From 76a255ebcd910d758b45e665f6ea6a31139b27ac Mon Sep 17 00:00:00 2001
From: Peter Bex <address@hidden>
Date: Sat, 24 Nov 2018 12:30:08 +0100
Subject: [PATCH] Change definition of "link", "chroot" and "C_getenv" from
 c-string to nonnull-c-string to fix C compiler warnings

In file-link and set-root-directory! we already checked the argument
for being a string.  In get-environment we did not do that, which
meant #f would be passed to getenv() directly, causing a segfault.
---
 NEWS          | 7 +++++++
 library.scm   | 2 +-
 posixunix.scm | 4 ++--
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/NEWS b/NEWS
index 18eefd7f..5eb7c803 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,10 @@
+5.0.1
+
+- Core libraries
+  - Fix get-environment from (chicken process-context) to raise an
+     error when passed #f instead of segfaulting.
+
+
 5.0.0
 
 - Runtime system
diff --git a/library.scm b/library.scm
index 72d32150..d11bd7f5 100644
--- a/library.scm
+++ b/library.scm
@@ -5971,7 +5971,7 @@ static C_word C_fcall C_setenv(C_word x, C_word y) {
 ;;; Environment access:
 
 (define get-environment-variable
-  (foreign-lambda c-string "C_getenv" c-string))
+  (foreign-lambda c-string "C_getenv" nonnull-c-string))
 
 (define (set-environment-variable! var val)
   (##sys#check-string var 'set-environment-variable!)
diff --git a/posixunix.scm b/posixunix.scm
index e569ce97..a85f9dce 100644
--- a/posixunix.scm
+++ b/posixunix.scm
@@ -771,7 +771,7 @@ static int set_file_mtime(char *filename, C_word atime, C_word mtime)
 	(##sys#read-symbolic-link fname 'read-symbolic-link))))
 
 (set! chicken.file.posix#file-link
-  (let ([link (foreign-lambda int "link" c-string c-string)])
+  (let ((link (foreign-lambda int "link" nonnull-c-string nonnull-c-string)))
     (lambda (old new)
       (##sys#check-string old 'file-link)
       (##sys#check-string new 'file-link)
@@ -1284,7 +1284,7 @@ static int set_file_mtime(char *filename, C_word atime, C_word mtime)
 ;;; chroot:
 
 (set! chicken.process-context.posix#set-root-directory!
-  (let ([chroot (foreign-lambda int "chroot" c-string)])
+  (let ((chroot (foreign-lambda int "chroot" nonnull-c-string)))
     (lambda (dir)
       (##sys#check-string dir 'set-root-directory!)
       (when (fx< (chroot dir) 0)
-- 
2.11.0