Clean up errno reporting and fix some errno-reporting bugs.

* callproc.c (Fcall_process):
* fileio.c (Fcopy_file, Finsert_file_contents, Fwrite_region):
* process.c (create_process, Fmake_network_process):
* unexaix.c (report_error):
* unexcoff.c (report_error):
Be more careful about reporting the errno of failed operations.
The code previously reported the wrong errno sometimes.
Also, prefer report_file_errno to setting errno + report_file_error.
(Fcall_process): Look at openp return value rather than at path,
as that's a bit faster and clearer when there's a numeric predicate.
* fileio.c (report_file_errno): New function, with most of the
old contents of report_file_error.
(report_file_error): Use it.
(Ffile_exists_p, Ffile_accessible_directory_p):
Set errno to 0 when it is junk.
* fileio.c (Faccess_file):
* image.c (x_create_bitmap_from_file):
Use faccessat rather than opening the file, to avoid the hassle of
having a file descriptor open.
* lisp.h (report_file_errno): New decl.
* lread.c (Flocate_file_internal): File descriptor 0 is valid, too.

1 files changed, 12 insertions, 14 deletions

diff --git a/src/process.c b/src/process.c
index 81be29082fc..4a38c47443a 100644
--- a/src/process.c
+++ b/src/process.c
@@ -1616,6 +1616,7 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
 {
   int inchannel, outchannel;
   pid_t pid;
+  int vfork_errno;
   int sv[2];
 #ifndef WINDOWSNT
   int wait_child_setup[2];
@@ -1656,9 +1657,10 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
       forkout = sv[1];
       if (pipe2 (sv, O_CLOEXEC) != 0)
         {
+          int pipe_errno = errno;
           emacs_close (inchannel);
           emacs_close (forkout);
-          report_file_error ("Creating pipe", Qnil);
+          report_file_errno ("Creating pipe", Qnil, pipe_errno);
         }
       outchannel = sv[1];
       forkin = sv[0];
@@ -1837,6 +1839,7 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
 
   /* Back in the parent process.  */
 
+  vfork_errno = errno;
   XPROCESS (process)->pid = pid;
   if (pid >= 0)
     XPROCESS (process)->alive = 1;
@@ -1851,6 +1854,7 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
         emacs_close (forkin);
       if (forkin != forkout && forkout >= 0)
         emacs_close (forkout);
+      report_file_errno ("Doing vfork", Qnil, vfork_errno);
     }
   else
     {
@@ -1896,10 +1900,6 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
       }
 #endif
     }
-
-  /* Now generate the error if vfork failed.  */
-  if (pid < 0)
-    report_file_error ("Doing vfork", Qnil);
 }
 
 void
@@ -3265,12 +3265,11 @@ usage: (make-network-process &rest ARGS)  */)
 
           len = sizeof xerrno;
           eassert (FD_ISSET (s, &fdset));
-          if (getsockopt (s, SOL_SOCKET, SO_ERROR, &xerrno, &len) == -1)
+          if (getsockopt (s, SOL_SOCKET, SO_ERROR, &xerrno, &len) < 0)
             report_file_error ("getsockopt failed", Qnil);
           if (xerrno)
-            errno = xerrno, report_file_error ("error during connect", Qnil);
-          else
-            break;
+            report_file_errno ("error during connect", Qnil, xerrno);
+          break;
         }
 #endif /* !WINDOWSNT */
 
@@ -3354,11 +3353,10 @@ usage: (make-network-process &rest ARGS)  */)
       if (is_non_blocking_client)
           return Qnil;
 
-      errno = xerrno;
-      if (is_server)
-        report_file_error ("make server process failed", contact);
-      else
-        report_file_error ("make client process failed", contact);
+      report_file_errno ((is_server
+                          ? "make server process failed"
+                          : "make client process failed"),
+                         contact, xerrno);
     }
 
   inch = s;