Backport Bug#11374 fix from trunk

2 files changed, 26 insertions, 19 deletions

diff --git a/lib-src/ChangeLog b/lib-src/ChangeLog
index 8e07193ae0c..90fd722141b 100644
--- a/lib-src/ChangeLog
+++ b/lib-src/ChangeLog
@@ -1,4 +1,7 @@
-2012-05-02  Jim Meyering  <meyering@redhat.com>
+2012-05-02  Jim Meyering  <jim@meyering.net>
+
+        * emacsclient.c (send_to_emacs): Avoid invalid strcpy upon partial
+        send (Bug#11374).
 
         * lib-src/pop.c (pop_stat, pop_list, pop_multi_first, pop_last):
         NUL-terminate the error buffer (Bug#11372).
diff --git a/lib-src/emacsclient.c b/lib-src/emacsclient.c
index 48b4384d487..931f6d10c5c 100644
--- a/lib-src/emacsclient.c
+++ b/lib-src/emacsclient.c
@@ -119,6 +119,8 @@ char *(getcwd) (char *, size_t);
 # define IF_LINT(Code) /* empty */
 #endif
 
+#define min(x, y) (((x) < (y)) ? (x) : (y))
+
 
 /* Name used to invoke this program.  */
 const char *progname;
@@ -783,33 +785,35 @@ sock_err_message (const char *function_name)
 static void
 send_to_emacs (HSOCKET s, const char *data)
 {
-  while (data)
+  size_t dlen;
+
+  if (!data)
+    return;
+
+  dlen = strlen (data);
+  while (*data)
     {
-      size_t dlen = strlen (data);
-      if (dlen + sblen >= SEND_BUFFER_SIZE)
-        {
-          int part = SEND_BUFFER_SIZE - sblen;
-          strncpy (&send_buffer[sblen], data, part);
-          data += part;
-          sblen = SEND_BUFFER_SIZE;
-        }
-      else if (dlen)
-        {
-          strcpy (&send_buffer[sblen], data);
-          data = NULL;
-          sblen += dlen;
-        }
-      else
-        break;
+      size_t part = min (dlen, SEND_BUFFER_SIZE - sblen);
+      memcpy (&send_buffer[sblen], data, part);
+      data += part;
+      sblen += part;
 
       if (sblen == SEND_BUFFER_SIZE
           || (sblen > 0 && send_buffer[sblen-1] == '\n'))
         {
           int sent = send (s, send_buffer, sblen, 0);
+          if (sent < 0)
+            {
+              message (TRUE, "%s: failed to send %d bytes to socket: %s\n",
+                       progname, sblen, strerror (errno));
+              fail ();
+            }
           if (sent != sblen)
-            strcpy (send_buffer, &send_buffer[sent]);
+            memmove (send_buffer, &send_buffer[sent], sblen - sent);
           sblen -= sent;
         }
+
+      dlen -= part;
     }
 }