Merge from mainline.

1 files changed, 19 insertions, 7 deletions

diff --git a/src/sysdep.c b/src/sysdep.c
index 3dc255933ee..0d9b31f35cd 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -1825,10 +1825,18 @@ emacs_close (int fd)
   return rtnval;
 }
 
-int
-emacs_read (int fildes, char *buf, unsigned int nbyte)
+ssize_t
+emacs_read (int fildes, char *buf, size_t nbyte)
 {
-  register int rtnval;
+  register ssize_t rtnval;
+
+  /* Defend against the possibility that a buggy caller passes a negative NBYTE
+     argument, which would be converted to a large unsigned size_t NBYTE.  This
+     defense prevents callers from doing large writes, unfortunately.  This
+     size restriction can be removed once we have carefully checked that there
+     are no such callers.  */
+  if ((ssize_t) nbyte < 0)
+    abort ();
 
   while ((rtnval = read (fildes, buf, nbyte)) == -1
          && (errno == EINTR))
@@ -1836,14 +1844,18 @@ emacs_read (int fildes, char *buf, unsigned int nbyte)
   return (rtnval);
 }
 
-int
-emacs_write (int fildes, const char *buf, unsigned int nbyte)
+ssize_t
+emacs_write (int fildes, const char *buf, size_t nbyte)
 {
-  register int rtnval, bytes_written;
+  register ssize_t rtnval, bytes_written;
+
+  /* Defend against negative NBYTE, as in emacs_read.  */
+  if ((ssize_t) nbyte < 0)
+    abort ();
 
   bytes_written = 0;
 
-  while (nbyte > 0)
+  while (nbyte != 0)
     {
       rtnval = write (fildes, buf, nbyte);