From: Christian Seiler <christian@iwakd.de>
Date: Wed, 6 Mar 2013 19:41:54 +0000 (+0100)
Subject: lxc-attach: Default to /bin/sh if shell cannot be determined or exec'd
X-Git-Tag: lxc-0.9.0.rc1~2^2~21
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=21da9912d453a8a3b9c05309b2c7c24774d233d3;p=thirdparty%2Flxc.git

lxc-attach: Default to /bin/sh if shell cannot be determined or exec'd

If getpwuid() fails and also the fallback of spawning of a 'getent'
process, and the user specified no command to execute, default to
/bin/sh and only fail if even that is not available. This should ensure
that unless the container is *really* weird, no matter what, the user
should always end up with a shell when calling lxc-attach with no
further arguments.

Signed-off-by: Christian Seiler <christian@iwakd.de>
---

diff --git a/src/lxc/lxc_attach.c b/src/lxc/lxc_attach.c
index fdf8a0664..69ebfacca 100644
--- a/src/lxc/lxc_attach.c
+++ b/src/lxc/lxc_attach.c
@@ -452,15 +452,21 @@ int main(int argc, char *argv[])
                 else
                         user_shell = passwd->pw_shell;
 
-		if (!user_shell) {
-			SYSERROR("failed to get passwd "		\
-				 "entry for uid '%d'", uid);
-			return -1;
+                if (user_shell) {
+			char *const args[] = {
+				user_shell,
+				NULL,
+			};
+
+			(void) execvp(args[0], args);
 		}
 
+		/* executed if either no passwd entry or execvp fails,
+		 * we will fall back on /bin/sh as a default shell
+		 */
 		{
 			char *const args[] = {
-				user_shell,
+				"/bin/sh",
 				NULL,
 			};