diff --git a/sys/include/ape/unistd.h b/sys/include/ape/unistd.h
index ae78fec36..936fbe8cb 100644
--- a/sys/include/ape/unistd.h
+++ b/sys/include/ape/unistd.h
@@ -121,6 +121,7 @@ extern pid_t setsid(void);
 
 /* files and directories */
 extern int chdir(const char *);
+extern int chroot(const char *);
 extern int link(const char *, const char *);
 extern char *getcwd(char *, size_t);
 extern int unlink(const char *);
diff --git a/sys/src/ape/lib/ap/plan9/chroot.c b/sys/src/ape/lib/ap/plan9/chroot.c
new file mode 100644
index 000000000..ed270ec81
--- /dev/null
+++ b/sys/src/ape/lib/ap/plan9/chroot.c
@@ -0,0 +1,9 @@
+#include <unistd.h>
+#include <errno.h>
+
+int
+chroot(const char*)
+{
+	errno = EIO;
+	return -1;
+}
diff --git a/sys/src/ape/lib/ap/plan9/mkfile b/sys/src/ape/lib/ap/plan9/mkfile
index 1da4318a4..8f9099e22 100644
--- a/sys/src/ape/lib/ap/plan9/mkfile
+++ b/sys/src/ape/lib/ap/plan9/mkfile
@@ -22,6 +22,7 @@ OFILES=\
 	brk.$O\
 	cfgetospeed.$O\
 	chdir.$O\
+	chroot.$O\
 	chmod.$O\
 	chown.$O\
 	close.$O\