at_wasip1.go

     1  // Copyright 2020 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build wasip1
     6  
     7  package unix
     8  
     9  import (
    10  	"syscall"
    11  	"unsafe"
    12  )
    13  
    14  // The values of these constants are not part of the WASI API.
    15  const (
    16  	// UTIME_OMIT is the sentinel value to indicate that a time value should not
    17  	// be changed. It is useful for example to indicate for example with UtimesNano
    18  	// to avoid changing AccessTime or ModifiedTime.
    19  	// Its value must match syscall/fs_wasip1.go
    20  	UTIME_OMIT = -0x2
    21  
    22  	AT_REMOVEDIR        = 0x200
    23  	AT_SYMLINK_NOFOLLOW = 0x100
    24  )
    25  
    26  func Unlinkat(dirfd int, path string, flags int) error {
    27  	if flags&AT_REMOVEDIR == 0 {
    28  		return errnoErr(path_unlink_file(
    29  			int32(dirfd),
    30  			unsafe.StringData(path),
    31  			size(len(path)),
    32  		))
    33  	} else {
    34  		return errnoErr(path_remove_directory(
    35  			int32(dirfd),
    36  			unsafe.StringData(path),
    37  			size(len(path)),
    38  		))
    39  	}
    40  }
    41  
    42  //go:wasmimport wasi_snapshot_preview1 path_unlink_file
    43  //go:noescape
    44  func path_unlink_file(fd int32, path *byte, pathLen size) syscall.Errno
    45  
    46  //go:wasmimport wasi_snapshot_preview1 path_remove_directory
    47  //go:noescape
    48  func path_remove_directory(fd int32, path *byte, pathLen size) syscall.Errno
    49  
    50  func Openat(dirfd int, path string, flags int, perm uint32) (int, error) {
    51  	return syscall.Openat(dirfd, path, flags, perm)
    52  }
    53  
    54  func Fstatat(dirfd int, path string, stat *syscall.Stat_t, flags int) error {
    55  	var filestatFlags uint32
    56  	if flags&AT_SYMLINK_NOFOLLOW == 0 {
    57  		filestatFlags |= syscall.LOOKUP_SYMLINK_FOLLOW
    58  	}
    59  	return errnoErr(path_filestat_get(
    60  		int32(dirfd),
    61  		uint32(filestatFlags),
    62  		unsafe.StringData(path),
    63  		size(len(path)),
    64  		unsafe.Pointer(stat),
    65  	))
    66  }
    67  
    68  //go:wasmimport wasi_snapshot_preview1 path_filestat_get
    69  //go:noescape
    70  func path_filestat_get(fd int32, flags uint32, path *byte, pathLen size, buf unsafe.Pointer) syscall.Errno
    71  
    72  func Readlinkat(dirfd int, path string, buf []byte) (int, error) {
    73  	var nwritten size
    74  	errno := path_readlink(
    75  		int32(dirfd),
    76  		unsafe.StringData(path),
    77  		size(len(path)),
    78  		&buf[0],
    79  		size(len(buf)),
    80  		&nwritten)
    81  	return int(nwritten), errnoErr(errno)
    82  
    83  }
    84  
    85  type (
    86  	size = uint32
    87  )
    88  
    89  //go:wasmimport wasi_snapshot_preview1 path_readlink
    90  //go:noescape
    91  func path_readlink(fd int32, path *byte, pathLen size, buf *byte, bufLen size, nwritten *size) syscall.Errno
    92  
    93  func Mkdirat(dirfd int, path string, mode uint32) error {
    94  	if path == "" {
    95  		return syscall.EINVAL
    96  	}
    97  	return errnoErr(path_create_directory(
    98  		int32(dirfd),
    99  		unsafe.StringData(path),
   100  		size(len(path)),
   101  	))
   102  }
   103  
   104  //go:wasmimport wasi_snapshot_preview1 path_create_directory
   105  //go:noescape
   106  func path_create_directory(fd int32, path *byte, pathLen size) syscall.Errno
   107  
   108  func Fchmodat(dirfd int, path string, mode uint32, flags int) error {
   109  	// WASI preview 1 doesn't support changing file modes.
   110  	return syscall.ENOSYS
   111  }
   112  
   113  func Fchownat(dirfd int, path string, uid, gid int, flags int) error {
   114  	// WASI preview 1 doesn't support changing file ownership.
   115  	return syscall.ENOSYS
   116  }
   117  
   118  func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) error {
   119  	if oldpath == "" || newpath == "" {
   120  		return syscall.EINVAL
   121  	}
   122  	return errnoErr(path_rename(
   123  		int32(olddirfd),
   124  		unsafe.StringData(oldpath),
   125  		size(len(oldpath)),
   126  		int32(newdirfd),
   127  		unsafe.StringData(newpath),
   128  		size(len(newpath)),
   129  	))
   130  }
   131  
   132  //go:wasmimport wasi_snapshot_preview1 path_rename
   133  //go:noescape
   134  func path_rename(oldFd int32, oldPath *byte, oldPathLen size, newFd int32, newPath *byte, newPathLen size) syscall.Errno
   135  
   136  func Linkat(olddirfd int, oldpath string, newdirfd int, newpath string, flag int) error {
   137  	if oldpath == "" || newpath == "" {
   138  		return syscall.EINVAL
   139  	}
   140  	return errnoErr(path_link(
   141  		int32(olddirfd),
   142  		0,
   143  		unsafe.StringData(oldpath),
   144  		size(len(oldpath)),
   145  		int32(newdirfd),
   146  		unsafe.StringData(newpath),
   147  		size(len(newpath)),
   148  	))
   149  }
   150  
   151  //go:wasmimport wasi_snapshot_preview1 path_link
   152  //go:noescape
   153  func path_link(oldFd int32, oldFlags uint32, oldPath *byte, oldPathLen size, newFd int32, newPath *byte, newPathLen size) syscall.Errno
   154  
   155  func Symlinkat(oldpath string, newdirfd int, newpath string) error {
   156  	if oldpath == "" || newpath == "" {
   157  		return syscall.EINVAL
   158  	}
   159  	return errnoErr(path_symlink(
   160  		unsafe.StringData(oldpath),
   161  		size(len(oldpath)),
   162  		int32(newdirfd),
   163  		unsafe.StringData(newpath),
   164  		size(len(newpath)),
   165  	))
   166  }
   167  
   168  //go:wasmimport wasi_snapshot_preview1 path_symlink
   169  //go:noescape
   170  func path_symlink(oldPath *byte, oldPathLen size, fd int32, newPath *byte, newPathLen size) syscall.Errno
   171  
   172  func errnoErr(errno syscall.Errno) error {
   173  	if errno == 0 {
   174  		return nil
   175  	}
   176  	return errno
   177  }
   178
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