[PATCH 4/4] enhance overflow and truncation detection in strncpy and strncat (PR 81117)

[Martin Sebor <msebor at gmail dot com>]

For completeness, patch 4 are the (already preapproved) fixups
to GCC to let it compile with the -Wstringop-truncation option.
I will commit this patch shortly.

Martin

PR c/81117 - Improve buffer overflow checking in strncpy

gcc/ada/ChangeLog:

	PR c/81117
	* adadecode.c (__gnat_decode): Replace pointless strncpy with
	memcpy.
	* argv.c (__gnat_fill_arg): Same.

gcc/c-family/ChangeLog:

	PR c/81117
	* c-common.c (resort_sorted_fields): Replace pointless strncpy
	with memcpy.

gcc/fortran/ChangeLog:

	PR c/81117
	* decl.c (build_sym): Replace pointless strncpy with strcpy.

gcc/objc/ChangeLog:

	PR c/81117
	* objc-encoding.c (encode_type): Replace pointless strncpy with
	memcpy.

diff --git a/gcc/ada/adadecode.c b/gcc/ada/adadecode.c
index 8c9c7ab..0cbef81 100644
--- a/gcc/ada/adadecode.c
+++ b/gcc/ada/adadecode.c
@@ -330,7 +330,7 @@ __gnat_decode (const char *coded_name, char *ada_name, int verbose)
 	      }
 
 	    /* Write symbol in the space.  */
-	    strncpy (optoken, trans_table[k][1], oplen);
+	    memcpy (optoken, trans_table[k][1], oplen);
 	  }
 	else
 	  k++;
diff --git a/gcc/ada/argv.c b/gcc/ada/argv.c
index 430404e..aee0f88 100644
--- a/gcc/ada/argv.c
+++ b/gcc/ada/argv.c
@@ -92,7 +92,7 @@ void
 __gnat_fill_arg (char *a, int i)
 {
   if (gnat_argv != NULL)
-    strncpy (a, gnat_argv[i], strlen(gnat_argv[i]));
+    memcpy (a, gnat_argv[i], strlen (gnat_argv[i]));
 }
 
 int
@@ -118,7 +118,7 @@ void
 __gnat_fill_env (char *a, int i)
 {
   if (gnat_envp != NULL)
-    strncpy (a, gnat_envp[i], strlen (gnat_envp[i]));
+    memcpy (a, gnat_envp[i], strlen (gnat_envp[i]));
 }
 
 #ifdef __cplusplus
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index feb0904..8c18caf 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -5942,10 +5942,10 @@ resort_sorted_fields (void *obj,
 static char *
 catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
 {
-  const int lhs_size = strlen (lhs);
+  const size_t lhs_size = strlen (lhs);
   char *result = XNEWVEC (char, lhs_size + rhs_size);
-  strncpy (result, lhs, lhs_size);
-  strncpy (result + lhs_size, rhs_start, rhs_size);
+  memcpy (result, lhs, lhs_size);
+  memcpy (result + lhs_size, rhs_start, rhs_size);
   return result;
 }
 
diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index 54ee5d3..82971e8 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -1417,11 +1417,9 @@ build_sym (const char *name, gfc_charlen *cl, bool cl_deferred,
     {
       char u_name[GFC_MAX_SYMBOL_LEN + 1];
       gfc_symtree *st;
-      int nlen;
 
-      nlen = strlen(name);
-      gcc_assert (nlen <= GFC_MAX_SYMBOL_LEN);
-      strncpy (u_name, name, nlen + 1);
+      gcc_assert (strlen(name) <= GFC_MAX_SYMBOL_LEN);
+      strcpy (u_name, name);
       u_name[0] = upper;
 
       st = gfc_find_symtree (gfc_current_ns->sym_root, u_name);
diff --git a/gcc/objc/objc-encoding.c b/gcc/objc/objc-encoding.c
index 2a2dfa5..e5d4f38 100644
--- a/gcc/objc/objc-encoding.c
+++ b/gcc/objc/objc-encoding.c
@@ -734,7 +734,7 @@ encode_type (tree type, int curtype, int format)
 
 	  /* Rewrite "in const" from "nr" to "rn".  */
 	  if (curtype >= 1 && !strncmp (enc - 1, "nr", 2))
-	    strncpy (enc - 1, "rn", 2);
+	    memcpy (enc - 1, "rn", 2);
 	}
     }
 }