1 /* ========================================================================

2 * Copyright 1988-2006 University of Washington

3 *

4 * Licensed under the Apache License, Version 2.0 (the "License");

5 * you may not use this file except in compliance with the License.

6 * You may obtain a copy of the License at

7 *

8 * http://www.apache.org/licenses/LICENSE-2.0

9 *

10 *

11 * ========================================================================

12 */

13

14 /*

15 * Program: Write data, treating partial writes as an error

16 *

17 * Author: Mark Crispin

18 * Networks and Distributed Computing

19 * Computing & Communications

20 * University of Washington

21 * Administration Building, AG-44

22 * Seattle, WA 98195

23 * Internet: MRC@CAC.Washington.EDU

24 *

25 * Date: 26 May 1995

26 * Last Edited: 30 August 2006

27 */

28

29 /* The whole purpose of this unfortunate routine is to deal with DOS and

30 * certain cretinous versions of UNIX which decided that the "bytes actually

31 * written" return value from write() gave them license to use that for things

32 * that are really errors, such as disk quota exceeded, maximum file size

33 * exceeded, disk full, etc.

34 *

35 * BSD won't screw us this way on the local filesystem, but who knows what

36 * some NFS-mounted filesystem will do.

37 */

38 

39 #undef write

40

41 /* Write data to file

42 * Accepts: file descriptor

43 * I/O vector structure

44 * number of vectors in structure

45 * Returns: number of bytes written if successful, -1 if failure

46 */

47

48 long maxposint = (long)((((unsigned long) 1) << ((sizeof(int) * 8) - 1)) - 1);

49

50 long safe_write (int fd,char *buf,long nbytes)

51 {

52 long i,j;

53 if (nbytes > 0) for (i = nbytes; i; i -= j,buf += j) {

54 while (((j = write (fd,buf,(int) min (maxposint,i))) < 0) &&

55 (errno == EINTR));

56 if (j < 0) return j;

57 }

58 return nbytes;

59 }