coverity/105985: Resource leak: RI.

Problem    : Resource leak @ 94, 98, 102.
Diagnostic : Real issue.
Rationale  : Coverity doesn't know that uv_pipe_open will save file
             descriptor to close them later. So, it signals file
             descriptors being leaked. This would then seem like a false
             positive we can fix by teaching coverity about uv_pipe_open
             through model file.
             But then we realize that the above is only true if
             uv_pipe_open succeeds. It it fails, then descriptors are
             really being leaked, which is why this is considered a real
             issue and not a false positive after all.
Resolution : Add error handling to correctly close descriptors if
             uv_pipe_open fails at any point.
             Add model for uv_pipe_open so that Coverity knows it will
             save descriptors when no error.

Helped-by: oni-link <knil.ino@gmail.com>

1 files changed, 26 insertions, 6 deletions

diff --git a/src/nvim/os/pty_process.c b/src/nvim/os/pty_process.c
index a1edebb846..ed98d3e0c0 100644
--- a/src/nvim/os/pty_process.c
+++ b/src/nvim/os/pty_process.c
@@ -70,6 +70,23 @@ void pty_process_destroy(Job *job)
   job->process = NULL;
 }
 
+static bool set_pipe_duplicating_descriptor(int fd, uv_pipe_t *pipe)
+{
+  int fd_dup = dup(fd);
+  if (fd_dup < 0) {
+    ELOG("Failed to dup descriptor %d: %s", fd, strerror(errno));
+    return false;
+  }
+  int uv_result = uv_pipe_open(pipe, fd_dup);
+  if (uv_result) {
+    ELOG("Failed to set pipe to descriptor %d: %s",
+         fd_dup, uv_strerror(uv_result));
+    close(fd_dup);
+    return false;
+  }
+  return true;
+}
+
 static const unsigned int KILL_RETRIES = 5;
 static const unsigned int KILL_TIMEOUT = 2;  // seconds
 
@@ -102,16 +119,19 @@ bool pty_process_spawn(Job *job)
     goto error;
   }
 
-  if (job->opts.writable) {
-    uv_pipe_open(&ptyproc->proc_stdin, dup(master));
+  if (job->opts.writable
+      && !set_pipe_duplicating_descriptor(master, &ptyproc->proc_stdin)) {
+    goto error;
   }
 
-  if (job->opts.stdout_cb) {
-    uv_pipe_open(&ptyproc->proc_stdout, dup(master));
+  if (job->opts.stdout_cb
+      && !set_pipe_duplicating_descriptor(master, &ptyproc->proc_stdout)) {
+    goto error;
   }
 
-  if (job->opts.stderr_cb) {
-    uv_pipe_open(&ptyproc->proc_stderr, dup(master));
+  if (job->opts.stderr_cb
+      && !set_pipe_duplicating_descriptor(master, &ptyproc->proc_stderr)) {
+    goto error;
   }
 
   uv_signal_init(uv_default_loop(), &ptyproc->schld);