bsd-closefrom.c revision 157016
1/* 2 * Copyright (c) 2004 Todd C. Miller <Todd.Miller@courtesan.com> 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15 */ 16 17#include "includes.h" 18 19#ifndef HAVE_CLOSEFROM 20 21#include <sys/types.h> 22#include <sys/param.h> 23#include <unistd.h> 24#include <stdio.h> 25#include <limits.h> 26#include <stdlib.h> 27#include <stddef.h> 28#ifdef HAVE_DIRENT_H 29# include <dirent.h> 30# define NAMLEN(dirent) strlen((dirent)->d_name) 31#else 32# define dirent direct 33# define NAMLEN(dirent) (dirent)->d_namlen 34# ifdef HAVE_SYS_NDIR_H 35# include <sys/ndir.h> 36# endif 37# ifdef HAVE_SYS_DIR_H 38# include <sys/dir.h> 39# endif 40# ifdef HAVE_NDIR_H 41# include <ndir.h> 42# endif 43#endif 44 45#ifndef OPEN_MAX 46# define OPEN_MAX 256 47#endif 48 49RCSID("$Id: bsd-closefrom.c,v 1.2 2005/11/10 08:29:13 dtucker Exp $"); 50 51#ifndef lint 52static const char sudorcsid[] = "$Sudo: closefrom.c,v 1.6 2004/06/01 20:51:56 millert Exp $"; 53#endif /* lint */ 54 55/* 56 * Close all file descriptors greater than or equal to lowfd. 57 */ 58void 59closefrom(int lowfd) 60{ 61 long fd, maxfd; 62#if defined(HAVE_DIRFD) && defined(HAVE_PROC_PID) 63 char fdpath[PATH_MAX], *endp; 64 struct dirent *dent; 65 DIR *dirp; 66 int len; 67 68 /* Check for a /proc/$$/fd directory. */ 69 len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid()); 70 if (len >= 0 && (u_int)len <= sizeof(fdpath) && (dirp = opendir(fdpath))) { 71 while ((dent = readdir(dirp)) != NULL) { 72 fd = strtol(dent->d_name, &endp, 10); 73 if (dent->d_name != endp && *endp == '\0' && 74 fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp)) 75 (void) close((int) fd); 76 } 77 (void) closedir(dirp); 78 } else 79#endif 80 { 81 /* 82 * Fall back on sysconf() or getdtablesize(). We avoid checking 83 * resource limits since it is possible to open a file descriptor 84 * and then drop the rlimit such that it is below the open fd. 85 */ 86#ifdef HAVE_SYSCONF 87 maxfd = sysconf(_SC_OPEN_MAX); 88#else 89 maxfd = getdtablesize(); 90#endif /* HAVE_SYSCONF */ 91 if (maxfd < 0) 92 maxfd = OPEN_MAX; 93 94 for (fd = lowfd; fd < maxfd; fd++) 95 (void) close((int) fd); 96 } 97} 98 99#endif /* HAVE_CLOSEFROM */ 100 101