[CRIU] [PATCH 5/7] crtools: dump pending signals

[Andrey Vagin]

signalfd is used for received pending signals, then all signal
are sent back and saved in a image.

Only shared signals are restored by now

Signed-off-by: Andrey Vagin <avagin at openvz.org>
---
 cr-dump.c                  |  6 ++++
 include/parasite-syscall.h |  1 +
 include/parasite.h         |  1 +
 parasite-syscall.c         | 17 +++++++++++
 pie/parasite.c             | 70 ++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 95 insertions(+)

diff --git a/cr-dump.c b/cr-dump.c
index 141caca..f0f31a2 100644
--- a/cr-dump.c
+++ b/cr-dump.c
@@ -1568,6 +1568,12 @@ static int dump_one_task(struct pstree_item *item)
 		goto err_cure;
 	}
 
+	ret = parasite_dump_signal_seized(parasite_ctl, cr_fdset);
+	if (ret) {
+		pr_err("Can't dump pending signals (pid: %d)\n", pid);
+		goto err_cure;
+	}
+
 	ret = parasite_dump_sigacts_seized(parasite_ctl, cr_fdset);
 	if (ret) {
 		pr_err("Can't dump sigactions (pid: %d) with parasite\n", pid);
diff --git a/include/parasite-syscall.h b/include/parasite-syscall.h
index f4586ef..d547be5 100644
--- a/include/parasite-syscall.h
+++ b/include/parasite-syscall.h
@@ -27,6 +27,7 @@ struct list_head;
 
 extern int parasite_dump_sigacts_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_fdset);
 extern int parasite_dump_itimers_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_fdset);
+extern int parasite_dump_signal_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_fdset);
 
 struct parasite_dump_misc;
 extern int parasite_dump_misc_seized(struct parasite_ctl *ctl, struct parasite_dump_misc *misc);
diff --git a/include/parasite.h b/include/parasite.h
index 3a586fc..5836089 100644
--- a/include/parasite.h
+++ b/include/parasite.h
@@ -36,6 +36,7 @@ enum {
 	PARASITE_CMD_DRAIN_FDS,
 	PARASITE_CMD_GET_PROC_FD,
 	PARASITE_CMD_DUMP_TTY,
+	PARASITE_CMD_DUMP_SIGNAL,
 
 	PARASITE_CMD_MAX,
 };
diff --git a/parasite-syscall.c b/parasite-syscall.c
index 708b1b9..efbbe1c 100644
--- a/parasite-syscall.c
+++ b/parasite-syscall.c
@@ -434,6 +434,23 @@ int parasite_dump_thread_seized(struct parasite_ctl *ctl, pid_t pid,
 	return ret;
 }
 
+int parasite_dump_signal_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_fdset)
+{
+	int ret, fd;
+
+	fd = fdset_fd(cr_fdset, CR_FD_SIGNAL);
+
+	ret = parasite_send_fd(ctl, fd);
+	if (ret < 0)
+		return ret;
+
+	ret = parasite_execute(PARASITE_CMD_DUMP_SIGNAL, ctl);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 int parasite_dump_sigacts_seized(struct parasite_ctl *ctl, struct cr_fdset *cr_fdset)
 {
 	struct parasite_dump_sa_args *args;
diff --git a/pie/parasite.c b/pie/parasite.c
index d9e2a1d..901919d 100644
--- a/pie/parasite.c
+++ b/pie/parasite.c
@@ -7,6 +7,7 @@
 #include <sys/ioctl.h>
 
 #include "syscall.h"
+#include "signalfd.h"
 #include "parasite.h"
 #include "log.h"
 
@@ -131,6 +132,73 @@ static int sys_write_safe(int fd, void *buf, int size)
 	return 0;
 }
 
+#define SIGINFO_BUF_SIZE PAGE_SIZE
+static int dump_signal()
+{
+	int ifd, fd, ret, i, size, exit_code = -1;
+	k_rtsigset_t mask;
+	siginfo_t *infos;
+
+	ksigfillset(&mask);
+
+	infos = brk_alloc(SIGINFO_BUF_SIZE);
+	if (infos == NULL)
+		return -1;
+
+	fd = sys_signalfd(-1, &mask, sizeof(rt_sigset_t),
+			SFD_RAW | SFD_GROUP | O_NONBLOCK);
+	if (fd < 0) {
+		pr_perror("signalfd returned %d\n", fd);
+		goto free;
+	}
+
+	size = sys_read(fd, infos, SIGINFO_BUF_SIZE);
+	ret = sys_read(fd, infos, sizeof(siginfo_t));
+	sys_close(fd);
+
+	if (size == -EAGAIN) {
+		exit_code = 0;
+		goto free;
+	}
+
+	if (size <= 0) {
+		pr_err("read() returned %d\n", size);
+		goto free;
+	}
+
+	if (ret > 0) {
+		pr_err("BUG: Too many pending signals\n");
+		goto free;
+	}
+
+	for (i = 0; i < size / sizeof(siginfo_t); i++) {
+		pr_debug("Dump siginfo for %d %x\n",
+				infos[i].si_signo, infos[i].si_code);
+		ret = sys_rt_sigqueueinfo(sys_gettid(),
+						infos[i].si_signo, infos + i);
+		if (ret < 0) {
+			pr_err("rt_sigqueueinfo() failed with code %d", ret);
+			return -1;
+		}
+	}
+
+	ifd = recv_fd(tsock);
+	if (ifd < 0)
+		goto free;
+
+	ret = sys_write(ifd, infos, size);
+	sys_close(ifd);
+	if (ret != size) {
+		pr_err("send() returned %d\n", ret);
+		goto free;
+	}
+
+	exit_code = 0;
+free:
+	brk_free(SIGINFO_BUF_SIZE);
+	return exit_code;
+}
+
 /*
  * This is the main page dumping routine, it's executed
  * inside a victim process space.
@@ -635,6 +703,8 @@ int __used parasite_service(unsigned int cmd, void *args)
 		return parasite_get_proc_fd();
 	case PARASITE_CMD_DUMP_TTY:
 		return parasite_dump_tty(args);
+	case PARASITE_CMD_DUMP_SIGNAL:
+		return dump_signal();
 	}
 
 	pr_err("Unknown command to parasite\n");
-- 
1.7.11.7