/* * Copyright (c) 2015 * The President and Fellows of Harvard College. * Written by David A. Holland. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #include #include #include #include #include "results.h" #define RESULTSFILE "endtimes" static int resultsfile = -1; /* * Create the file that the timing results are written to. * This is done first, in the main process. */ void createresultsfile(void) { int fd; assert(resultsfile == -1); fd = open(RESULTSFILE, O_RDWR|O_CREAT|O_TRUNC, 0664); if (fd < 0) { err(1, "%s", RESULTSFILE); } if (close(fd) == -1) { warn("%s: close", RESULTSFILE); } } /* * Remove the timing results file. * This is done last, in the main process. */ void destroyresultsfile(void) { if (remove(RESULTSFILE) == -1) { if (errno != ENOSYS) { warn("%s: remove", RESULTSFILE); } } } /* * Open the timing results file. This is done separately for writing * in each process to avoid sharing the seek position (which would * then require extra semaphoring to coordinate...) and afterwards * done for reading in the main process. */ void openresultsfile(int openflags) { assert(openflags == O_RDONLY || openflags == O_WRONLY); assert(resultsfile == -1); resultsfile = open(RESULTSFILE, openflags, 0); if (resultsfile < 0) { err(1, "%s", RESULTSFILE); } } /* * Close the timing results file. */ void closeresultsfile(void) { assert(resultsfile >= 0); if (close(resultsfile) == -1) { warn("%s: close", RESULTSFILE); } resultsfile = -1; } /* * Write a result into the timing results file. */ void putresult(unsigned groupid, time_t secs, unsigned long nsecs) { off_t pos; ssize_t r; assert(resultsfile >= 0); pos = groupid * (sizeof(secs) + sizeof(nsecs)); if (lseek(resultsfile, pos, SEEK_SET) == -1) { err(1, "%s: lseek", RESULTSFILE); } r = write(resultsfile, &secs, sizeof(secs)); if (r < 0) { err(1, "%s: write (seconds)", RESULTSFILE); } if ((size_t)r < sizeof(secs)) { errx(1, "%s: write (seconds): Short write", RESULTSFILE); } r = write(resultsfile, &nsecs, sizeof(nsecs)); if (r < 0) { err(1, "%s: write (nsecs)", RESULTSFILE); } if ((size_t)r < sizeof(nsecs)) { errx(1, "%s: write (nsecs): Short write", RESULTSFILE); } } /* * Read a result from the timing results file. */ void getresult(unsigned groupid, time_t *secs, unsigned long *nsecs) { off_t pos; ssize_t r; assert(resultsfile >= 0); pos = groupid * (sizeof(*secs) + sizeof(*nsecs)); if (lseek(resultsfile, pos, SEEK_SET) == -1) { err(1, "%s: lseek", RESULTSFILE); } r = read(resultsfile, secs, sizeof(*secs)); if (r < 0) { err(1, "%s: read (seconds)", RESULTSFILE); } if ((size_t)r < sizeof(*secs)) { errx(1, "%s: read (seconds): Unexpected EOF", RESULTSFILE); } r = read(resultsfile, nsecs, sizeof(*nsecs)); if (r < 0) { err(1, "%s: read (nsecs)", RESULTSFILE); } if ((size_t)r < sizeof(*nsecs)) { errx(1, "%s: read (nsecs): Unexpected EOF", RESULTSFILE); } }