add bzero and explicit_bzero

Signed-off-by: Mattias Andrée <maandree@operamail.com>

4 files changed, 125 insertions, 0 deletions

diff --git a/README b/README
index 35fe6d2..0dd19b9 100644
--- a/README
+++ b/README
@@ -10,6 +10,7 @@ Macro definitions:
 
 	_SLIBC_SOURCE             -- Enable slibc extensions.
 	_GNU_SOURCE               -- Enable glibc extensions (GNU extensions.)
+	_BSD_SOURCE               -- Enable BSD extensions.
 	_SLIBC_SUPPRESS_WARNINGS  -- Suppress all #warning, this is primarily
 	                               intended to be used when compiling slibc.
 	_PORTABLE_SOURCE          -- Unconditionally disable all extensions.
diff --git a/include/slibc/features.h b/include/slibc/features.h
index 0cbc326..f62f5cb 100644
--- a/include/slibc/features.h
+++ b/include/slibc/features.h
@@ -68,6 +68,18 @@
 #endif
 
 
+/**
+ * Mark a function, variable or type as deprecated,
+ * with a message that tells the user why the the
+ * function is deprecated, or functions to use instead.
+ */
+#if !defined(_SLIBC_SUPPRESS_WARNINGS)
+# define __deprecated(msg)  __GCC_ONLY(__attribute__((deprecated(msg))))
+#else
+# define __deprecated(msg)  /* ignore */
+#endif
+
+
 
 #endif
 
diff --git a/include/strings.h b/include/strings.h
new file mode 100644
index 0000000..6186b1a
--- /dev/null
+++ b/include/strings.h
@@ -0,0 +1,57 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _STRINGS_H
+#define _STRINGS_H
+#include <slibc/version.h>
+
+
+#include <slibc/features.h>
+
+
+
+#define __NEED_size_t
+
+#include <bits/types.h>
+
+
+
+/**
+ * Override a memory segment with zeroes.
+ * 
+ * @param  segment  The memory segment to override.
+ * @param  size     The size of the memory segment.
+ */
+void bzero(void*, size_t) __deprecated("Use 'memset', 'explicit_bzero' or 'secure_free' instead.");
+
+#if !defined(_PORTABLE_SOURCE) && (defined(_SLIBC_SOURCE) || defined(_BSD_SOURCE))
+/**
+ * Override a memory segment with zeroes.
+ * 
+ * Unlike `bzero` and `memset`, calls to this function
+ * cannot be removed, as an optimisation, by the compiler.
+ * 
+ * @param  segment  The memory segment to override.
+ * @param  size     The size of the memory segment.
+ */
+void explicit_bzero(void*, size_t);
+#endif
+
+
+
+#endif
+
diff --git a/src/strings/bzero.c b/src/strings/bzero.c
new file mode 100644
index 0000000..ab7a5f8
--- /dev/null
+++ b/src/strings/bzero.c
@@ -0,0 +1,55 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <strings.h>
+#include <string.h>
+
+
+
+/**
+ * `memset`, except calls to it cannot be removed by the compiler.
+ */
+void* (volatile *__slibc_explicit_memset)(void*, int, size_t) = memset;
+
+
+
+/**
+ * Override a memory segment with zeroes.
+ * 
+ * @param  segment  The memory segment to override.
+ * @param  size     The size of the memory segment.
+ */
+void bzero(void* segment, size_t size)
+{
+  memset(segment, 0, size);
+}
+
+
+/**
+ * Override a memory segment with zeroes.
+ * 
+ * Unlike `bzero` and `memset`, calls to this function
+ * cannot be removed, as an optimisation, by the compiler.
+ * 
+ * @param  segment  The memory segment to override.
+ * @param  size     The size of the memory segment.
+ */
+void explicit_bzero(void* segment, size_t size)
+{
+  __slibc_explicit_memset(segment, 0, size);
+}
+