[git commit master 1/1] improve --install operation in chroot jails

[Denys Vlasenko]

commit: http://git.busybox.net/busybox/commit/?id=4a2a86d5e7e7bf284a31af604a738dfa1f1a2240
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 libbb/appletlib.c |   21 ++++++++++++++++-----
 1 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index fc3e962..69cac2e 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -713,12 +713,23 @@ static int busybox_main(char **argv)
 	if (ENABLE_FEATURE_INSTALLER && strcmp(argv[1], "--install") == 0) {
 		int use_symbolic_links;
 		const char *busybox;
+
 		busybox = xmalloc_readlink(bb_busybox_exec_path);
-		if (!busybox)
-			busybox = bb_busybox_exec_path;
-		/* busybox --install [-s] [DIR]: */
-		/* -s: make symlinks */
-		/* DIR: directory to install links to */
+		if (!busybox) {
+			/* bb_busybox_exec_path is usually "/proc/self/exe".
+			 * In chroot, readlink("/proc/self/exe") usually fails.
+			 * In such case, better use argv[0] as symlink target
+			 * if it is a full path name.
+			 */
+			if (argv[0][0] == '/')
+				busybox = argv[0];
+			else
+				busybox = bb_busybox_exec_path;
+		}
+		/* busybox --install [-s] [DIR]:
+		 * -s: make symlinks
+		 * DIR: directory to install links to
+		 */
 		use_symbolic_links = (argv[2] && strcmp(argv[2], "-s") == 0 && argv++);
 		install_links(busybox, use_symbolic_links, argv[2]);
 		return 0;
-- 
1.7.3.4