I truncated the patch I just sent out. Here is the correct siginfo patch
for kernel 2.3.39. The case for this patch is:
1. Fixes some XXX comments in kernel/signal.c
2. Simplifies/removes redundancies in dequeue_signal
3. Causes SEGVs when SA_SIGINFO is set to correctly fill in the
si_addr and si_code fields on i386. Other architectures will need to
change their do_page_fault implementations to get the same benefit.
4. Causes force_sig_info to behave as expected, for non-rt signals
as well as rt signals.
The patch looks much larger than it really is, because some code has
been yanked out of conditional blocks. The patch is well tested, and
curious parties are welcome to have a look at my test code. Any
feedback is appreciated.
Thanks,
Keith Adams
--diff -ur linux-2.3.39/arch/i386/mm/fault.c linux/arch/i386/mm/fault.c --- linux-2.3.39/arch/i386/mm/fault.c Sat Nov 20 13:09:05 1999 +++ linux/arch/i386/mm/fault.c Sat Jan 15 14:55:16 2000 @@ -123,6 +123,7 @@ unsigned long page; unsigned long fixup; int write; + int si_code = SEGV_MAPERR; /* get the address */ __asm__("movl %%cr2,%0":"=r" (address)); @@ -164,6 +165,8 @@ */ good_area: write = 0; + si_code = SEGV_ACCERR; + switch (error_code & 3) { default: /* 3: write, present */ #ifdef TEST_VERIFY_AREA @@ -216,10 +219,14 @@ /* User mode accesses just cause a SIGSEGV */ if (error_code & 4) { + struct siginfo si; tsk->thread.cr2 = address; tsk->thread.error_code = error_code; tsk->thread.trap_no = 14; - force_sig(SIGSEGV, tsk); + si.si_signo = SIGSEGV; + si.si_code = si_code; + si.si_addr = (void*) address; + force_sig_info(SIGSEGV, &si, tsk); return; } diff -ur linux-2.3.39/kernel/signal.c linux/kernel/signal.c --- linux-2.3.39/kernel/signal.c Mon Jan 10 21:15:58 2000 +++ linux/kernel/signal.c Sat Jan 15 14:54:20 2000 @@ -130,58 +130,42 @@ if (sig) { int reset = 1; - /* Collect the siginfo appropriate to this signal. */ - if (sig < SIGRTMIN) { - /* XXX: As an extension, support queueing exactly - one non-rt signal if SA_SIGINFO is set, so that - we can get more detailed information about the - cause of the signal. */ - /* Deciding not to init these couple of fields is - more expensive that just initializing them. */ + struct signal_queue *q, **pp; + pp = ¤t->sigqueue; + q = current->sigqueue; + + /* Find the one we're interested in ... */ + for ( ; q ; pp = &q->next, q = q->next) + if (q->info.si_signo == sig) + break; + if (q) { + if ((*pp = q->next) == NULL) + current->sigqueue_tail = pp; + *info = q->info; + kmem_cache_free(signal_queue_cachep,q); + atomic_dec(&nr_queued_signals); + + /* then see if this signal is still pending. */ + q = *pp; + while (q) { + if (q->info.si_signo == sig) { + reset = 0; + break; + } + q = q->next; + } + } else { + /* Ok, it wasn't in the queue. It must have + been sent either by a non-rt mechanism and + we ran out of queue space. So zero out the + info. */ info->si_signo = sig; info->si_errno = 0; info->si_code = 0; info->si_pid = 0; info->si_uid = 0; SET_UID16(info->si_uid16, 0); - } else { - struct signal_queue *q, **pp; - pp = ¤t->sigqueue; - q = current->sigqueue; - - /* Find the one we're interested in ... */ - for ( ; q ; pp = &q->next, q = q->next) - if (q->info.si_signo == sig) - break; - if (q) { - if ((*pp = q->next) == NULL) - current->sigqueue_tail = pp; - *info = q->info; - kmem_cache_free(signal_queue_cachep,q); - atomic_dec(&nr_queued_signals); - - /* then see if this signal is still pending. */ - q = *pp; - while (q) { - if (q->info.si_signo == sig) { - reset = 0; - break; - } - q = q->next; - } - } else { - /* Ok, it wasn't in the queue. It must have - been sent either by a non-rt mechanism and - we ran out of queue space. So zero out the - info. */ - info->si_signo = sig; - info->si_errno = 0; - info->si_code = 0; - info->si_pid = 0; - info->si_uid = 0; - SET_UID16(info->si_uid16, 0); - } } if (reset) @@ -255,6 +239,8 @@ { unsigned long flags; int ret; + struct signal_queue *q = 0; + #if DEBUG_SIG printk("SIG queue (%s:%d): %d ", t->comm, t->pid, sig); @@ -307,36 +293,31 @@ if (ignored_signal(sig, t)) goto out; - if (sig < SIGRTMIN) { - /* Non-real-time signals are not queued. */ - /* XXX: As an extension, support queueing exactly one - non-rt signal if SA_SIGINFO is set, so that we can - get more detailed information about the cause of - the signal. */ - if (sigismember(&t->signal, sig)) - goto out; - } else { - /* Real-time signals must be queued if sent by sigqueue, or - some other real-time mechanism. It is implementation - defined whether kill() does so. We attempt to do so, on - the principle of least surprise, but since kill is not - allowed to fail with EAGAIN when low on memory we just - make sure at least one signal gets delivered and don't - pass on the info struct. */ - - struct signal_queue *q = 0; - - if (atomic_read(&nr_queued_signals) < max_queued_signals) { - q = (struct signal_queue *) - kmem_cache_alloc(signal_queue_cachep, GFP_ATOMIC); - } - - if (q) { - atomic_inc(&nr_queued_signals); - q->next = NULL; - *t->sigqueue_tail = q; - t->sigqueue_tail = &q->next; - switch ((unsigned long) info) { + /* Support queueing exactly one non-rt signal, so that we + can get more detailed information about the cause of + the signal. */ + if (sig < SIGRTMIN && sigismember(&t->signal, sig)) + goto out; + + /* Real-time signals must be queued if sent by sigqueue, or + some other real-time mechanism. It is implementation + defined whether kill() does so. We attempt to do so, on + the principle of least surprise, but since kill is not + allowed to fail with EAGAIN when low on memory we just + make sure at least one signal gets delivered and don't + pass on the info struct. */ + + if (atomic_read(&nr_queued_signals) < max_queued_signals) { + q = (struct signal_queue *) + kmem_cache_alloc(signal_queue_cachep, GFP_ATOMIC); + } + + if (q) { + atomic_inc(&nr_queued_signals); + q->next = NULL; + *t->sigqueue_tail = q; + t->sigqueue_tail = &q->next; + switch ((unsigned long) info) { case 0: q->info.si_signo = sig; q->info.si_errno = 0; @@ -356,12 +337,11 @@ default: q->info = *info; break; - } - } else { - /* Queue overflow, we have to abort. */ - ret = -EAGAIN; - goto out; } + } else { + /* Queue overflow, we have to abort. */ + ret = -EAGAIN; + goto out; } sigaddset(&t->signal, sig);
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This archive was generated by hypermail 2b29 : Sun Jan 23 2000 - 21:00:12 EST