Merge pull request #1864 from brauner/2017-10-18/ringbuffer

ringbuffer: implement efficient and performant ringbuffer

src/lxc/Makefile.am

@@ -116,6 +116,7 @@ liblxc_la_SOURCES = \
 	log.c log.h \
 	attach.c attach.h \
 	criu.c criu.h \
+	ringbuf.c ringbuf.h \
 	\
 	network.c network.h \
 	nl.c nl.h \

src/lxc/conf.c

@@ -68,10 +68,6 @@
 #include <../include/openpty.h>
 #endif
 
-#ifdef HAVE_LINUX_MEMFD_H
-#include <linux/memfd.h>
-#endif
-
 #include "af_unix.h"
 #include "caps.h"       /* for lxc_caps_last_cap() */
 #include "cgroup.h"
@@ -84,6 +80,7 @@
 #include "namespace.h"
 #include "network.h"
 #include "parse.h"
+#include "ringbuf.h"
 #include "storage.h"
 #include "storage/aufs.h"
 #include "storage/overlay.h"
@@ -181,59 +178,6 @@ static int sethostname(const char * name, size_t len)
 #define MS_LAZYTIME (1<<25)
 #endif
 
-/* memfd_create() */
-#ifndef MFD_CLOEXEC
-#define MFD_CLOEXEC 0x0001U
-#endif
-
-#ifndef MFD_ALLOW_SEALING
-#define MFD_ALLOW_SEALING 0x0002U
-#endif
-
-#ifndef HAVE_MEMFD_CREATE
-static int memfd_create(const char *name, unsigned int flags) {
-	#ifndef __NR_memfd_create
-		#if defined __i386__
-			#define __NR_memfd_create 356
-		#elif defined __x86_64__
-			#define __NR_memfd_create 319
-		#elif defined __arm__
-			#define __NR_memfd_create 385
-		#elif defined __aarch64__
-			#define __NR_memfd_create 279
-		#elif defined __s390__
-			#define __NR_memfd_create 350
-		#elif defined __powerpc__
-			#define __NR_memfd_create 360
-		#elif defined __sparc__
-			#define __NR_memfd_create 348
-		#elif defined __blackfin__
-			#define __NR_memfd_create 390
-		#elif defined __ia64__
-			#define __NR_memfd_create 1340
-		#elif defined _MIPS_SIM
-			#if _MIPS_SIM == _MIPS_SIM_ABI32
-				#define __NR_memfd_create 4354
-			#endif
-			#if _MIPS_SIM == _MIPS_SIM_NABI32
-				#define __NR_memfd_create 6318
-			#endif
-			#if _MIPS_SIM == _MIPS_SIM_ABI64
-				#define __NR_memfd_create 5314
-			#endif
-		#endif
-	#endif
-	#ifdef __NR_memfd_create
-	return syscall(__NR_memfd_create, name, flags);
-	#else
-	errno = ENOSYS;
-	return -1;
-	#endif
-}
-#else
-extern int memfd_create(const char *name, unsigned int flags);
-#endif
-
 char *lxchook_names[NUM_LXC_HOOKS] = {"pre-start", "pre-mount", "mount",
 				      "autodev",   "start",     "stop",
 				      "post-stop", "clone",     "destroy",
@@ -2485,6 +2429,7 @@ struct lxc_conf *lxc_conf_init(void)
 	new->autodev = 1;
 	new->console.log_path = NULL;
 	new->console.log_fd = -1;
+	new->console.log_size = 0;
 	new->console.path = NULL;
 	new->console.peer = -1;
 	new->console.peerpty.busy = -1;
@@ -2493,6 +2438,7 @@ struct lxc_conf *lxc_conf_init(void)
 	new->console.master = -1;
 	new->console.slave = -1;
 	new->console.name[0] = '\0';
+	memset(&new->console.ringbuf, 0, sizeof(struct lxc_ringbuf));
 	new->maincmd_fd = -1;
 	new->nbd_idx = -1;
 	new->rootfs.mount = strdup(default_rootfs_mount);
@@ -3136,7 +3082,65 @@ static bool verify_start_hooks(struct lxc_conf *conf)
 	return true;
 }
 
-int lxc_setup(struct lxc_handler *handler)
+/**
+ * Note that this function needs to run before the mainloop starts. Since we
+ * register a handler for the console's masterfd when we create the mainloop
+ * the console handler needs to see an allocated ringbuffer.
+ */
+static int lxc_setup_console_ringbuf(struct lxc_console *console)
+{
+	int ret;
+	struct lxc_ringbuf *buf = &console->ringbuf;
+	uint64_t size = console->log_size;
+
+	/* no ringbuffer previously allocated and no ringbuffer requested */
+	if (!buf->addr && size <= 0)
+		return 0;
+
+	/* ringbuffer allocated but no new ringbuffer requested */
+	if (buf->addr && size <= 0) {
+		lxc_ringbuf_release(buf);
+		buf->addr = NULL;
+		buf->r_off = 0;
+		buf->w_off = 0;
+		buf->size = 0;
+		TRACE("Deallocated console ringbuffer");
+		return 0;
+	}
+
+	if (size <= 0)
+		return 0;
+
+	/* check wether the requested size for the ringbuffer has changed */
+	if (buf->addr && buf->size != size) {
+		TRACE("Console ringbuffer size changed from %" PRIu64
+		      " to %" PRIu64 " bytes. Deallocating console ringbuffer",
+		      buf->size, size);
+		lxc_ringbuf_release(buf);
+	}
+
+	ret = lxc_ringbuf_create(buf, size);
+	if (ret < 0) {
+		ERROR("Failed to setup %" PRIu64 " byte console ringbuffer", size);
+		return -1;
+	}
+
+	TRACE("Allocated %" PRIu64 " byte console ringbuffer", size);
+	return 0;
+}
+
+int lxc_setup_parent(struct lxc_handler *handler)
+{
+	int ret;
+
+	ret = lxc_setup_console_ringbuf(&handler->conf->console);
+	if (ret < 0)
+		return -1;
+
+	return 0;
+}
+
+int lxc_setup_child(struct lxc_handler *handler)
 {
 	int ret;
 	const char *name = handler->name;
@@ -3516,6 +3520,8 @@ void lxc_conf_free(struct lxc_conf *conf)
 		current_config = NULL;
 	free(conf->console.log_path);
 	free(conf->console.path);
+	if (conf->console.log_size > 0 && conf->console.ringbuf.addr)
+		lxc_ringbuf_release(&conf->console.ringbuf);
 	free(conf->rootfs.mount);
 	free(conf->rootfs.bdev_type);
 	free(conf->rootfs.options);

src/lxc/conf.h

@@ -36,6 +36,7 @@
 #include <stdbool.h>
 
 #include "list.h"
+#include "ringbuf.h"
 #include "start.h" /* for lxc_handler */
 
 #if HAVE_SCMP_FILTER_CTX
@@ -152,6 +153,8 @@ struct lxc_console {
 	char name[MAXPATHLEN];
 	struct termios *tios;
 	struct lxc_tty_state *tty_state;
+	uint64_t log_size;
+	struct lxc_ringbuf ringbuf;
 };
 
 /*
@@ -376,7 +379,8 @@ extern int lxc_delete_autodev(struct lxc_handler *handler);
 extern void lxc_clear_includes(struct lxc_conf *conf);
 extern int do_rootfs_setup(struct lxc_conf *conf, const char *name,
 			   const char *lxcpath);
-extern int lxc_setup(struct lxc_handler *handler);
+extern int lxc_setup_child(struct lxc_handler *handler);
+extern int lxc_setup_parent(struct lxc_handler *handler);
 extern int setup_resource_limits(struct lxc_list *limits, pid_t pid);
 extern int find_unmapped_nsid(struct lxc_conf *conf, enum idtype idtype);
 extern int mapped_hostid(unsigned id, struct lxc_conf *conf,

src/lxc/confile.c

@@ -83,6 +83,7 @@ lxc_config_define(cap_keep);
 lxc_config_define(cgroup_controller);
 lxc_config_define(cgroup_dir);
 lxc_config_define(console_logfile);
+lxc_config_define(console_logsize);
 lxc_config_define(console_path);
 lxc_config_define(environment);
 lxc_config_define(ephemeral);
@@ -148,6 +149,7 @@ static struct lxc_config_t config[] = {
 	{ "lxc.cgroup.dir",                false,                  set_config_cgroup_dir,                  get_config_cgroup_dir,                  clr_config_cgroup_dir,                },
 	{ "lxc.cgroup",                    false,                  set_config_cgroup_controller,           get_config_cgroup_controller,           clr_config_cgroup_controller,         },
 	{ "lxc.console.logfile",           false,                  set_config_console_logfile,             get_config_console_logfile,             clr_config_console_logfile,           },
+	{ "lxc.console.logsize",           false,                  set_config_console_logsize,             get_config_console_logsize,             clr_config_console_logsize,           },
 	{ "lxc.console.path",              false,                  set_config_console_path,                get_config_console_path,                clr_config_console_path,              },
 	{ "lxc.environment",               false,                  set_config_environment,                 get_config_environment,                 clr_config_environment,               },
 	{ "lxc.ephemeral",                 false,                  set_config_ephemeral,                   get_config_ephemeral,                   clr_config_ephemeral,                 },
@@ -1790,6 +1792,53 @@ static int set_config_console_logfile(const char *key, const char *value,
 	return set_config_path_item(&lxc_conf->console.log_path, value);
 }
 
+static int set_config_console_logsize(const char *key, const char *value,
+				      struct lxc_conf *lxc_conf, void *data)
+{
+	int ret;
+	int64_t size;
+	uint64_t logsize, pgsz;
+
+	if (lxc_config_value_empty(value)) {
+		lxc_conf->console.log_size = 0;
+		return 0;
+	}
+
+	/* If the user specified "auto" the default log size is 2^17 = 128 Kib */
+	if (!strcmp(value, "auto")) {
+		lxc_conf->console.log_size = 1 << 17;
+		return 0;
+	}
+
+	ret = parse_byte_size_string(value, &size);
+	if (ret < 0)
+		return -1;
+
+	if (size < 0)
+		return -EINVAL;
+
+	/* must be at least a page size */
+	pgsz = lxc_getpagesize();
+	if ((uint64_t)size < pgsz) {
+		NOTICE("Requested ringbuffer size for the console is %" PRId64
+		       " but must be at least %" PRId64
+		       " bytes. Setting ringbuffer size to %" PRId64 " bytes",
+		       size, pgsz, pgsz);
+		size = pgsz;
+	}
+
+	logsize = lxc_find_next_power2((uint64_t)size);
+	if (logsize == 0)
+		return -EINVAL;
+
+	if (logsize != size)
+		NOTICE("Passed size was not a power of 2. Rounding log size to "
+		       "next power of two: %" PRIu64 " bytes", logsize);
+
+	lxc_conf->console.log_size = logsize;
+	return 0;
+}
+
 int append_unexp_config_line(const char *line, struct lxc_conf *conf)
 {
 	size_t len = conf->unexpanded_len, linelen = strlen(line);
@@ -3023,6 +3072,12 @@ static int get_config_console_logfile(const char *key, char *retv, int inlen,
 	return lxc_get_conf_str(retv, inlen, c->console.log_path);
 }
 
+static int get_config_console_logsize(const char *key, char *retv, int inlen,
+				      struct lxc_conf *c, void *data)
+{
+	return lxc_get_conf_uint64(c, retv, inlen, c->autodev);
+}
+
 static int get_config_seccomp_profile(const char *key, char *retv, int inlen,
 				      struct lxc_conf *c, void *data)
 {
@@ -3405,6 +3460,13 @@ static inline int clr_config_console_logfile(const char *key,
 	return 0;
 }
 
+static inline int clr_config_console_logsize(const char *key,
+					     struct lxc_conf *c, void *data)
+{
+	c->console.log_size = 0;
+	return 0;
+}
+
 static inline int clr_config_seccomp_profile(const char *key,
 					     struct lxc_conf *c, void *data)
 {

src/lxc/confile_utils.c

@@ -672,6 +672,16 @@ int lxc_get_conf_int(struct lxc_conf *c, char *retv, int inlen, int v)
 	return snprintf(retv, inlen, "%d", v);
 }
 
+int lxc_get_conf_uint64(struct lxc_conf *c, char *retv, int inlen, uint64_t v)
+{
+	if (!retv)
+		inlen = 0;
+	else
+		memset(retv, 0, inlen);
+
+	return snprintf(retv, inlen, "%"PRIu64, v);
+}
+
 bool parse_limit_value(const char **value, rlim_t *res)
 {
 	char *endptr = NULL;

src/lxc/confile_utils.h

@@ -84,5 +84,7 @@ extern void update_hwaddr(const char *line);
 extern bool new_hwaddr(char *hwaddr);
 extern int lxc_get_conf_str(char *retv, int inlen, const char *value);
 extern int lxc_get_conf_int(struct lxc_conf *c, char *retv, int inlen, int v);
+extern int lxc_get_conf_uint64(struct lxc_conf *c, char *retv, int inlen, uint64_t v);
 extern bool parse_limit_value(const char **value, rlim_t *res);
+
 #endif /* __LXC_CONFILE_UTILS_H */

src/lxc/console.c

@@ -51,6 +51,8 @@
 #include <../include/openpty.h>
 #endif
 
+#define LXC_CONSOLE_BUFFER_SIZE 1024
+
 lxc_log_define(console, lxc);
 
 static struct lxc_list lxc_ttys;
@@ -167,12 +169,12 @@ static int lxc_console_cb_con(int fd, uint32_t events, void *data,
 			      struct lxc_epoll_descr *descr)
 {
 	struct lxc_console *console = (struct lxc_console *)data;
-	char buf[1024];
-	int r, w;
+	char buf[LXC_CONSOLE_BUFFER_SIZE];
+	int r, w, w_log, w_rbuf;
 
 	w = r = lxc_read_nointr(fd, buf, sizeof(buf));
 	if (r <= 0) {
-		INFO("console client on fd %d has exited", fd);
+		INFO("Console client on fd %d has exited", fd);
 		lxc_mainloop_del_handler(descr, fd);
 		if (fd == console->peer) {
 			if (console->tty_state) {
@@ -190,16 +192,30 @@ static int lxc_console_cb_con(int fd, uint32_t events, void *data,
 	if (fd == console->peer)
 		w = lxc_write_nointr(console->master, buf, r);
 
+	w_rbuf = w_log = 0;
 	if (fd == console->master) {
-		if (console->log_fd >= 0)
-			w = lxc_write_nointr(console->log_fd, buf, r);
-
+		/* write to peer first */
 		if (console->peer >= 0)
 			w = lxc_write_nointr(console->peer, buf, r);
+
+		/* write to console ringbuffer */
+		if (console->log_size > 0)
+			w_rbuf = lxc_ringbuf_write(&console->ringbuf, buf, r);
+
+		/* write to console log */
+		if (console->log_fd >= 0)
+			w_log = lxc_write_nointr(console->log_fd, buf, r);
 	}
 
 	if (w != r)
-		WARN("console short write r:%d w:%d", r, w);
+		WARN("Console short write r:%d != w:%d", r, w);
+
+	if (w_rbuf < 0)
+		TRACE("%s - Failed to write %d bytes to console ringbuffer",
+		      strerror(-w_rbuf), r);
+
+	if (w_log < 0)
+		TRACE("Failed to write %d bytes to console log", r);
 
 	return 0;
 }
@@ -632,7 +648,7 @@ int lxc_console_cb_tty_master(int fd, uint32_t events, void *cbdata,
 		struct lxc_epoll_descr *descr)
 {
 	struct lxc_tty_state *ts = cbdata;
-	char buf[1024];
+	char buf[LXC_CONSOLE_BUFFER_SIZE];
 	int r, w;
 
 	if (fd != ts->masterfd)

src/lxc/namespace.c

@@ -21,17 +21,18 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#include <unistd.h>
 #include <alloca.h>
 #include <errno.h>
-#include <signal.h>
-#include <sys/param.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <fcntl.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 
-#include "namespace.h"
 #include "log.h"
+#include "namespace.h"
+#include "utils.h"
 
 lxc_log_define(lxc_namespace, lxc);
 
@@ -53,7 +54,7 @@ pid_t lxc_clone(int (*fn)(void *), void *arg, int flags)
 		.arg = arg,
 	};
 
-	size_t stack_size = sysconf(_SC_PAGESIZE);
+	size_t stack_size = lxc_getpagesize();
 	void *stack = alloca(stack_size);
 	pid_t ret;
 

src/lxc/ringbuf.c

@@ -0,0 +1,145 @@
+/* liblxcapi
+ *
+ * Copyright © 2017 Christian Brauner <christian.brauner@ubuntu.com>.
+ * Copyright © 2017 Canonical Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#define _GNU_SOURCE
+#define __STDC_FORMAT_MACROS
+#include <errno.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#include "ringbuf.h"
+#include "utils.h"
+
+int lxc_ringbuf_create(struct lxc_ringbuf *buf, size_t size)
+{
+	char *tmp;
+	int ret;
+	int memfd = -1;
+
+	buf->size = size;
+	buf->r_off = 0;
+	buf->w_off = 0;
+
+	/* verify that we are at least given the multiple of a page size */
+	if (buf->size % lxc_getpagesize())
+		return -EINVAL;
+
+	buf->addr = mmap(NULL, buf->size * 2, PROT_NONE,
+			 MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (buf->addr == MAP_FAILED)
+		return -EINVAL;
+
+	memfd = memfd_create(".lxc_ringbuf", MFD_CLOEXEC);
+	if (memfd < 0) {
+		if (errno != ENOSYS)
+			goto on_error;
+
+		memfd = lxc_make_tmpfile((char *){P_tmpdir"/.lxc_ringbuf_XXXXXX"}, true);
+	}
+	if (memfd < 0)
+		goto on_error;
+
+	ret = ftruncate(memfd, buf->size);
+	if (ret < 0)
+		goto on_error;
+
+	tmp = mmap(buf->addr, buf->size, PROT_READ | PROT_WRITE,
+		   MAP_FIXED | MAP_SHARED, memfd, 0);
+	if (tmp == MAP_FAILED || tmp != buf->addr)
+		goto on_error;
+
+	tmp = mmap(buf->addr + buf->size, buf->size, PROT_READ | PROT_WRITE,
+		   MAP_FIXED | MAP_SHARED, memfd, 0);
+	if (tmp == MAP_FAILED || tmp != (buf->addr + buf->size))
+		goto on_error;
+
+	close(memfd);
+
+	return 0;
+
+on_error:
+	lxc_ringbuf_release(buf);
+	if (memfd >= 0)
+		close(memfd);
+	return -1;
+}
+
+void lxc_ringbuf_move_read_addr(struct lxc_ringbuf *buf, size_t len)
+{
+	buf->r_off += len;
+
+	if (buf->r_off < buf->size)
+		return;
+
+	/* wrap around */
+	buf->r_off -= buf->size;
+	buf->w_off -= buf->size;
+}
+
+/**
+ * lxc_ringbuf_write - write a message to the ringbuffer
+ * - The size of the message should never be greater than the size of the whole
+ *   ringbuffer.
+ * - The write method will always succeed i.e. it will always advance the r_off
+ *   if it detects that there's not enough space available to write the
+ *   message.
+ */
+int lxc_ringbuf_write(struct lxc_ringbuf *buf, const char *msg, size_t len)
+{
+	char *w_addr;
+	uint64_t free;
+
+	/* sanity check: a write should never exceed the ringbuffer's total size */
+	if (len > buf->size)
+		return -EFBIG;
+
+	free = lxc_ringbuf_free(buf);
+
+	/* not enough space left so advance read address */
+	if (len > free)
+		lxc_ringbuf_move_read_addr(buf, len);
+	w_addr = lxc_ringbuf_get_write_addr(buf);
+	memcpy(w_addr, msg, len);
+	lxc_ringbuf_move_write_addr(buf, len);
+	return 0;
+}
+
+int lxc_ringbuf_read(struct lxc_ringbuf *buf, char *out, size_t *len)
+{
+	uint64_t used;
+
+	/* there's nothing to read */
+	if (buf->r_off == buf->w_off)
+		return -ENODATA;
+
+	/* read maximum amount available */
+	used = lxc_ringbuf_used(buf);
+	if (used < *len)
+		*len = used;
+
+	/* copy data to reader but don't advance addr */
+	memcpy(out, lxc_ringbuf_get_read_addr(buf), *len);
+	out[*len - 1] = '\0';
+	return 0;
+}

src/lxc/ringbuf.h

@@ -0,0 +1,90 @@
+/* liblxcapi
+ *
+ * Copyright © 2017 Christian Brauner <christian.brauner@ubuntu.com>.
+ * Copyright © 2017 Canonical Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef __LXC_RINGBUF_H
+#define __LXC_RINGBUF_H
+
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/mman.h>
+
+/**
+ * lxc_ringbuf - Implements a simple and efficient memory mapped ringbuffer.
+ * - The "addr" field of struct lxc_ringbuf is considered immutable. Instead the
+ *   read and write offsets r_off and w_off are used to calculate the current
+ *   read and write addresses. There should never be a need to use any of those
+ *   fields directly. Instead use the appropriate helpers below.
+ * - Callers are expected to synchronize read and write accesses to the
+ *   ringbuffer.
+ */
+struct lxc_ringbuf {
+	char *addr; /* start address of the ringbuffer */
+	uint64_t size; /* total size of the ringbuffer in bytes */
+	uint64_t r_off; /* read offset */
+	uint64_t w_off; /* write offset */
+};
+
+/**
+ * lxc_ringbuf_create - Initialize a new ringbuffer.
+ *
+ * @param[in] size	Size of the new ringbuffer as a power of 2.
+ */
+extern int lxc_ringbuf_create(struct lxc_ringbuf *buf, size_t size);
+extern void lxc_ringbuf_move_read_addr(struct lxc_ringbuf *buf, size_t len);
+extern int lxc_ringbuf_write(struct lxc_ringbuf *buf, const char *msg, size_t len);
+extern int lxc_ringbuf_read(struct lxc_ringbuf *buf, char *out, size_t *len);
+
+static inline void lxc_ringbuf_release(struct lxc_ringbuf *buf)
+{
+	munmap(buf->addr, buf->size * 2);
+}
+
+static inline void lxc_ringbuf_clear(struct lxc_ringbuf *buf)
+{
+	buf->r_off = 0;
+	buf->w_off = 0;
+}
+
+static inline uint64_t lxc_ringbuf_used(struct lxc_ringbuf *buf)
+{
+	return buf->w_off - buf->r_off;
+}
+
+static inline uint64_t lxc_ringbuf_free(struct lxc_ringbuf *buf)
+{
+	return buf->size - lxc_ringbuf_used(buf);
+}
+
+static inline char *lxc_ringbuf_get_read_addr(struct lxc_ringbuf *buf)
+{
+	return buf->addr + buf->r_off;
+}
+
+static inline char *lxc_ringbuf_get_write_addr(struct lxc_ringbuf *buf)
+{
+	return buf->addr + buf->w_off;
+}
+
+static inline void lxc_ringbuf_move_write_addr(struct lxc_ringbuf *buf, size_t len)
+{
+	buf->w_off += len;
+}
+
+#endif /* __LXC_RINGBUF_H */

src/lxc/start.c

@@ -937,7 +937,7 @@ static int do_start(void *data)
 	}
 
 	/* Setup the container, ip, names, utsname, ... */
-	ret = lxc_setup(handler);
+	ret = lxc_setup_child(handler);
 	close(handler->data_sock[0]);
 	close(handler->data_sock[1]);
 	if (ret < 0) {
@@ -1254,6 +1254,11 @@ static int lxc_spawn(struct lxc_handler *handler)
 		 */
 		flags &= ~CLONE_NEWNET;
 	}
+
+	ret = lxc_setup_parent(handler);
+	if (ret < 0)
+		goto out_delete_net;
+
 	handler->pid = lxc_clone(do_start, handler, flags);
 	if (handler->pid < 0) {
 		SYSERROR("Failed to clone a new set of namespaces.");

src/lxc/utils.c

@@ -47,6 +47,7 @@
 #include "log.h"
 #include "lxclock.h"
 #include "namespace.h"
+#include "parse.h"
 #include "utils.h"
 
 #ifndef O_PATH
@@ -2003,6 +2004,26 @@ int lxc_safe_long(const char *numstr, long int *converted)
 	return 0;
 }
 
+int lxc_safe_long_long(const char *numstr, long long int *converted)
+{
+	char *err = NULL;
+	signed long long int sli;
+
+	errno = 0;
+	sli = strtoll(numstr, &err, 0);
+	if (errno == ERANGE && (sli == LLONG_MAX || sli == LLONG_MIN))
+		return -ERANGE;
+
+	if (errno != 0 && sli == 0)
+		return -EINVAL;
+
+	if (err == numstr || *err != '\0')
+		return -EINVAL;
+
+	*converted = sli;
+	return 0;
+}
+
 int lxc_switch_uid_gid(uid_t uid, gid_t gid)
 {
 	if (setgid(gid) < 0) {
@@ -2339,3 +2360,118 @@ bool lxc_nic_exists(char *nic)
 
 	return true;
 }
+
+int lxc_make_tmpfile(char *template, bool rm)
+{
+	int fd, ret;
+
+	fd = mkstemp(template);
+	if (fd < 0)
+		return -1;
+
+	if (!rm)
+		return fd;
+
+	ret = unlink(template);
+	if (ret < 0) {
+		close(fd);
+		return -1;
+	}
+
+	return fd;
+}
+
+uint64_t lxc_getpagesize(void)
+{
+	int64_t pgsz;
+
+	pgsz = sysconf(_SC_PAGESIZE);
+	if (pgsz <= 0)
+		pgsz = 1 << 12;
+
+	return pgsz;
+}
+
+int parse_byte_size_string(const char *s, int64_t *converted)
+{
+	int ret, suffix_len;
+	long long int conv;
+	int64_t mltpl, overflow;
+	char *end;
+	char dup[LXC_NUMSTRLEN64 + 2];
+	char suffix[3];
+
+	if (!s || !strcmp(s, ""))
+		return -EINVAL;
+
+	end = stpncpy(dup, s, sizeof(dup));
+	if (*end != '\0')
+		return -EINVAL;
+
+	if (isdigit(*(end - 1)))
+		suffix_len = 0;
+	else if (isalpha(*(end - 1)))
+		suffix_len = 1;
+	else
+		return -EINVAL;
+
+	if ((end - 2) == dup && !isdigit(*(end - 2)))
+		return -EINVAL;
+
+	if (isalpha(*(end - 2))) {
+		if (suffix_len == 1)
+			suffix_len++;
+		else
+			return -EINVAL;
+	}
+
+	if (suffix_len > 0) {
+		memcpy(suffix, end - suffix_len, suffix_len);
+		*(suffix + suffix_len) = '\0';
+		*(end - suffix_len) = '\0';
+	}
+	dup[lxc_char_right_gc(dup, strlen(dup))] = '\0';
+
+	ret = lxc_safe_long_long(dup, &conv);
+	if (ret < 0)
+		return -ret;
+
+	if (suffix_len != 2) {
+		*converted = conv;
+		return 0;
+	}
+
+	if (!strcmp(suffix, "kB"))
+		mltpl = 1024;
+	else if (!strcmp(suffix, "MB"))
+		mltpl = 1024 * 1024;
+	else if (!strcmp(suffix, "GB"))
+		mltpl = 1024 * 1024 * 1024;
+	else
+		return -EINVAL;
+
+	overflow = conv * mltpl;
+	if (conv != 0 && (overflow / conv) != mltpl)
+		return -ERANGE;
+
+	*converted = overflow;
+	return 0;
+}
+
+uint64_t lxc_find_next_power2(uint64_t n)
+{
+	/* 0 is not valid input. We return 0 to the caller since 0 is not a
+	 * valid power of two.
+	 */
+	if (n == 0)
+		return 0;
+
+	if (!(n & (n - 1)))
+		return n;
+
+	while (n & (n - 1))
+		n = n & (n - 1);
+
+	n = n << 1;
+	return n;
+}

src/lxc/utils.h

@@ -39,6 +39,10 @@
 #include <sys/types.h>
 #include <sys/vfs.h>
 
+#ifdef HAVE_LINUX_MEMFD_H
+#include <linux/memfd.h>
+#endif
+
 #include "initutils.h"
 
 /* Define __S_ISTYPE if missing from the C library. */
@@ -184,6 +188,64 @@ static inline int signalfd(int fd, const sigset_t *mask, int flags)
 #define LOOP_CTL_GET_FREE 0x4C82
 #endif
 
+/* memfd_create() */
+#ifndef MFD_CLOEXEC
+#define MFD_CLOEXEC 0x0001U
+#endif
+
+#ifndef MFD_ALLOW_SEALING
+#define MFD_ALLOW_SEALING 0x0002U
+#endif
+
+#ifndef HAVE_MEMFD_CREATE
+static inline int memfd_create(const char *name, unsigned int flags) {
+	#ifndef __NR_memfd_create
+		#if defined __i386__
+			#define __NR_memfd_create 356
+		#elif defined __x86_64__
+			#define __NR_memfd_create 319
+		#elif defined __arm__
+			#define __NR_memfd_create 385
+		#elif defined __aarch64__
+			#define __NR_memfd_create 279
+		#elif defined __s390__
+			#define __NR_memfd_create 350
+		#elif defined __powerpc__
+			#define __NR_memfd_create 360
+		#elif defined __sparc__
+			#define __NR_memfd_create 348
+		#elif defined __blackfin__
+			#define __NR_memfd_create 390
+		#elif defined __ia64__
+			#define __NR_memfd_create 1340
+		#elif defined _MIPS_SIM
+			#if _MIPS_SIM == _MIPS_SIM_ABI32
+				#define __NR_memfd_create 4354
+			#endif
+			#if _MIPS_SIM == _MIPS_SIM_NABI32
+				#define __NR_memfd_create 6318
+			#endif
+			#if _MIPS_SIM == _MIPS_SIM_ABI64
+				#define __NR_memfd_create 5314
+			#endif
+		#endif
+	#endif
+	#ifdef __NR_memfd_create
+	return syscall(__NR_memfd_create, name, flags);
+	#else
+	errno = ENOSYS;
+	return -1;
+	#endif
+}
+#else
+extern int memfd_create(const char *name, unsigned int flags);
+#endif
+
+static inline int lxc_set_cloexec(int fd)
+{
+	return fcntl(fd, F_SETFD, FD_CLOEXEC);
+}
+
 /* Struct to carry child pid from lxc_popen() to lxc_pclose().
  * Not an opaque struct to allow direct access to the underlying FILE *
  * (i.e., struct lxc_popen_FILE *file; fgets(buf, sizeof(buf), file->f))
@@ -357,7 +419,10 @@ extern bool task_blocking_signal(pid_t pid, int signal);
 extern int lxc_safe_uint(const char *numstr, unsigned int *converted);
 extern int lxc_safe_int(const char *numstr, int *converted);
 extern int lxc_safe_long(const char *numstr, long int *converted);
+extern int lxc_safe_long_long(const char *numstr, long long int *converted);
 extern int lxc_safe_ulong(const char *numstr, unsigned long *converted);
+/* Handles B, kb, MB, GB. Detects overflows and reports -ERANGE. */
+extern int parse_byte_size_string(const char *s, int64_t *converted);
 
 /* Switch to a new uid and gid. */
 extern int lxc_switch_uid_gid(uid_t uid, gid_t gid);
@@ -404,5 +469,17 @@ typedef __typeof__(((struct statfs *)NULL)->f_type) fs_type_magic;
 extern bool has_fs_type(const char *path, fs_type_magic magic_val);
 extern bool is_fs_type(const struct statfs *fs, fs_type_magic magic_val);
 extern bool lxc_nic_exists(char *nic);
+extern int lxc_make_tmpfile(char *template, bool rm);
+extern uint64_t lxc_getpagesize(void);
+
+/* If n is not a power of 2 this function will return the next power of 2
+ * greater than that number. Note that this function always returns the *next*
+ * power of 2 *greater* that number not the *nearest*. For example, passing 1025
+ * as argument this function will return 2048 although the closest power of 2
+ * would be 1024.
+ * If the caller passes in 0 they will receive 0 in return since this is invalid
+ * input and 0 is not a power of 2.
+ */
+extern uint64_t lxc_find_next_power2(uint64_t n);
 
 #endif /* __LXC_UTILS_H */

src/tests/lxc-test-utils.c

@@ -380,6 +380,88 @@ void test_lxc_string_in_array(void)
 	lxc_test_assert_abort(lxc_string_in_array("XYZ", (const char *[]){"BERTA", "ARQWE(9", "C8Zhkd", "7U", "XYZ", "UOIZ9", "=)()", NULL}));
 }
 
+void test_parse_byte_size_string(void)
+{
+	int ret;
+	int64_t n;
+
+	ret = parse_byte_size_string("0", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 0)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 1)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1 ", &n);
+	if (ret == 0)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1B", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 1)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1kB", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 1024)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1MB", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 1048576)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1GB", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 1073741824)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1TB", &n);
+	if (ret == 0)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1 B", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 1)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1 kB", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 1024)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1 MB", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 1048576)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1 GB", &n);
+	if (ret < 0)
+		exit(EXIT_FAILURE);
+	if (n != 1073741824)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("1 TB", &n);
+	if (ret == 0)
+		exit(EXIT_FAILURE);
+
+	ret = parse_byte_size_string("asdf", &n);
+	if (ret == 0)
+		exit(EXIT_FAILURE);
+}
+
 int main(int argc, char *argv[])
 {
 	test_lxc_string_replace();
@@ -389,6 +471,7 @@ int main(int argc, char *argv[])
 	test_lxc_safe_uint();
 	test_lxc_safe_int();
 	test_lxc_safe_long();
+	test_parse_byte_size_string();
 
 	exit(EXIT_SUCCESS);
 }