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123 lines
2.9 KiB
C
123 lines
2.9 KiB
C
/*
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* Copyright (c) 2004-2005, 2007, 2010
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* Todd C. Miller <Todd.Miller@courtesan.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <config.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <unistd.h>
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#include <stdio.h>
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#ifdef STDC_HEADERS
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# include <stdlib.h>
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# include <stddef.h>
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#else
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# ifdef HAVE_STDLIB_H
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# include <stdlib.h>
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# endif
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#endif /* STDC_HEADERS */
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#include <fcntl.h>
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#ifdef HAVE_DIRENT_H
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# include <dirent.h>
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# define NAMLEN(dirent) strlen((dirent)->d_name)
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#else
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# define dirent direct
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# define NAMLEN(dirent) (dirent)->d_namlen
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# ifdef HAVE_SYS_NDIR_H
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# include <sys/ndir.h>
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# endif
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# ifdef HAVE_SYS_DIR_H
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# include <sys/dir.h>
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# endif
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# ifdef HAVE_NDIR_H
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# include <ndir.h>
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# endif
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#endif
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#ifndef OPEN_MAX
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# define OPEN_MAX 256
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#endif
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#ifndef HAVE_FCNTL_CLOSEM
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# ifndef HAVE_DIRFD
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# define closefrom_fallback closefrom
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# endif
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#endif
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/*
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* Close all file descriptors greater than or equal to lowfd.
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* This is the expensive (ballback) method.
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*/
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void
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closefrom_fallback(int lowfd)
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{
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long fd, maxfd;
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/*
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* Fall back on sysconf() or getdtablesize(). We avoid checking
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* resource limits since it is possible to open a file descriptor
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* and then drop the rlimit such that it is below the open fd.
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*/
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#ifdef HAVE_SYSCONF
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maxfd = sysconf(_SC_OPEN_MAX);
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#else
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maxfd = getdtablesize();
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#endif /* HAVE_SYSCONF */
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if (maxfd < 0)
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maxfd = OPEN_MAX;
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for (fd = lowfd; fd < maxfd; fd++)
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(void)close((int)fd);
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}
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/*
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* Close all file descriptors greater than or equal to lowfd.
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* We try the fast way first, falling back on the slow method.
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*/
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#ifdef HAVE_FCNTL_CLOSEM
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void
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closefrom(int lowfd)
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{
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if (fcntl(lowfd, F_CLOSEM, 0) == -1)
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closefrom_fallback(lowfd);
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}
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#else
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# ifdef HAVE_DIRFD
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void
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closefrom(int lowfd)
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{
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struct dirent *dent;
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DIR *dirp;
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char *endp;
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long fd;
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/* Use /proc/self/fd directory if it exists. */
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dirp = opendir("/proc/self/fd");
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if (dirp != NULL) {
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while ((dent = readdir(dirp)) != NULL) {
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fd = strtol(dent->d_name, &endp, 10);
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if (dent->d_name != endp && *endp == '\0' &&
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fd >= 0 && fd < INT_MAX && fd >= lowfd &&
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fd != dirfd(dirp))
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(void)close((int)fd);
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}
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(void)closedir(dirp);
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} else
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closefrom_fallback(lowfd);
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}
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#endif /* HAVE_DIRFD */
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#endif /* HAVE_FCNTL_CLOSEM */
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