Merge #2598 'set stdin as "blocking" on exit'

8 files changed, 52 insertions, 13 deletions

diff --git a/src/nvim/if_cscope.c b/src/nvim/if_cscope.c
index 407709866c..99926ecf16 100644
--- a/src/nvim/if_cscope.c
+++ b/src/nvim/if_cscope.c
@@ -820,6 +820,7 @@ err_closing:
     if (execl("/bin/sh", "sh", "-c", cmd, (char *)NULL) == -1)
       PERROR(_("cs_create_connection exec failed"));
 
+    stream_set_blocking(input_global_fd(), true);  // normalize stream (#2598)
     exit(127);
   /* NOTREACHED */
   default:      /* parent. */
diff --git a/src/nvim/main.c b/src/nvim/main.c
index 5f0372f30e..fc72039b5f 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -271,17 +271,15 @@ int main(int argc, char **argv)
       || params.output_isatty || params.err_isatty);
 
   if (reading_input) {
-    // Its possible that one of the startup commands(arguments, sourced scripts
-    // or plugins) will prompt the user, so start reading from a tty stream
-    // now. 
+    // One of the startup commands (arguments, sourced scripts or plugins) may
+    // prompt the user, so start reading from a tty now.
     int fd = fileno(stdin);
     if (!params.input_isatty || params.edit_type == EDIT_STDIN) {
-      // use stderr or stdout since stdin is not a tty and/or could be used to
-      // read the file we'll edit when the "-" argument is given(eg: cat file |
-      // nvim -)
+      // Use stderr or stdout since stdin is not a tty and/or could be used to
+      // read the "-" file (eg: cat file | nvim -)
       fd = params.err_isatty ? fileno(stderr) : fileno(stdout);
     }
-    input_start_stdin(fd);
+    input_start(fd);
   }
 
   // open terminals when opening files that start with term://
@@ -388,8 +386,8 @@ int main(int argc, char **argv)
   }
 
   if (!params.headless) {
-    // Stop reading from stdin, the UI layer will take over now
-    input_stop_stdin();
+    // Stop reading from input stream, the UI layer will take over now.
+    input_stop();
     ui_builtin_start();
   }
 
diff --git a/src/nvim/misc1.c b/src/nvim/misc1.c
index 3ae3d6e30e..0737caec5d 100644
--- a/src/nvim/misc1.c
+++ b/src/nvim/misc1.c
@@ -2679,6 +2679,7 @@ void preserve_exit(void)
 
   // Prevent repeated calls into this method.
   if (really_exiting) {
+    stream_set_blocking(input_global_fd(), true);  //normalize stream (#2598)
     exit(2);
   }
 
diff --git a/src/nvim/os/event.c b/src/nvim/os/event.c
index 0560da1e2e..b0bd7ca55a 100644
--- a/src/nvim/os/event.c
+++ b/src/nvim/os/event.c
@@ -73,7 +73,7 @@ void event_teardown(void)
   // is required because the `process_events_from` above may call `event_push`
   // which will set the stop_flag to 1(uv_stop)
   uv_default_loop()->stop_flag = 0;
-  input_stop_stdin();
+  input_stop();
   channel_teardown();
   job_teardown();
   server_teardown();
diff --git a/src/nvim/os/input.c b/src/nvim/os/input.c
index 486171b48a..74a5d3bc2e 100644
--- a/src/nvim/os/input.c
+++ b/src/nvim/os/input.c
@@ -1,6 +1,5 @@
 #include <assert.h>
 #include <string.h>
-#include <stdint.h>
 #include <stdbool.h>
 
 #include <uv.h>
@@ -34,6 +33,7 @@ typedef enum {
 static RStream *read_stream = NULL;
 static RBuffer *read_buffer = NULL, *input_buffer = NULL;
 static bool input_eof = false;
+static int global_fd = 0;
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "os/input.c.generated.h"
@@ -46,19 +46,26 @@ void input_init(void)
   input_buffer = rbuffer_new(INPUT_BUFFER_SIZE + MAX_KEY_CODE_LEN);
 }
 
-void input_start_stdin(int fd)
+/// Gets the file from which input was gathered at startup.
+int input_global_fd(void)
+{
+  return global_fd;
+}
+
+void input_start(int fd)
 {
   if (read_stream) {
     return;
   }
 
+  global_fd = fd;
   read_buffer = rbuffer_new(READ_BUFFER_SIZE);
   read_stream = rstream_new(read_cb, read_buffer, NULL);
   rstream_set_file(read_stream, fd);
   rstream_start(read_stream);
 }
 
-void input_stop_stdin(void)
+void input_stop(void)
 {
   if (!read_stream) {
     return;
diff --git a/src/nvim/os/os.h b/src/nvim/os/os.h
index 69bd1ff4fd..3dd099890c 100644
--- a/src/nvim/os/os.h
+++ b/src/nvim/os/os.h
@@ -12,6 +12,7 @@
 # include "os/mem.h.generated.h"
 # include "os/env.h.generated.h"
 # include "os/users.h.generated.h"
+# include "os/stream.h.generated.h"
 #endif
 
 #endif  // NVIM_OS_OS_H
diff --git a/src/nvim/os/stream.c b/src/nvim/os/stream.c
new file mode 100644
index 0000000000..0c448872c3
--- /dev/null
+++ b/src/nvim/os/stream.c
@@ -0,0 +1,30 @@
+// Functions for working with stdio streams (as opposed to RStream/WStream).
+
+#include <stdio.h>
+#include <stdbool.h>
+
+#include <uv.h>
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "os/stream.c.generated.h"
+#endif
+
+/// Sets the stream associated with `fd` to "blocking" mode.
+///
+/// @return `0` on success, or `-errno` on failure.
+int stream_set_blocking(int fd, bool blocking)
+{
+  // Private loop to avoid conflict with existing watcher(s):
+  //    uv__io_stop: Assertion `loop->watchers[w->fd] == w' failed.
+  uv_loop_t loop;
+  uv_pipe_t stream;
+  uv_loop_init(&loop);
+  uv_pipe_init(&loop, &stream, 0);
+  uv_pipe_open(&stream, fd);
+  int retval = uv_stream_set_blocking((uv_stream_t *)&stream, blocking);
+  uv_close((uv_handle_t *)&stream, NULL);
+  uv_run(&loop, UV_RUN_NOWAIT);  // not necessary, but couldn't hurt.
+  uv_loop_close(&loop);
+  return retval;
+}
+
diff --git a/src/nvim/os_unix.c b/src/nvim/os_unix.c
index b2d5bae477..ccd0073db1 100644
--- a/src/nvim/os_unix.c
+++ b/src/nvim/os_unix.c
@@ -181,6 +181,7 @@ void mch_exit(int r)
   ml_close_all(TRUE);           /* remove all memfiles */
 
   event_teardown();
+  stream_set_blocking(input_global_fd(), true);  // normalize stream (#2598)
 
 #ifdef EXITFREE
   free_all_mem();