mirror of
https://github.com/openvswitch/ovs
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279c9e0308
If a daemon doesn't start, we need to know why. Being able to consistently consult the log to find out is helpful.
66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/* Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <config.h>
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#include "entropy.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include "socket-util.h"
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#include "vlog.h"
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VLOG_DEFINE_THIS_MODULE(entropy);
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static const char urandom[] = "/dev/urandom";
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/* Initializes 'buffer' with 'n' bytes of high-quality random numbers. Returns
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* 0 if successful, otherwise a positive errno value or EOF on error. */
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int
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get_entropy(void *buffer, size_t n)
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{
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size_t bytes_read;
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int error;
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int fd;
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fd = open(urandom, O_RDONLY);
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if (fd < 0) {
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VLOG_ERR("%s: open failed (%s)", urandom, strerror(errno));
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return errno ? errno : EINVAL;
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}
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error = read_fully(fd, buffer, n, &bytes_read);
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close(fd);
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if (error) {
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VLOG_ERR("%s: read error (%s)", urandom, ovs_retval_to_string(error));
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}
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return error;
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}
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/* Initializes 'buffer' with 'n' bytes of high-quality random numbers. Exits
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* if an error occurs. */
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void
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get_entropy_or_die(void *buffer, size_t n)
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{
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int error = get_entropy(buffer, n);
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if (error) {
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VLOG_FATAL("%s: read error (%s)",
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urandom, ovs_retval_to_string(error));
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}
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}
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