On Wednesday 04 June 2008 02:43, Bernard Blackham wrote:
> Mike Frysinger wrote:
> > you'll also need to make sure you do this somewhere which has temporary
> > storage ... otherwise you'll wreck embedded flash systems
>
> /dev is on tmpfs anyway.
>
> > *shrug* anything not daemon/netlink based looks like a hack to me
>
> And I'm inclined to agree.
>
> > which means i still dont understand why people dont go use udevd if
> > they need a real setup.
>
> s/real/reliable/
>
> What good is using mdev if it cannot be relied upon? (apart from using
> mdev -s at boot and an otherwise completely-static /dev).
Try attached 2.patch. It adds mdev options -f SEQFILE and -t TIMEOUT_MSEC.
If -f is not given, the behavious is unchanged.
If -f SEQFILE is given, and if SEQNUM env var is set, mdev will check
whether SEQFILE contains exactly the same line as $SEQNUM
(must match exactly, not even '\n' is allowed to be there).
It will proceed immediately if file can't be read.
It will time out (default 1000 msec) and proceed
even if SEQFILE contains non-matching line.
After mdev is done, and if both -f was given and $SEQNUM is set,
mdev will write $SEQNUM + 1 to SEQFILE prior to exit.
Note that if SEQFILE is not absolute, it will be read/written relative to /dev.
Only compile tested...
--
vda
diff -d -urpN busybox.1/util-linux/mdev.c busybox.2/util-linux/mdev.c
--- busybox.1/util-linux/mdev.c 2008-05-31 20:24:36.000000000 +0200
+++ busybox.2/util-linux/mdev.c 2008-06-04 10:32:43.000000000 +0200
@@ -14,10 +14,12 @@
struct globals {
int root_major, root_minor;
+ const char *seqfile;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
#define root_major (G.root_major)
#define root_minor (G.root_minor)
+#define seqfile (G.seqfile )
#define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
@@ -386,10 +388,10 @@ static void load_firmware(const char *co
}
int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int mdev_main(int argc, char **argv)
+int mdev_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
- char *action;
- char *env_path;
+ int opt;
+ int timeout = 1000;
RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
#ifdef YOU_WANT_TO_DEBUG_HOTPLUG_EVENTS
@@ -401,9 +403,15 @@ int mdev_main(int argc, char **argv)
xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDERR_FILENO);
#endif
+/* TODO: force validity of fds 0,1,2 as in init? */
+
xchdir("/dev");
- if (argc == 2 && !strcmp(argv[1], "-s")) {
+ opt_complementary = "t+"; /* -t MSEC */
+ opt = getopt32(argv, "sf:t:", &seqfile, &timeout);
+ /* NB: path in -f FNAME is relative to /dev: /dev/FNAME */
+
+ if (opt & 1) {
/* Scan:
* mdev -s
*/
@@ -422,8 +430,13 @@ int mdev_main(int argc, char **argv)
fileAction, dirAction, temp, 0);
} else {
+ char *seq = seq; /* for compiler */
+ char *action;
+ char *env_path;
+ char seqbuf[sizeof(int)*3 + 2];
+
/* Hotplug:
- * env ACTION=... DEVPATH=... mdev
+ * env ACTION=... DEVPATH=... [SEQNUM=...] mdev
* ACTION can be "add" or "remove"
* DEVPATH is like "/block/sda" or "/class/input/mice"
*/
@@ -432,6 +445,22 @@ int mdev_main(int argc, char **argv)
if (!action || !env_path)
bb_show_usage();
+ if (seqfile) {
+ seq = getenv("SEQNUM");
+ if (seq) {
+ timeout >>= 5; /* unsigned /= 32 */
+ do {
+ int len = open_read_close(seqfile, seqbuf, sizeof(seqbuf-1));
+ if (len < 0)
+ break;
+ seqbuf[len] = '\0';
+ if (strcmp(seq, seqbuf) == 0)
+ break;
+ usleep(32*1000);
+ } while (--timeout >= 0);
+ }
+ }
+
snprintf(temp, PATH_MAX, "/sys%s", env_path);
if (!strcmp(action, "remove"))
make_device(temp, 1);
@@ -444,6 +473,10 @@ int mdev_main(int argc, char **argv)
load_firmware(fw, temp);
}
}
+
+ if (seqfile && seq) {
+ xopen_xwrite_close(seqfile, utoa(xatou(seq) + 1));
+ }
}
if (ENABLE_FEATURE_CLEAN_UP)
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