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 extern void remove_trailing_slashes(char *p);
  41 extern const char *get_rundir(void);
  42
  43 /*
  44  * Return a buffer containing the default container path.
  45  * Caller must NOT free this buffer, since it may be static.
  46  */
  47 extern const char *lxc_global_config_value(const char *option_name);
  48 extern const char *default_lxc_path(void);
  49 extern const char *default_zfs_root(void);
  50 extern const char *default_lvm_vg(void);
  51 extern const char *default_lvm_thin_pool(void);
  52 extern const char *default_cgroup_use(void);
  53 extern const char *default_cgroup_pattern(void);
  54 /* Define getline() if missing from the C library */
  55 #ifndef HAVE_GETLINE
  56 #ifdef HAVE_FGETLN
  57 #include <../include/getline.h>
  58 #endif
  59 #endif
  60
  61 /* Define setns() if missing from the C library */
  62 #ifndef HAVE_SETNS
  63 static inline int setns(int fd, int nstype)
  64 {
  65 #ifdef __NR_setns
  66         return syscall(__NR_setns, fd, nstype);
  67 #else
  68         errno = ENOSYS;
  69         return -1;
  70 #endif
  71 }
  72 #endif
  73
  74 /* Define unshare() if missing from the C library */
  75 #ifndef HAVE_UNSHARE
  76 static inline int unshare(int flags)
  77 {
  78 #ifdef __NR_unshare
  79         return syscall(__NR_unshare, flags);
  80 #else
  81         errno = ENOSYS;
  82         return -1;
  83 #endif
  84 }
  85 #else
  86 int unshare(int);
  87 #endif
  88
  89 /* Define signalfd() if missing from the C library */
  90 #ifdef HAVE_SYS_SIGNALFD_H
  91 #  include <sys/signalfd.h>
  92 #else
  93 /* assume kernel headers are too old */
  94 #include <stdint.h>
  95 struct signalfd_siginfo
  96 {
  97         uint32_t ssi_signo;
  98         int32_t ssi_errno;
  99         int32_t ssi_code;
 100         uint32_t ssi_pid;
 101         uint32_t ssi_uid;
 102         int32_t ssi_fd;
 103         uint32_t ssi_tid;
 104         uint32_t ssi_band;
 105         uint32_t ssi_overrun;
 106         uint32_t ssi_trapno;
 107         int32_t ssi_status;
 108         int32_t ssi_int;
 109         uint64_t ssi_ptr;
 110         uint64_t ssi_utime;
 111         uint64_t ssi_stime;
 112         uint64_t ssi_addr;
 113         uint8_t __pad[48];
 114 };
 115
 116 #  ifndef __NR_signalfd4
 117 /* assume kernel headers are too old */
 118 #    if __i386__
 119 #      define __NR_signalfd4 327
 120 #    elif __x86_64__
 121 #      define __NR_signalfd4 289
 122 #    elif __powerpc__
 123 #      define __NR_signalfd4 313
 124 #    elif __s390x__
 125 #      define __NR_signalfd4 322
 126 #    elif __arm__
 127 #      define __NR_signalfd4 355
 128 #    endif
 129 #endif
 130
 131 #  ifndef __NR_signalfd
 132 /* assume kernel headers are too old */
 133 #    if __i386__
 134 #      define __NR_signalfd 321
 135 #    elif __x86_64__
 136 #      define __NR_signalfd 282
 137 #    elif __powerpc__
 138 #      define __NR_signalfd 305
 139 #    elif __s390x__
 140 #      define __NR_signalfd 316
 141 #    elif __arm__
 142 #      define __NR_signalfd 349
 143 #    endif
 144 #endif
 145
 146 static inline int signalfd(int fd, const sigset_t *mask, int flags)
 147 {
 148         int retval;
 149
 150         retval = syscall (__NR_signalfd4, fd, mask, _NSIG / 8, flags);
 151         if (errno == ENOSYS && flags == 0)
 152                 retval = syscall (__NR_signalfd, fd, mask, _NSIG / 8);
 153         return retval;
 154 }
 155 #endif
 156
 157 /* open a file with O_CLOEXEC */
 158 FILE *fopen_cloexec(const char *path, const char *mode);
 159
 160
 161 /**
 162  * BUILD_BUG_ON - break compile if a condition is true.
 163  * @condition: the condition which the compiler should know is false.
 164  *
 165  * If you have some code which relies on certain constants being equal, or
 166  * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 167  * detect if someone changes it.
 168  *
 169  * The implementation uses gcc's reluctance to create a negative array, but
 170  * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 171  * to inline functions).  So as a fallback we use the optimizer; if it can't
 172  * prove the condition is false, it will cause a link error on the undefined
 173  * "__build_bug_on_failed".  This error message can be harder to track down
 174  * though, hence the two different methods.
 175  */
 176 #ifndef __OPTIMIZE__
 177 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 178 #else
 179 extern int __build_bug_on_failed;
 180 #define BUILD_BUG_ON(condition)                                 \
 181         do {                                                    \
 182                 ((void)sizeof(char[1 - 2*!!(condition)]));      \
 183                 if (condition) __build_bug_on_failed = 1;       \
 184         } while(0)
 185 #endif
 186
 187 /*
 188  * wait on a child we forked
 189  */
 190 extern int wait_for_pid(pid_t pid);
 191 extern int lxc_wait_for_pid_status(pid_t pid);
 192
 193 /* send and receive buffers completely */
 194 extern ssize_t lxc_write_nointr(int fd, const void* buf, size_t count);
 195 extern ssize_t lxc_read_nointr(int fd, void* buf, size_t count);
 196 extern ssize_t lxc_read_nointr_expect(int fd, void* buf, size_t count, const void* expected_buf);
 197 #if HAVE_LIBGNUTLS
 198 #define SHA_DIGEST_LENGTH 20
 199 extern int sha1sum_file(char *fnam, unsigned char *md_value);
 200 #endif
 201
 202 /* read and write whole files */
 203 extern int lxc_write_to_file(const char *filename, const void* buf, size_t count, bool add_newline);
 204 extern int lxc_read_from_file(const char *filename, void* buf, size_t count);
 205
 206 /* convert variadic argument lists to arrays (for execl type argument lists) */
 207 extern char** lxc_va_arg_list_to_argv(va_list ap, size_t skip, int do_strdup);
 208 extern const char** lxc_va_arg_list_to_argv_const(va_list ap, size_t skip);
 209
 210 /* Some simple string functions; if they return pointers, they are allocated buffers. */
 211 extern char *lxc_string_replace(const char *needle, const char *replacement, const char *haystack);
 212 extern bool lxc_string_in_array(const char *needle, const char **haystack);
 213 extern char *lxc_string_join(const char *sep, const char **parts, bool use_as_prefix);
 214 /* Normalize and split path: Leading and trailing / are removed, multiple
 215  * / are compactified, .. and . are resolved (.. on the top level is considered
 216  * identical to .).
 217  * Examples:
 218  *     /            ->   { NULL }
 219  *     foo/../bar   ->   { bar, NULL }
 220  *     ../../       ->   { NULL }
 221  *     ./bar/baz/.. ->   { bar, NULL }
 222  *     foo//bar     ->   { foo, bar, NULL }
 223  */
 224 extern char **lxc_normalize_path(const char *path);
 225 extern char *lxc_append_paths(const char *first, const char *second);
 226 /* Note: the following two functions use strtok(), so they will never
 227  *       consider an empty element, even if two delimiters are next to
 228  *       each other.
 229  */
 230 extern bool lxc_string_in_list(const char *needle, const char *haystack, char sep);
 231 extern char **lxc_string_split(const char *string, char sep);
 232 extern char **lxc_string_split_and_trim(const char *string, char sep);
 233
 234 /* some simple array manipulation utilities */
 235 typedef void (*lxc_free_fn)(void *);
 236 typedef void *(*lxc_dup_fn)(void *);
 237 extern int lxc_grow_array(void ***array, size_t* capacity, size_t new_size, size_t capacity_increment);
 238 extern void lxc_free_array(void **array, lxc_free_fn element_free_fn);
 239 extern size_t lxc_array_len(void **array);
 240 extern void **lxc_dup_array(void **array, lxc_dup_fn element_dup_fn, lxc_free_fn element_free_fn);
 241
 242 extern void **lxc_append_null_to_array(void **array, size_t count);
 243
 244 extern void dump_stacktrace(void);
 245 #endif