lxc-stop: use api, remove lxc_shutdown, extend lxc-stop functionality

[mirror_lxc.git] / src / lxc / utils.h

/*
 * lxc: linux Container library
 *
 * (C) Copyright IBM Corp. 2007, 2008
 *
 * Authors:
 * Daniel Lezcano <daniel.lezcano at free.fr>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#ifndef _utils_h
#define _utils_h

#include <errno.h>
#include <sys/types.h>
#include "config.h"

extern int lxc_setup_fs(void);
extern int get_u16(unsigned short *val, const char *arg, int base);
extern int mkdir_p(const char *dir, mode_t mode);
/*
 * Return a newly allocated buffer containing the default container
 * path.  Caller must free this buffer.
 */
extern const char *default_lxc_path(void);
extern const char *default_zfs_root(void);
extern const char *default_lvm_vg(void);

/* Define getline() if missing from the C library */
#ifndef HAVE_GETLINE
#ifdef HAVE_FGETLN
#include <../include/getline.h>
#endif
#endif

/* Define setns() if missing from the C library */
#ifndef HAVE_SETNS
static inline int setns(int fd, int nstype)
{
#ifdef __NR_setns
	return syscall(__NR_setns, fd, nstype);
#else
	errno = ENOSYS;
	return -1;
#endif
}
#endif

/* Define unshare() if missing from the C library */
#ifndef HAVE_UNSHARE
static inline int unshare(int flags)
{
#ifdef __NR_unshare
	return syscall(__NR_unshare, flags);
#else
	errno = ENOSYS;
	return -1;
#endif
}
#else
int unshare(int);
#endif

/**
 * BUILD_BUG_ON - break compile if a condition is true.
 * @condition: the condition which the compiler should know is false.
 *
 * If you have some code which relies on certain constants being equal, or
 * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 * detect if someone changes it.
 *
 * The implementation uses gcc's reluctance to create a negative array, but
 * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 * to inline functions).  So as a fallback we use the optimizer; if it can't
 * prove the condition is false, it will cause a link error on the undefined
 * "__build_bug_on_failed".  This error message can be harder to track down
 * though, hence the two different methods.
 */
#ifndef __OPTIMIZE__
#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
#else
extern int __build_bug_on_failed;
#define BUILD_BUG_ON(condition)					\
	do {							\
		((void)sizeof(char[1 - 2*!!(condition)]));	\
		if (condition) __build_bug_on_failed = 1;	\
	} while(0)
#endif

/*
 * wait on a child we forked
 */
extern int wait_for_pid(pid_t pid);
extern int lxc_wait_for_pid_status(pid_t pid);

/* send and receive buffers completely */
extern int lxc_write_nointr(int fd, const void* buf, size_t count);
extern int lxc_read_nointr(int fd, void* buf, size_t count);
extern int lxc_read_nointr_expect(int fd, void* buf, size_t count, const void* expected_buf);

#endif