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pcg |
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/* |
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dropin.c -- a set of drop-in replacements for libc functions |
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Copyright (C) 2000,2001 Ivo Timmermans <ivo@o2w.nl>, |
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2000,2001 Guus Sliepen <guus@sliepen.eu.org> |
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2003 Marc Lehmann <pcg@goof.com> |
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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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/stat.h> |
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#include <fcntl.h> |
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#include <unistd.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <stdarg.h> |
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#include <errno.h> |
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#ifndef HAVE_DAEMON |
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/* |
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Replacement for the daemon() function. |
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The daemon() function is for programs wishing to detach themselves |
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from the controlling terminal and run in the background as system |
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daemons. |
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Unless the argument nochdir is non-zero, daemon() changes the |
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current working directory to the root (``/''). |
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Unless the argument noclose is non-zero, daemon() will redirect |
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standard input, standard output and standard error to /dev/null. |
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*/ |
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int daemon(int nochdir, int noclose) |
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{ |
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pid_t pid; |
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int fd; |
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pid = fork(); |
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/* Check if forking failed */ |
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if(pid < 0) { |
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perror("fork"); |
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exit(-1); |
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} |
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/* If we are the parent, terminate */ |
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if(pid) |
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exit(0); |
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/* Detach by becoming the new process group leader */ |
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if(setsid() < 0) { |
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perror("setsid"); |
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return -1; |
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} |
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/* Change working directory to the root (to avoid keeping mount |
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points busy) */ |
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if(!nochdir) { |
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chdir("/"); |
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} |
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/* Redirect stdin/out/err to /dev/null */ |
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if(!noclose) { |
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fd = open("/dev/null", O_RDWR); |
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if(fd < 0) { |
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perror("opening /dev/null"); |
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return -1; |
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} else { |
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dup2(fd, 0); |
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dup2(fd, 1); |
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dup2(fd, 2); |
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} |
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} |
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return 0; |
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} |
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#endif |
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#ifndef HAVE_GET_CURRENT_DIR_NAME |
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/* |
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Replacement for the GNU get_current_dir_name function: |
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get_current_dir_name will malloc(3) an array big enough to hold the |
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current directory name. If the environment variable PWD is set, and |
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its value is correct, then that value will be returned. |
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*/ |
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char *get_current_dir_name(void) |
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{ |
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size_t size; |
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char *buf; |
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char *r; |
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/* Start with 100 bytes. If this turns out to be insufficient to |
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contain the working directory, double the size. */ |
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size = 100; |
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buf = malloc(size); |
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errno = 0; /* Success */ |
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r = getcwd(buf, size); |
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/* getcwd returns NULL and sets errno to ERANGE if the bufferspace |
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is insufficient to contain the entire working directory. */ |
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while(r == NULL && errno == ERANGE) { |
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free(buf); |
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size <<= 1; /* double the size */ |
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buf = malloc(size); |
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r = getcwd(buf, size); |
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} |
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return buf; |
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} |
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#endif |
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#ifndef HAVE_ASPRINTF |
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int asprintf(char **buf, const char *fmt, ...) |
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{ |
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int status; |
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va_list ap; |
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int len; |
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len = 4096; |
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*buf = malloc(len); |
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va_start(ap, fmt); |
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status = vsnprintf(*buf, len, fmt, ap); |
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va_end(ap); |
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if(status >= 0) |
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*buf = realloc(*buf, status); |
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if(status > len - 1) { |
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len = status; |
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va_start(ap, fmt); |
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status = vsnprintf(*buf, len, fmt, ap); |
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va_end(ap); |
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} |
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return status; |
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} |
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#endif |
