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Annotation of embedaddon/sudo/compat/closefrom.c, revision 1.1

1.1     ! misho       1: /*
        !             2:  * Copyright (c) 2004-2005, 2007, 2010
        !             3:  *     Todd C. Miller <Todd.Miller@courtesan.com>
        !             4:  *
        !             5:  * Permission to use, copy, modify, and distribute this software for any
        !             6:  * purpose with or without fee is hereby granted, provided that the above
        !             7:  * copyright notice and this permission notice appear in all copies.
        !             8:  *
        !             9:  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
        !            10:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
        !            11:  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
        !            12:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
        !            13:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
        !            14:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
        !            15:  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
        !            16:  */
        !            17: 
        !            18: #include <config.h>
        !            19: 
        !            20: #include <sys/types.h>
        !            21: #include <sys/param.h>
        !            22: #include <unistd.h>
        !            23: #include <stdio.h>
        !            24: #ifdef STDC_HEADERS
        !            25: # include <stdlib.h>
        !            26: # include <stddef.h>
        !            27: #else
        !            28: # ifdef HAVE_STDLIB_H
        !            29: #  include <stdlib.h>
        !            30: # endif
        !            31: #endif /* STDC_HEADERS */
        !            32: #include <fcntl.h>
        !            33: #ifdef HAVE_DIRENT_H
        !            34: # include <dirent.h>
        !            35: # define NAMLEN(dirent) strlen((dirent)->d_name)
        !            36: #else
        !            37: # define dirent direct
        !            38: # define NAMLEN(dirent) (dirent)->d_namlen
        !            39: # ifdef HAVE_SYS_NDIR_H
        !            40: #  include <sys/ndir.h>
        !            41: # endif
        !            42: # ifdef HAVE_SYS_DIR_H
        !            43: #  include <sys/dir.h>
        !            44: # endif
        !            45: # ifdef HAVE_NDIR_H
        !            46: #  include <ndir.h>
        !            47: # endif
        !            48: #endif
        !            49: 
        !            50: #include "missing.h"
        !            51: 
        !            52: #ifndef HAVE_FCNTL_CLOSEM
        !            53: # ifndef HAVE_DIRFD
        !            54: #   define closefrom_fallback  closefrom
        !            55: # endif
        !            56: #endif
        !            57: 
        !            58: /*
        !            59:  * Close all file descriptors greater than or equal to lowfd.
        !            60:  * This is the expensive (ballback) method.
        !            61:  */
        !            62: void
        !            63: closefrom_fallback(int lowfd)
        !            64: {
        !            65:     long fd, maxfd;
        !            66: 
        !            67:     /*
        !            68:      * Fall back on sysconf() or getdtablesize().  We avoid checking
        !            69:      * resource limits since it is possible to open a file descriptor
        !            70:      * and then drop the rlimit such that it is below the open fd.
        !            71:      */
        !            72: #ifdef HAVE_SYSCONF
        !            73:     maxfd = sysconf(_SC_OPEN_MAX);
        !            74: #else
        !            75:     maxfd = getdtablesize();
        !            76: #endif /* HAVE_SYSCONF */
        !            77:     if (maxfd < 0)
        !            78:        maxfd = OPEN_MAX;
        !            79: 
        !            80:     for (fd = lowfd; fd < maxfd; fd++)
        !            81:        (void) close((int) fd);
        !            82: }
        !            83: 
        !            84: /*
        !            85:  * Close all file descriptors greater than or equal to lowfd.
        !            86:  * We try the fast way first, falling back on the slow method.
        !            87:  */
        !            88: #ifdef HAVE_FCNTL_CLOSEM
        !            89: void
        !            90: closefrom(int lowfd)
        !            91: {
        !            92:     if (fcntl(lowfd, F_CLOSEM, 0) == -1)
        !            93:        closefrom_fallback(lowfd);
        !            94: }
        !            95: #else
        !            96: # ifdef HAVE_DIRFD
        !            97: void
        !            98: closefrom(int lowfd)
        !            99: {
        !           100:     struct dirent *dent;
        !           101:     DIR *dirp;
        !           102:     char *endp;
        !           103:     long fd;
        !           104: 
        !           105:     /* Use /proc/self/fd directory if it exists. */
        !           106:     if ((dirp = opendir("/proc/self/fd")) != NULL) {
        !           107:        while ((dent = readdir(dirp)) != NULL) {
        !           108:            fd = strtol(dent->d_name, &endp, 10);
        !           109:            if (dent->d_name != endp && *endp == '\0' &&
        !           110:                fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
        !           111:                (void) close((int) fd);
        !           112:        }
        !           113:        (void) closedir(dirp);
        !           114:     } else
        !           115:        closefrom_fallback(lowfd);
        !           116: }
        !           117: #endif /* HAVE_DIRFD */
        !           118: #endif /* HAVE_FCNTL_CLOSEM */