switch_root: don't bail out when console doesn't exist

Busybox is very often used in initramfs at the end of which usually
there is a switch_root to the actual rootfs. There are many cases where
the console kernel argument is either just a placeholder (for example
RaspberryPi uses serial0 and serial1) or configured as null to avoid any
console messages - usually you would see such of a setup in production
environments.

Currently busybox bails out if can't open the console argument. If this
happenes in initramfs and if the console=null for example, you get in a
blind kernel panic. Avoid this by only warning instead of dying.

function                                             old     new   delta
switch_root_main                                     371     368      -3

Signed-off-by: Andrei Gherzan <andrei@gherzan.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/util-linux/switch_root.c b/util-linux/switch_root.c
index 6034485d7424873d06044c86ecc94d9c3ca57468..aaee35a3e4b7f20dd1c8b782ad91b2c30d573920 100644 (file)
--- a/util-linux/switch_root.c
+++ b/util-linux/switch_root.c
@@ -141,10 +141,12 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv)
 
        // If a new console specified, redirect stdin/stdout/stderr to it
        if (console) {
-               close(0);
-               xopen(console, O_RDWR);
-               xdup2(0, 1);
-               xdup2(0, 2);
+               int fd = open_or_warn(console, O_RDWR);
+               if (fd >= 0) {
+                       xmove_fd(fd, 0);
+                       xdup2(0, 1);
+                       xdup2(0, 2);
+               }
        }
 
        // Exec real init