81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
/*
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* libcompat - system compatibility library
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*
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* Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
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* Copyright © 2008-2012 Guillem Jover <guillem@debian.org>
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*
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* This is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include "compat.h"
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int
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vsnprintf(char *buf, size_t maxsize, const char *fmt, va_list args)
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{
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static FILE *file = NULL;
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static pid_t file_pid;
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size_t want, nr;
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int total;
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if (maxsize != 0 && buf == NULL)
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return -1;
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/* Avoid race conditions from children after a fork(2). */
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if (file_pid > 0 && file_pid != getpid()) {
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fclose(file);
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file = NULL;
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}
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if (!file) {
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file = tmpfile();
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if (!file)
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return -1;
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file_pid = getpid();
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} else {
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if (fseek(file, 0, 0))
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return -1;
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if (ftruncate(fileno(file), 0))
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return -1;
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}
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total = vfprintf(file, fmt, args);
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if (total < 0)
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return -1;
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if (maxsize == 0)
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return total;
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if (total >= (int)maxsize)
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want = maxsize - 1;
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else
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want = total;
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if (fflush(file))
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return -1;
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if (fseek(file, 0, SEEK_SET))
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return -1;
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nr = fread(buf, 1, want, file);
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if (nr != want)
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return -1;
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buf[want] = '\0';
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return total;
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}
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