/* * libcompat - system compatibility library * * Copyright © 1995 Ian Jackson * Copyright © 2008-2012 Guillem Jover * * This is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #include #include #include #include #include #include "compat.h" int vsnprintf(char *buf, size_t maxsize, const char *fmt, va_list args) { static FILE *file = NULL; static pid_t file_pid; size_t want, nr; int total; if (maxsize != 0 && buf == NULL) return -1; /* Avoid race conditions from children after a fork(2). */ if (file_pid > 0 && file_pid != getpid()) { fclose(file); file = NULL; } if (!file) { file = tmpfile(); if (!file) return -1; file_pid = getpid(); } else { if (fseek(file, 0, 0)) return -1; if (ftruncate(fileno(file), 0)) return -1; } total = vfprintf(file, fmt, args); if (total < 0) return -1; if (maxsize == 0) return total; if (total >= (int)maxsize) want = maxsize - 1; else want = total; if (fflush(file)) return -1; if (fseek(file, 0, SEEK_SET)) return -1; nr = fread(buf, 1, want, file); if (nr != want) return -1; buf[want] = '\0'; return total; }