mdev: do not follow symlinks in /sys (as was intended prior to rev 18811).
If this breaks things, please document why!
mdev,init: use shared code for fd sanitization
function old new delta
bb_daemonize_or_rexec 155 172 +17
mdev_main 500 505 +5
init_main 907 856 -51
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 22/-51) Total: -29 bytes
diff --git a/init/init.c b/init/init.c
index 2328967..4b2bd9c 100644
--- a/init/init.c
+++ b/init/init.c
@@ -221,20 +221,7 @@
} else {
/* Make sure fd 0,1,2 are not closed
* (so that they won't be used by future opens) */
-
- /* bb_sanitize_stdio(); - WRONG.
- * It fails if "/dev/null" doesnt exist, and for init
- * this is a real possibility! Open code it instead. */
-
- int fd = open(bb_dev_null, O_RDWR);
- if (fd < 0) {
- /* Give me _ANY_ open descriptor! */
- fd = xopen("/", O_RDONLY); /* we don't believe this can fail */
- }
- while ((unsigned)fd < 2)
- fd = dup(fd);
- if (fd > 2)
- close(fd);
+ bb_sanitize_stdio();
}
s = getenv("TERM");
diff --git a/libbb/vfork_daemon_rexec.c b/libbb/vfork_daemon_rexec.c
index 37d4c27..da0dc03 100644
--- a/libbb/vfork_daemon_rexec.c
+++ b/libbb/vfork_daemon_rexec.c
@@ -265,7 +265,14 @@
close(2);
}
- fd = xopen(bb_dev_null, O_RDWR);
+ fd = open(bb_dev_null, O_RDWR);
+ if (fd < 0) {
+ /* NB: we can be called as bb_sanitize_stdio() from init
+ * or mdev, and there /dev/null may legitimately not (yet) exist!
+ * Do not use xopen above, but obtain _ANY_ open descriptor,
+ * even bogus one as below. */
+ fd = xopen("/", O_RDONLY); /* don't believe this can fail */
+ }
while ((unsigned)fd < 2)
fd = dup(fd); /* have 0,1,2 open at least to /dev/null */
diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index c710937..9c4938a 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -19,7 +19,8 @@
#define root_major (G.root_major)
#define root_minor (G.root_minor)
-#define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
+/* Prevent infinite loops in /sys symlinks */
+#define MAX_SYSFS_DEPTH 3
/* We use additional 64+ bytes in make_device() */
#define SCRATCH_SIZE 80
@@ -392,11 +393,17 @@
char *env_path;
RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
-#ifdef YOU_WANT_TO_DEBUG_HOTPLUG_EVENTS
+ /* We can be called as hotplug helper */
/* Kernel cannot provide suitable stdio fds for us, do it ourself */
+#if 1
+ bb_sanitize_stdio();
+#else
+ /* Debug code */
/* Replace LOGFILE by other file or device name if you need */
#define LOGFILE "/dev/console"
- xmove_fd(xopen("/dev/null", O_RDONLY), STDIN_FILENO);
+ /* Just making sure fd 0 is not closed,
+ * we don't really intend to read from it */
+ xmove_fd(xopen("/", O_RDONLY), STDIN_FILENO);
xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDOUT_FILENO);
xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDERR_FILENO);
#endif
@@ -414,11 +421,11 @@
root_minor = minor(st.st_dev);
recursive_action("/sys/block",
- ACTION_RECURSE | ACTION_FOLLOWLINKS,
+ ACTION_RECURSE /* no ACTION_FOLLOWLINKS! */,
fileAction, dirAction, temp, 0);
recursive_action("/sys/class",
- ACTION_RECURSE | ACTION_FOLLOWLINKS,
+ ACTION_RECURSE /* no ACTION_FOLLOWLINKS! */,
fileAction, dirAction, temp, 0);
} else {