Prefer stpcpy to strcat

* admin/merge-gnulib (GNULIB_MODULES): Add stpcpy.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* lib/stpcpy.c, m4/stpcpy.m4: New files, from gnulib.
* lib-src/ebrowse.c (sym_scope_1, operator_name, open_file):
* lib-src/emacsclient.c (get_server_config, set_local_socket)
(start_daemon_and_retry_set_socket):
* lib-src/etags.c (main, C_entries, relative_filename):
* lib-src/pop.c (sendline):
* lib-src/update-game-score.c (main):
* lwlib/xlwmenu.c (resource_widget_value):
* src/callproc.c (child_setup):
* src/dbusbind.c (xd_signature_cat):
* src/doc.c (get_doc_string, Fsnarf_documentation):
* src/editfns.c (Fuser_full_name):
* src/frame.c (xrdb_get_resource):
* src/gtkutil.c (xg_get_file_with_chooser):
* src/tparam.c (tparam1):
* src/xfns.c (xic_create_fontsetname):
* src/xrdb.c (gethomedir, get_user_db, get_environ_db):
* src/xsmfns.c (smc_save_yourself_CB):
Rewrite to avoid the need for strcat, typically by using stpcpy
and/or lispstpcpy.  strcat tends to be part of O(N**2) algorithms.
* src/doc.c (sibling_etc):
* src/xrdb.c (xdefaults):
Now a top-level static constant.

1 files changed, 20 insertions, 24 deletions

diff --git a/src/xrdb.c b/src/xrdb.c
index 32ad3c7f01e..e21206d0800 100644
--- a/src/xrdb.c
+++ b/src/xrdb.c
@@ -232,9 +232,10 @@ gethomedir (void)
   if (ptr == NULL)
     return xstrdup ("/");
 
-  copy = xmalloc (strlen (ptr) + 2);
-  strcpy (copy, ptr);
-  return strcat (copy, "/");
+  ptrdiff_t len = strlen (ptr);
+  copy = xmalloc (len + 2);
+  strcpy (copy + len, "/");
+  return memcpy (copy, ptr, len);
 }
 
 
@@ -334,6 +335,7 @@ get_user_app (const char *class)
   return db;
 }
 
+static char const xdefaults[] = ".Xdefaults";
 
 static XrmDatabase
 get_user_db (Display *display)
@@ -351,16 +353,12 @@ get_user_db (Display *display)
     db = XrmGetStringDatabase (xdefs);
   else
     {
-      char *home;
-      char *xdefault;
-
-      home = gethomedir ();
-      xdefault = xmalloc (strlen (home) + sizeof ".Xdefaults");
-      strcpy (xdefault, home);
-      strcat (xdefault, ".Xdefaults");
-      db = XrmGetFileDatabase (xdefault);
-      xfree (home);
-      xfree (xdefault);
+      char *home = gethomedir ();
+      ptrdiff_t homelen = strlen (home);
+      char *filename = xrealloc (home, homelen + sizeof xdefaults);
+      strcpy (filename + homelen, xdefaults);
+      db = XrmGetFileDatabase (filename);
+      xfree (filename);
     }
 
 #ifdef HAVE_XSCREENRESOURCESTRING
@@ -380,24 +378,22 @@ static XrmDatabase
 get_environ_db (void)
 {
   XrmDatabase db;
-  char *p;
-  char *path = 0;
+  char *p = getenv ("XENVIRONMENT");
+  char *filename = 0;
 
-  if ((p = getenv ("XENVIRONMENT")) == NULL)
+  if (!p)
     {
-      static char const xdefaults[] = ".Xdefaults-";
       char *home = gethomedir ();
-      char const *host = SSDATA (Vsystem_name);
-      ptrdiff_t pathsize = (strlen (home) + sizeof xdefaults
-                            + SBYTES (Vsystem_name));
-      path = xrealloc (home, pathsize);
-      strcat (strcat (path, xdefaults), host);
-      p = path;
+      ptrdiff_t homelen = strlen (home);
+      ptrdiff_t filenamesize = (homelen + sizeof xdefaults
+                                + SBYTES (Vsystem_name));
+      p = filename = xrealloc (home, filenamesize);
+      lispstpcpy (stpcpy (filename + homelen, xdefaults), Vsystem_name);
     }
 
   db = XrmGetFileDatabase (p);
 
-  xfree (path);
+  xfree (filename);
 
   return db;
 }