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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23 #ifndef _utils_h
  24 #define _utils_h
  25
  26 #include <errno.h>
  27 #include <sys/types.h>
  28 #include <unistd.h>
  29 #include "config.h"
  30
  31 /* returns 1 on success, 0 if there were any failures */
  32 extern int lxc_rmdir_onedev(char *path);
  33 extern int lxc_setup_fs(void);
  34 extern int get_u16(unsigned short *val, const char *arg, int base);
  35 extern int mkdir_p(const char *dir, mode_t mode);
  36 /*
  37  * Return a newly allocated buffer containing the default container
  38  * path.  Caller must free this buffer.
  39  */
  40 extern const char *default_lxc_path(void);
  41 extern const char *default_zfs_root(void);
  42 extern const char *default_lvm_vg(void);
  43
  44 /* Define getline() if missing from the C library */
  45 #ifndef HAVE_GETLINE
  46 #ifdef HAVE_FGETLN
  47 #include <../include/getline.h>
  48 #endif
  49 #endif
  50
  51 /* Define setns() if missing from the C library */
  52 #ifndef HAVE_SETNS
  53 static inline int setns(int fd, int nstype)
  54 {
  55 #ifdef __NR_setns
  56         return syscall(__NR_setns, fd, nstype);
  57 #else
  58         errno = ENOSYS;
  59         return -1;
  60 #endif
  61 }
  62 #endif
  63
  64 /* Define unshare() if missing from the C library */
  65 #ifndef HAVE_UNSHARE
  66 static inline int unshare(int flags)
  67 {
  68 #ifdef __NR_unshare
  69         return syscall(__NR_unshare, flags);
  70 #else
  71         errno = ENOSYS;
  72         return -1;
  73 #endif
  74 }
  75 #else
  76 int unshare(int);
  77 #endif
  78
  79 /* Define signalfd() if missing from the C library */
  80 #ifdef HAVE_SYS_SIGNALFD_H
  81 #  include <sys/signalfd.h>
  82 #else
  83 /* assume kernel headers are too old */
  84 #include <stdint.h>
  85 struct signalfd_siginfo
  86 {
  87         uint32_t ssi_signo;
  88         int32_t ssi_errno;
  89         int32_t ssi_code;
  90         uint32_t ssi_pid;
  91         uint32_t ssi_uid;
  92         int32_t ssi_fd;
  93         uint32_t ssi_tid;
  94         uint32_t ssi_band;
  95         uint32_t ssi_overrun;
  96         uint32_t ssi_trapno;
  97         int32_t ssi_status;
  98         int32_t ssi_int;
  99         uint64_t ssi_ptr;
 100         uint64_t ssi_utime;
 101         uint64_t ssi_stime;
 102         uint64_t ssi_addr;
 103         uint8_t __pad[48];
 104 };
 105
 106 #  ifndef __NR_signalfd4
 107 /* assume kernel headers are too old */
 108 #    if __i386__
 109 #      define __NR_signalfd4 327
 110 #    elif __x86_64__
 111 #      define __NR_signalfd4 289
 112 #    elif __powerpc__
 113 #      define __NR_signalfd4 313
 114 #    elif __s390x__
 115 #      define __NR_signalfd4 322
 116 #    endif
 117 #endif
 118
 119 #  ifndef __NR_signalfd
 120 /* assume kernel headers are too old */
 121 #    if __i386__
 122 #      define __NR_signalfd 321
 123 #    elif __x86_64__
 124 #      define __NR_signalfd 282
 125 #    elif __powerpc__
 126 #      define __NR_signalfd 305
 127 #    elif __s390x__
 128 #      define __NR_signalfd 316
 129 #    endif
 130 #endif
 131
 132 static inline int signalfd(int fd, const sigset_t *mask, int flags)
 133 {
 134         int retval;
 135
 136         retval = syscall (__NR_signalfd4, fd, mask, _NSIG / 8, flags);
 137         if (errno == ENOSYS && flags == 0)
 138                 retval = syscall (__NR_signalfd, fd, mask, _NSIG / 8);
 139         return retval;
 140 }
 141 #endif
 142
 143
 144 /**
 145  * BUILD_BUG_ON - break compile if a condition is true.
 146  * @condition: the condition which the compiler should know is false.
 147  *
 148  * If you have some code which relies on certain constants being equal, or
 149  * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 150  * detect if someone changes it.
 151  *
 152  * The implementation uses gcc's reluctance to create a negative array, but
 153  * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 154  * to inline functions).  So as a fallback we use the optimizer; if it can't
 155  * prove the condition is false, it will cause a link error on the undefined
 156  * "__build_bug_on_failed".  This error message can be harder to track down
 157  * though, hence the two different methods.
 158  */
 159 #ifndef __OPTIMIZE__
 160 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 161 #else
 162 extern int __build_bug_on_failed;
 163 #define BUILD_BUG_ON(condition)                                 \
 164         do {                                                    \
 165                 ((void)sizeof(char[1 - 2*!!(condition)]));      \
 166                 if (condition) __build_bug_on_failed = 1;       \
 167         } while(0)
 168 #endif
 169
 170 /*
 171  * wait on a child we forked
 172  */
 173 extern int wait_for_pid(pid_t pid);
 174 extern int lxc_wait_for_pid_status(pid_t pid);
 175
 176 /* send and receive buffers completely */
 177 extern ssize_t lxc_write_nointr(int fd, const void* buf, size_t count);
 178 extern ssize_t lxc_read_nointr(int fd, void* buf, size_t count);
 179 extern ssize_t lxc_read_nointr_expect(int fd, void* buf, size_t count, const void* expected_buf);
 180 #if HAVE_LIBGNUTLS
 181 #define SHA_DIGEST_LENGTH 20
 182 extern int sha1sum_file(char *fnam, unsigned char *md_value);
 183 #endif
 184
 185 #endif