Add ttyname_r(3).

libc/Makefile

@@ -532,6 +532,7 @@ unistd/tfork.o \
 unistd/truncateat.o \
 unistd/truncate.o \
 unistd/ttyname.o \
+unistd/ttyname_r.o \
 unistd/unlinkat.o \
 unistd/unlink.o \
 unistd/usleep.o \

libc/include/unistd.h

@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013.
+    Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2014.
 
     This file is part of the Sortix C Library.
 
@@ -320,7 +320,6 @@ int setreuid(uid_t, uid_t);
 pid_t setsid(void);
 void swab(const void* __restrict, void* __restrict, ssize_t);
 void sync(void);
-int ttyname_r(int, char*, size_t);
 #endif
 
 int access(const char*, int);
@@ -390,6 +389,7 @@ int tcsetpgrp(int, pid_t);
 int truncate(const char*, off_t);
 int truncateat(int dirfd, const char*, off_t);
 char* ttyname(int);
+int ttyname_r(int, char*, size_t);
 int usleep(useconds_t useconds);
 int unlinkat(int, const char*, int);
 int unlink(const char*);

libc/unistd/ttyname.cpp

@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2013.
+    Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
 
     This file is part of the Sortix C Library.
 
@@ -18,13 +18,28 @@
     along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
 
     unistd/ttyname.cpp
-    Returns the name of a terminal.
+    Returns the pathname of a terminal.
 
 *******************************************************************************/
 
+#include <errno.h>
+#include <stdlib.h>
 #include <unistd.h>
 
 extern "C" char* ttyname(int fd)
 {
-	return isatty(fd) ? (char*) "/dev/tty" : NULL;
+	static char* result = NULL;
+	static size_t result_size = 0;
+	while ( ttyname_r(fd, result, result_size) < 0 )
+	{
+		if ( errno != ERANGE )
+			return NULL;
+		size_t new_result_size = result_size ? 2 * result_size : 16;
+		char* new_result = (char*) realloc(result, new_result_size);
+		if ( !new_result )
+			return NULL;
+		result = new_result;
+		result_size = new_result_size;
+	}
+	return result;
 }

libc/unistd/ttyname_r.cpp

@@ -0,0 +1,38 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
+
+    This file is part of the Sortix C Library.
+
+    The Sortix C Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    The Sortix C Library 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 Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
+
+    unistd/ttyname_r.cpp
+    Returns the pathname of a terminal.
+
+*******************************************************************************/
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+extern "C" int ttyname_r(int fd, char* path, size_t path_size)
+{
+	if ( isatty(fd) < 1 )
+		return -1;
+	const char* result = "/dev/tty";
+	size_t result_length = strlen(result);
+	if ( result_length + 1 < path_size )
+		return errno = ERANGE, -1;
+	return strcpy(path, result), 0;
+}