src/lib/sendfile-util.c

	sendfile-util.c revision 55941eeb02253dbff768222a47c911ae6fd8690a
/* kludge a bit to remove _FILE_OFFSET_BITS definition from config.h.
   It's required to be able to include sys/sendfile.h with Linux. */
#include "../../config.h"
#undef HAVE_CONFIG_H

#ifdef HAVE_LINUX_SENDFILE
#  undef _FILE_OFFSET_BITS
#endif

#include "lib.h"
#include "sendfile-util.h"

#ifdef HAVE_LINUX_SENDFILE

#include <sys/sendfile.h>

ssize_t safe_sendfile(int out_fd, int in_fd, uoff_t *offset, size_t count)
{
    /* REMEBER: uoff_t and off_t may not be of same size. */
    off_t safe_offset;
    ssize_t ret;

    /* make sure given offset fits into off_t */
    if (sizeof(off_t) * CHAR_BIT == 32) {
        /* 32bit off_t */
        if (*offset > 2147483647L) {
            errno = EOVERFLOW;
            return -1;
        }
    } else {
        /* they're most likely the same size. if not, fix this
           code later */
        i_assert(sizeof(off_t) == sizeof(uoff_t));

        if (*offset > OFF_T_MAX) {
            errno = EOVERFLOW;
            return -1;
        }
    }

    safe_offset = (off_t)*offset;
    ret = sendfile(out_fd, in_fd, &safe_offset, count);
    *offset = (uoff_t)safe_offset;

    return ret;
}

#elif defined(HAVE_FREEBSD_SENDFILE)

#include <sys/socket.h>
#include <sys/uio.h>

ssize_t safe_sendfile(int out_fd, int in_fd, uoff_t *offset, size_t count)
{
    struct sf_hdtr hdtr;
    off_t sbytes;
    int ret;

    i_assert(count <= SSIZE_T_MAX);

    memset(&hdtr, 0, sizeof(hdtr));
    ret = sendfile(in_fd, out_fd, *offset, count, &hdtr, &sbytes, 0);

    *offset += sbytes;

    if (ret == 0 || (ret == 0 && errno == EAGAIN && sbytes > 0))
        return (ssize_t)sbytes;
    else
        return -1;
}
#else
ssize_t safe_sendfile(int out_fd __attr_unused__, int in_fd __attr_unused__,
              uoff_t *offset __attr_unused__,
              size_t count __attr_unused__)
{
    errno = EINVAL;
    return -1;
}
#endif