105436638acc7c010349a69c3395f1a57c642dc62Ying Wang/* closexec.c - set or clear the close-on-exec descriptor flag 205436638acc7c010349a69c3395f1a57c642dc62Ying Wang 305436638acc7c010349a69c3395f1a57c642dc62Ying Wang Copyright (C) 1991, 2004-2006, 2009-2012 Free Software Foundation, Inc. 405436638acc7c010349a69c3395f1a57c642dc62Ying Wang 505436638acc7c010349a69c3395f1a57c642dc62Ying Wang This program is free software: you can redistribute it and/or modify 605436638acc7c010349a69c3395f1a57c642dc62Ying Wang it under the terms of the GNU General Public License as published by 705436638acc7c010349a69c3395f1a57c642dc62Ying Wang the Free Software Foundation; either version 3 of the License, or 805436638acc7c010349a69c3395f1a57c642dc62Ying Wang (at your option) any later version. 905436638acc7c010349a69c3395f1a57c642dc62Ying Wang 1005436638acc7c010349a69c3395f1a57c642dc62Ying Wang This program is distributed in the hope that it will be useful, 1105436638acc7c010349a69c3395f1a57c642dc62Ying Wang but WITHOUT ANY WARRANTY; without even the implied warranty of 1205436638acc7c010349a69c3395f1a57c642dc62Ying Wang MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 1305436638acc7c010349a69c3395f1a57c642dc62Ying Wang GNU General Public License for more details. 1405436638acc7c010349a69c3395f1a57c642dc62Ying Wang 1505436638acc7c010349a69c3395f1a57c642dc62Ying Wang You should have received a copy of the GNU General Public License 1605436638acc7c010349a69c3395f1a57c642dc62Ying Wang along with this program. If not, see <http://www.gnu.org/licenses/>. 1705436638acc7c010349a69c3395f1a57c642dc62Ying Wang 1805436638acc7c010349a69c3395f1a57c642dc62Ying Wang The code is taken from glibc/manual/llio.texi */ 1905436638acc7c010349a69c3395f1a57c642dc62Ying Wang 2005436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include <config.h> 2105436638acc7c010349a69c3395f1a57c642dc62Ying Wang 2205436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include "cloexec.h" 2305436638acc7c010349a69c3395f1a57c642dc62Ying Wang 2405436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include <errno.h> 2505436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include <fcntl.h> 2605436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include <unistd.h> 2705436638acc7c010349a69c3395f1a57c642dc62Ying Wang 2805436638acc7c010349a69c3395f1a57c642dc62Ying Wang/* Set the 'FD_CLOEXEC' flag of DESC if VALUE is true, 2905436638acc7c010349a69c3395f1a57c642dc62Ying Wang or clear the flag if VALUE is false. 3005436638acc7c010349a69c3395f1a57c642dc62Ying Wang Return 0 on success, or -1 on error with 'errno' set. 3105436638acc7c010349a69c3395f1a57c642dc62Ying Wang 3205436638acc7c010349a69c3395f1a57c642dc62Ying Wang Note that on MingW, this function does NOT protect DESC from being 3305436638acc7c010349a69c3395f1a57c642dc62Ying Wang inherited into spawned children. Instead, either use dup_cloexec 3405436638acc7c010349a69c3395f1a57c642dc62Ying Wang followed by closing the original DESC, or use interfaces such as 3505436638acc7c010349a69c3395f1a57c642dc62Ying Wang open or pipe2 that accept flags like O_CLOEXEC to create DESC 3605436638acc7c010349a69c3395f1a57c642dc62Ying Wang non-inheritable in the first place. */ 3705436638acc7c010349a69c3395f1a57c642dc62Ying Wang 3805436638acc7c010349a69c3395f1a57c642dc62Ying Wangint 3905436638acc7c010349a69c3395f1a57c642dc62Ying Wangset_cloexec_flag (int desc, bool value) 4005436638acc7c010349a69c3395f1a57c642dc62Ying Wang{ 4105436638acc7c010349a69c3395f1a57c642dc62Ying Wang#ifdef F_SETFD 4205436638acc7c010349a69c3395f1a57c642dc62Ying Wang 4305436638acc7c010349a69c3395f1a57c642dc62Ying Wang int flags = fcntl (desc, F_GETFD, 0); 4405436638acc7c010349a69c3395f1a57c642dc62Ying Wang 4505436638acc7c010349a69c3395f1a57c642dc62Ying Wang if (0 <= flags) 4605436638acc7c010349a69c3395f1a57c642dc62Ying Wang { 4705436638acc7c010349a69c3395f1a57c642dc62Ying Wang int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC); 4805436638acc7c010349a69c3395f1a57c642dc62Ying Wang 4905436638acc7c010349a69c3395f1a57c642dc62Ying Wang if (flags == newflags 5005436638acc7c010349a69c3395f1a57c642dc62Ying Wang || fcntl (desc, F_SETFD, newflags) != -1) 5105436638acc7c010349a69c3395f1a57c642dc62Ying Wang return 0; 5205436638acc7c010349a69c3395f1a57c642dc62Ying Wang } 5305436638acc7c010349a69c3395f1a57c642dc62Ying Wang 5405436638acc7c010349a69c3395f1a57c642dc62Ying Wang return -1; 5505436638acc7c010349a69c3395f1a57c642dc62Ying Wang 5605436638acc7c010349a69c3395f1a57c642dc62Ying Wang#else /* !F_SETFD */ 5705436638acc7c010349a69c3395f1a57c642dc62Ying Wang 5805436638acc7c010349a69c3395f1a57c642dc62Ying Wang /* Use dup2 to reject invalid file descriptors; the cloexec flag 5905436638acc7c010349a69c3395f1a57c642dc62Ying Wang will be unaffected. */ 6005436638acc7c010349a69c3395f1a57c642dc62Ying Wang if (desc < 0) 6105436638acc7c010349a69c3395f1a57c642dc62Ying Wang { 6205436638acc7c010349a69c3395f1a57c642dc62Ying Wang errno = EBADF; 6305436638acc7c010349a69c3395f1a57c642dc62Ying Wang return -1; 6405436638acc7c010349a69c3395f1a57c642dc62Ying Wang } 6505436638acc7c010349a69c3395f1a57c642dc62Ying Wang if (dup2 (desc, desc) < 0) 6605436638acc7c010349a69c3395f1a57c642dc62Ying Wang /* errno is EBADF here. */ 6705436638acc7c010349a69c3395f1a57c642dc62Ying Wang return -1; 6805436638acc7c010349a69c3395f1a57c642dc62Ying Wang 6905436638acc7c010349a69c3395f1a57c642dc62Ying Wang /* There is nothing we can do on this kind of platform. Punt. */ 7005436638acc7c010349a69c3395f1a57c642dc62Ying Wang return 0; 7105436638acc7c010349a69c3395f1a57c642dc62Ying Wang#endif /* !F_SETFD */ 7205436638acc7c010349a69c3395f1a57c642dc62Ying Wang} 7305436638acc7c010349a69c3395f1a57c642dc62Ying Wang 7405436638acc7c010349a69c3395f1a57c642dc62Ying Wang 7505436638acc7c010349a69c3395f1a57c642dc62Ying Wang/* Duplicates a file handle FD, while marking the copy to be closed 7605436638acc7c010349a69c3395f1a57c642dc62Ying Wang prior to exec or spawn. Returns -1 and sets errno if FD could not 7705436638acc7c010349a69c3395f1a57c642dc62Ying Wang be duplicated. */ 7805436638acc7c010349a69c3395f1a57c642dc62Ying Wang 7905436638acc7c010349a69c3395f1a57c642dc62Ying Wangint 8005436638acc7c010349a69c3395f1a57c642dc62Ying Wangdup_cloexec (int fd) 8105436638acc7c010349a69c3395f1a57c642dc62Ying Wang{ 8205436638acc7c010349a69c3395f1a57c642dc62Ying Wang return fcntl (fd, F_DUPFD_CLOEXEC, 0); 8305436638acc7c010349a69c3395f1a57c642dc62Ying Wang} 84