Add getlogin(2) and getlogin_r(2).

libc/Makefile

@@ -221,6 +221,8 @@ getegid.o \
 geteuid.o \
 getgid.o \
 gethostname.o \
+getlogin.o \
+getlogin_r.o \
 getpagesize.o \
 getpid.o \
 getppid.o \

libc/getlogin.cpp

@@ -0,0 +1,48 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013.
+
+    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/>.
+
+    getlogin.cpp
+    Get name of user logged in at the controlling terminal.
+
+*******************************************************************************/
+
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+extern "C" char* getlogin()
+{
+	static char* buffer = NULL;
+	static size_t buffer_size = 0;
+
+	int ret;
+	while ( !buffer_size ||
+	        ((ret = getlogin_r(buffer, buffer_size)) < 0 && errno == ERANGE) )
+	{
+		size_t new_buffer_size = buffer_size ? buffer_size * 2 : 64;
+		char* new_buffer = (char*) realloc(buffer, new_buffer_size);
+		if ( !new_buffer )
+			return NULL;
+		buffer = new_buffer;
+		buffer_size = new_buffer_size;
+	}
+
+	return ret == 0 ? buffer : NULL;
+}

libc/getlogin_r.cpp

@@ -0,0 +1,39 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013.
+
+    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/>.
+
+    getlogin_r.cpp
+    Get name of user logged ina t the controlling terminal.
+
+*******************************************************************************/
+
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+extern "C" int getlogin_r(char* buf, size_t size)
+{
+	const char* env_username = getenv("USERNAME");
+	const char* username = env_username ? env_username : "root";
+	size_t username_len = strlen(username);
+	if ( size < (username_len + 1) * sizeof(char) )
+		return errno = ERANGE, -1;
+	strcpy(buf, username);
+	return 0;
+}

libc/include/unistd.h

@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
+    Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013.
 
     This file is part of the Sortix C Library.
 
@@ -115,8 +115,6 @@ int fexecve(int, char* const [], char* const []);
 long fpathconf(int, int);
 int getgroups(int, gid_t []);
 long gethostid(void);
-char* getlogin(void);
-int getlogin_r(char*, size_t);
 int getopt(int, char* const [], const char*);
 pid_t getpgid(pid_t);
 pid_t getpgrp(void);
@@ -170,6 +168,8 @@ char* get_current_dir_name(void);
 gid_t getegid(void);
 uid_t geteuid(void);
 int gethostname(char*, size_t);
+char* getlogin(void);
+int getlogin_r(char*, size_t);
 pid_t getpid(void);
 pid_t getppid(void);
 uid_t getuid(void);

libc/pwent.cpp

@@ -113,11 +113,3 @@ extern "C" int getpwuid_r(uid_t uid, struct passwd* pw, char* buf,
 	*ret = pw;
 	return 0;
 }
-
-extern "C" char* getlogin()
-{
-	static char username[64];
-	// TODO: Potential buffer overflow.
-	strcpy(username, getenv("USERNAME") ? getenv("USERNAME") : ROOT_NAME);
-	return username;
-}