Simplify by avoiding confusing use of strncpy etc.

17 files changed, 91 insertions, 94 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 84703fcdc2..af0fc3a8e3 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,37 @@
+2012-07-10  Paul Eggert  <[email protected]>
+
+	Simplify by avoiding confusing use of strncpy etc.
+	* doc.c (Fsnarf_documentation):
+	* fileio.c (Ffile_name_directory, Fsubstitute_in_file_name):
+	* frame.c (Fmake_terminal_frame):
+	* gtkutil.c (get_utf8_string):
+	* lread.c (openp):
+	* nsmenu.m (ns_update_menubar):
+	* regex.c (regerror):
+	Prefer memcpy to strncpy and strncat when either will do.
+	* fileio.c (Fsubstitute_in_file_name):
+	* keyboard.c (MULTI_LETTER_MOD, parse_modifiers_uncached)
+	(menu_separator_name_p):
+	* nsmenu.m (ns_update_menubar):
+	Prefer memcmp to strncmp when either will do.
+	* nsterm.m: Include <ftoastr.h>.
+	(ns_get_color):
+	* s/gnu-linux.h, s/sol2-6.h, s/unixware.h (PTY_TTY_NAME_SPRINTF):
+	Prefer snprintf to strncpy.
+	* nsterm.m (ns_term_init):
+	* widget.c (set_frame_size) [0]: Prefer xstrdup to xmalloc + strncpy.
+	* nsterm.m (ns_term_init):
+	Avoid the need for strncpy, by using build_string or
+	make_unibyte_string directly.  Use dtoastr, not snprintf.
+	* process.c (Fmake_network_process): Diagnose service names that
+	are too long, rather than silently truncating them or creating
+	non-null-terminated names.
+	(Fnetwork_interface_info): Likewise, for interface names.
+	* sysdep.c (system_process_attributes) [GNU_LINUX]:
+	Prefer sprintf to strncat.
+	* xdisp.c (debug_method_add) [GLYPH_DEBUG]:
+	Prefer vsnprintf to vsprintf + strncpy.
+
 2012-07-10  Glenn Morris  <[email protected]>
 
 	* dispnew.c (PENDING_OUTPUT_COUNT) [!__GNU_LIBRARY__]:
diff --git a/src/doc.c b/src/doc.c
index 7d82211fae..44363e30e8 100644
--- a/src/doc.c
+++ b/src/doc.c
@@ -645,7 +645,7 @@ the same file name is found in the `doc-directory'.  */)
                 {
                   ptrdiff_t len = end - p - 2;
                   char *fromfile = alloca (len + 1);
-                  strncpy (fromfile, &p[2], len);
+                  memcpy (fromfile, &p[2], len);
                   fromfile[len] = 0;
                   if (fromfile[len-1] == 'c')
                     fromfile[len-1] = 'o';
diff --git a/src/fileio.c b/src/fileio.c
index 5d4ee1bde0..eccb1fbb55 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -365,7 +365,7 @@ Given a Unix syntax file name, returns a string ending in slash.  */)
 
       if (p == beg + 4 && IS_DIRECTORY_SEP (*beg) && beg[1] == ':')
 	{
-	  strncpy (res, beg, 2);
+	  memcpy (res, beg, 2);
 	  beg += 2;
 	  r += 2;
 	}
@@ -1648,7 +1648,7 @@ those `/' is discarded.  */)
 
 	/* Copy out the variable name.  */
 	target = alloca (s - o + 1);
-	strncpy (target, o, s - o);
+	memcpy (target, o, s - o);
 	target[s - o] = 0;
 #ifdef DOS_NT
 	strupr (target); /* $home == $HOME etc.  */
@@ -1711,7 +1711,7 @@ those `/' is discarded.  */)
 
 	/* Copy out the variable name.  */
 	target = alloca (s - o + 1);
-	strncpy (target, o, s - o);
+	memcpy (target, o, s - o);
 	target[s - o] = 0;
 #ifdef DOS_NT
 	strupr (target); /* $home == $HOME etc.  */
@@ -1732,13 +1732,13 @@ those `/' is discarded.  */)
 	    orig = make_unibyte_string (o, orig_length);
 	    decoded = DECODE_FILE (orig);
 	    decoded_length = SBYTES (decoded);
-	    strncpy (x, SSDATA (decoded), decoded_length);
+	    memcpy (x, SDATA (decoded), decoded_length);
 	    x += decoded_length;
 
 	    /* If environment variable needed decoding, return value
 	       needs to be multibyte.  */
 	    if (decoded_length != orig_length
-		|| strncmp (SSDATA (decoded), o, orig_length))
+		|| memcmp (SDATA (decoded), o, orig_length))
 	      multibyte = 1;
 	  }
       }
diff --git a/src/frame.c b/src/frame.c
index 3a3f552603..8d7981777b 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -646,7 +646,7 @@ affects all frames on the same terminal device.  */)
       if (!NILP (tty))
         {
           name = alloca (SBYTES (tty) + 1);
-          strncpy (name, SSDATA (tty), SBYTES (tty));
+          memcpy (name, SSDATA (tty), SBYTES (tty));
           name[SBYTES (tty)] = 0;
         }
 
@@ -657,7 +657,7 @@ affects all frames on the same terminal device.  */)
       if (!NILP (tty_type))
         {
           type = alloca (SBYTES (tty_type) + 1);
-          strncpy (type, SSDATA (tty_type), SBYTES (tty_type));
+          memcpy (type, SSDATA (tty_type), SBYTES (tty_type));
           type[SBYTES (tty_type)] = 0;
         }
 
diff --git a/src/gtkutil.c b/src/gtkutil.c
index f4551b4b9f..290ecef921 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -529,7 +529,7 @@ get_utf8_string (const char *str)
                                        &bytes_written, &err))
              && err->code == G_CONVERT_ERROR_ILLEGAL_SEQUENCE)
         {
-          strncpy (up, (char *)p, bytes_written);
+          memcpy (up, p, bytes_written);
           sprintf (up + bytes_written, "\\%03o", p[bytes_written]);
           up += bytes_written+4;
           p += bytes_written+1;
diff --git a/src/keyboard.c b/src/keyboard.c
index 71c8d869ec..b34d3c470a 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -6134,7 +6134,7 @@ parse_modifiers_uncached (Lisp_Object symbol, ptrdiff_t *modifier_end)
 
 #define MULTI_LETTER_MOD(BIT, NAME, LEN)			\
 	  if (i + LEN + 1 <= SBYTES (name)			\
-	      && ! strncmp (SSDATA (name) + i, NAME, LEN))	\
+	      && ! memcmp (SDATA (name) + i, NAME, LEN))	\
 	    {							\
 	      this_mod_end = i + LEN;				\
 	      this_mod = BIT;					\
@@ -6172,13 +6172,13 @@ parse_modifiers_uncached (Lisp_Object symbol, ptrdiff_t *modifier_end)
   if (! (modifiers & (down_modifier | drag_modifier
 		      | double_modifier | triple_modifier))
       && i + 7 == SBYTES (name)
-      && strncmp (SSDATA (name) + i, "mouse-", 6) == 0
+      && memcmp (SDATA (name) + i, "mouse-", 6) == 0
       && ('0' <= SREF (name, i + 6) && SREF (name, i + 6) <= '9'))
     modifiers |= click_modifier;
 
   if (! (modifiers & (double_modifier | triple_modifier))
       && i + 6 < SBYTES (name)
-      && strncmp (SSDATA (name) + i, "wheel-", 6) == 0)
+      && memcmp (SDATA (name) + i, "wheel-", 6) == 0)
     modifiers |= click_modifier;
 
   if (modifier_end)
@@ -6630,7 +6630,7 @@ parse_solitary_modifier (Lisp_Object symbol)
 
 #define MULTI_LETTER_MOD(BIT, NAME, LEN)		\
       if (LEN == SBYTES (name)				\
-	  && ! strncmp (SSDATA (name), NAME, LEN))	\
+	  && ! memcmp (SDATA (name), NAME, LEN))	\
 	return BIT;
 
     case 'A':
@@ -7418,7 +7418,7 @@ menu_separator_name_p (const char *label)
   if (!label)
     return 0;
   else if (strlen (label) > 3
-	   && strncmp (label, "--", 2) == 0
+	   && memcmp (label, "--", 2) == 0
 	   && label[2] != '-')
     {
       int i;
diff --git a/src/lread.c b/src/lread.c
index bd85e44093..640414b3e9 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -1495,26 +1495,14 @@ openp (Lisp_Object path, Lisp_Object str, Lisp_Object suffixes, Lisp_Object *sto
 
 	  /* Concatenate path element/specified name with the suffix.
 	     If the directory starts with /:, remove that.  */
-	  if (SCHARS (filename) > 2
-	      && SREF (filename, 0) == '/'
-	      && SREF (filename, 1) == ':')
-	    {
-	      fnlen = SBYTES (filename) - 2;
-	      strncpy (fn, SSDATA (filename) + 2, fnlen);
-	      fn[fnlen] = '\0';
-	    }
-	  else
-	    {
-	      fnlen = SBYTES (filename);
-	      strncpy (fn, SSDATA (filename), fnlen);
-	      fn[fnlen] = '\0';
-	    }
-
-	  if (lsuffix != 0)  /* Bug happens on CCI if lsuffix is 0.  */
-	    {
-	      strncat (fn, SSDATA (XCAR (tail)), lsuffix);
-	      fnlen += lsuffix;
-	    }
+	  int prefixlen = ((SCHARS (filename) > 2
+			    && SREF (filename, 0) == '/'
+			    && SREF (filename, 1) == ':')
+			   ? 2 : 0);
+	  fnlen = SBYTES (filename) - prefixlen;
+	  memcpy (fn, SDATA (filename) + prefixlen, fnlen);
+	  memcpy (fn + fnlen, SDATA (XCAR (tail)), lsuffix + 1);
+	  fnlen += lsuffix;
 	  /* Check that the file exists and is not a directory.  */
 	  /* We used to only check for handlers on non-absolute file names:
 	        if (absolute)
diff --git a/src/nsmenu.m b/src/nsmenu.m
index cccecffb42..2cd626e131 100644
--- a/src/nsmenu.m
+++ b/src/nsmenu.m
@@ -426,7 +426,8 @@ ns_update_menubar (struct frame *f, int deep_p, EmacsMenu *submenu)
                   break;
               else
                 continue;
-              if (strncmp (previous_strings[i], SDATA (string), 10))
+              if (memcmp (previous_strings[i], SDATA (string),
+			  min (10, SBYTES (string) + 1)))
                 break;
             }
 
@@ -447,7 +448,8 @@ ns_update_menubar (struct frame *f, int deep_p, EmacsMenu *submenu)
 	    break;
 
           if (n < 100)
-            strncpy (previous_strings[i/4], SDATA (string), 10);
+	    memcpy (previous_strings[i/4], min (10, SBYTES (string) + 1),
+		    SDATA (string));
 
 	  wv = xmalloc_widget_value ();
 	  wv->name = SSDATA (string);
diff --git a/src/nsterm.m b/src/nsterm.m
index fde02f3ec9..0745efc35b 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -37,6 +37,7 @@ GNUstep port and post-20 update by Adrian Robert ([email protected])
 #include <unistd.h>
 #include <setjmp.h>
 #include <c-strcase.h>
+#include <ftoastr.h>
 
 #include "lisp.h"
 #include "blockinput.h"
@@ -1442,21 +1443,16 @@ ns_get_color (const char *name, NSColor **col)
       [scanner scanFloat: &b];
     }
   else if (!strncmp(name, "rgb:", 4))  /* A newer X11 format -- rgb:r/g/b */
-    {
-      strncpy (hex, name + 4, 19);
-      hex[19] = '\0';
-      scaling = (strlen(hex) - 2) / 3;
-    }
+    scaling = (snprintf (hex, sizeof hex, "%s", name + 4) - 2) / 3;
   else if (name[0] == '#')        /* An old X11 format; convert to newer */
     {
       int len = (strlen(name) - 1);
       int start = (len % 3 == 0) ? 1 : len / 4 + 1;
       int i;
       scaling = strlen(name+start) / 3;
-      for (i=0; i<3; i++) {
-        strncpy(hex + i * (scaling + 1), name + start + i * scaling, scaling);
-        hex[(i+1) * (scaling + 1) - 1] = '/';
-      }
+      for (i = 0; i < 3; i++)
+	snprintf (hex + i * (scaling + 1), "%.*s/", scaling,
+		  name + start + i * scaling);
       hex[3 * (scaling + 1) - 1] = '\0';
     }
 
@@ -4107,10 +4103,7 @@ ns_term_init (Lisp_Object display_name)
                                 ns_display_name_list);
   dpyinfo->name_list_element = XCAR (ns_display_name_list);
 
-  /* Set the name of the terminal. */
-  terminal->name = xmalloc (SBYTES (display_name) + 1);
-  strncpy (terminal->name, SDATA (display_name), SBYTES (display_name));
-  terminal->name[SBYTES (display_name)] = 0;
+  terminal->name = xstrdup (SSDATA (display_name));
 
   UNBLOCK_INPUT;
 
@@ -4167,14 +4160,14 @@ ns_term_init (Lisp_Object display_name)
   }
 
   {
-    char c[128];
 #ifdef NS_IMPL_GNUSTEP
-    strncpy (c, gnustep_base_version, sizeof (c));
+    Vwindow_system_version = build_string (gnustep_base_version);
 #else
     /*PSnextrelease (128, c); */
-    snprintf (c, sizeof (c), "%g", NSAppKitVersionNumber);
+    char c[DBL_BUFSIZE_BOUND];
+    int len = dtoastr (c, sizeof c, 0, 0, NSAppKitVersionNumber);
+    Vwindow_system_version = make_unibyte_string (c, len);
 #endif
-    Vwindow_system_version = build_string (c);
   }
 
   delete_keyboard_wait_descriptor (0);
diff --git a/src/process.c b/src/process.c
index b8c3a18b33..79100eb7a2 100644
--- a/src/process.c
+++ b/src/process.c
@@ -3013,7 +3013,9 @@ usage: (make-network-process &rest ARGS)  */)
       CHECK_STRING (service);
       memset (&address_un, 0, sizeof address_un);
       address_un.sun_family = AF_LOCAL;
-      strncpy (address_un.sun_path, SSDATA (service), sizeof address_un.sun_path);
+      if (sizeof address_un.sun_path <= SBYTES (service))
+	error ("Service name too long");
+      strcpy (address_un.sun_path, SSDATA (service));
       ai.ai_addr = (struct sockaddr *) &address_un;
       ai.ai_addrlen = sizeof address_un;
       goto open_socket;
@@ -3717,8 +3719,9 @@ FLAGS is the current flags of the interface.  */)
 
   CHECK_STRING (ifname);
 
-  memset (rq.ifr_name, 0, sizeof rq.ifr_name);
-  strncpy (rq.ifr_name, SSDATA (ifname), sizeof (rq.ifr_name));
+  if (sizeof rq.ifr_name <= SBYTES (ifname))
+    error ("interface name too long");
+  strcpy (rq.ifr_name, SSDATA (ifname));
 
   s = socket (AF_INET, SOCK_STREAM, 0);
   if (s < 0)
diff --git a/src/regex.c b/src/regex.c
index 751006d57b..4bf119402a 100644
--- a/src/regex.c
+++ b/src/regex.c
@@ -6644,7 +6644,7 @@ regerror (int err_code, const regex_t *preg, char *errbuf, size_t errbuf_size)
     {
       if (msg_size > errbuf_size)
 	{
-	  strncpy (errbuf, msg, errbuf_size - 1);
+	  memcpy (errbuf, msg, errbuf_size - 1);
 	  errbuf[errbuf_size - 1] = 0;
 	}
       else
diff --git a/src/s/gnu-linux.h b/src/s/gnu-linux.h
index e3d43249d8..6f45ee00b7 100644
--- a/src/s/gnu-linux.h
+++ b/src/s/gnu-linux.h
@@ -63,8 +63,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 	close (fd);					\
 	return -1;					\
       }							\
-    strncpy (pty_name, ptyname, sizeof (pty_name));	\
-    pty_name[sizeof (pty_name) - 1] = 0;		\
+    snprintf (pty_name, sizeof pty_name, "%s", ptyname); \
     sigunblock (sigmask (SIGCHLD));			\
   }
 
diff --git a/src/s/sol2-6.h b/src/s/sol2-6.h
index bb7a9859b7..ec45748e03 100644
--- a/src/s/sol2-6.h
+++ b/src/s/sol2-6.h
@@ -54,8 +54,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
       { emacs_close (fd); return -1; }		\
     if (!(ptyname = ptsname (fd)))		\
       { emacs_close (fd); return -1; }		\
-    strncpy (pty_name, ptyname, sizeof (pty_name)); \
-    pty_name[sizeof (pty_name) - 1] = 0;	\
+    snprintf (pty_name, sizeof pty_name, "%s", ptyname); \
   }
 
 #define GC_SETJMP_WORKS 1
diff --git a/src/s/unixware.h b/src/s/unixware.h
index e9ebb63f30..5bda987ffe 100644
--- a/src/s/unixware.h
+++ b/src/s/unixware.h
@@ -40,8 +40,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
       fatal("could not unlock slave pty");	\
     if (!(ptyname = ptsname(fd)))		\
       fatal ("could not enable slave pty");	\
-    strncpy(pty_name, ptyname, sizeof(pty_name)); \
-    pty_name[sizeof(pty_name) - 1] = 0;		\
+    snprintf (pty_name, sizeof pty_name, "%s", ptyname); \
   }
 
 /* Conservative garbage collection has not been tested, so for now
diff --git a/src/sysdep.c b/src/sysdep.c
index 0639b72285..ed92676041 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -2744,9 +2744,11 @@ system_process_attributes (Lisp_Object pid)
   char procbuf[1025], *p, *q;
   int fd;
   ssize_t nread;
-  const char *cmd = NULL;
+  static char const default_cmd[] = "???";
+  const char *cmd = default_cmd;
+  int cmdsize = sizeof default_cmd - 1;
   char *cmdline = NULL;
-  ptrdiff_t cmdsize = 0, cmdline_size;
+  ptrdiff_t cmdline_size;
   unsigned char c;
   printmax_t proc_id;
   int ppid, pgrp, sess, tty, tpgid, thcount;
@@ -2808,11 +2810,6 @@ system_process_attributes (Lisp_Object pid)
 	}
       else
 	q = NULL;
-      if (cmd == NULL)
-	{
-	  cmd = "???";
-	  cmdsize = 3;
-	}
       /* Command name is encoded in locale-coding-system; decode it.  */
       cmd_str = make_unibyte_string (cmd, cmdsize);
       decoded_cmd = code_convert_string_norecord (cmd_str,
@@ -2950,14 +2947,9 @@ system_process_attributes (Lisp_Object pid)
 	}
       if (!cmdline_size)
 	{
-	  if (!cmd)
-	    cmd = "???";
-	  if (!cmdsize)
-	    cmdsize = strlen (cmd);
 	  cmdline_size = cmdsize + 2;
 	  cmdline = xmalloc (cmdline_size + 1);
-	  strcpy (cmdline, "[");
-	  strcat (strncat (cmdline, cmd, cmdsize), "]");
+	  sprintf (cmdline, "[%.*s]", cmdsize, cmd);
 	}
       emacs_close (fd);
       /* Command line is encoded in locale-coding-system; decode it.  */
diff --git a/src/widget.c b/src/widget.c
index e219c200e0..b94c30f4e9 100644
--- a/src/widget.c
+++ b/src/widget.c
@@ -429,25 +429,15 @@ set_frame_size (EmacsFrame ew)
       {
 	/* the tricky things with the sign is to make sure that
 	   -0 is printed -0. */
-	int len;
-	char *tem;
 	sprintf (shell_position, "=%c%d%c%d",
 		 flags & XNegative ? '-' : '+', x < 0 ? -x : x,
 		 flags & YNegative ? '-' : '+', y < 0 ? -y : y);
-	len = strlen (shell_position) + 1;
-	tem = xmalloc (len);
-	strncpy (tem, shell_position, len);
-	XtVaSetValues (wmshell, XtNgeometry, tem, NULL);
+	XtVaSetValues (wmshell, XtNgeometry, xstrdup (shell_position), NULL);
       }
     else if (flags & (WidthValue | HeightValue))
       {
-	int len;
-	char *tem;
 	sprintf (shell_position, "=%dx%d", pixel_width, pixel_height);
-	len = strlen (shell_position) + 1;
-	tem = xmalloc (len);
-	strncpy (tem, shell_position, len);
-	XtVaSetValues (wmshell, XtNgeometry, tem, NULL);
+	XtVaSetValues (wmshell, XtNgeometry, xstrdup (shell_position), NULL);
       }
 
     /* If the geometry spec we're using has W/H components, mark the size
diff --git a/src/xdisp.c b/src/xdisp.c
index 1732e3dfe5..4c9f3fda0a 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -12492,23 +12492,21 @@ static void debug_method_add (struct window *, char const *, ...)
 static void
 debug_method_add (struct window *w, char const *fmt, ...)
 {
-  char buffer[512];
   char *method = w->desired_matrix->method;
   int len = strlen (method);
   int size = sizeof w->desired_matrix->method;
   int remaining = size - len - 1;
   va_list ap;
 
-  va_start (ap, fmt);
-  vsprintf (buffer, fmt, ap);
-  va_end (ap);
   if (len && remaining)
     {
       method[len] = '|';
       --remaining, ++len;
     }
 
-  strncpy (method + len, buffer, remaining);
+  va_start (ap, fmt);
+  vsnprintf (method + len, remaining + 1, fmt, ap);
+  va_end (ap);
 
   if (trace_redisplay_p)
     fprintf (stderr, "%p (%s): %s\n",
@@ -12517,7 +12515,7 @@ debug_method_add (struct window *w, char const *fmt, ...)
 	       && STRINGP (BVAR (XBUFFER (w->buffer), name)))
 	      ? SSDATA (BVAR (XBUFFER (w->buffer), name))
 	      : "no buffer"),
-	     buffer);
+	     method + len);
 }
 
 #endif /* GLYPH_DEBUG */