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1481a7551d
Between fork() and execvp() calls in the process_start() function both child and parent processes share the same file descriptors. This means that, if a child process received a signal during this time interval, then it could potentially write data to a shared file descriptor. One such example is fatal signal handler, where, if child process received SIGTERM signal, then it would write data into pipe. Then a read event would occur on the other end of the pipe where parent process is listening and this would make parent process to incorrectly believe that it was the one who received SIGTERM. Also, since parent process never reads data from this pipe, then this bug would make parent process to consume 100% CPU by immediately waking up from the event loop. This patch will help to avoid this problem by blocking signals until child closes all its file descriptors. Signed-off-by: Ansis Atteka <aatteka@nicira.com> Reported-by: Suganya Ramachandran <suganyar@vmware.com> Issue: 1255110
52 lines
1.6 KiB
C
52 lines
1.6 KiB
C
/*
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* Copyright (c) 2008, 2009, 2010, 2013 Nicira, Inc.
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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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#ifndef FATAL_SIGNAL_H
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#define FATAL_SIGNAL_H 1
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#ifndef _WIN32
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#include <signal.h>
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#endif
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#include <stdbool.h>
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/* Basic interface. */
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void fatal_signal_init(void);
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void fatal_signal_add_hook(void (*hook_cb)(void *aux),
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void (*cancel_cb)(void *aux), void *aux,
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bool run_at_exit);
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void fatal_signal_fork(void);
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void fatal_signal_run(void);
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void fatal_signal_wait(void);
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void fatal_ignore_sigpipe(void);
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/* Convenience functions for unlinking files upon termination.
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*
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* These functions also unlink the files upon normal process termination via
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* exit(). */
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void fatal_signal_add_file_to_unlink(const char *);
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void fatal_signal_remove_file_to_unlink(const char *);
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int fatal_signal_unlink_file_now(const char *);
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/* Interface for other code that catches one of our signals and needs to pass
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* it through. */
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void fatal_signal_handler(int sig_nr);
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#ifndef _WIN32
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void fatal_signal_block(sigset_t *prev_mask);
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#endif
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#endif /* fatal-signal.h */
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