diff options
| author | jhb <jhb@FreeBSD.org> | 2006-08-01 16:32:20 +0000 |
|---|---|---|
| committer | jhb <jhb@FreeBSD.org> | 2006-08-01 16:32:20 +0000 |
| commit | 023ecadf48622b9accaf88dd47b13cd8a99ae035 (patch) | |
| tree | b9ddf54c00e1c5c2b880e5c041c164917b3311e2 /sys | |
| parent | 4dc640e56e164af7bfa43acfe36b6a8037512f66 (diff) | |
| download | FreeBSD-src-023ecadf48622b9accaf88dd47b13cd8a99ae035.zip FreeBSD-src-023ecadf48622b9accaf88dd47b13cd8a99ae035.tar.gz | |
Make system call modules a bit more robust:
- If we fail to register the system call during MOD_LOAD, then note that
so that we don't try to deregister it or invoke the chained event handler
during the subsequent MOD_UNLOAD event. Doing the deregister when the
register failed could result in trashing system call entries.
- Add a SI_SUB_SYSCALLS just before starting up init and use that to
register syscall modules instead of SI_SUB_DRIVERS. Registering system
calls as late as possible increases the chances that any other module
event handlers or SYSINITs in a module are executed to initialize the
data in a kld before a syscall dependent on that data is able to be
invoked.
MFC after: 3 days
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/kern/kern_syscalls.c | 12 | ||||
| -rw-r--r-- | sys/sys/kernel.h | 1 | ||||
| -rw-r--r-- | sys/sys/sysent.h | 2 |
3 files changed, 13 insertions, 2 deletions
diff --git a/sys/kern/kern_syscalls.c b/sys/kern/kern_syscalls.c index a437fb3..6452d96 100644 --- a/sys/kern/kern_syscalls.c +++ b/sys/kern/kern_syscalls.c @@ -97,8 +97,11 @@ syscall_module_handler(struct module *mod, int what, void *arg) case MOD_LOAD : error = syscall_register(data->offset, data->new_sysent, &data->old_sysent); - if (error) + if (error) { + /* Leave a mark so we know to safely unload below. */ + data->offset = NULL; return error; + } ms.intval = *data->offset; MOD_XLOCK; module_setspecific(mod, &ms); @@ -108,6 +111,13 @@ syscall_module_handler(struct module *mod, int what, void *arg) return error; case MOD_UNLOAD : + /* + * MOD_LOAD failed, so just return without calling the + * chained handler since we didn't pass along the MOD_LOAD + * event. + */ + if (data->offset == NULL) + return (0); if (data->chainevh) { error = data->chainevh(mod, what, data->chainarg); if (error) diff --git a/sys/sys/kernel.h b/sys/sys/kernel.h index 7cb3d80..cc36ede 100644 --- a/sys/sys/kernel.h +++ b/sys/sys/kernel.h @@ -157,6 +157,7 @@ enum sysinit_sub_id { SI_SUB_MOUNT_ROOT = 0xb400000, /* root mount*/ SI_SUB_SWAP = 0xc000000, /* swap */ SI_SUB_INTRINSIC_POST = 0xd000000, /* proc 0 cleanup*/ + SI_SUB_SYSCALLS = 0xd800000, /* register system calls */ SI_SUB_KTHREAD_INIT = 0xe000000, /* init process*/ SI_SUB_KTHREAD_PAGE = 0xe400000, /* pageout daemon*/ SI_SUB_KTHREAD_VM = 0xe800000, /* vm daemon*/ diff --git a/sys/sys/sysent.h b/sys/sys/sysent.h index 0566794..4e4f25e 100644 --- a/sys/sys/sysent.h +++ b/sys/sys/sysent.h @@ -113,7 +113,7 @@ static moduledata_t name##_mod = { \ syscall_module_handler, \ &name##_syscall_mod \ }; \ -DECLARE_MODULE(name, name##_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE) +DECLARE_MODULE(name, name##_mod, SI_SUB_SYSCALLS, SI_ORDER_MIDDLE) #define SYSCALL_MODULE_HELPER(syscallname) \ static int syscallname##_syscall = SYS_##syscallname; \ |
