fix: GCC8 and later gives warnings for strncpy and strncat

When we use strncpy and strncat, we have allocated one more byte for the terminal NULL character. However, the GCC after version 8 will report warnings (-Wstringop-truncation) even when we use strncpy and strncat correctly. Replace strncpy and strncat with memcpy to avoid these warnings.
argtable · Nov 24, 2019 · 1c1bb23 · 1c1bb23
1 parent fef63d8
commit 1c1bb23
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Showing 2 changed files with 9 additions and 8 deletions.
diff --git a/src/arg_cmd.c b/src/arg_cmd.c
@@ -61,7 +61,7 @@ void arg_set_module_name(const char* name) {
 #if (defined(__STDC_LIB_EXT1__) && defined(__STDC_WANT_LIB_EXT1__)) || (defined(__STDC_SECURE_LIB__) && defined(__STDC_WANT_SECURE_LIB__))
     strncpy_s(s_module_name, slen + 1, name, slen);
 #else
-    strncpy(s_module_name, name, slen);
+    memcpy(s_module_name, name, slen);
 #endif
 }
 
@@ -81,7 +81,7 @@ void arg_set_module_version(int major, int minor, int patch, const char* tag) {
 #if (defined(__STDC_LIB_EXT1__) && defined(__STDC_WANT_LIB_EXT1__)) || (defined(__STDC_SECURE_LIB__) && defined(__STDC_WANT_SECURE_LIB__))
     strncpy_s(s_mod_ver_tag, slen_tag + 1, tag, slen_tag);
 #else
-    strncpy(s_mod_ver_tag, tag, slen_tag);
+    memcpy(s_mod_ver_tag, tag, slen_tag);
 #endif
 
     ds = arg_dstr_create();
@@ -98,7 +98,7 @@ void arg_set_module_version(int major, int minor, int patch, const char* tag) {
 #if (defined(__STDC_LIB_EXT1__) && defined(__STDC_WANT_LIB_EXT1__)) || (defined(__STDC_SECURE_LIB__) && defined(__STDC_WANT_SECURE_LIB__))
     strncpy_s(s_mod_ver, slen_ds + 1, arg_dstr_cstr(ds), slen_ds);
 #else
-    strncpy(s_mod_ver, arg_dstr_cstr(ds), slen_ds);
+    memcpy(s_mod_ver, arg_dstr_cstr(ds), slen_ds);
 #endif
 
     arg_dstr_destroy(ds);
@@ -153,8 +153,8 @@ void arg_cmd_register(const char* name, arg_cmdfn* proc, const char* description
     strncpy_s(cmd_info->name, ARG_CMD_NAME_LEN, name, strlen(name));
     strncpy_s(cmd_info->description, ARG_CMD_DESCRIPTION_LEN, description, strlen(description));
 #else
-    strncpy(cmd_info->name, name, strlen(name));
-    strncpy(cmd_info->description, description, strlen(description));
+    memcpy(cmd_info->name, name, strlen(name));
+    memcpy(cmd_info->description, description, strlen(description));
 #endif
 
     cmd_info->proc = proc;
@@ -166,7 +166,7 @@ void arg_cmd_register(const char* name, arg_cmdfn* proc, const char* description
 #if (defined(__STDC_LIB_EXT1__) && defined(__STDC_WANT_LIB_EXT1__)) || (defined(__STDC_SECURE_LIB__) && defined(__STDC_WANT_SECURE_LIB__))
     strncpy_s((char*)k, slen_name + 1, name, slen_name);
 #else
-    strncpy((char*)k, name, slen_name);
+    memcpy((char*)k, name, slen_name);
 #endif
 
     arg_hashtable_insert(s_hashtable, k, cmd_info);

diff --git a/src/arg_dstr.c b/src/arg_dstr.c
@@ -174,12 +174,12 @@ char* arg_dstr_cstr(arg_dstr_t ds) /* Interpreter whose result to return. */
 
 void arg_dstr_cat(arg_dstr_t ds, const char* str) {
     setup_append_buf(ds, (int)strlen(str) + 1);
-    strncat(ds->data, str, strlen(str));
+    memcpy(ds->data + strlen(ds->data), str, strlen(str));
 }
 
 void arg_dstr_catc(arg_dstr_t ds, char c) {
     setup_append_buf(ds, 2);
-    strncat(ds->data, &c, 1);
+    memcpy(ds->data + strlen(ds->data), &c, 1);
 }
 
 /*
@@ -296,6 +296,7 @@ static void setup_append_buf(arg_dstr_t ds, int new_space) {
             total_space *= 2;
         }
         newbuf = (char*)xmalloc((unsigned)total_space);
+        memset(newbuf, 0, total_space);
         strcpy(newbuf, ds->data);
         if (ds->append_data != NULL) {
             xfree(ds->append_data);