diff options
author | Ian Jackson <ian.jackson@eu.citrix.com> | 2012-05-11 18:58:59 +0100 |
---|---|---|
committer | Ian Jackson <ian.jackson@eu.citrix.com> | 2012-05-11 18:58:59 +0100 |
commit | f6898bcae4860c57314189ab409b53fb01ab496d (patch) | |
tree | 462093cca502b69d27b7a2ec400688cd226dc512 /tools/libxl/libxl_aoutils.c | |
parent | 9c4e31b554240821393facd0a7d803f2269419d2 (diff) | |
download | xen-f6898bcae4860c57314189ab409b53fb01ab496d.tar.gz xen-f6898bcae4860c57314189ab409b53fb01ab496d.tar.bz2 xen-f6898bcae4860c57314189ab409b53fb01ab496d.zip |
libxl: provide libxl__datacopier_*
General facility for ao operations to shovel data between fds.
This will be used by the bootloader machinery.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Changes in v7:
* assert that the ao is non-null on _init.
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Diffstat (limited to 'tools/libxl/libxl_aoutils.c')
-rw-r--r-- | tools/libxl/libxl_aoutils.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/tools/libxl/libxl_aoutils.c b/tools/libxl/libxl_aoutils.c new file mode 100644 index 0000000000..4c60ad9601 --- /dev/null +++ b/tools/libxl/libxl_aoutils.c @@ -0,0 +1,189 @@ +/* + * Copyright (C) 2010 Citrix Ltd. + * + * This program 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; version 2.1 only. with the special + * exception on linking described in file LICENSE. + * + * This program 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. + */ + +#include "libxl_osdeps.h" /* must come before any other headers */ + +#include "libxl_internal.h" + +/*----- data copier -----*/ + +void libxl__datacopier_init(libxl__datacopier_state *dc) +{ + assert(dc->ao); + libxl__ev_fd_init(&dc->toread); + libxl__ev_fd_init(&dc->towrite); + LIBXL_TAILQ_INIT(&dc->bufs); +} + +void libxl__datacopier_kill(libxl__datacopier_state *dc) +{ + STATE_AO_GC(dc->ao); + libxl__datacopier_buf *buf, *tbuf; + + libxl__ev_fd_deregister(gc, &dc->toread); + libxl__ev_fd_deregister(gc, &dc->towrite); + LIBXL_TAILQ_FOREACH_SAFE(buf, &dc->bufs, entry, tbuf) + free(buf); + LIBXL_TAILQ_INIT(&dc->bufs); +} + +static void datacopier_callback(libxl__egc *egc, libxl__datacopier_state *dc, + int onwrite, int errnoval) +{ + libxl__datacopier_kill(dc); + dc->callback(egc, dc, onwrite, errnoval); +} + +static void datacopier_writable(libxl__egc *egc, libxl__ev_fd *ev, + int fd, short events, short revents); + +static void datacopier_check_state(libxl__egc *egc, libxl__datacopier_state *dc) +{ + STATE_AO_GC(dc->ao); + int rc; + + if (dc->used) { + if (!libxl__ev_fd_isregistered(&dc->towrite)) { + rc = libxl__ev_fd_register(gc, &dc->towrite, datacopier_writable, + dc->writefd, POLLOUT); + if (rc) { + LOG(ERROR, "unable to establish write event on %s" + " during copy of %s", dc->writewhat, dc->copywhat); + datacopier_callback(egc, dc, -1, 0); + return; + } + } + } else if (!libxl__ev_fd_isregistered(&dc->toread)) { + /* we have had eof */ + datacopier_callback(egc, dc, 0, 0); + return; + } else { + /* nothing buffered, but still reading */ + libxl__ev_fd_deregister(gc, &dc->towrite); + } +} + +static void datacopier_readable(libxl__egc *egc, libxl__ev_fd *ev, + int fd, short events, short revents) { + libxl__datacopier_state *dc = CONTAINER_OF(ev, *dc, toread); + STATE_AO_GC(dc->ao); + + if (revents & ~POLLIN) { + LOG(ERROR, "unexpected poll event 0x%x (should be POLLIN)" + " on %s during copy of %s", revents, dc->readwhat, dc->copywhat); + datacopier_callback(egc, dc, -1, 0); + return; + } + assert(revents & POLLIN); + for (;;) { + while (dc->used >= dc->maxsz) { + libxl__datacopier_buf *rm = LIBXL_TAILQ_FIRST(&dc->bufs); + dc->used -= rm->used; + assert(dc->used >= 0); + LIBXL_TAILQ_REMOVE(&dc->bufs, rm, entry); + free(rm); + } + + libxl__datacopier_buf *buf = + LIBXL_TAILQ_LAST(&dc->bufs, libxl__datacopier_bufs); + if (!buf || buf->used >= sizeof(buf->buf)) { + buf = malloc(sizeof(*buf)); + if (!buf) libxl__alloc_failed(CTX, __func__, 1, sizeof(*buf)); + buf->used = 0; + LIBXL_TAILQ_INSERT_TAIL(&dc->bufs, buf, entry); + } + int r = read(ev->fd, + buf->buf + buf->used, + sizeof(buf->buf) - buf->used); + if (r < 0) { + if (errno == EINTR) continue; + if (errno == EWOULDBLOCK) break; + LOGE(ERROR, "error reading %s during copy of %s", + dc->readwhat, dc->copywhat); + datacopier_callback(egc, dc, 0, errno); + return; + } + if (r == 0) { + libxl__ev_fd_deregister(gc, &dc->toread); + break; + } + buf->used += r; + dc->used += r; + assert(buf->used <= sizeof(buf->buf)); + } + datacopier_check_state(egc, dc); +} + +static void datacopier_writable(libxl__egc *egc, libxl__ev_fd *ev, + int fd, short events, short revents) { + libxl__datacopier_state *dc = CONTAINER_OF(ev, *dc, towrite); + STATE_AO_GC(dc->ao); + + if (revents & ~POLLOUT) { + LOG(ERROR, "unexpected poll event 0x%x (should be POLLOUT)" + " on %s during copy of %s", revents, dc->writewhat, dc->copywhat); + datacopier_callback(egc, dc, -1, 0); + return; + } + assert(revents & POLLOUT); + for (;;) { + libxl__datacopier_buf *buf = LIBXL_TAILQ_FIRST(&dc->bufs); + if (!buf) + break; + if (!buf->used) { + LIBXL_TAILQ_REMOVE(&dc->bufs, buf, entry); + free(buf); + continue; + } + int r = write(ev->fd, buf->buf, buf->used); + if (r < 0) { + if (errno == EINTR) continue; + if (errno == EWOULDBLOCK) break; + LOGE(ERROR, "error writing to %s during copy of %s", + dc->writewhat, dc->copywhat); + datacopier_callback(egc, dc, 1, errno); + return; + } + assert(r > 0); + assert(r <= buf->used); + buf->used -= r; + dc->used -= r; + assert(dc->used >= 0); + memmove(buf->buf, buf->buf+r, buf->used); + } + datacopier_check_state(egc, dc); +} + +int libxl__datacopier_start(libxl__datacopier_state *dc) +{ + int rc; + STATE_AO_GC(dc->ao); + + libxl__datacopier_init(dc); + + rc = libxl__ev_fd_register(gc, &dc->toread, datacopier_readable, + dc->readfd, POLLIN); + if (rc) goto out; + + rc = libxl__ev_fd_register(gc, &dc->towrite, datacopier_writable, + dc->writefd, POLLOUT); + if (rc) goto out; + + return 0; + + out: + libxl__datacopier_kill(dc); + return rc; +} + |