migrate to go-modules

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 0 insertions, 995 deletions

diff --git a/vendor/github.com/opencontainers/runc/libcontainer/nsenter/nsexec.c b/vendor/github.com/opencontainers/runc/libcontainer/nsenter/nsexec.c
deleted file mode 100644
index 28269dfc0..000000000
--- a/vendor/github.com/opencontainers/runc/libcontainer/nsenter/nsexec.c
+++ /dev/null
@@ -1,995 +0,0 @@
-
-#define _GNU_SOURCE
-#include <endian.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <grp.h>
-#include <sched.h>
-#include <setjmp.h>
-#include <signal.h>
-#include <stdarg.h>
-#include <stdbool.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdbool.h>
-#include <string.h>
-#include <unistd.h>
-
-#include <sys/ioctl.h>
-#include <sys/prctl.h>
-#include <sys/socket.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-
-#include <linux/limits.h>
-#include <linux/netlink.h>
-#include <linux/types.h>
-
-/* Get all of the CLONE_NEW* flags. */
-#include "namespace.h"
-
-/* Synchronisation values. */
-enum sync_t {
-	SYNC_USERMAP_PLS = 0x40,	/* Request parent to map our users. */
-	SYNC_USERMAP_ACK = 0x41,	/* Mapping finished by the parent. */
-	SYNC_RECVPID_PLS = 0x42,	/* Tell parent we're sending the PID. */
-	SYNC_RECVPID_ACK = 0x43,	/* PID was correctly received by parent. */
-	SYNC_GRANDCHILD = 0x44,	/* The grandchild is ready to run. */
-	SYNC_CHILD_READY = 0x45,	/* The child or grandchild is ready to return. */
-
-	/* XXX: This doesn't help with segfaults and other such issues. */
-	SYNC_ERR = 0xFF,	/* Fatal error, no turning back. The error code follows. */
-};
-
-/*
- * Synchronisation value for cgroup namespace setup.
- * The same constant is defined in process_linux.go as "createCgroupns".
- */
-#define CREATECGROUPNS 0x80
-
-/* longjmp() arguments. */
-#define JUMP_PARENT 0x00
-#define JUMP_CHILD  0xA0
-#define JUMP_INIT   0xA1
-
-/* JSON buffer. */
-#define JSON_MAX 4096
-
-/* Assume the stack grows down, so arguments should be above it. */
-struct clone_t {
-	/*
-	 * Reserve some space for clone() to locate arguments
-	 * and retcode in this place
-	 */
-	char stack[4096] __attribute__ ((aligned(16)));
-	char stack_ptr[0];
-
-	/* There's two children. This is used to execute the different code. */
-	jmp_buf *env;
-	int jmpval;
-};
-
-struct nlconfig_t {
-	char *data;
-
-	/* Process settings. */
-	uint32_t cloneflags;
-	char *oom_score_adj;
-	size_t oom_score_adj_len;
-
-	/* User namespace settings. */
-	char *uidmap;
-	size_t uidmap_len;
-	char *gidmap;
-	size_t gidmap_len;
-	char *namespaces;
-	size_t namespaces_len;
-	uint8_t is_setgroup;
-
-	/* Rootless container settings. */
-	uint8_t is_rootless_euid;	/* boolean */
-	char *uidmappath;
-	size_t uidmappath_len;
-	char *gidmappath;
-	size_t gidmappath_len;
-};
-
-/*
- * List of netlink message types sent to us as part of bootstrapping the init.
- * These constants are defined in libcontainer/message_linux.go.
- */
-#define INIT_MSG			62000
-#define CLONE_FLAGS_ATTR	27281
-#define NS_PATHS_ATTR		27282
-#define UIDMAP_ATTR			27283
-#define GIDMAP_ATTR			27284
-#define SETGROUP_ATTR		27285
-#define OOM_SCORE_ADJ_ATTR	27286
-#define ROOTLESS_EUID_ATTR	27287
-#define UIDMAPPATH_ATTR	    27288
-#define GIDMAPPATH_ATTR	    27289
-
-/*
- * Use the raw syscall for versions of glibc which don't include a function for
- * it, namely (glibc 2.12).
- */
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 14
-#	define _GNU_SOURCE
-#	include "syscall.h"
-#	if !defined(SYS_setns) && defined(__NR_setns)
-#		define SYS_setns __NR_setns
-#	endif
-
-#ifndef SYS_setns
-#	error "setns(2) syscall not supported by glibc version"
-#endif
-
-int setns(int fd, int nstype)
-{
-	return syscall(SYS_setns, fd, nstype);
-}
-#endif
-
-/* XXX: This is ugly. */
-static int syncfd = -1;
-
-/* TODO(cyphar): Fix this so it correctly deals with syncT. */
-#define bail(fmt, ...)								\
-	do {									\
-		int ret = __COUNTER__ + 1;					\
-		fprintf(stderr, "nsenter: " fmt ": %m\n", ##__VA_ARGS__);	\
-		if (syncfd >= 0) {						\
-			enum sync_t s = SYNC_ERR;				\
-			if (write(syncfd, &s, sizeof(s)) != sizeof(s))		\
-				fprintf(stderr, "nsenter: failed: write(s)");	\
-			if (write(syncfd, &ret, sizeof(ret)) != sizeof(ret))	\
-				fprintf(stderr, "nsenter: failed: write(ret)");	\
-		}								\
-		exit(ret);							\
-	} while(0)
-
-static int write_file(char *data, size_t data_len, char *pathfmt, ...)
-{
-	int fd, len, ret = 0;
-	char path[PATH_MAX];
-
-	va_list ap;
-	va_start(ap, pathfmt);
-	len = vsnprintf(path, PATH_MAX, pathfmt, ap);
-	va_end(ap);
-	if (len < 0)
-		return -1;
-
-	fd = open(path, O_RDWR);
-	if (fd < 0) {
-		return -1;
-	}
-
-	len = write(fd, data, data_len);
-	if (len != data_len) {
-		ret = -1;
-		goto out;
-	}
-
- out:
-	close(fd);
-	return ret;
-}
-
-enum policy_t {
-	SETGROUPS_DEFAULT = 0,
-	SETGROUPS_ALLOW,
-	SETGROUPS_DENY,
-};
-
-/* This *must* be called before we touch gid_map. */
-static void update_setgroups(int pid, enum policy_t setgroup)
-{
-	char *policy;
-
-	switch (setgroup) {
-	case SETGROUPS_ALLOW:
-		policy = "allow";
-		break;
-	case SETGROUPS_DENY:
-		policy = "deny";
-		break;
-	case SETGROUPS_DEFAULT:
-	default:
-		/* Nothing to do. */
-		return;
-	}
-
-	if (write_file(policy, strlen(policy), "/proc/%d/setgroups", pid) < 0) {
-		/*
-		 * If the kernel is too old to support /proc/pid/setgroups,
-		 * open(2) or write(2) will return ENOENT. This is fine.
-		 */
-		if (errno != ENOENT)
-			bail("failed to write '%s' to /proc/%d/setgroups", policy, pid);
-	}
-}
-
-static int try_mapping_tool(const char *app, int pid, char *map, size_t map_len)
-{
-	int child;
-
-	/*
-	 * If @app is NULL, execve will segfault. Just check it here and bail (if
-	 * we're in this path, the caller is already getting desperate and there
-	 * isn't a backup to this failing). This usually would be a configuration
-	 * or programming issue.
-	 */
-	if (!app)
-		bail("mapping tool not present");
-
-	child = fork();
-	if (child < 0)
-		bail("failed to fork");
-
-	if (!child) {
-#define MAX_ARGV 20
-		char *argv[MAX_ARGV];
-		char *envp[] = { NULL };
-		char pid_fmt[16];
-		int argc = 0;
-		char *next;
-
-		snprintf(pid_fmt, 16, "%d", pid);
-
-		argv[argc++] = (char *)app;
-		argv[argc++] = pid_fmt;
-		/*
-		 * Convert the map string into a list of argument that
-		 * newuidmap/newgidmap can understand.
-		 */
-
-		while (argc < MAX_ARGV) {
-			if (*map == '\0') {
-				argv[argc++] = NULL;
-				break;
-			}
-			argv[argc++] = map;
-			next = strpbrk(map, "\n ");
-			if (next == NULL)
-				break;
-			*next++ = '\0';
-			map = next + strspn(next, "\n ");
-		}
-
-		execve(app, argv, envp);
-		bail("failed to execv");
-	} else {
-		int status;
-
-		while (true) {
-			if (waitpid(child, &status, 0) < 0) {
-				if (errno == EINTR)
-					continue;
-				bail("failed to waitpid");
-			}
-			if (WIFEXITED(status) || WIFSIGNALED(status))
-				return WEXITSTATUS(status);
-		}
-	}
-
-	return -1;
-}
-
-static void update_uidmap(const char *path, int pid, char *map, size_t map_len)
-{
-	if (map == NULL || map_len <= 0)
-		return;
-
-	if (write_file(map, map_len, "/proc/%d/uid_map", pid) < 0) {
-		if (errno != EPERM)
-			bail("failed to update /proc/%d/uid_map", pid);
-		if (try_mapping_tool(path, pid, map, map_len))
-			bail("failed to use newuid map on %d", pid);
-	}
-}
-
-static void update_gidmap(const char *path, int pid, char *map, size_t map_len)
-{
-	if (map == NULL || map_len <= 0)
-		return;
-
-	if (write_file(map, map_len, "/proc/%d/gid_map", pid) < 0) {
-		if (errno != EPERM)
-			bail("failed to update /proc/%d/gid_map", pid);
-		if (try_mapping_tool(path, pid, map, map_len))
-			bail("failed to use newgid map on %d", pid);
-	}
-}
-
-static void update_oom_score_adj(char *data, size_t len)
-{
-	if (data == NULL || len <= 0)
-		return;
-
-	if (write_file(data, len, "/proc/self/oom_score_adj") < 0)
-		bail("failed to update /proc/self/oom_score_adj");
-}
-
-/* A dummy function that just jumps to the given jumpval. */
-static int child_func(void *arg) __attribute__ ((noinline));
-static int child_func(void *arg)
-{
-	struct clone_t *ca = (struct clone_t *)arg;
-	longjmp(*ca->env, ca->jmpval);
-}
-
-static int clone_parent(jmp_buf *env, int jmpval) __attribute__ ((noinline));
-static int clone_parent(jmp_buf *env, int jmpval)
-{
-	struct clone_t ca = {
-		.env = env,
-		.jmpval = jmpval,
-	};
-
-	return clone(child_func, ca.stack_ptr, CLONE_PARENT | SIGCHLD, &ca);
-}
-
-/*
- * Gets the init pipe fd from the environment, which is used to read the
- * bootstrap data and tell the parent what the new pid is after we finish
- * setting up the environment.
- */
-static int initpipe(void)
-{
-	int pipenum;
-	char *initpipe, *endptr;
-
-	initpipe = getenv("_LIBCONTAINER_INITPIPE");
-	if (initpipe == NULL || *initpipe == '\0')
-		return -1;
-
-	pipenum = strtol(initpipe, &endptr, 10);
-	if (*endptr != '\0')
-		bail("unable to parse _LIBCONTAINER_INITPIPE");
-
-	return pipenum;
-}
-
-/* Returns the clone(2) flag for a namespace, given the name of a namespace. */
-static int nsflag(char *name)
-{
-	if (!strcmp(name, "cgroup"))
-		return CLONE_NEWCGROUP;
-	else if (!strcmp(name, "ipc"))
-		return CLONE_NEWIPC;
-	else if (!strcmp(name, "mnt"))
-		return CLONE_NEWNS;
-	else if (!strcmp(name, "net"))
-		return CLONE_NEWNET;
-	else if (!strcmp(name, "pid"))
-		return CLONE_NEWPID;
-	else if (!strcmp(name, "user"))
-		return CLONE_NEWUSER;
-	else if (!strcmp(name, "uts"))
-		return CLONE_NEWUTS;
-
-	/* If we don't recognise a name, fallback to 0. */
-	return 0;
-}
-
-static uint32_t readint32(char *buf)
-{
-	return *(uint32_t *) buf;
-}
-
-static uint8_t readint8(char *buf)
-{
-	return *(uint8_t *) buf;
-}
-
-static void nl_parse(int fd, struct nlconfig_t *config)
-{
-	size_t len, size;
-	struct nlmsghdr hdr;
-	char *data, *current;
-
-	/* Retrieve the netlink header. */
-	len = read(fd, &hdr, NLMSG_HDRLEN);
-	if (len != NLMSG_HDRLEN)
-		bail("invalid netlink header length %zu", len);
-
-	if (hdr.nlmsg_type == NLMSG_ERROR)
-		bail("failed to read netlink message");
-
-	if (hdr.nlmsg_type != INIT_MSG)
-		bail("unexpected msg type %d", hdr.nlmsg_type);
-
-	/* Retrieve data. */
-	size = NLMSG_PAYLOAD(&hdr, 0);
-	current = data = malloc(size);
-	if (!data)
-		bail("failed to allocate %zu bytes of memory for nl_payload", size);
-
-	len = read(fd, data, size);
-	if (len != size)
-		bail("failed to read netlink payload, %zu != %zu", len, size);
-
-	/* Parse the netlink payload. */
-	config->data = data;
-	while (current < data + size) {
-		struct nlattr *nlattr = (struct nlattr *)current;
-		size_t payload_len = nlattr->nla_len - NLA_HDRLEN;
-
-		/* Advance to payload. */
-		current += NLA_HDRLEN;
-
-		/* Handle payload. */
-		switch (nlattr->nla_type) {
-		case CLONE_FLAGS_ATTR:
-			config->cloneflags = readint32(current);
-			break;
-		case ROOTLESS_EUID_ATTR:
-			config->is_rootless_euid = readint8(current);	/* boolean */
-			break;
-		case OOM_SCORE_ADJ_ATTR:
-			config->oom_score_adj = current;
-			config->oom_score_adj_len = payload_len;
-			break;
-		case NS_PATHS_ATTR:
-			config->namespaces = current;
-			config->namespaces_len = payload_len;
-			break;
-		case UIDMAP_ATTR:
-			config->uidmap = current;
-			config->uidmap_len = payload_len;
-			break;
-		case GIDMAP_ATTR:
-			config->gidmap = current;
-			config->gidmap_len = payload_len;
-			break;
-		case UIDMAPPATH_ATTR:
-			config->uidmappath = current;
-			config->uidmappath_len = payload_len;
-			break;
-		case GIDMAPPATH_ATTR:
-			config->gidmappath = current;
-			config->gidmappath_len = payload_len;
-			break;
-		case SETGROUP_ATTR:
-			config->is_setgroup = readint8(current);
-			break;
-		default:
-			bail("unknown netlink message type %d", nlattr->nla_type);
-		}
-
-		current += NLA_ALIGN(payload_len);
-	}
-}
-
-void nl_free(struct nlconfig_t *config)
-{
-	free(config->data);
-}
-
-void join_namespaces(char *nslist)
-{
-	int num = 0, i;
-	char *saveptr = NULL;
-	char *namespace = strtok_r(nslist, ",", &saveptr);
-	struct namespace_t {
-		int fd;
-		int ns;
-		char type[PATH_MAX];
-		char path[PATH_MAX];
-	} *namespaces = NULL;
-
-	if (!namespace || !strlen(namespace) || !strlen(nslist))
-		bail("ns paths are empty");
-
-	/*
-	 * We have to open the file descriptors first, since after
-	 * we join the mnt namespace we might no longer be able to
-	 * access the paths.
-	 */
-	do {
-		int fd;
-		char *path;
-		struct namespace_t *ns;
-
-		/* Resize the namespace array. */
-		namespaces = realloc(namespaces, ++num * sizeof(struct namespace_t));
-		if (!namespaces)
-			bail("failed to reallocate namespace array");
-		ns = &namespaces[num - 1];
-
-		/* Split 'ns:path'. */
-		path = strstr(namespace, ":");
-		if (!path)
-			bail("failed to parse %s", namespace);
-		*path++ = '\0';
-
-		fd = open(path, O_RDONLY);
-		if (fd < 0)
-			bail("failed to open %s", path);
-
-		ns->fd = fd;
-		ns->ns = nsflag(namespace);
-		strncpy(ns->path, path, PATH_MAX - 1);
-		ns->path[PATH_MAX - 1] = '\0';
-	} while ((namespace = strtok_r(NULL, ",", &saveptr)) != NULL);
-
-	/*
-	 * The ordering in which we join namespaces is important. We should
-	 * always join the user namespace *first*. This is all guaranteed
-	 * from the container_linux.go side of this, so we're just going to
-	 * follow the order given to us.
-	 */
-
-	for (i = 0; i < num; i++) {
-		struct namespace_t ns = namespaces[i];
-
-		if (setns(ns.fd, ns.ns) < 0)
-			bail("failed to setns to %s", ns.path);
-
-		close(ns.fd);
-	}
-
-	free(namespaces);
-}
-
-void nsexec(void)
-{
-	int pipenum;
-	jmp_buf env;
-	int sync_child_pipe[2], sync_grandchild_pipe[2];
-	struct nlconfig_t config = { 0 };
-
-	/*
-	 * If we don't have an init pipe, just return to the go routine.
-	 * We'll only get an init pipe for start or exec.
-	 */
-	pipenum = initpipe();
-	if (pipenum == -1)
-		return;
-
-	/* Parse all of the netlink configuration. */
-	nl_parse(pipenum, &config);
-
-	/* Set oom_score_adj. This has to be done before !dumpable because
-	 * /proc/self/oom_score_adj is not writeable unless you're an privileged
-	 * user (if !dumpable is set). All children inherit their parent's
-	 * oom_score_adj value on fork(2) so this will always be propagated
-	 * properly.
-	 */
-	update_oom_score_adj(config.oom_score_adj, config.oom_score_adj_len);
-
-	/*
-	 * Make the process non-dumpable, to avoid various race conditions that
-	 * could cause processes in namespaces we're joining to access host
-	 * resources (or potentially execute code).
-	 *
-	 * However, if the number of namespaces we are joining is 0, we are not
-	 * going to be switching to a different security context. Thus setting
-	 * ourselves to be non-dumpable only breaks things (like rootless
-	 * containers), which is the recommendation from the kernel folks.
-	 */
-	if (config.namespaces) {
-		if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0) < 0)
-			bail("failed to set process as non-dumpable");
-	}
-
-	/* Pipe so we can tell the child when we've finished setting up. */
-	if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sync_child_pipe) < 0)
-		bail("failed to setup sync pipe between parent and child");
-
-	/*
-	 * We need a new socketpair to sync with grandchild so we don't have
-	 * race condition with child.
-	 */
-	if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sync_grandchild_pipe) < 0)
-		bail("failed to setup sync pipe between parent and grandchild");
-
-	/* TODO: Currently we aren't dealing with child deaths properly. */
-
-	/*
-	 * Okay, so this is quite annoying.
-	 *
-	 * In order for this unsharing code to be more extensible we need to split
-	 * up unshare(CLONE_NEWUSER) and clone() in various ways. The ideal case
-	 * would be if we did clone(CLONE_NEWUSER) and the other namespaces
-	 * separately, but because of SELinux issues we cannot really do that. But
-	 * we cannot just dump the namespace flags into clone(...) because several
-	 * usecases (such as rootless containers) require more granularity around
-	 * the namespace setup. In addition, some older kernels had issues where
-	 * CLONE_NEWUSER wasn't handled before other namespaces (but we cannot
-	 * handle this while also dealing with SELinux so we choose SELinux support
-	 * over broken kernel support).
-	 *
-	 * However, if we unshare(2) the user namespace *before* we clone(2), then
-	 * all hell breaks loose.
-	 *
-	 * The parent no longer has permissions to do many things (unshare(2) drops
-	 * all capabilities in your old namespace), and the container cannot be set
-	 * up to have more than one {uid,gid} mapping. This is obviously less than
-	 * ideal. In order to fix this, we have to first clone(2) and then unshare.
-	 *
-	 * Unfortunately, it's not as simple as that. We have to fork to enter the
-	 * PID namespace (the PID namespace only applies to children). Since we'll
-	 * have to double-fork, this clone_parent() call won't be able to get the
-	 * PID of the _actual_ init process (without doing more synchronisation than
-	 * I can deal with at the moment). So we'll just get the parent to send it
-	 * for us, the only job of this process is to update
-	 * /proc/pid/{setgroups,uid_map,gid_map}.
-	 *
-	 * And as a result of the above, we also need to setns(2) in the first child
-	 * because if we join a PID namespace in the topmost parent then our child
-	 * will be in that namespace (and it will not be able to give us a PID value
-	 * that makes sense without resorting to sending things with cmsg).
-	 *
-	 * This also deals with an older issue caused by dumping cloneflags into
-	 * clone(2): On old kernels, CLONE_PARENT didn't work with CLONE_NEWPID, so
-	 * we have to unshare(2) before clone(2) in order to do this. This was fixed
-	 * in upstream commit 1f7f4dde5c945f41a7abc2285be43d918029ecc5, and was
-	 * introduced by 40a0d32d1eaffe6aac7324ca92604b6b3977eb0e. As far as we're
-	 * aware, the last mainline kernel which had this bug was Linux 3.12.
-	 * However, we cannot comment on which kernels the broken patch was
-	 * backported to.
-	 *
-	 * -- Aleksa "what has my life come to?" Sarai
-	 */
-
-	switch (setjmp(env)) {
-		/*
-		 * Stage 0: We're in the parent. Our job is just to create a new child
-		 *          (stage 1: JUMP_CHILD) process and write its uid_map and
-		 *          gid_map. That process will go on to create a new process, then
-		 *          it will send us its PID which we will send to the bootstrap
-		 *          process.
-		 */
-	case JUMP_PARENT:{
-			int len;
-			pid_t child, first_child = -1;
-			bool ready = false;
-
-			/* For debugging. */
-			prctl(PR_SET_NAME, (unsigned long)"runc:[0:PARENT]", 0, 0, 0);
-
-			/* Start the process of getting a container. */
-			child = clone_parent(&env, JUMP_CHILD);
-			if (child < 0)
-				bail("unable to fork: child_func");
-
-			/*
-			 * State machine for synchronisation with the children.
-			 *
-			 * Father only return when both child and grandchild are
-			 * ready, so we can receive all possible error codes
-			 * generated by children.
-			 */
-			while (!ready) {
-				enum sync_t s;
-				int ret;
-
-				syncfd = sync_child_pipe[1];
-				close(sync_child_pipe[0]);
-
-				if (read(syncfd, &s, sizeof(s)) != sizeof(s))
-					bail("failed to sync with child: next state");
-
-				switch (s) {
-				case SYNC_ERR:
-					/* We have to mirror the error code of the child. */
-					if (read(syncfd, &ret, sizeof(ret)) != sizeof(ret))
-						bail("failed to sync with child: read(error code)");
-
-					exit(ret);
-				case SYNC_USERMAP_PLS:
-					/*
-					 * Enable setgroups(2) if we've been asked to. But we also
-					 * have to explicitly disable setgroups(2) if we're
-					 * creating a rootless container for single-entry mapping.
-					 * i.e. config.is_setgroup == false.
-					 * (this is required since Linux 3.19).
-					 *
-					 * For rootless multi-entry mapping, config.is_setgroup shall be true and
-					 * newuidmap/newgidmap shall be used.
-					 */
-
-					if (config.is_rootless_euid && !config.is_setgroup)
-						update_setgroups(child, SETGROUPS_DENY);
-
-					/* Set up mappings. */
-					update_uidmap(config.uidmappath, child, config.uidmap, config.uidmap_len);
-					update_gidmap(config.gidmappath, child, config.gidmap, config.gidmap_len);
-
-					s = SYNC_USERMAP_ACK;
-					if (write(syncfd, &s, sizeof(s)) != sizeof(s)) {
-						kill(child, SIGKILL);
-						bail("failed to sync with child: write(SYNC_USERMAP_ACK)");
-					}
-					break;
-				case SYNC_RECVPID_PLS:{
-						first_child = child;
-
-						/* Get the init_func pid. */
-						if (read(syncfd, &child, sizeof(child)) != sizeof(child)) {
-							kill(first_child, SIGKILL);
-							bail("failed to sync with child: read(childpid)");
-						}
-
-						/* Send ACK. */
-						s = SYNC_RECVPID_ACK;
-						if (write(syncfd, &s, sizeof(s)) != sizeof(s)) {
-							kill(first_child, SIGKILL);
-							kill(child, SIGKILL);
-							bail("failed to sync with child: write(SYNC_RECVPID_ACK)");
-						}
-
-						/* Send the init_func pid back to our parent.
-						 *
-						 * Send the init_func pid and the pid of the first child back to our parent.
-						 * We need to send both back because we can't reap the first child we created (CLONE_PARENT).
-						 * It becomes the responsibility of our parent to reap the first child.
-						 */
-						len = dprintf(pipenum, "{\"pid\": %d, \"pid_first\": %d}\n", child, first_child);
-						if (len < 0) {
-							kill(child, SIGKILL);
-							bail("unable to generate JSON for child pid");
-						}
-					}
-					break;
-				case SYNC_CHILD_READY:
-					ready = true;
-					break;
-				default:
-					bail("unexpected sync value: %u", s);
-				}
-			}
-
-			/* Now sync with grandchild. */
-
-			ready = false;
-			while (!ready) {
-				enum sync_t s;
-				int ret;
-
-				syncfd = sync_grandchild_pipe[1];
-				close(sync_grandchild_pipe[0]);
-
-				s = SYNC_GRANDCHILD;
-				if (write(syncfd, &s, sizeof(s)) != sizeof(s)) {
-					kill(child, SIGKILL);
-					bail("failed to sync with child: write(SYNC_GRANDCHILD)");
-				}
-
-				if (read(syncfd, &s, sizeof(s)) != sizeof(s))
-					bail("failed to sync with child: next state");
-
-				switch (s) {
-				case SYNC_ERR:
-					/* We have to mirror the error code of the child. */
-					if (read(syncfd, &ret, sizeof(ret)) != sizeof(ret))
-						bail("failed to sync with child: read(error code)");
-
-					exit(ret);
-				case SYNC_CHILD_READY:
-					ready = true;
-					break;
-				default:
-					bail("unexpected sync value: %u", s);
-				}
-			}
-			exit(0);
-		}
-
-		/*
-		 * Stage 1: We're in the first child process. Our job is to join any
-		 *          provided namespaces in the netlink payload and unshare all
-		 *          of the requested namespaces. If we've been asked to
-		 *          CLONE_NEWUSER, we will ask our parent (stage 0) to set up
-		 *          our user mappings for us. Then, we create a new child
-		 *          (stage 2: JUMP_INIT) for PID namespace. We then send the
-		 *          child's PID to our parent (stage 0).
-		 */
-	case JUMP_CHILD:{
-			pid_t child;
-			enum sync_t s;
-
-			/* We're in a child and thus need to tell the parent if we die. */
-			syncfd = sync_child_pipe[0];
-			close(sync_child_pipe[1]);
-
-			/* For debugging. */
-			prctl(PR_SET_NAME, (unsigned long)"runc:[1:CHILD]", 0, 0, 0);
-
-			/*
-			 * We need to setns first. We cannot do this earlier (in stage 0)
-			 * because of the fact that we forked to get here (the PID of
-			 * [stage 2: JUMP_INIT]) would be meaningless). We could send it
-			 * using cmsg(3) but that's just annoying.
-			 */
-			if (config.namespaces)
-				join_namespaces(config.namespaces);
-
-			/*
-			 * Deal with user namespaces first. They are quite special, as they
-			 * affect our ability to unshare other namespaces and are used as
-			 * context for privilege checks.
-			 *
-			 * We don't unshare all namespaces in one go. The reason for this
-			 * is that, while the kernel documentation may claim otherwise,
-			 * there are certain cases where unsharing all namespaces at once
-			 * will result in namespace objects being owned incorrectly.
-			 * Ideally we should just fix these kernel bugs, but it's better to
-			 * be safe than sorry, and fix them separately.
-			 *
-			 * A specific case of this is that the SELinux label of the
-			 * internal kern-mount that mqueue uses will be incorrect if the
-			 * UTS namespace is cloned before the USER namespace is mapped.
-			 * I've also heard of similar problems with the network namespace
-			 * in some scenarios. This also mirrors how LXC deals with this
-			 * problem.
-			 */
-			if (config.cloneflags & CLONE_NEWUSER) {
-				if (unshare(CLONE_NEWUSER) < 0)
-					bail("failed to unshare user namespace");
-				config.cloneflags &= ~CLONE_NEWUSER;
-
-				/*
-				 * We don't have the privileges to do any mapping here (see the
-				 * clone_parent rant). So signal our parent to hook us up.
-				 */
-
-				/* Switching is only necessary if we joined namespaces. */
-				if (config.namespaces) {
-					if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) < 0)
-						bail("failed to set process as dumpable");
-				}
-				s = SYNC_USERMAP_PLS;
-				if (write(syncfd, &s, sizeof(s)) != sizeof(s))
-					bail("failed to sync with parent: write(SYNC_USERMAP_PLS)");
-
-				/* ... wait for mapping ... */
-
-				if (read(syncfd, &s, sizeof(s)) != sizeof(s))
-					bail("failed to sync with parent: read(SYNC_USERMAP_ACK)");
-				if (s != SYNC_USERMAP_ACK)
-					bail("failed to sync with parent: SYNC_USERMAP_ACK: got %u", s);
-				/* Switching is only necessary if we joined namespaces. */
-				if (config.namespaces) {
-					if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0) < 0)
-						bail("failed to set process as dumpable");
-				}
-
-				/* Become root in the namespace proper. */
-				if (setresuid(0, 0, 0) < 0)
-					bail("failed to become root in user namespace");
-			}
-			/*
-			 * Unshare all of the namespaces. Now, it should be noted that this
-			 * ordering might break in the future (especially with rootless
-			 * containers). But for now, it's not possible to split this into
-			 * CLONE_NEWUSER + [the rest] because of some RHEL SELinux issues.
-			 *
-			 * Note that we don't merge this with clone() because there were
-			 * some old kernel versions where clone(CLONE_PARENT | CLONE_NEWPID)
-			 * was broken, so we'll just do it the long way anyway.
-			 */
-			if (unshare(config.cloneflags & ~CLONE_NEWCGROUP) < 0)
-				bail("failed to unshare namespaces");
-
-			/*
-			 * TODO: What about non-namespace clone flags that we're dropping here?
-			 *
-			 * We fork again because of PID namespace, setns(2) or unshare(2) don't
-			 * change the PID namespace of the calling process, because doing so
-			 * would change the caller's idea of its own PID (as reported by getpid()),
-			 * which would break many applications and libraries, so we must fork
-			 * to actually enter the new PID namespace.
-			 */
-			child = clone_parent(&env, JUMP_INIT);
-			if (child < 0)
-				bail("unable to fork: init_func");
-
-			/* Send the child to our parent, which knows what it's doing. */
-			s = SYNC_RECVPID_PLS;
-			if (write(syncfd, &s, sizeof(s)) != sizeof(s)) {
-				kill(child, SIGKILL);
-				bail("failed to sync with parent: write(SYNC_RECVPID_PLS)");
-			}
-			if (write(syncfd, &child, sizeof(child)) != sizeof(child)) {
-				kill(child, SIGKILL);
-				bail("failed to sync with parent: write(childpid)");
-			}
-
-			/* ... wait for parent to get the pid ... */
-
-			if (read(syncfd, &s, sizeof(s)) != sizeof(s)) {
-				kill(child, SIGKILL);
-				bail("failed to sync with parent: read(SYNC_RECVPID_ACK)");
-			}
-			if (s != SYNC_RECVPID_ACK) {
-				kill(child, SIGKILL);
-				bail("failed to sync with parent: SYNC_RECVPID_ACK: got %u", s);
-			}
-
-			s = SYNC_CHILD_READY;
-			if (write(syncfd, &s, sizeof(s)) != sizeof(s)) {
-				kill(child, SIGKILL);
-				bail("failed to sync with parent: write(SYNC_CHILD_READY)");
-			}
-
-			/* Our work is done. [Stage 2: JUMP_INIT] is doing the rest of the work. */
-			exit(0);
-		}
-
-		/*
-		 * Stage 2: We're the final child process, and the only process that will
-		 *          actually return to the Go runtime. Our job is to just do the
-		 *          final cleanup steps and then return to the Go runtime to allow
-		 *          init_linux.go to run.
-		 */
-	case JUMP_INIT:{
-			/*
-			 * We're inside the child now, having jumped from the
-			 * start_child() code after forking in the parent.
-			 */
-			enum sync_t s;
-
-			/* We're in a child and thus need to tell the parent if we die. */
-			syncfd = sync_grandchild_pipe[0];
-			close(sync_grandchild_pipe[1]);
-			close(sync_child_pipe[0]);
-			close(sync_child_pipe[1]);
-
-			/* For debugging. */
-			prctl(PR_SET_NAME, (unsigned long)"runc:[2:INIT]", 0, 0, 0);
-
-			if (read(syncfd, &s, sizeof(s)) != sizeof(s))
-				bail("failed to sync with parent: read(SYNC_GRANDCHILD)");
-			if (s != SYNC_GRANDCHILD)
-				bail("failed to sync with parent: SYNC_GRANDCHILD: got %u", s);
-
-			if (setsid() < 0)
-				bail("setsid failed");
-
-			if (setuid(0) < 0)
-				bail("setuid failed");
-
-			if (setgid(0) < 0)
-				bail("setgid failed");
-
-			if (!config.is_rootless_euid && config.is_setgroup) {
-				if (setgroups(0, NULL) < 0)
-					bail("setgroups failed");
-			}
-
-			/* ... wait until our topmost parent has finished cgroup setup in p.manager.Apply() ... */
-			if (config.cloneflags & CLONE_NEWCGROUP) {
-				uint8_t value;
-				if (read(pipenum, &value, sizeof(value)) != sizeof(value))
-					bail("read synchronisation value failed");
-				if (value == CREATECGROUPNS) {
-					if (unshare(CLONE_NEWCGROUP) < 0)
-						bail("failed to unshare cgroup namespace");
-				} else
-					bail("received unknown synchronisation value");
-			}
-
-			s = SYNC_CHILD_READY;
-			if (write(syncfd, &s, sizeof(s)) != sizeof(s))
-				bail("failed to sync with patent: write(SYNC_CHILD_READY)");
-
-			/* Close sync pipes. */
-			close(sync_grandchild_pipe[0]);
-
-			/* Free netlink data. */
-			nl_free(&config);
-
-			/* Finish executing, let the Go runtime take over. */
-			return;
-		}
-	default:
-		bail("unexpected jump value");
-	}
-
-	/* Should never be reached. */
-	bail("should never be reached");
-}