src/lxc/utils.h

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Daniel Lezcano <daniel.lezcano at free.fr>
   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
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23 #ifndef _utils_h
  24 #define _utils_h
  25
  26 #include <errno.h>
  27 #include <stdarg.h>
  28 #include <stdio.h>
  29 #include <stdbool.h>
  30 #include <sys/syscall.h>
  31 #include <sys/types.h>
  32 #include <unistd.h>
  33 #include "config.h"
  34
  35 /* returns 1 on success, 0 if there were any failures */
  36 extern int lxc_rmdir_onedev(char *path);
  37 extern int lxc_setup_fs(void);
  38 extern int get_u16(unsigned short *val, const char *arg, int base);
  39 extern int mkdir_p(const char *dir, mode_t mode);
  40 /*
  41  * Return a buffer containing the default container path.
  42  * Caller must NOT free this buffer, since it may be static.
  43  */
  44 extern const char *lxc_global_config_value(const char *option_name);
  45 extern const char *default_lxc_path(void);
  46 extern const char *default_zfs_root(void);
  47 extern const char *default_lvm_vg(void);
  48
  49 /* Define getline() if missing from the C library */
  50 #ifndef HAVE_GETLINE
  51 #ifdef HAVE_FGETLN
  52 #include <../include/getline.h>
  53 #endif
  54 #endif
  55
  56 /* Define setns() if missing from the C library */
  57 #ifndef HAVE_SETNS
  58 static inline int setns(int fd, int nstype)
  59 {
  60 #ifdef __NR_setns
  61         return syscall(__NR_setns, fd, nstype);
  62 #else
  63         errno = ENOSYS;
  64         return -1;
  65 #endif
  66 }
  67 #endif
  68
  69 /* Define unshare() if missing from the C library */
  70 #ifndef HAVE_UNSHARE
  71 static inline int unshare(int flags)
  72 {
  73 #ifdef __NR_unshare
  74         return syscall(__NR_unshare, flags);
  75 #else
  76         errno = ENOSYS;
  77         return -1;
  78 #endif
  79 }
  80 #else
  81 int unshare(int);
  82 #endif
  83
  84 /* Define signalfd() if missing from the C library */
  85 #ifdef HAVE_SYS_SIGNALFD_H
  86 #  include <sys/signalfd.h>
  87 #else
  88 /* assume kernel headers are too old */
  89 #include <stdint.h>
  90 struct signalfd_siginfo
  91 {
  92         uint32_t ssi_signo;
  93         int32_t ssi_errno;
  94         int32_t ssi_code;
  95         uint32_t ssi_pid;
  96         uint32_t ssi_uid;
  97         int32_t ssi_fd;
  98         uint32_t ssi_tid;
  99         uint32_t ssi_band;
 100         uint32_t ssi_overrun;
 101         uint32_t ssi_trapno;
 102         int32_t ssi_status;
 103         int32_t ssi_int;
 104         uint64_t ssi_ptr;
 105         uint64_t ssi_utime;
 106         uint64_t ssi_stime;
 107         uint64_t ssi_addr;
 108         uint8_t __pad[48];
 109 };
 110
 111 #  ifndef __NR_signalfd4
 112 /* assume kernel headers are too old */
 113 #    if __i386__
 114 #      define __NR_signalfd4 327
 115 #    elif __x86_64__
 116 #      define __NR_signalfd4 289
 117 #    elif __powerpc__
 118 #      define __NR_signalfd4 313
 119 #    elif __s390x__
 120 #      define __NR_signalfd4 322
 121 #    elif __arm__
 122 #      define __NR_signalfd4 355
 123 #    endif
 124 #endif
 125
 126 #  ifndef __NR_signalfd
 127 /* assume kernel headers are too old */
 128 #    if __i386__
 129 #      define __NR_signalfd 321
 130 #    elif __x86_64__
 131 #      define __NR_signalfd 282
 132 #    elif __powerpc__
 133 #      define __NR_signalfd 305
 134 #    elif __s390x__
 135 #      define __NR_signalfd 316
 136 #    elif __arm__
 137 #      define __NR_signalfd 349
 138 #    endif
 139 #endif
 140
 141 static inline int signalfd(int fd, const sigset_t *mask, int flags)
 142 {
 143         int retval;
 144
 145         retval = syscall (__NR_signalfd4, fd, mask, _NSIG / 8, flags);
 146         if (errno == ENOSYS && flags == 0)
 147                 retval = syscall (__NR_signalfd, fd, mask, _NSIG / 8);
 148         return retval;
 149 }
 150 #endif
 151
 152 /* open a file with O_CLOEXEC */
 153 FILE *fopen_cloexec(const char *path, const char *mode);
 154
 155
 156 /**
 157  * BUILD_BUG_ON - break compile if a condition is true.
 158  * @condition: the condition which the compiler should know is false.
 159  *
 160  * If you have some code which relies on certain constants being equal, or
 161  * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 162  * detect if someone changes it.
 163  *
 164  * The implementation uses gcc's reluctance to create a negative array, but
 165  * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 166  * to inline functions).  So as a fallback we use the optimizer; if it can't
 167  * prove the condition is false, it will cause a link error on the undefined
 168  * "__build_bug_on_failed".  This error message can be harder to track down
 169  * though, hence the two different methods.
 170  */
 171 #ifndef __OPTIMIZE__
 172 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 173 #else
 174 extern int __build_bug_on_failed;
 175 #define BUILD_BUG_ON(condition)                                 \
 176         do {                                                    \
 177                 ((void)sizeof(char[1 - 2*!!(condition)]));      \
 178                 if (condition) __build_bug_on_failed = 1;       \
 179         } while(0)
 180 #endif
 181
 182 /*
 183  * wait on a child we forked
 184  */
 185 extern int wait_for_pid(pid_t pid);
 186 extern int lxc_wait_for_pid_status(pid_t pid);
 187
 188 /* send and receive buffers completely */
 189 extern ssize_t lxc_write_nointr(int fd, const void* buf, size_t count);
 190 extern ssize_t lxc_read_nointr(int fd, void* buf, size_t count);
 191 extern ssize_t lxc_read_nointr_expect(int fd, void* buf, size_t count, const void* expected_buf);
 192 #if HAVE_LIBGNUTLS
 193 #define SHA_DIGEST_LENGTH 20
 194 extern int sha1sum_file(char *fnam, unsigned char *md_value);
 195 #endif
 196
 197 /* read and write whole files */
 198 extern int lxc_write_to_file(const char *filename, const void* buf, size_t count, bool add_newline);
 199 extern int lxc_read_from_file(const char *filename, void* buf, size_t count);
 200
 201 /* convert variadic argument lists to arrays (for execl type argument lists) */
 202 extern char** lxc_va_arg_list_to_argv(va_list ap, size_t skip, int do_strdup);
 203 extern const char** lxc_va_arg_list_to_argv_const(va_list ap, size_t skip);
 204
 205 /* Some simple string functions; if they return pointers, they are allocated buffers. */
 206 extern char *lxc_string_replace(const char *needle, const char *replacement, const char *haystack);
 207 extern bool lxc_string_in_array(const char *needle, const char **haystack);
 208 extern char *lxc_string_join(const char *sep, const char **parts, bool use_as_prefix);
 209 /* Normalize and split path: Leading and trailing / are removed, multiple
 210  * / are compactified, .. and . are resolved (.. on the top level is considered
 211  * identical to .).
 212  * Examples:
 213  *     /            ->   { NULL }
 214  *     foo/../bar   ->   { bar, NULL }
 215  *     ../../       ->   { NULL }
 216  *     ./bar/baz/.. ->   { bar, NULL }
 217  *     foo//bar     ->   { foo, bar, NULL }
 218  */
 219 extern char **lxc_normalize_path(const char *path);
 220 /* Note: the following two functions use strtok(), so they will never
 221  *       consider an empty element, even if two delimiters are next to
 222  *       each other.
 223  */
 224 extern bool lxc_string_in_list(const char *needle, const char *haystack, char sep);
 225 extern char **lxc_string_split(const char *string, char sep);
 226 extern char **lxc_string_split_and_trim(const char *string, char sep);
 227
 228 /* some simple array manipulation utilities */
 229 typedef void (*lxc_free_fn)(void *);
 230 typedef void *(*lxc_dup_fn)(void *);
 231 extern int lxc_grow_array(void ***array, size_t* capacity, size_t new_size, size_t capacity_increment);
 232 extern void lxc_free_array(void **array, lxc_free_fn element_free_fn);
 233 extern size_t lxc_array_len(void **array);
 234 extern void **lxc_dup_array(void **array, lxc_dup_fn element_dup_fn, lxc_free_fn element_free_fn);
 235
 236 #endif