1. Change prototype of trapsignal and sendsig to use ksiginfo_t *, most

   changes in MD code are trivial, before this change, trapsignal and
   sendsig use discrete parameters, now they uses member fields of
   ksiginfo_t structure. For sendsig, this change allows us to pass
   POSIX realtime signal value to user code.

2. Remove cpu_thread_siginfo, it is no longer needed because we now always
   generate ksiginfo_t data and feed it to libpthread.

3. Add p_sigqueue to proc structure to hold shared signals which were
   blocked by all threads in the proc.

4. Add td_sigqueue to thread structure to hold all signals delivered to
   thread.

5. i386 and amd64 now return POSIX standard si_code, other arches will
   be fixed.

6. In this sigqueue implementation, pending signal set is kept as before,
   an extra siginfo list holds additional siginfo_t data for signals.
   kernel code uses psignal() still behavior as before, it won't be failed
   even under memory pressure, only exception is when deleting a signal,
   we should call sigqueue_delete to remove signal from sigqueue but
   not SIGDELSET. Current there is no kernel code will deliver a signal
   with additional data, so kernel should be as stable as before,
   a ksiginfo can carry more information, for example, allow signal to
   be delivered but throw away siginfo data if memory is not enough.
   SIGKILL and SIGSTOP have fast path in sigqueue_add, because they can
   not be caught or masked.
   The sigqueue() syscall allows user code to queue a signal to target
   process, if resource is unavailable, EAGAIN will be returned as
   specification said.
   Just before thread exits, signal queue memory will be freed by
   sigqueue_flush.
   Current, all signals are allowed to be queued, not only realtime signals.

Earlier patch reviewed by: jhb, deischen
Tested on: i386, amd64

1 files changed, 26 insertions, 10 deletions

diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
index db1b617..8916183 100644
--- a/sys/i386/linux/linux_sysvec.c
+++ b/sys/i386/linux/linux_sysvec.c
@@ -107,8 +107,7 @@ static int	elf_linux_fixup(register_t **stack_base,
 		    struct image_params *iparams);
 static void	linux_prepsyscall(struct trapframe *tf, int *args, u_int *code,
 		    caddr_t *params);
-static void     linux_sendsig(sig_t catcher, int sig, sigset_t *mask,
-		    u_long code);
+static void     linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask);
 static void	exec_linux_setregs(struct thread *td, u_long entry,
 				   u_long stack, u_long ps_strings);
 
@@ -267,15 +266,18 @@ extern int _ucodesel, _udatasel;
 extern unsigned long linux_sznonrtsigcode;
 
 static void
-linux_rt_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
+linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 {
 	struct thread *td = curthread;
 	struct proc *p = td->td_proc;
 	struct sigacts *psp;
 	struct trapframe *regs;
 	struct l_rt_sigframe *fp, frame;
+	int sig, code;
 	int oonstack;
 
+	sig = ksi->ksi_signo;
+	code = ksi->ksi_code;	
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	psp = p->p_sigacts;
 	mtx_assert(&psp->ps_mtx, MA_OWNED);
@@ -315,7 +317,7 @@ linux_rt_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
 	/* Fill in POSIX parts */
 	frame.sf_si.lsi_signo = sig;
 	frame.sf_si.lsi_code = code;
-	frame.sf_si.lsi_addr = (void *)regs->tf_err;
+	frame.sf_si.lsi_addr = ksi->ksi_addr;
 
 	/*
 	 * Build the signal context to be used by sigreturn.
@@ -400,7 +402,7 @@ linux_rt_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
  * specified pc, psl.
  */
 static void
-linux_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
+linux_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 {
 	struct thread *td = curthread;
 	struct proc *p = td->td_proc;
@@ -408,17 +410,19 @@ linux_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
 	struct trapframe *regs;
 	struct l_sigframe *fp, frame;
 	l_sigset_t lmask;
+	int sig, code;
 	int oonstack, i;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	psp = p->p_sigacts;
+	sig = ksi->ksi_signo;
+	code = ksi->ksi_code;
 	mtx_assert(&psp->ps_mtx, MA_OWNED);
 	if (SIGISMEMBER(psp->ps_siginfo, sig)) {
 		/* Signal handler installed with SA_SIGINFO. */
-		linux_rt_sendsig(catcher, sig, mask, code);
+		linux_rt_sendsig(catcher, ksi, mask);
 		return;
 	}
-
 	regs = td->td_frame;
 	oonstack = sigonstack(regs->tf_esp);
 
@@ -475,7 +479,7 @@ linux_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
 	frame.sf_sc.sc_esp_at_signal = regs->tf_esp;
 	frame.sf_sc.sc_ss     = regs->tf_ss;
 	frame.sf_sc.sc_err    = regs->tf_err;
-	frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(code);
+	frame.sf_sc.sc_trapno = bsd_to_linux_trapcode(ksi->ksi_trapno);
 
 	for (i = 0; i < (LINUX_NSIG_WORDS-1); i++)
 		frame.sf_extramask[i] = lmask.__bits[i+1];
@@ -522,6 +526,7 @@ linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
 	struct trapframe *regs;
 	l_sigset_t lmask;
 	int eflags, i;
+	ksiginfo_t ksi;
 
 	regs = td->td_frame;
 
@@ -562,7 +567,12 @@ linux_sigreturn(struct thread *td, struct linux_sigreturn_args *args)
 	 */
 #define	CS_SECURE(cs)	(ISPL(cs) == SEL_UPL)
 	if (!CS_SECURE(frame.sf_sc.sc_cs)) {
-		trapsignal(td, SIGBUS, T_PROTFLT);
+		ksiginfo_init_trap(&ksi);
+		ksi.ksi_signo = SIGBUS;
+		ksi.ksi_code = BUS_OBJERR;
+		ksi.ksi_trapno = T_PROTFLT;
+		ksi.ksi_addr = (void *)regs->tf_eip;
+		trapsignal(td, &ksi);
 		return(EINVAL);
 	}
 
@@ -618,6 +628,7 @@ linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
 	stack_t ss;
 	struct trapframe *regs;
 	int eflags;
+	ksiginfo_t ksi;
 
 	regs = td->td_frame;
 
@@ -660,7 +671,12 @@ linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
 	 */
 #define	CS_SECURE(cs)	(ISPL(cs) == SEL_UPL)
 	if (!CS_SECURE(context->sc_cs)) {
-		trapsignal(td, SIGBUS, T_PROTFLT);
+		ksiginfo_init_trap(&ksi);
+		ksi.ksi_signo = SIGBUS;
+		ksi.ksi_code = BUS_OBJERR;
+		ksi.ksi_trapno = T_PROTFLT;
+		ksi.ksi_addr = (void *)regs->tf_eip;
+		trapsignal(td, &ksi);
 		return(EINVAL);
 	}