[CRIU] [PATCH 2/9] The .c file containing the functions

[prakriti goyal]

From: prakritigoyal19 <prakritigoyal19 at gmail.com>

Signed-off-by: prakritigoyal19 <prakritigoyal19 at gmail.com>
Repo link: https://github.com/prakritigoyal19/criu/tree/sigactions

---
 criu/sigaction.c | 331 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 331 insertions(+)
 create mode 100644 criu/sigaction.c

diff --git a/criu/sigaction.c b/criu/sigaction.c
new file mode 100644
index 00000000..e5b48b44
--- /dev/null
+++ b/criu/sigaction.c
@@ -0,0 +1,331 @@
+#include <unistd.h>
+#include <inttypes.h>
+
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <sys/mman.h>
+
+#include "parasite.h"
+#include "parasite-syscall.h"
+#include "pstree.h"
+#include "sigframe.h" 
+
+#include "image.h"
+#include "img-remote.h"
+#include "images/core.pb-c.h"
+#include "images/sa.pb-c.h"
+#include "infect.h"
+#include "protobuf.h"
+
+#include <compel/compel.h>
+#include "restore.h"
+#include "restorer.h"
+#include "sigaction.h"
+
+#include <compel/compel.h>
+
+#include "pie/pie-relocs.h"
+
+int parasite_dump_sigacts_seized(struct parasite_ctl *ctl, struct pstree_item *item)
+{
+	TaskCoreEntry *tc = item->core[0]->tc; 
+	struct parasite_dump_sa_args *args;
+	int ret, sig;
+	SaEntry *sa, **psa;
+
+	args = compel_parasite_args(ctl, struct parasite_dump_sa_args);
+
+	ret = compel_rpc_call_sync(PARASITE_CMD_DUMP_SIGACTS, ctl); //imported??
+	if (ret < 0)
+		return ret;
+
+	psa = xmalloc((SIGMAX - 2) * (sizeof(SaEntry *) + sizeof(SaEntry))); //SIGMAX??
+	if (!psa)
+		return -1;
+
+	sa = (SaEntry *)(psa + SIGMAX - 2);
+
+	tc->n_sigactions = SIGMAX - 2;
+	tc->sigactions = psa;
+
+	for (sig = 1; sig <= SIGMAX; sig++) {
+		int i = sig - 1;
+
+		if (sig == SIGSTOP || sig == SIGKILL)
+			continue;
+
+		sa_entry__init(sa);
+		ASSIGN_TYPED(sa->sigaction, encode_pointer(args->sas[i].rt_sa_handler)); //import???
+		ASSIGN_TYPED(sa->flags, args->sas[i].rt_sa_flags);
+		ASSIGN_TYPED(sa->restorer, encode_pointer(args->sas[i].rt_sa_restorer));
+		BUILD_BUG_ON(sizeof(sa->mask) != sizeof(args->sas[0].rt_sa_mask.sig)); //import??
+		memcpy(&sa->mask, args->sas[i].rt_sa_mask.sig, sizeof(sa->mask));
+		sa->has_compat_sigaction = true;
+		sa->compat_sigaction = !compel_mode_native(ctl);
+
+		*(psa++) = sa++;
+	}
+
+	return 0;
+}
+
+
+
+rt_sigaction_t sigchld_act;
+/*
+ * If parent's sigaction has blocked SIGKILL (which is non-sense),
+ * this parent action is non-valid and shouldn't be inherited.
+ * Used to mark parent_act* no more valid.
+ */
+static rt_sigaction_t parent_act[SIGMAX];
+#ifdef CONFIG_COMPAT
+static rt_sigaction_t_compat parent_act_compat[SIGMAX];
+#endif
+
+static bool sa_inherited(int sig, rt_sigaction_t *sa)
+{
+	rt_sigaction_t *pa;
+	int i;
+
+	if (current == root_item)
+		return false; /* XXX -- inherit from CRIU? */
+
+	pa = &parent_act[sig];
+
+	/* Omitting non-valid sigaction */
+	if (pa->rt_sa_mask.sig[0] & (1 << SIGKILL))
+		return false;
+
+	for (i = 0; i < _KNSIG_WORDS; i++)
+		if (pa->rt_sa_mask.sig[i] != sa->rt_sa_mask.sig[i])
+			return false;
+
+	return pa->rt_sa_handler == sa->rt_sa_handler &&
+		pa->rt_sa_flags == sa->rt_sa_flags &&
+		pa->rt_sa_restorer == sa->rt_sa_restorer;
+}
+
+static int restore_native_sigaction(int sig, SaEntry *e)
+{
+	rt_sigaction_t act;
+	int ret;
+
+	ASSIGN_TYPED(act.rt_sa_handler, decode_pointer(e->sigaction));
+	ASSIGN_TYPED(act.rt_sa_flags, e->flags);
+	ASSIGN_TYPED(act.rt_sa_restorer, decode_pointer(e->restorer));
+	BUILD_BUG_ON(sizeof(e->mask) != sizeof(act.rt_sa_mask.sig));
+	memcpy(act.rt_sa_mask.sig, &e->mask, sizeof(act.rt_sa_mask.sig));
+
+	if (sig == SIGCHLD) {
+		sigchld_act = act;
+		return 0;
+	}
+
+	if (sa_inherited(sig - 1, &act))
+		return 1;
+
+	/*
+	 * A pure syscall is used, because glibc
+	 * sigaction overwrites se_restorer.
+	 */
+	ret = syscall(SYS_rt_sigaction, sig, &act, NULL, sizeof(k_rtsigset_t));
+	if (ret < 0) {
+		pr_perror("Can't restore sigaction");
+		return ret;
+	}
+
+	parent_act[sig - 1] = act;
+	/* Mark SIGKILL blocked which makes compat sigaction non-valid */
+#ifdef CONFIG_COMPAT
+	parent_act_compat[sig - 1].rt_sa_mask.sig[0] |= 1 << SIGKILL;
+#endif
+
+	return 1;
+}
+
+static void *stack32;
+
+#ifdef CONFIG_COMPAT
+static bool sa_compat_inherited(int sig, rt_sigaction_t_compat *sa)
+{
+	rt_sigaction_t_compat *pa;
+	int i;
+
+	if (current == root_item)
+		return false;
+
+	pa = &parent_act_compat[sig];
+
+	/* Omitting non-valid sigaction */
+	if (pa->rt_sa_mask.sig[0] & (1 << SIGKILL))
+		return false;
+
+	for (i = 0; i < _KNSIG_WORDS; i++)
+		if (pa->rt_sa_mask.sig[i] != sa->rt_sa_mask.sig[i])
+			return false;
+
+	return pa->rt_sa_handler == sa->rt_sa_handler &&
+		pa->rt_sa_flags == sa->rt_sa_flags &&
+		pa->rt_sa_restorer == sa->rt_sa_restorer;
+}
+
+static int restore_compat_sigaction(int sig, SaEntry *e)
+{
+	rt_sigaction_t_compat act;
+	int ret;
+
+	ASSIGN_TYPED(act.rt_sa_handler, (u32)e->sigaction);
+	ASSIGN_TYPED(act.rt_sa_flags, e->flags);
+	ASSIGN_TYPED(act.rt_sa_restorer, (u32)e->restorer);
+	BUILD_BUG_ON(sizeof(e->mask) != sizeof(act.rt_sa_mask.sig));
+	memcpy(act.rt_sa_mask.sig, &e->mask, sizeof(act.rt_sa_mask.sig));
+
+	if (sig == SIGCHLD) {
+		memcpy(&sigchld_act, &act, sizeof(rt_sigaction_t_compat));
+		return 0;
+	}
+
+	if (sa_compat_inherited(sig - 1, &act))
+		return 1;
+
+	if (!stack32) {
+		stack32 = alloc_compat_syscall_stack();
+		if (!stack32)
+			return -1;
+	}
+
+	ret = arch_compat_rt_sigaction(stack32, sig, &act);
+	if (ret < 0) {
+		pr_err("Can't restore compat sigaction: %d\n", ret);
+		return ret;
+	}
+
+	parent_act_compat[sig - 1] = act;
+	/* Mark SIGKILL blocked which makes native sigaction non-valid */
+	parent_act[sig - 1].rt_sa_mask.sig[0] |= 1 << SIGKILL;
+
+	return 1;
+}
+#else
+static int restore_compat_sigaction(int sig, SaEntry *e)
+{
+	return -1;
+}
+#endif
+
+static int prepare_sigactions_from_core(TaskCoreEntry *tc)
+{
+	int sig, i;
+
+	if (tc->n_sigactions != SIGMAX - 2) {
+		pr_err("Bad number of sigactions in the image (%d, want %d)\n",
+				(int)tc->n_sigactions, SIGMAX - 2);
+		return -1;
+	}
+
+	pr_info("Restore on-core sigactions for %d\n", vpid(current));
+
+	for (sig = 1, i = 0; sig <= SIGMAX; sig++) {
+		int ret;
+		SaEntry *e;
+		bool sigaction_is_compat;
+
+		if (sig == SIGKILL || sig == SIGSTOP)
+			continue;
+
+		e = tc->sigactions[i++];
+		sigaction_is_compat = e->has_compat_sigaction && e->compat_sigaction;
+		if (sigaction_is_compat)
+			ret = restore_compat_sigaction(sig, e);
+		else
+			ret = restore_native_sigaction(sig, e);
+
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/* Returns number of restored signals, -1 or negative errno on fail */
+static int restore_one_sigaction(int sig, struct cr_img *img, int pid)
+{
+	bool sigaction_is_compat;
+	SaEntry *e;
+	int ret = 0;
+
+	BUG_ON(sig == SIGKILL || sig == SIGSTOP);
+
+	ret = pb_read_one_eof(img, &e, PB_SIGACT);
+	if (ret == 0) {
+		if (sig != SIGMAX_OLD + 1) { /* backward compatibility */
+			pr_err("Unexpected EOF %d\n", sig);
+			return -1;
+		}
+		pr_warn("This format of sigacts-%d.img is deprecated\n", pid);
+		return -1;
+	}
+	if (ret < 0)
+		return ret;
+
+	sigaction_is_compat = e->has_compat_sigaction && e->compat_sigaction;
+	if (sigaction_is_compat)
+		ret = restore_compat_sigaction(sig, e);
+	else
+		ret = restore_native_sigaction(sig, e);
+
+	sa_entry__free_unpacked(e, NULL);
+
+	return ret;
+}
+
+static int prepare_sigactions_from_image(void)
+{
+	int pid = vpid(current);
+	struct cr_img *img;
+	int sig, rst = 0;
+	int ret = 0;
+
+	pr_info("Restore sigacts for %d\n", pid);
+
+	img = open_image(CR_FD_SIGACT, O_RSTR, pid);
+	if (!img)
+		return -1;
+
+	for (sig = 1; sig <= SIGMAX; sig++) {
+		if (sig == SIGKILL || sig == SIGSTOP)
+			continue;
+
+		ret = restore_one_sigaction(sig, img, pid);
+		if (ret < 0)
+			break;
+		if (ret)
+			rst++;
+	}
+
+	pr_info("Restored %d/%d sigacts\n", rst,
+			SIGMAX - 3 /* KILL, STOP and CHLD */);
+
+	close_image(img);
+	return ret;
+}
+
+int prepare_sigactions(CoreEntry *core)
+{
+	int ret;
+
+	if (!task_alive(current))
+		return 0;
+
+	if (core->tc->n_sigactions != 0)
+		ret = prepare_sigactions_from_core(core->tc);
+	else
+		ret = prepare_sigactions_from_image();
+
+	if (stack32) {
+		free_compat_syscall_stack(stack32);
+		stack32 = NULL;
+	}
+
+	return ret;
+}
\ No newline at end of file
-- 
2.17.1