dump,restore: Use rt_sigaction_t for sys_sigaction

Since we operate with syscalls directly we are
to convert signal's structures between image and
kernel formats, without intermediate glibc layer.

Note this involves chaging sa_entry::flags to u64
(since it's long int value in kernel).
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>

cr-restore.c

@@ -1052,11 +1052,11 @@ static int open_pipe(int pid, struct pipe_entry *e, int *pipes_fd)
 
 static int prepare_sigactions(int pid)
 {
-	u32 type = 0;
+	rt_sigaction_t act, oact;
 	int fd_sigact, ret;
-	int sig, i;
-	struct sigaction act, oact;
 	struct sa_entry e;
+	u32 type = 0;
+	int sig, i;
 
 	fd_sigact = open_fmt_ro(FMT_FNAME_SIGACTS, pid);
 	if (fd_sigact < 0) {
@@ -1081,13 +1081,11 @@ static int prepare_sigactions(int pid)
 			goto err;
 		}
 
-		BUILD_BUG_ON(sizeof(e.mask) != sizeof(act.sa_mask));
-
-		act.sa_sigaction	= (void *)(long)e.sigaction;
-		act.sa_flags		= (int)e.flags;
-		act.sa_restorer		= (void *)(long)e.restorer;
+		ASSIGN_TYPED(act.rt_sa_handler, e.sigaction);
+		ASSIGN_TYPED(act.rt_sa_flags, e.flags);
+		ASSIGN_TYPED(act.rt_sa_restorer, e.restorer);
 
-		memcpy(&act.sa_mask, &e.mask, sizeof(act.sa_mask));
+		memcpy(&act.rt_sa_mask, &e.mask, sizeof(act.rt_sa_mask));
 
 		/*
 		 * A pure syscall is used, because glibc

include/image.h

@@ -90,7 +90,7 @@ struct page_entry {
 struct sa_entry {
 	u64		sigaction;
 	u8		mask[128];
-	u32		flags;
+	u64		flags;
 	u64		restorer;
 } __packed;
 

include/syscall.h

@@ -154,9 +154,9 @@ static always_inline long sys_open(const char *filename, unsigned long flags, un
 
 struct sigaction;
 
-static always_inline long sys_sigaction(int signum, const struct sigaction *act, struct sigaction *oldact)
+static always_inline long sys_sigaction(int signum, const rt_sigaction_t *act, rt_sigaction_t *oldact)
 {
-	return syscall4(__NR_rt_sigaction, signum, (unsigned long) act, (unsigned long) oldact, sizeof(rt_sigset_t));
+	return syscall4(__NR_rt_sigaction, signum, (unsigned long)act, (unsigned long)oldact, sizeof(rt_sigset_t));
 }
 
 static always_inline long sys_close(int fd)

include/types.h

@@ -98,6 +98,19 @@ typedef struct {
 	unsigned long sig[1];
 } rt_sigset_t;
 
+typedef void rt_signalfn_t(int);
+typedef rt_signalfn_t *rt_sighandler_t;
+
+typedef void rt_restorefn_t(void);
+typedef rt_restorefn_t *rt_sigrestore_t;
+
+typedef struct {
+	rt_sighandler_t	rt_sa_handler;
+	unsigned long	rt_sa_flags;
+	rt_sigrestore_t	rt_sa_restorer;
+	rt_sigset_t	rt_sa_mask;
+} rt_sigaction_t;
+
 typedef struct {
 	unsigned int	entry_number;
 	unsigned int	base_addr;
@@ -180,6 +193,8 @@ typedef struct {
 
 #endif /* CONFIG_X86_64 */
 
+#define ASSIGN_TYPED(a,b) a = (typeof(a))b
+
 #ifndef PAGE_SIZE
 # define PAGE_SIZE	4096
 #endif

parasite.c

@@ -226,7 +226,7 @@ err:
 static int dump_sigact(parasite_args_cmd_dumpsigacts_t *args)
 {
 	parasite_status_t *st = &args->status;
-	struct sigaction act;
+	rt_sigaction_t act;
 	struct sa_entry e;
 	int fd, sig;
 
@@ -254,13 +254,11 @@ static int dump_sigact(parasite_args_cmd_dumpsigacts_t *args)
 			goto err_close;
 		}
 
-		BUILD_BUG_ON(sizeof(e.mask) != sizeof(act.sa_mask));
+		ASSIGN_TYPED(e.sigaction, act.rt_sa_handler);
+		ASSIGN_TYPED(e.flags, act.rt_sa_flags);
+		ASSIGN_TYPED(e.restorer, act.rt_sa_restorer);
 
-		e.sigaction	= (u64)act.sa_sigaction;
-		e.flags		= (u32)act.sa_flags;
-		e.restorer	= (u64)act.sa_restorer;
-
-		inline_memcpy(&e.mask, &act.sa_mask, sizeof(e.mask));
+		inline_memcpy(&e.mask, &act.rt_sa_mask, sizeof(e.mask));
 
 		ret = sys_write(fd, &e, sizeof(e));
 		if (ret != sizeof(e)) {