From 711cefa8ee63c5e1c0cb8feaf7376ba74e9de522 Mon Sep 17 00:00:00 2001
From: Piotr Roszatycki <piotr.roszatycki@gmail.com>
Date: Fri, 2 Dec 2011 02:24:28 +0100
Subject: [PATCH] Substitute commands only if FAKECHROOT_CMD_ORIG is not set.
 Unset it if is empty.

---
 man/fakechroot.pod           |  2 +-
 scripts/chroot.fakechroot.sh | 13 ++++++++-----
 src/execve.c                 |  7 ++++++-
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/man/fakechroot.pod b/man/fakechroot.pod
index 7b4e511c..86450e7f 100644
--- a/man/fakechroot.pod
+++ b/man/fakechroot.pod
@@ -263,7 +263,7 @@ It is suggested to substitute at least:
 to make debootstrap(8) working correctly.
 
 To prevent some looping, the command substitution is done only if
-C<FAKECHROOT_BASE_ORIG> variable is not set currently.
+C<FAKECHROOT_CMD_ORIG> variable is not set currently.
 
 =item B<LD_LIBRARY_PATH>, B<LD_PRELOAD>
 
diff --git a/scripts/chroot.fakechroot.sh b/scripts/chroot.fakechroot.sh
index 56306163..b5230619 100644
--- a/scripts/chroot.fakechroot.sh
+++ b/scripts/chroot.fakechroot.sh
@@ -29,8 +29,11 @@ load_ldsoconf () {
     done
 }
 
-chroot=${FAKECHROOT_CMD_ORIG:-chroot}
-unset FAKECHROOT_CMD_ORIG
+chroot="${FAKECHROOT_CMD_ORIG:-chroot}"
+FAKECHROOT_CMD_ORIG=
+
+base="$FAKECHROOT_BASE_ORIG"
+unset FAKECHROOT_BASE_ORIG
 
 for opt in "$@"; do
     case "$opt" in
@@ -50,12 +53,12 @@ if [ -n "$newroot" ]; then
     # append newroot to each directory from original LD_LIBRARY_PATH
     IFS_bak="$IFS" IFS=:
     for d in $LD_LIBRARY_PATH; do
-        paths="${paths:+$paths:}$FAKECHROOT_BASE_ORIG$newroot/${d#/}"
+        paths="${paths:+$paths:}$base$newroot/${d#/}"
     done
     IFS="$IFS_bak"
 
     # append newroot to each directory from new /etc/ld.so.conf
-    paths_ldsoconf=`load_ldsoconf "/etc/ld.so.conf" "$newroot" | while read line; do printf ":%s%s" "$FAKECHROOT_BASE_ORIG" "$line"; done`
+    paths_ldsoconf=`load_ldsoconf "/etc/ld.so.conf" "$newroot" | while read line; do printf ":%s%s" "$base" "$line"; done`
     paths_ldsoconf="${paths_ldsoconf#:}"
 
     paths="$paths${paths_ldsoconf:+:$paths_ldsoconf}${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}"
@@ -63,5 +66,5 @@ if [ -n "$newroot" ]; then
 fi
 
 # call real chroot
-env LD_LIBRARY_PATH="$paths" FAKECHROOT_BASE_ORIG=$FAKECHROOT_BASE_ORIG FAKECHROOT_BASE=$FAKECHROOT_BASE_ORIG "$chroot" "$@"
+env LD_LIBRARY_PATH="$paths" FAKECHROOT_BASE="$base" "$chroot" "$@"
 exit $?
diff --git a/src/execve.c b/src/execve.c
index 048567c2..5e0e7618 100644
--- a/src/execve.c
+++ b/src/execve.c
@@ -79,6 +79,7 @@ wrapper(execve, int, (const char * filename, char * const argv [], char * const
     const char **newargv = alloca(argv_max * sizeof (const char *));
     char **newenvp, **ep;
     char *key, *env;
+    char *cmdorig;
     char tmp[FAKECHROOT_PATH_MAX];
     char substfilename[FAKECHROOT_PATH_MAX];
     char newfilename[FAKECHROOT_PATH_MAX];
@@ -106,8 +107,12 @@ wrapper(execve, int, (const char * filename, char * const argv [], char * const
 
     strncpy(argv0, filename, FAKECHROOT_PATH_MAX);
 
-    if (!getenv("FAKECHROOT_BASE_ORIG"))
+    /* Substitute command only if FAKECHROOT_CMD_ORIG is not set. Unset variable if it is empty. */
+    cmdorig = getenv("FAKECHROOT_CMD_ORIG");
+    if (cmdorig == NULL)
         do_cmd_subst = try_cmd_subst(getenv("FAKECHROOT_CMD_SUBST"), argv0, substfilename);
+    else if (!*cmdorig)
+        unsetenv("FAKECHROOT_CMD_ORIG");
 
     /* Scan envp and check its size */
     sizeenvp = 0;