bsd/man/man2/utimensat.2

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  31 .\"     @(#)utimes.2    8.1 (Berkeley) 6/4/93
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  34 .Dd January 17, 2016
  35 .Dt UTIMENSAT 2
  36 .Os
  37 .Sh NAME
  38 .Nm futimens ,
  39 .Nm utimensat
  40 .Nd set file access and modification times
  41 .Sh SYNOPSIS
  42 .In sys/stat.h
  43 .Ft int
  44 .Fn futimens "int fd" "const struct timespec times[2]"
  45 .Ft int
  46 .Fo utimensat
  47 .Fa "int fd"
  48 .Fa "const char *path"
  49 .Fa "const struct timespec times[2]"
  50 .Fa "int flag"
  51 .Fc
  52 .Sh DESCRIPTION
  53 The access and modification times of the file named by
  54 .Fa path
  55 or referenced by
  56 .Fa fd
  57 are changed as specified by the argument
  58 .Fa times .
  59 The inode-change-time of the file is set to the current time.
  60 .Pp
  61 If
  62 .Fa path
  63 specifies a relative path,
  64 it is relative to the current working directory if
  65 .Fa fd
  66 is
  67 .Dv AT_FDCWD
  68 and otherwise relative to the directory associated with the file descriptor
  69 .Fa fd .
  70 .Pp
  71 The
  72 .Va tv_nsec
  73 field of a
  74 .Vt timespec
  75 structure
  76 can be set to the special value
  77 .Dv UTIME_NOW
  78 to set the current time, or to
  79 .Dv UTIME_OMIT
  80 to leave the time unchanged.
  81 In either case, the
  82 .Va tv_sec
  83 field is ignored.
  84 .Pp
  85 If
  86 .Fa times
  87 is
  88 .No non- Ns Dv NULL ,
  89 it is assumed to point to an array of two timespec structures.
  90 The access time is set to the value of the first element, and the
  91 modification time is set to the value of the second element.
  92 If
  93 .Fa times
  94 is
  95 .Dv NULL ,
  96 this is equivalent to passing
  97 a pointer to an array of two timespec structures
  98 with both
  99 .Va tv_nsec
 100 fields set to
 101 .Dv UTIME_NOW .
 102 .Pp
 103 If both
 104 .Va tv_nsec
 105 fields are
 106 .Dv UTIME_OMIT ,
 107 the timestamps remain unchanged and
 108 no permissions are needed for the file itself,
 109 although search permissions may be required for the path prefix.
 110 The call may or may not succeed if the named file does not exist.
 111 .Pp
 112 If both
 113 .Va tv_nsec
 114 fields are
 115 .Dv UTIME_NOW ,
 116 the caller must be the owner of the file, have permission to
 117 write the file, or be the super-user.
 118 .Pp
 119 For all other values of the timestamps,
 120 the caller must be the owner of the file or be the super-user.
 121 .Pp
 122 The values for the
 123 .Fa flag
 124 argument of the
 125 .Fn utimensat
 126 system call
 127 are constructed by a bitwise-inclusive OR of flags from the following list,
 128 defined in
 129 .In fcntl.h :
 130 .Bl -tag -width indent
 131 .It Dv AT_SYMLINK_NOFOLLOW
 132 If
 133 .Fa path
 134 names a symbolic link, the symbolic link's times are changed.
 135 By default,
 136 .Fn utimensat
 137 changes the times of the file referenced by the symbolic link.
 138 .El
 139 .Sh RETURN VALUES
 140 .Rv -std
 141 .Sh ERRORS
 142 These system calls will fail if:
 143 .Bl -tag -width Er
 144 .It Bq Er EACCES
 145 The
 146 .Fa times
 147 argument is
 148 .Dv NULL ,
 149 or both
 150 .Va tv_nsec
 151 values are
 152 .Dv UTIME_NOW ,
 153 and the effective user ID of the process does not
 154 match the owner of the file, and is not the super-user, and write
 155 access is denied.
 156 .It Bq Er EINVAL
 157 The
 158 .Va tv_nsec
 159 component of at least one of the values specified by the
 160 .Fa times
 161 argument has a value less than 0 or greater than 999999999 and is not equal to
 162 .Dv UTIME_NOW
 163 or
 164 .Dv UTIME_OMIT .
 165 .It Bq Er EIO
 166 An I/O error occurred while reading or writing the affected inode.
 167 .It Bq Er EPERM
 168 The
 169 .Fa times
 170 argument is not
 171 .Dv NULL
 172 nor are both
 173 .Va tv_nsec
 174 values
 175 .Dv UTIME_NOW ,
 176 nor are both
 177 .Va tv_nsec
 178 values
 179 .Dv UTIME_OMIT
 180 and the calling process's effective user ID
 181 does not match the owner of the file and is not the super-user.
 182 .It Bq Er EPERM
 183 The named file has its immutable or append-only flag set, see the
 184 .Xr chflags 2
 185 manual page for more information.
 186 .It Bq Er EROFS
 187 The file system containing the file is mounted read-only.
 188 .El
 189 .Pp
 190 The
 191 .Fn futimens
 192 system call
 193 will fail if:
 194 .Bl -tag -width Er
 195 .It Bq Er EBADF
 196 The
 197 .Fa fd
 198 argument
 199 does not refer to a valid descriptor.
 200 .El
 201 .Pp
 202 The
 203 .Fn utimensat
 204 system call
 205 will fail if:
 206 .Bl -tag -width Er
 207 .It Bq Er EACCES
 208 Search permission is denied for a component of the path prefix.
 209 .It Bq Er EBADF
 210 The
 211 .Fa path
 212 argument does not specify an absolute path and the
 213 .Fa fd
 214 argument is neither
 215 .Dv AT_FDCWD
 216 nor a valid file descriptor.
 217 .It Bq Er EFAULT
 218 The
 219 .Fa path
 220 argument
 221 points outside the process's allocated address space.
 222 .It Bq Er ELOOP
 223 Too many symbolic links were encountered in translating the pathname.
 224 .It Bq Er ENAMETOOLONG
 225 A component of a pathname exceeded
 226 .Dv NAME_MAX
 227 characters, or an entire path name exceeded
 228 .Dv PATH_MAX
 229 characters.
 230 .It Bq Er ENOENT
 231 The named file does not exist.
 232 .It Bq Er ENOTDIR
 233 A component of the path prefix is not a directory.
 234 .It Bq Er ENOTDIR
 235 The
 236 .Fa path
 237 argument is not an absolute path and
 238 .Fa fd
 239 is neither
 240 .Dv AT_FDCWD
 241 nor a file descriptor associated with a directory.
 242 .El
 243 .Sh SEE ALSO
 244 .Xr chflags 2 ,
 245 .Xr stat 2 ,
 246 .Xr symlink 2 ,
 247 .Xr utimes 2 ,
 248 .Xr utime 3 ,
 249 .Xr symlink 7
 250 .Sh STANDARDS
 251 The
 252 .Fn futimens
 253 and
 254 .Fn utimensat
 255 system calls are expected to conform to
 256 .St -p1003.1-2008 .