c8f755015e4724ba45bd84137d41efa40a3025
parent 896968cad1ea853521ea71a9fef854337a21843c
Author: zeertzjq <zeertzjq@outlook.com>
Date: Fri, 9 Jan 2026 10:45:44 +0800
refactor(process): don't read from PTY master using uv_pipe_t
Using uv_pipe_t to read from PTY master may drop data if the PTY process
exits immediately after output, as libuv treats a partial read after
POLLHUP as EOF, which isn't true for PTY master on Linux. Therefore use
uv_poll_t instead.
This commit can be reverted if libuv/libuv#4992 is fixed for uv_pipe_t.
Diffstat:
7 files changed, 103 insertions(+), 18 deletions(-)
diff --git a/src/nvim/event/defs.h b/src/nvim/event/defs.h
@@ -78,12 +78,15 @@ typedef void (*stream_close_cb)(Stream *stream, void *data);
struct stream {
bool closed;
+ bool use_poll;
union {
uv_pipe_t pipe;
uv_tcp_t tcp;
uv_idle_t idle;
#ifdef MSWIN
uv_tty_t tty;
+#else
+ uv_poll_t poll;
#endif
} uv;
uv_stream_t *uvstream; ///< NULL when the stream is a file
diff --git a/src/nvim/event/proc.c b/src/nvim/event/proc.c
@@ -46,6 +46,16 @@ int proc_spawn(Proc *proc, bool in, bool out, bool err)
// forwarding stderr contradicts with processing it internally
assert(!(err && proc->fwd_err));
+#ifdef MSWIN
+ const bool out_use_poll = false;
+#else
+ // Using uv_pipe_t to read from PTY master may drop data if the PTY process exits
+ // immediately after output, as libuv treats a partial read after POLLHUP as EOF,
+ // which isn't true for PTY master on Linux. Therefore use uv_poll_t instead. #3030
+ // Ref: https://github.com/libuv/libuv/issues/4992
+ const bool out_use_poll = proc->type == kProcTypePty;
+#endif
+
if (in) {
uv_pipe_init(&proc->loop->uv, &proc->in.uv.pipe, 0);
} else {
@@ -53,7 +63,9 @@ int proc_spawn(Proc *proc, bool in, bool out, bool err)
}
if (out) {
- uv_pipe_init(&proc->loop->uv, &proc->out.s.uv.pipe, 0);
+ if (!out_use_poll) {
+ uv_pipe_init(&proc->loop->uv, &proc->out.s.uv.pipe, 0);
+ }
} else {
proc->out.s.closed = true;
}
@@ -83,7 +95,7 @@ int proc_spawn(Proc *proc, bool in, bool out, bool err)
if (in) {
uv_close((uv_handle_t *)&proc->in.uv.pipe, NULL);
}
- if (out) {
+ if (out && !out_use_poll) {
uv_close((uv_handle_t *)&proc->out.s.uv.pipe, NULL);
}
if (err) {
@@ -101,21 +113,29 @@ int proc_spawn(Proc *proc, bool in, bool out, bool err)
}
if (in) {
- stream_init(NULL, &proc->in, -1, (uv_stream_t *)&proc->in.uv.pipe);
+ stream_init(NULL, &proc->in, -1, false, (uv_stream_t *)&proc->in.uv.pipe);
proc->in.internal_data = proc;
proc->in.internal_close_cb = on_proc_stream_close;
proc->refcount++;
}
if (out) {
- stream_init(NULL, &proc->out.s, -1, (uv_stream_t *)&proc->out.s.uv.pipe);
+ if (out_use_poll) {
+#ifdef MSWIN
+ abort();
+#else
+ stream_init(proc->loop, &proc->out.s, ((PtyProc *)proc)->tty_fd, true, NULL);
+#endif
+ } else {
+ stream_init(NULL, &proc->out.s, -1, false, (uv_stream_t *)&proc->out.s.uv.pipe);
+ }
proc->out.s.internal_data = proc;
proc->out.s.internal_close_cb = on_proc_stream_close;
proc->refcount++;
}
if (err) {
- stream_init(NULL, &proc->err.s, -1, (uv_stream_t *)&proc->err.s.uv.pipe);
+ stream_init(NULL, &proc->err.s, -1, false, (uv_stream_t *)&proc->err.s.uv.pipe);
proc->err.s.internal_data = proc;
proc->err.s.internal_close_cb = on_proc_stream_close;
proc->refcount++;
diff --git a/src/nvim/event/rstream.c b/src/nvim/event/rstream.c
@@ -13,19 +13,25 @@
#include "nvim/os/os_defs.h"
#include "nvim/types_defs.h"
+#ifndef MSWIN
+# include <errno.h>
+
+# include "nvim/fileio.h"
+#endif
+
#include "event/rstream.c.generated.h"
void rstream_init_fd(Loop *loop, RStream *stream, int fd)
FUNC_ATTR_NONNULL_ARG(1, 2)
{
- stream_init(loop, &stream->s, fd, NULL);
+ stream_init(loop, &stream->s, fd, false, NULL);
rstream_init(stream);
}
void rstream_init_stream(RStream *stream, uv_stream_t *uvstream)
FUNC_ATTR_NONNULL_ARG(1, 2)
{
- stream_init(NULL, &stream->s, -1, uvstream);
+ stream_init(NULL, &stream->s, -1, false, uvstream);
rstream_init(stream);
}
@@ -45,6 +51,10 @@ void rstream_start_inner(RStream *stream)
{
if (stream->s.uvstream) {
uv_read_start(stream->s.uvstream, alloc_cb, read_cb);
+#ifndef MSWIN
+ } else if (stream->s.use_poll) {
+ uv_poll_start(&stream->s.uv.poll, UV_READABLE, poll_cb);
+#endif
} else {
uv_idle_start(&stream->s.uv.idle, fread_idle_cb);
}
@@ -72,6 +82,10 @@ void rstream_stop_inner(RStream *stream)
{
if (stream->s.uvstream) {
uv_read_stop(stream->s.uvstream);
+#ifndef MSWIN
+ } else if (stream->s.use_poll) {
+ uv_poll_stop(&stream->s.uv.poll);
+#endif
} else {
uv_idle_stop(&stream->s.uv.idle);
}
@@ -171,6 +185,46 @@ static void fread_idle_cb(uv_idle_t *handle)
invoke_read_cb(stream, false);
}
+#ifndef MSWIN
+static void poll_cb(uv_poll_t *handle, int status, int events)
+{
+ RStream *stream = handle->data;
+
+ if (status < 0) {
+ ELOG("poll error on Stream (%p) with descriptor %d: %s (%s)", (void *)stream,
+ stream->s.fd, uv_err_name(status), os_strerror(status));
+ return;
+ }
+ if (!(events & UV_READABLE)) {
+ return;
+ }
+
+ ssize_t cnt = read_eintr(stream->s.fd, stream->write_pos, rstream_space(stream));
+
+ if (cnt < 0) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK) {
+ return;
+ }
+ DLOG("closing Stream (%p) with descriptor %d: %s", (void *)stream,
+ stream->s.fd, strerror(errno));
+ }
+
+ if (cnt <= 0) {
+ // Read error or EOF, either way stop the stream and invoke the callback
+ // with eof == true
+ uv_poll_stop(handle);
+ invoke_read_cb(stream, true);
+ return;
+ }
+
+ // at this point we're sure that cnt is positive, no error occurred
+ size_t nread = (size_t)cnt;
+ stream->num_bytes += nread;
+ stream->write_pos += cnt;
+ invoke_read_cb(stream, false);
+}
+#endif
+
static void read_event(void **argv)
{
RStream *stream = argv[0];
diff --git a/src/nvim/event/socket.c b/src/nvim/event/socket.c
@@ -154,7 +154,7 @@ int socket_watcher_accept(SocketWatcher *watcher, RStream *stream)
return result;
}
- stream_init(NULL, &stream->s, -1, client);
+ stream_init(NULL, &stream->s, -1, false, client);
return 0;
}
@@ -244,7 +244,7 @@ tcp_retry:
status = 1;
LOOP_PROCESS_EVENTS_UNTIL(&main_loop, NULL, timeout, status != 1);
if (status == 0) {
- stream_init(NULL, &stream->s, -1, uv_stream);
+ stream_init(NULL, &stream->s, -1, false, uv_stream);
success = true;
} else {
if (!uv_is_closing((uv_handle_t *)uv_stream)) {
diff --git a/src/nvim/event/stream.c b/src/nvim/event/stream.c
@@ -40,11 +40,14 @@ int stream_set_blocking(int fd, bool blocking)
return retval;
}
-void stream_init(Loop *loop, Stream *stream, int fd, uv_stream_t *uvstream)
+void stream_init(Loop *loop, Stream *stream, int fd, bool poll, uv_stream_t *uvstream)
FUNC_ATTR_NONNULL_ARG(2)
{
// The underlying stream is either a file or an existing uv stream.
- assert(uvstream == NULL ? fd >= 0 && loop != NULL : fd < 0 && loop == NULL);
+ assert(uvstream == NULL ? fd >= 0 && loop != NULL : fd < 0 && loop == NULL && !poll);
+#ifdef MSWIN
+ assert(!poll);
+#endif
stream->uvstream = uvstream;
if (fd >= 0) {
@@ -52,6 +55,7 @@ void stream_init(Loop *loop, Stream *stream, int fd, uv_stream_t *uvstream)
stream->fd = fd;
if (type == UV_FILE) {
+ assert(!poll);
// Non-blocking file reads are simulated with an idle handle that reads in
// chunks of the ring buffer size, giving time for other events to be
// processed between reads.
@@ -67,6 +71,11 @@ void stream_init(Loop *loop, Stream *stream, int fd, uv_stream_t *uvstream)
SetConsoleMode(stream->uv.tty.handle, dwMode);
}
stream->uvstream = (uv_stream_t *)&stream->uv.tty;
+#else
+ } else if (poll) {
+ uv_poll_init(&loop->uv, &stream->uv.poll, fd);
+ stream->uv.poll.data = stream;
+ stream->use_poll = true;
#endif
} else {
assert(type == UV_NAMED_PIPE || type == UV_TTY);
@@ -125,7 +134,8 @@ void stream_close_handle(Stream *stream)
}
handle = (uv_handle_t *)stream->uvstream;
} else {
- handle = (uv_handle_t *)&stream->uv.idle;
+ // All members of the stream->uv union share the same address.
+ handle = (uv_handle_t *)&stream->uv;
}
assert(handle != NULL);
diff --git a/src/nvim/event/wstream.c b/src/nvim/event/wstream.c
@@ -23,14 +23,14 @@ typedef struct {
void wstream_init_fd(Loop *loop, Stream *stream, int fd, size_t maxmem)
FUNC_ATTR_NONNULL_ARG(1) FUNC_ATTR_NONNULL_ARG(2)
{
- stream_init(loop, stream, fd, NULL);
+ stream_init(loop, stream, fd, false, NULL);
wstream_init(stream, maxmem);
}
void wstream_init_stream(Stream *stream, uv_stream_t *uvstream, size_t maxmem)
FUNC_ATTR_NONNULL_ARG(1) FUNC_ATTR_NONNULL_ARG(2)
{
- stream_init(NULL, stream, -1, uvstream);
+ stream_init(NULL, stream, -1, false, uvstream);
wstream_init(stream, maxmem);
}
@@ -68,6 +68,7 @@ bool wstream_write(Stream *stream, WBuffer *buffer)
FUNC_ATTR_NONNULL_ALL
{
assert(stream->maxmem);
+ assert(!stream->use_poll);
// This should not be called after a stream was freed
assert(!stream->closed);
diff --git a/src/nvim/os/pty_proc_unix.c b/src/nvim/os/pty_proc_unix.c
@@ -214,10 +214,7 @@ int pty_proc_spawn(PtyProc *ptyproc)
&& (status = set_duplicating_descriptor(master, &proc->in.uv.pipe))) {
goto error;
}
- if (!proc->out.s.closed
- && (status = set_duplicating_descriptor(master, &proc->out.s.uv.pipe))) {
- goto error;
- }
+ // The stream_init() call in proc_spawn() will initialize proc->out.s.uv.poll.
ptyproc->tty_fd = master;
proc->pid = pid;
