[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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#ifndef _utils_h
#define _utils_h

#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdbool.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>

#include "config.h"

/* returns 1 on success, 0 if there were any failures */
extern int lxc_rmdir_onedev(char *path);
extern void 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);
extern void remove_trailing_slashes(char *p);
extern const char *get_rundir(void);

extern const char *lxc_global_config_value(const char *option_name);

/* 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

/* Define signalfd() if missing from the C library */
#ifdef HAVE_SYS_SIGNALFD_H
#  include <sys/signalfd.h>
#else
/* assume kernel headers are too old */
#include <stdint.h>
struct signalfd_siginfo
{
	uint32_t ssi_signo;
	int32_t ssi_errno;
	int32_t ssi_code;
	uint32_t ssi_pid;
	uint32_t ssi_uid;
	int32_t ssi_fd;
	uint32_t ssi_tid;
	uint32_t ssi_band;
	uint32_t ssi_overrun;
	uint32_t ssi_trapno;
	int32_t ssi_status;
	int32_t ssi_int;
	uint64_t ssi_ptr;
	uint64_t ssi_utime;
	uint64_t ssi_stime;
	uint64_t ssi_addr;
	uint8_t __pad[48];
};

#  ifndef __NR_signalfd4
/* assume kernel headers are too old */
#    if __i386__
#      define __NR_signalfd4 327
#    elif __x86_64__
#      define __NR_signalfd4 289
#    elif __powerpc__
#      define __NR_signalfd4 313
#    elif __s390x__
#      define __NR_signalfd4 322
#    elif __arm__
#      define __NR_signalfd4 355
#    endif
#endif

#  ifndef __NR_signalfd
/* assume kernel headers are too old */
#    if __i386__
#      define __NR_signalfd 321
#    elif __x86_64__
#      define __NR_signalfd 282
#    elif __powerpc__
#      define __NR_signalfd 305
#    elif __s390x__
#      define __NR_signalfd 316
#    elif __arm__
#      define __NR_signalfd 349
#    endif
#endif

static inline int signalfd(int fd, const sigset_t *mask, int flags)
{
	int retval;

	retval = syscall (__NR_signalfd4, fd, mask, _NSIG / 8, flags);
	if (errno == ENOSYS && flags == 0)
		retval = syscall (__NR_signalfd, fd, mask, _NSIG / 8);
	return retval;
}
#endif

/* open a file with O_CLOEXEC */
FILE *fopen_cloexec(const char *path, const char *mode);


/* 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))
 * without additional wrappers.
 */
struct lxc_popen_FILE {
	FILE *f;
	pid_t child_pid;
};

/* popen(command, "re") replacement that restores default signal mask
 * via sigprocmask(2) (unblocks all signals) after fork(2) but prior to calling exec(3).
 * In short, popen(command, "re") does pipe() + fork()                 + exec()
 * while lxc_popen(command)       does pipe() + fork() + sigprocmask() + exec().
 * Returns pointer to struct lxc_popen_FILE, that should be freed with lxc_pclose().
 * On error returns NULL.
 */
extern struct lxc_popen_FILE *lxc_popen(const char *command);

/* pclose() replacement to be used on struct lxc_popen_FILE *,
 * returned by lxc_popen().
 * Waits for associated process to terminate, returns its exit status and
 * frees resources, pointed to by struct lxc_popen_FILE *.
 */
extern int lxc_pclose(struct lxc_popen_FILE *fp);

/**
 * 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 ssize_t lxc_write_nointr(int fd, const void* buf, size_t count);
extern ssize_t lxc_read_nointr(int fd, void* buf, size_t count);
extern ssize_t lxc_read_nointr_expect(int fd, void* buf, size_t count, const void* expected_buf);
#if HAVE_LIBGNUTLS
#define SHA_DIGEST_LENGTH 20
extern int sha1sum_file(char *fnam, unsigned char *md_value);
#endif

/* read and write whole files */
extern int lxc_write_to_file(const char *filename, const void* buf, size_t count, bool add_newline);
extern int lxc_read_from_file(const char *filename, void* buf, size_t count);

/* convert variadic argument lists to arrays (for execl type argument lists) */
extern char** lxc_va_arg_list_to_argv(va_list ap, size_t skip, int do_strdup);
extern const char** lxc_va_arg_list_to_argv_const(va_list ap, size_t skip);

/* Some simple string functions; if they return pointers, they are allocated buffers. */
extern char *lxc_string_replace(const char *needle, const char *replacement, const char *haystack);
extern bool lxc_string_in_array(const char *needle, const char **haystack);
extern char *lxc_string_join(const char *sep, const char **parts, bool use_as_prefix);
/* Normalize and split path: Leading and trailing / are removed, multiple
 * / are compactified, .. and . are resolved (.. on the top level is considered
 * identical to .).
 * Examples:
 *     /            ->   { NULL }
 *     foo/../bar   ->   { bar, NULL }
 *     ../../       ->   { NULL }
 *     ./bar/baz/.. ->   { bar, NULL }
 *     foo//bar     ->   { foo, bar, NULL }
 */
extern char **lxc_normalize_path(const char *path);
extern char *lxc_append_paths(const char *first, const char *second);
/* Note: the following two functions use strtok(), so they will never
 *       consider an empty element, even if two delimiters are next to
 *       each other.
 */
extern bool lxc_string_in_list(const char *needle, const char *haystack, char sep);
extern char **lxc_string_split(const char *string, char sep);
extern char **lxc_string_split_and_trim(const char *string, char sep);

/* some simple array manipulation utilities */
typedef void (*lxc_free_fn)(void *);
typedef void *(*lxc_dup_fn)(void *);
extern int lxc_grow_array(void ***array, size_t* capacity, size_t new_size, size_t capacity_increment);
extern void lxc_free_array(void **array, lxc_free_fn element_free_fn);
extern size_t lxc_array_len(void **array);

extern void **lxc_append_null_to_array(void **array, size_t count);

#endif
Commit	Line	Data
0ad19a3f	1	/*
	2	* lxc: linux Container library
	3	*
	4	* (C) Copyright IBM Corp. 2007, 2008
	5	*
	6	* Authors:
9afe19d6	7	* Daniel Lezcano <daniel.lezcano at free.fr>
0ad19a3f	8	*
	9	* This library is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU Lesser General Public
	11	* License as published by the Free Software Foundation; either
	12	* version 2.1 of the License, or (at your option) any later version.
	13	*
	14	* This library is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	17	* Lesser General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU Lesser General Public
	20	* License along with this library; if not, write to the Free Software
250b1eec	21	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
0ad19a3f	22	*/
	23	#ifndef _utils_h
	24	#define _utils_h
	25
6a44839f	26	#include <errno.h>
61a1d519	27	#include <stdarg.h>
d0386d66	28	#include <stdio.h>
502657d5	29	#include <stdbool.h>
ec346ea1	30	#include <sys/syscall.h>
c797a220	31	#include <sys/types.h>
9c4693b8	32	#include <unistd.h>
f2363e38	33
6a44839f	34	#include "config.h"
c797a220	35
60bf62d4 SH	36	/* returns 1 on success, 0 if there were any failures */
60bf62d4 SH	37	extern int lxc_rmdir_onedev(char *path);
ea0da529	38	extern void lxc_setup_fs(void);
7c11d57a	39	extern int get_u16(unsigned short val, const char arg, int base);
1b09f2c0	40	extern int mkdir_p(const char *dir, mode_t mode);
89cd7793	41	extern void remove_trailing_slashes(char *p);
9e60f51d DE	42	extern const char *get_rundir(void);
9e60f51d DE	43
593e8478 SG	44	extern const char lxc_global_config_value(const char option_name);
593e8478 SG	45
6a44839f DE	46	/* Define getline() if missing from the C library */
	47	#ifndef HAVE_GETLINE
	48	#ifdef HAVE_FGETLN
	49	#include <../include/getline.h>
	50	#endif
	51	#endif
	52
	53	/* Define setns() if missing from the C library */
	54	#ifndef HAVE_SETNS
	55	static inline int setns(int fd, int nstype)
	56	{
	57	#ifdef __NR_setns
	58	return syscall(__NR_setns, fd, nstype);
	59	#else
	60	errno = ENOSYS;
	61	return -1;
	62	#endif
	63	}
	64	#endif
	65
	66	/* Define unshare() if missing from the C library */
	67	#ifndef HAVE_UNSHARE
	68	static inline int unshare(int flags)
	69	{
	70	#ifdef __NR_unshare
	71	return syscall(__NR_unshare, flags);
	72	#else
	73	errno = ENOSYS;
	74	return -1;
	75	#endif
	76	}
	77	#else
	78	int unshare(int);
	79	#endif
	80
b5159817 DE	81	/* Define signalfd() if missing from the C library */
	82	#ifdef HAVE_SYS_SIGNALFD_H
	83	# include <sys/signalfd.h>
	84	#else
	85	/* assume kernel headers are too old */
	86	#include <stdint.h>
	87	struct signalfd_siginfo
	88	{
	89	uint32_t ssi_signo;
	90	int32_t ssi_errno;
	91	int32_t ssi_code;
	92	uint32_t ssi_pid;
	93	uint32_t ssi_uid;
	94	int32_t ssi_fd;
	95	uint32_t ssi_tid;
	96	uint32_t ssi_band;
	97	uint32_t ssi_overrun;
	98	uint32_t ssi_trapno;
	99	int32_t ssi_status;
	100	int32_t ssi_int;
	101	uint64_t ssi_ptr;
	102	uint64_t ssi_utime;
	103	uint64_t ssi_stime;
	104	uint64_t ssi_addr;
	105	uint8_t __pad[48];
	106	};
	107
	108	# ifndef __NR_signalfd4
	109	/* assume kernel headers are too old */
	110	# if __i386__
	111	# define __NR_signalfd4 327
	112	# elif __x86_64__
	113	# define __NR_signalfd4 289
	114	# elif __powerpc__
	115	# define __NR_signalfd4 313
	116	# elif __s390x__
	117	# define __NR_signalfd4 322
180edd67 SG	118	# elif __arm__
180edd67 SG	119	# define __NR_signalfd4 355
b5159817 DE	120	# endif
	121	#endif
	122
	123	# ifndef __NR_signalfd
	124	/* assume kernel headers are too old */
	125	# if __i386__
	126	# define __NR_signalfd 321
	127	# elif __x86_64__
	128	# define __NR_signalfd 282
	129	# elif __powerpc__
	130	# define __NR_signalfd 305
	131	# elif __s390x__
	132	# define __NR_signalfd 316
180edd67 SG	133	# elif __arm__
180edd67 SG	134	# define __NR_signalfd 349
b5159817 DE	135	# endif
	136	#endif
	137
	138	static inline int signalfd(int fd, const sigset_t *mask, int flags)
	139	{
	140	int retval;
	141
	142	retval = syscall (__NR_signalfd4, fd, mask, _NSIG / 8, flags);
	143	if (errno == ENOSYS && flags == 0)
	144	retval = syscall (__NR_signalfd, fd, mask, _NSIG / 8);
	145	return retval;
	146	}
	147	#endif
	148
db27c8d7 CS	149	/* open a file with O_CLOEXEC */
	150	FILE fopen_cloexec(const char path, const char *mode);
	151
b5159817	152
ebec9176 AM	153	/* Struct to carry child pid from lxc_popen() to lxc_pclose().
	154	* Not an opaque struct to allow direct access to the underlying FILE *
	155	* (i.e., struct lxc_popen_FILE *file; fgets(buf, sizeof(buf), file->f))
	156	* without additional wrappers.
	157	*/
	158	struct lxc_popen_FILE {
	159	FILE *f;
	160	pid_t child_pid;
	161	};
	162
	163	/* popen(command, "re") replacement that restores default signal mask
	164	* via sigprocmask(2) (unblocks all signals) after fork(2) but prior to calling exec(3).
	165	* In short, popen(command, "re") does pipe() + fork() + exec()
	166	* while lxc_popen(command) does pipe() + fork() + sigprocmask() + exec().
ebec9176 AM	167	* Returns pointer to struct lxc_popen_FILE, that should be freed with lxc_pclose().
	168	* On error returns NULL.
	169	*/
	170	extern struct lxc_popen_FILE lxc_popen(const char command);
	171
	172	/* pclose() replacement to be used on struct lxc_popen_FILE *,
	173	* returned by lxc_popen().
	174	* Waits for associated process to terminate, returns its exit status and
	175	* frees resources, pointed to by struct lxc_popen_FILE *.
ebec9176 AM	176	*/
	177	extern int lxc_pclose(struct lxc_popen_FILE *fp);
	178
e51d4895 DE	179	/**
	180	* BUILD_BUG_ON - break compile if a condition is true.
	181	* @condition: the condition which the compiler should know is false.
	182	*
	183	* If you have some code which relies on certain constants being equal, or
	184	* other compile-time-evaluated condition, you should use BUILD_BUG_ON to
	185	* detect if someone changes it.
	186	*
	187	* The implementation uses gcc's reluctance to create a negative array, but
	188	* gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
	189	* to inline functions). So as a fallback we use the optimizer; if it can't
	190	* prove the condition is false, it will cause a link error on the undefined
	191	* "__build_bug_on_failed". This error message can be harder to track down
	192	* though, hence the two different methods.
	193	*/
	194	#ifndef __OPTIMIZE__
	195	#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
	196	#else
	197	extern int __build_bug_on_failed;
	198	#define BUILD_BUG_ON(condition) \
	199	do { \
	200	((void)sizeof(char[1 - 2*!!(condition)])); \
	201	if (condition) __build_bug_on_failed = 1; \
	202	} while(0)
	203	#endif
	204
9be53773 SH	205	/*
	206	* wait on a child we forked
	207	*/
	208	extern int wait_for_pid(pid_t pid);
c797a220	209	extern int lxc_wait_for_pid_status(pid_t pid);
9be53773	210
92f023dc	211	/* send and receive buffers completely */
650468bb CS	212	extern ssize_t lxc_write_nointr(int fd, const void* buf, size_t count);
	213	extern ssize_t lxc_read_nointr(int fd, void* buf, size_t count);
	214	extern ssize_t lxc_read_nointr_expect(int fd, void* buf, size_t count, const void* expected_buf);
3ce74686 SH	215	#if HAVE_LIBGNUTLS
	216	#define SHA_DIGEST_LENGTH 20
	217	extern int sha1sum_file(char fnam, unsigned char md_value);
	218	#endif
92f023dc	219
0e95426b CS	220	/* read and write whole files */
	221	extern int lxc_write_to_file(const char filename, const void buf, size_t count, bool add_newline);
	222	extern int lxc_read_from_file(const char filename, void buf, size_t count);
0e95426b	223
61a1d519 CS	224	/* convert variadic argument lists to arrays (for execl type argument lists) */
	225	extern char** lxc_va_arg_list_to_argv(va_list ap, size_t skip, int do_strdup);
	226	extern const char** lxc_va_arg_list_to_argv_const(va_list ap, size_t skip);
	227
502657d5 CS	228	/* Some simple string functions; if they return pointers, they are allocated buffers. */
	229	extern char lxc_string_replace(const char needle, const char replacement, const char haystack);
	230	extern bool lxc_string_in_array(const char needle, const char *haystack);
	231	extern char lxc_string_join(const char sep, const char **parts, bool use_as_prefix);
	232	/* Normalize and split path: Leading and trailing / are removed, multiple
	233	* / are compactified, .. and . are resolved (.. on the top level is considered
	234	* identical to .).
	235	* Examples:
	236	* / -> { NULL }
	237	* foo/../bar -> { bar, NULL }
	238	* ../../ -> { NULL }
	239	* ./bar/baz/.. -> { bar, NULL }
	240	* foo//bar -> { foo, bar, NULL }
	241	*/
	242	extern char *lxc_normalize_path(const char path);
24b51482	243	extern char lxc_append_paths(const char first, const char *second);
502657d5 CS	244	/* Note: the following two functions use strtok(), so they will never
	245	* consider an empty element, even if two delimiters are next to
	246	* each other.
	247	*/
	248	extern bool lxc_string_in_list(const char needle, const char haystack, char sep);
	249	extern char *lxc_string_split(const char string, char sep);
	250	extern char *lxc_string_split_and_trim(const char string, char sep);
	251
	252	/* some simple array manipulation utilities */
	253	typedef void (lxc_free_fn)(void );
	254	typedef void (lxc_dup_fn)(void *);
	255	extern int lxc_grow_array(void **array, size_t capacity, size_t new_size, size_t capacity_increment);
	256	extern void lxc_free_array(void **array, lxc_free_fn element_free_fn);
	257	extern size_t lxc_array_len(void **array);
502657d5	258
799f29ab	259	extern void lxc_append_null_to_array(void array, size_t count);
052616eb	260
307cf2a6	261	#endif