diff --git a/headers/posix/stdlib.h b/headers/posix/stdlib.h
index 0544c8af2e..cdb1b3838d 100644
--- a/headers/posix/stdlib.h
+++ b/headers/posix/stdlib.h
@@ -168,6 +168,9 @@ extern size_t	wcstombs(char *string, const wchar_t *pwcs, size_t maxSize);
 /* crypt */
 extern void 	setkey(const char *key);
 
+/* sub-option parsing */
+extern int		getsubopt(char **optionp, char * const *keylistp,
+					char **valuep);
 
 /* pty functions */
 extern int		posix_openpt(int openFlags);
diff --git a/src/system/libroot/posix/stdlib/Jamfile b/src/system/libroot/posix/stdlib/Jamfile
index 5983951358..dd2711e0ad 100644
--- a/src/system/libroot/posix/stdlib/Jamfile
+++ b/src/system/libroot/posix/stdlib/Jamfile
@@ -12,6 +12,7 @@ MergeObject posix_stdlib.o :
 	div.c
 	env.cpp
 	exit.c
+	getsubopt.cpp
 	heapsort.c
 	merge.c
 	mktemp.c
diff --git a/src/system/libroot/posix/stdlib/getsubopt.cpp b/src/system/libroot/posix/stdlib/getsubopt.cpp
new file mode 100644
index 0000000000..9346bcef32
--- /dev/null
+++ b/src/system/libroot/posix/stdlib/getsubopt.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2010, Oliver Tappe <zooey@hirschkaefer.de>.
+ * Distributed under the terms of the MIT License.
+ */
+
+
+#include <stdlib.h>
+#include <string.h>
+
+
+int
+getsubopt(char** optionPtr, char* const* keys, char** valuePtr)
+{
+	if (optionPtr == NULL || valuePtr == NULL)
+		return -1;
+
+	char* option = *optionPtr;
+	if (*option == '\0')
+		return -1;
+
+	char* startOfNextOption = strchr(option, ',');
+	if (startOfNextOption != NULL)
+		*startOfNextOption++ = '\0';
+	else
+		startOfNextOption = option + strlen(option);
+	*optionPtr = startOfNextOption;
+
+	char* startOfValue = strchr(option, '=');
+	if (startOfValue != NULL)
+		*startOfValue++ = '\0';
+	*valuePtr = startOfValue;
+
+	for (int keyIndex = 0; keys[keyIndex] != NULL; ++keyIndex) {
+		if (strcmp(option, keys[keyIndex]) == 0)
+			return keyIndex;
+	}
+
+	return -1;
+}
diff --git a/src/tests/system/libroot/posix/Jamfile b/src/tests/system/libroot/posix/Jamfile
index 4b83b2f42e..aced757751 100644
--- a/src/tests/system/libroot/posix/Jamfile
+++ b/src/tests/system/libroot/posix/Jamfile
@@ -12,6 +12,7 @@ SimpleTest SyslogTest : SyslogTest.cpp syslog.cpp ;
 SimpleTest clearenv : clearenv.cpp ;
 SimpleTest dirent_test : dirent_test.cpp ;
 SimpleTest flock_test : flock_test.cpp ;
+SimpleTest getsubopt_test : getsubopt_test.cpp ;
 SimpleTest locale_test : locale_test.cpp ;
 SimpleTest memalign_test : memalign_test.cpp ;
 SimpleTest mprotect_test : mprotect_test.cpp ;
diff --git a/src/tests/system/libroot/posix/getsubopt_test.cpp b/src/tests/system/libroot/posix/getsubopt_test.cpp
new file mode 100644
index 0000000000..6a2c56e745
--- /dev/null
+++ b/src/tests/system/libroot/posix/getsubopt_test.cpp
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2010, Oliver Tappe <zooey@hirschkaefer.de>.
+ * Distributed under the terms of the MIT License.
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+int
+main()
+{
+	char* const keys[] = {
+		"mode", "be-lenient", NULL
+	};
+
+	char* option = strdup("mode=readwrite,unknown,be-lenient");
+	char* value = NULL;
+	int result = getsubopt(&option, keys, &value);
+	if (result != 0)
+		fprintf(stderr, "failed 1: result=%d, expected %d\n", result, 0);
+	if (value == NULL || strcmp(value, "readwrite") != 0)
+		fprintf(stderr, "failed 2: value=%s, expected 'readwrite'\n", value);
+	result = getsubopt(&option, keys, &value);
+	if (result != -1)
+		fprintf(stderr, "failed 3: result=%d, expected %d\n", result, -1);
+	if (value != NULL)
+		fprintf(stderr, "failed 4: value=%p, expected NULL\n", value);
+	result = getsubopt(&option, keys, &value);
+	if (result != 1)
+		fprintf(stderr, "failed 5: result=%d, expected %d\n", result, 1);
+	if (value != NULL)
+		fprintf(stderr, "failed 6: value=%p, expected NULL\n", value);
+
+	return 0;
+}