diff --git a/include/errno.h b/include/errno.h
new file mode 100644
index 0000000..957302c
--- /dev/null
+++ b/include/errno.h
@@ -0,0 +1,166 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/* See the end of this file for copyright, licensing, and warranty information. */
+
+#pragma once
+
+#define EPERM		1
+#define ENOENT		2
+#define ESRCH		3
+#define EINTR		4
+#define EIO		5
+#define ENXIO		6
+#define E2BIG		7
+#define ENOEXEC		8
+#define EBADF		9
+#define ECHILD		10
+#define EAGAIN		11
+#define ENOMEM		12
+#define EACCES		13
+#define EFAULT		14
+#define ENOTBLK		15
+#define EBUSY		16
+#define EEXIST		17
+#define EXDEV		18
+#define ENODEV		19
+#define ENOTDIR		20
+#define EISDIR		21
+#define EINVAL		22
+#define ENFILE		23
+#define EMFILE		24
+#define ENOTTY		25
+#define ETXTBSY		26
+#define EFBIG		27
+#define ENOSPC		28
+#define ESPIPE		29
+#define EROFS		30
+#define EMLINK		31
+#define EPIPE		32
+#define EDOM		33
+#define ERANGE		34
+#define EDEADLK		35
+#define ENAMETOOLONG	36
+#define ENOLCK		37
+#define ENOSYS		38
+#define ENOTEMPTY	39
+#define ELOOP		40
+#define EWOULDBLOCK	11
+#define ENOMSG		42
+#define EIDRM		43
+#define ECHRNG		44
+#define EL2NSYNC	45
+#define EL3HLT		46
+#define EL3RST		47
+#define ELNRNG		48
+#define EUNATCH		49
+#define ENOCSI		50
+#define EL2HLT		51
+#define EBADE		52
+#define EBADR		53
+#define EXFULL		54
+#define ENOANO		55
+#define EBADRQC		56
+#define EBADSLT		57
+#define EDEADLOCK	35
+#define EBFONT		59
+#define ENOSTR		60
+#define ENODATA		61
+#define ETIME		62
+#define ENOSR		63
+#define ENONET		64
+#define ENOPKG		65
+#define EREMOTE		66
+#define ENOLINK		67
+#define EADV		68
+#define ESRMNT		69
+#define ECOMM		70
+#define EPROTO		71
+#define EMULTIHOP	72
+#define EDOTDOT		73
+#define EBADMSG		74
+#define EOVERFLOW	75
+#define ENOTUNIQ	76
+#define EBADFD		77
+#define EREMCHG		78
+#define ELIBACC		79
+#define ELIBBAD		80
+#define ELIBSCN		81
+#define ELIBMAX		82
+#define ELIBEXEC	83
+#define EILSEQ		84
+#define ERESTART	85
+#define ESTRPIPE	86
+#define EUSERS		87
+#define ENOTSOCK	88
+#define EDESTADDRREQ	89
+#define EMSGSIZE	90
+#define EPROTOTYPE	91
+#define ENOPROTOOPT	92
+#define EPROTONOSUPPORT	93
+#define ESOCKTNOSUPPORT	94
+#define EOPNOTSUPP	95
+#define ENOTSUP		95
+#define EPFNOSUPPORT	96
+#define EAFNOSUPPORT	97
+#define EADDRINUSE	98
+#define EADDRNOTAVAIL	99
+#define ENETDOWN	100
+#define ENETUNREACH	101
+#define ENETRESET	102
+#define ECONNABORTED	103
+#define ECONNRESET	104
+#define ENOBUFS		105
+#define EISCONN		106
+#define ENOTCONN	107
+#define ESHUTDOWN	108
+#define ETOOMANYREFS	109
+#define ETIMEDOUT	110
+#define ECONNREFUSED	111
+#define EHOSTDOWN	112
+#define EHOSTUNREACH	113
+#define EALREADY	114
+#define EINPROGRESS	115
+#define ESTALE		116
+#define EUCLEAN		117
+#define ENOTNAM		118
+#define ENAVAIL		119
+#define EISNAM		120
+#define EREMOTEIO	121
+#define EDQUOT		122
+#define ENOMEDIUM	123
+#define EMEDIUMTYPE	124
+#define ECANCELED	125
+#define ENOKEY		126
+#define EKEYEXPIRED	127
+#define EKEYREVOKED	128
+#define EKEYREJECTED	129
+#define EOWNERDEAD	130
+#define ENOTRECOVERABLE	131
+#define ERFKILL		132
+#define EHWPOISON	133
+
+/* TODO: actually define errno */
+
+/*
+ * Copyright (c) 2020 Felix Kopp <sandtler@sandtler.club>
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are permitted
+ * provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this list of
+ *    conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
+ *    conditions and the following disclaimer in the documentation and/or other materials
+ *    provided with the distribution.
+ * 3. Neither the name of the copyright holder nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
+ * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */