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Diffstat (limited to 'sysdeps/mach/hurd/sendfile.c')
-rw-r--r-- | sysdeps/mach/hurd/sendfile.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/sysdeps/mach/hurd/sendfile.c b/sysdeps/mach/hurd/sendfile.c new file mode 100644 index 0000000000..b1849d2bf9 --- /dev/null +++ b/sysdeps/mach/hurd/sendfile.c @@ -0,0 +1,60 @@ +/* sendfile -- copy data directly from one file descriptor to another + Copyright (C) 2002 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <sys/sendfile.h> +#include <hurd.h> +#include <hurd/fd.h> +#include <sys/mman.h> + +/* Send COUNT bytes from file associated with IN_FD starting at OFFSET to + descriptor OUT_FD. */ +ssize_t +sendfile (int out_fd, int in_fd, off_t *offset, size_t count) +{ + /* We just do a vanilla io_read followed by a vanilla io_write here. + In theory the IN_FD filesystem can return us out-of-line data that + we then send out-of-line to the OUT_FD filesystem and no copying + takes place until those pages need to be flushed or packaged by + that filesystem (e.g. packetized by a network socket). However, + we momentarily consume COUNT bytes of our local address space, + which might blow if it's huge or address space is real tight. */ + + char *data = 0; + size_t datalen = 0; + error_t err = HURD_DPORT_USE (in_fd, + __io_read (port, &data, &datalen, + offset ? *offset : (off_t) -1, + count)); + if (err == 0) + { + size_t nwrote; + if (datalen == 0) + return 0; + err = HURD_DPORT_USE (out_fd, __io_write (port, data, datalen, + (off_t) -1, &nwrote)); + munmap (data, datalen); + if (err == 0) + { + if (offset) + *offset += datalen; + return nwrote; + } + } + return __hurd_fail (err); +} |