[patch 0/3] add rt_tgsigqueueinfo syscall for 2.6.30

[patch 0/3] add rt_tgsigqueueinfo syscall for 2.6.30

[Thomas Gleixner]

Linus, Andrew,

the following patch set has been discussed and reviewed on LKML for
quite a while and has reached its final state.

It implements sys_rt_tgsigqueueinfo which allows to queue signals to
a particulart thread. It's the counterpart for sys_rt_sigqueueinfo
and complements the sys_kill / sys_tgkill interface pair.

While I think that the ability to target a particular thread is useful
itself the lack of this interface is a serious show stopper for migrating
existing applications from other Unix like OSes which provide this.

The new syscall interface is acked by Ulrich and the implementation has
been reviewed by Oleg and acked by Roland.

Please apply.

Thanks,

	tglx

[patch 1/3] signals: split do_tkill

[Thomas Gleixner]

[-- Attachment #1: signals-split-do-tkill.patch --]
[-- Type: text/plain, Size: 1990 bytes --]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
---
 kernel/signal.c |   30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

Index: linux-2.6/kernel/signal.c
===================================================================
--- linux-2.6.orig/kernel/signal.c
+++ linux-2.6/kernel/signal.c
@@ -2278,24 +2278,17 @@ SYSCALL_DEFINE2(kill, pid_t, pid, int, s
 	return kill_something_info(sig, &info, pid);
 }
 
-static int do_tkill(pid_t tgid, pid_t pid, int sig)
+static int
+do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
 {
-	int error;
-	struct siginfo info;
 	struct task_struct *p;
 	unsigned long flags;
-
-	error = -ESRCH;
-	info.si_signo = sig;
-	info.si_errno = 0;
-	info.si_code = SI_TKILL;
-	info.si_pid = task_tgid_vnr(current);
-	info.si_uid = current_uid();
+	int error = -ESRCH;
 
 	rcu_read_lock();
 	p = find_task_by_vpid(pid);
 	if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
-		error = check_kill_permission(sig, &info, p);
+		error = check_kill_permission(sig, info, p);
 		/*
 		 * The null signal is a permissions and process existence
 		 * probe.  No signal is actually delivered.
@@ -2305,7 +2298,7 @@ static int do_tkill(pid_t tgid, pid_t pi
 		 * signal is private anyway.
 		 */
 		if (!error && sig && lock_task_sighand(p, &flags)) {
-			error = specific_send_sig_info(sig, &info, p);
+			error = specific_send_sig_info(sig, info, p);
 			unlock_task_sighand(p, &flags);
 		}
 	}
@@ -2314,6 +2307,19 @@ static int do_tkill(pid_t tgid, pid_t pi
 	return error;
 }
 
+static int do_tkill(pid_t tgid, pid_t pid, int sig)
+{
+	struct siginfo info;
+
+	info.si_signo = sig;
+	info.si_errno = 0;
+	info.si_code = SI_TKILL;
+	info.si_pid = task_tgid_vnr(current);
+	info.si_uid = current_uid();
+
+	return do_send_specific(tgid, pid, sig, &info);
+}
+
 /**
  *  sys_tgkill - send signal to one specific thread
  *  @tgid: the thread group ID of the thread

[patch 2/3] signals: implement sys_rt_tgsigqueueinfo

[Thomas Gleixner]

[-- Attachment #1: signals-implement-sys-rt-tgsigqueueinfo.patch --]
[-- Type: text/plain, Size: 3488 bytes --]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Ulrich Drepper <drepper@redhat.com>
---
 include/linux/compat.h |    2 ++
 include/linux/signal.h |    2 ++
 kernel/compat.c        |   11 +++++++++++
 kernel/signal.c        |   26 ++++++++++++++++++++++++++
 4 files changed, 41 insertions(+)

Index: linux-2.6/include/linux/compat.h
===================================================================
--- linux-2.6.orig/include/linux/compat.h
+++ linux-2.6/include/linux/compat.h
@@ -222,6 +222,8 @@ int copy_siginfo_from_user32(siginfo_t *
 int copy_siginfo_to_user32(struct compat_siginfo __user *to, siginfo_t *from);
 int get_compat_sigevent(struct sigevent *event,
 		const struct compat_sigevent __user *u_event);
+long compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid, compat_pid_t pid, int sig,
+				  struct compat_siginfo __user *uinfo);
 
 static inline int compat_timeval_compare(struct compat_timeval *lhs,
 					struct compat_timeval *rhs)
Index: linux-2.6/include/linux/signal.h
===================================================================
--- linux-2.6.orig/include/linux/signal.h
+++ linux-2.6/include/linux/signal.h
@@ -235,6 +235,8 @@ static inline int valid_signal(unsigned 
 extern int next_signal(struct sigpending *pending, sigset_t *mask);
 extern int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p);
 extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
+extern long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig,
+				 siginfo_t *info);
 extern long do_sigpending(void __user *, unsigned long);
 extern int sigprocmask(int, sigset_t *, sigset_t *);
 extern int show_unhandled_signals;
Index: linux-2.6/kernel/compat.c
===================================================================
--- linux-2.6.orig/kernel/compat.c
+++ linux-2.6/kernel/compat.c
@@ -882,6 +882,17 @@ compat_sys_rt_sigtimedwait (compat_sigse
 
 }
 
+asmlinkage long
+compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid, compat_pid_t pid, int sig,
+			     struct compat_siginfo __user *uinfo)
+{
+	siginfo_t info;
+
+	if (copy_siginfo_from_user32(&info, uinfo))
+		return -EFAULT;
+	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
+}
+
 #ifdef __ARCH_WANT_COMPAT_SYS_TIME
 
 /* compat_time_t is a 32 bit "long" and needs to get converted. */
Index: linux-2.6/kernel/signal.c
===================================================================
--- linux-2.6.orig/kernel/signal.c
+++ linux-2.6/kernel/signal.c
@@ -2369,6 +2369,32 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, 
 	return kill_proc_info(sig, &info, pid);
 }
 
+long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
+{
+	/* This is only valid for single tasks */
+	if (pid <= 0 || tgid <= 0)
+		return -EINVAL;
+
+	/* Not even root can pretend to send signals from the kernel.
+	   Nor can they impersonate a kill(), which adds source info.  */
+	if (info->si_code >= 0)
+		return -EPERM;
+	info->si_signo = sig;
+
+	return do_send_specific(tgid, pid, sig, info);
+}
+
+SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
+		siginfo_t __user *, uinfo)
+{
+	siginfo_t info;
+
+	if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
+		return -EFAULT;
+
+	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
+}
+
 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
 {
 	struct task_struct *t = current;

[patch 3/3] x86: hookup sys_rt_tgsigqueueinfo

[Thomas Gleixner]

[-- Attachment #1: x86-hookup-sys-rt-tgsigqueueinfo.patch --]
[-- Type: text/plain, Size: 1910 bytes --]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/ia32/ia32entry.S          |    1 +
 arch/x86/include/asm/unistd_32.h   |    1 +
 arch/x86/include/asm/unistd_64.h   |    2 ++
 arch/x86/kernel/syscall_table_32.S |    1 +
 4 files changed, 5 insertions(+)

Index: linux-2.6/arch/x86/ia32/ia32entry.S
===================================================================
--- linux-2.6.orig/arch/x86/ia32/ia32entry.S
+++ linux-2.6/arch/x86/ia32/ia32entry.S
@@ -830,4 +830,5 @@ ia32_sys_call_table:
 	.quad sys_inotify_init1
 	.quad compat_sys_preadv
 	.quad compat_sys_pwritev
+ 	.quad compat_sys_rt_tgsigqueueinfo	/* 335 */
 ia32_syscall_end:
Index: linux-2.6/arch/x86/include/asm/unistd_32.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/unistd_32.h
+++ linux-2.6/arch/x86/include/asm/unistd_32.h
@@ -340,6 +340,7 @@
 #define __NR_inotify_init1	332
 #define __NR_preadv		333
 #define __NR_pwritev		334
+#define __NR_rt_tgsigqueueinfo	335
 
 #ifdef __KERNEL__
 
Index: linux-2.6/arch/x86/include/asm/unistd_64.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/unistd_64.h
+++ linux-2.6/arch/x86/include/asm/unistd_64.h
@@ -657,6 +657,8 @@ __SYSCALL(__NR_inotify_init1, sys_inotif
 __SYSCALL(__NR_preadv, sys_preadv)
 #define __NR_pwritev				296
 __SYSCALL(__NR_pwritev, sys_pwritev)
+#define __NR_rt_tgsigqueueinfo			297
+__SYSCALL(__NR_rt_tgsigqueueinfo, sys_rt_tgsigqueueinfo)
 
 
 #ifndef __NO_STUBS
Index: linux-2.6/arch/x86/kernel/syscall_table_32.S
===================================================================
--- linux-2.6.orig/arch/x86/kernel/syscall_table_32.S
+++ linux-2.6/arch/x86/kernel/syscall_table_32.S
@@ -334,3 +334,4 @@ ENTRY(sys_call_table)
 	.long sys_inotify_init1
 	.long sys_preadv
 	.long sys_pwritev
+ 	.long sys_rt_tgsigqueueinfo	/* 335 */