[pacman-dev] [PATCH 6/6] makepkg: safely change directories

[Allan McRae]

In preparation for the removal of the global error trap we need a
way to ensure changing directories succeeds.  Add a "cd_safe"
wrapper that performs the necessary check.

Signed-off-by: Allan McRae <allan at archlinux.org>
---
 scripts/makepkg.sh.in |   40 ++++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/scripts/makepkg.sh.in b/scripts/makepkg.sh.in
index 534f6f8..f21c638 100644
--- a/scripts/makepkg.sh.in
+++ b/scripts/makepkg.sh.in
@@ -874,6 +874,14 @@ error_function() {
 	exit 2 # $E_BUILD_FAILED
 }
 
+cd_safe() {
+	if ! cd "$1"; then
+		error "$(gettext "Failed to change to directory %s")" "$1"
+		plain "$(gettext "Aborting...")"
+		exit 1
+	fi
+}
+
 run_function() {
 	if [[ -z $1 ]]; then
 		return 1
@@ -891,7 +899,7 @@ run_function() {
 	fi
 
 	msg "$(gettext "Starting %s()...")" "$pkgfunc"
-	cd "$srcdir"
+	cd_safe "$srcdir"
 
 	# ensure all necessary build variables are exported
 	export CFLAGS CXXFLAGS LDFLAGS MAKEFLAGS CHOST
@@ -969,7 +977,7 @@ run_package() {
 }
 
 tidy_install() {
-	cd "$pkgdir"
+	cd_safe "$pkgdir"
 	msg "$(gettext "Tidying install...")"
 
 	if [[ $(check_option docs) = "n" && -n ${DOC_DIRS[*]} ]]; then
@@ -1219,7 +1227,7 @@ write_pkginfo() {
 }
 
 check_package() {
-	cd "$pkgdir"
+	cd_safe "$pkgdir"
 
 	# check existence of backup files
 	local file
@@ -1248,7 +1256,7 @@ create_package() {
 
 	check_package
 
-	cd "$pkgdir"
+	cd_safe "$pkgdir"
 	msg "$(gettext "Creating package...")"
 
 	local nameofpkg
@@ -1407,7 +1415,7 @@ create_srcpackage() {
 
 	# tar it up
 	msg2 "$(gettext "Compressing source package...")"
-	cd "${srclinks}"
+	cd_safe "${srclinks}"
 	if ! bsdtar -c${TAR_OPT}Lf "$pkg_file" ${pkgbase}; then
 		error "$(gettext "Failed to create source package file.")"
 		exit 1 # TODO: error code
@@ -1423,7 +1431,7 @@ create_srcpackage() {
 		warning "$(gettext "Failed to create symlink to source package file.")"
 	fi
 
-	cd "${startdir}"
+	cd_safe "${startdir}"
 	rm -rf "${srclinks}"
 }
 
@@ -1757,7 +1765,7 @@ devel_check() {
 			fi
 			msg "$(gettext "Determining latest %s revision...")" 'hg'
 			if [[ -d ./src/$_hgrepo ]] ; then
-				cd ./src/$_hgrepo
+				cd_safe ./src/$_hgrepo
 				local ret=0
 				hg pull || ret=$?
 				if (( ! ret )); then
@@ -1768,10 +1776,10 @@ devel_check() {
 			else
 				[[ ! -d ./src/ ]] && mkdir ./src/
 				hg clone $_hgroot/$_hgrepo ./src/$_hgrepo
-				cd ./src/$_hgrepo
+				cd_safe ./src/$_hgrepo
 			fi
 			newpkgver=$(hg tip --template "{rev}")
-			cd ../../
+			cd_safe ../../
 		fi
 
 		if [[ -n $newpkgver ]]; then
@@ -1847,7 +1855,7 @@ canonicalize_path() {
 
 	if [[ -d $path ]]; then
 		(
-			cd "$path"
+			cd_safe "$path"
 			pwd -P
 		)
 	else
@@ -2171,7 +2179,7 @@ fi
 if (( GENINTEG )); then
 	mkdir -p "$srcdir"
 	chmod a-s "$srcdir"
-	cd "$srcdir"
+	cd_safe "$srcdir"
 	download_sources
 	generate_checksums
 	exit 0 # $E_OK
@@ -2321,14 +2329,14 @@ if (( SOURCEONLY )); then
 	# Get back to our src directory so we can begin with sources.
 	mkdir -p "$srcdir"
 	chmod a-s "$srcdir"
-	cd "$srcdir"
+	cd_safe "$srcdir"
 	if ( (( ! SKIPCHECKSUMS )) || \
 			( (( ! SKIPPGPCHECK )) && source_has_signatures ) ) || \
 			(( SOURCEONLY == 2 )); then
 		download_sources
 	fi
 	check_source_integrity
-	cd "$startdir"
+	cd_safe "$startdir"
 
 	# if we are root or if fakeroot is not enabled, then we don't use it
 	if [[ $(check_buildenv fakeroot) != "y" ]] || (( EUID == 0 )); then
@@ -2384,7 +2392,7 @@ umask 0022
 # get back to our src directory so we can begin with sources
 mkdir -p "$srcdir"
 chmod a-s "$srcdir"
-cd "$srcdir"
+cd_safe "$srcdir"
 
 if (( NOEXTRACT )); then
 	warning "$(gettext "Skipping source retrieval        -- using existing %s tree")" "src/"
@@ -2420,7 +2428,7 @@ else
 	fi
 	mkdir -p "$pkgdir"
 	chmod a-s "$pkgdir"
-	cd "$startdir"
+	cd_safe "$startdir"
 
 	# if we are root or if fakeroot is not enabled, then we don't use it
 	if [[ $(check_buildenv fakeroot) != "y" ]] || (( EUID == 0 )); then
@@ -2450,7 +2458,7 @@ else
 			devel_update
 			(( BUILDFUNC )) && run_build
 			(( CHECKFUNC )) && run_check
-			cd "$startdir"
+			cd_safe "$startdir"
 		fi
 
 		enter_fakeroot
-- 
1.7.9.3