+++ /dev/null
-/* $Id: xwrite.c 5771 2002-09-17 17:00:05Z alexk $
-**
-** write and writev replacements to handle partial writes.
-**
-** Usage:
-**
-** ssize_t xwrite(int fildes, const void *buf, size_t nbyte);
-** ssize_t xpwrite(int fildes, const void *buf, size_t nbyte,
-** off_t offset);
-** ssize_t xwritev(int fildes, const struct iovec *iov, int iovcnt);
-**
-** xwrite, xpwrite, and xwritev behave exactly like their C library
-** counterparts except that, if write or writev succeeds but returns a number
-** of bytes written less than the total bytes, the write is repeated picking
-** up where it left off until the full amount of the data is written. The
-** write is also repeated if it failed with EINTR. The write will be aborted
-** after 10 successive writes with no forward progress.
-**
-** Both functions return the number of bytes written on success or -1 on an
-** error, and will leave errno set to whatever the underlying system call
-** set it to. Note that it is possible for a write to fail after some data
-** was written, on the subsequent additional write; in that case, these
-** functions will return -1 and the number of bytes actually written will
-** be lost.
-*/
-
-#include "config.h"
-#include "clibrary.h"
-#include <errno.h>
-#include <sys/uio.h>
-
-#include "libinn.h"
-
-/* If we're running the test suite, call testing versions of the write
- functions. #undef pwrite first because large file support may define a
- macro pwrite (pointing to pwrite64) on some platforms (e.g. Solaris). */
-#if TESTING
-# undef pwrite
-# define pwrite fake_pwrite
-# define write fake_write
-# define writev fake_writev
-ssize_t fake_pwrite(int, const void *, size_t, off_t);
-ssize_t fake_write(int, const void *, size_t);
-ssize_t fake_writev(int, const struct iovec *, int);
-#endif
-
-ssize_t
-xwrite(int fd, const void *buffer, size_t size)
-{
- size_t total;
- ssize_t status;
- int count = 0;
-
- if (size == 0)
- return 0;
-
- /* Abort the write if we try ten times with no forward progress. */
- for (total = 0; total < size; total += status) {
- if (++count > 10)
- break;
- status = write(fd, (const char *) buffer + total, size - total);
- if (status > 0)
- count = 0;
- if (status < 0) {
- if (errno != EINTR)
- break;
- status = 0;
- }
- }
- return (total < size) ? -1 : (ssize_t) total;
-}
-
-ssize_t
-xpwrite(int fd, const void *buffer, size_t size, off_t offset)
-{
- size_t total;
- ssize_t status;
- int count = 0;
-
- if (size == 0)
- return 0;
-
- /* Abort the write if we try ten times with no forward progress. */
- for (total = 0; total < size; total += status) {
- if (++count > 10)
- break;
- status = pwrite(fd, (const char *) buffer + total, size - total,
- offset + total);
- if (status > 0)
- count = 0;
- if (status < 0) {
- if (errno != EINTR)
- break;
- status = 0;
- }
- }
- return (total < size) ? -1 : (ssize_t) total;
-}
-
-ssize_t
-xwritev(int fd, const struct iovec iov[], int iovcnt)
-{
- ssize_t total, status = 0;
- size_t left, offset;
- int iovleft, i, count;
- struct iovec *tmpiov;
-
- if (iovcnt == 0)
- return 0;
-
- /* Get a count of the total number of bytes in the iov array. */
- for (total = 0, i = 0; i < iovcnt; i++)
- total += iov[i].iov_len;
-
- if (total == 0)
- return 0;
-
- /* First, try just writing it all out. Most of the time this will
- succeed and save us lots of work. Abort the write if we try ten times
- with no forward progress. */
- count = 0;
- do {
- if (++count > 10)
- break;
- status = writev(fd, iov, iovcnt);
- if (status > 0)
- count = 0;
- } while (status < 0 && errno == EINTR);
- if (status < 0)
- return -1;
- if (status == total)
- return total;
-
- /* If we fell through to here, the first write partially succeeded.
- Figure out how far through the iov array we got, and then duplicate
- the rest of it so that we can modify it to reflect how much we manage
- to write on successive tries. */
- offset = status;
- left = total - offset;
- for (i = 0; offset >= (size_t) iov[i].iov_len; i++)
- offset -= iov[i].iov_len;
- iovleft = iovcnt - i;
- tmpiov = xmalloc(iovleft * sizeof(struct iovec));
- memcpy(tmpiov, iov + i, iovleft * sizeof(struct iovec));
-
- /* status now contains the offset into the first iovec struct in tmpiov.
- Go into the write loop, trying to write out everything remaining at
- each point. At the top of the loop, status will contain a count of
- bytes written out at the beginning of the set of iovec structs. */
- i = 0;
- do {
- if (++count > 10)
- break;
-
- /* Skip any leading data that has been written out. */
- for (; offset >= (size_t) tmpiov[i].iov_len && iovleft > 0; i++) {
- offset -= tmpiov[i].iov_len;
- iovleft--;
- }
- tmpiov[i].iov_base = (char *) tmpiov[i].iov_base + offset;
- tmpiov[i].iov_len -= offset;
-
- /* Write out what's left and return success if it's all written. */
- status = writev(fd, tmpiov + i, iovleft);
- if (status <= 0)
- offset = 0;
- else {
- offset = status;
- left -= offset;
- count = 0;
- }
- } while (left > 0 && (status >= 0 || errno == EINTR));
-
- /* We're either done or got an error; if we're done, left is now 0. */
- free(tmpiov);
- return (left == 0) ? total : -1;
-}
~ian / innduct.git / blobdiff