505 lines
12 KiB
C
505 lines
12 KiB
C
/*
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conf.c -- configuration code
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Copyright (C) 1998 Robert van der Meulen
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Copyright (C) 1998,1999,2000 Ivo Timmermans <itimmermans@bigfoot.com>
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2000 Guus Sliepen <guus@sliepen.warande.net>
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2000 Cris van Pelt <tribbel@arise.dhs.org>
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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., 675 Mass Ave, Cambridge, MA 02139, USA.
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$Id: conf.c,v 1.9.4.34 2000/12/06 13:33:48 zarq Exp $
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*/
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#include "config.h"
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#include <assert.h>
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#include <ctype.h>
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#include <errno.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <xalloc.h>
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#include <utils.h> /* for cp */
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#include "conf.h"
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#include "netutl.h" /* for strtoip */
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#include "system.h"
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config_t *config = NULL;
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int debug_lvl = 0;
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int timeout = 0; /* seconds before timeout */
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char *confbase = NULL; /* directory in which all config files are */
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char *netname = NULL; /* name of the vpn network */
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/* Will be set if HUP signal is received. It will be processed when it is safe. */
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int sighup = 0;
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/*
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These are all the possible configurable values
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*/
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static internal_config_t hazahaza[] = {
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/* Main configuration file keywords */
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{ "ConnectTo", config_connectto, TYPE_NAME },
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{ "Hostnames", config_hostnames, TYPE_BOOL },
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{ "Interface", config_interface, TYPE_NAME },
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{ "InterfaceIP", config_interfaceip, TYPE_IP },
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{ "KeyExpire", config_keyexpire, TYPE_INT },
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{ "MyVirtualIP", config_dummy, TYPE_IP },
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{ "MyOwnVPNIP", config_dummy, TYPE_IP },
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{ "Name", config_name, TYPE_NAME },
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{ "PingTimeout", config_pingtimeout, TYPE_INT },
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{ "PrivateKey", config_privatekey, TYPE_NAME },
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{ "TapDevice", config_tapdevice, TYPE_NAME },
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{ "VpnMask", config_dummy, TYPE_IP },
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/* Host configuration file keywords */
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{ "Address", config_address, TYPE_NAME },
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{ "IndirectData", config_indirectdata, TYPE_BOOL },
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{ "Port", config_port, TYPE_INT },
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{ "PublicKey", config_publickey, TYPE_NAME },
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{ "RestrictAddress", config_restrictaddress, TYPE_BOOL },
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{ "RestrictHosts", config_restricthosts, TYPE_BOOL },
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{ "RestrictPort", config_restrictport, TYPE_BOOL },
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{ "RestrictSubnets", config_restrictsubnets, TYPE_BOOL },
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{ "Subnet", config_subnet, TYPE_IP }, /* Use IPv4 subnets only for now */
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{ "TCPonly", config_tcponly, TYPE_BOOL },
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{ NULL, 0, 0 }
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};
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/*
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Add given value to the list of configs cfg
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*/
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config_t *
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add_config_val(config_t **cfg, int argtype, char *val)
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{
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config_t *p;
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char *q;
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cp
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p = (config_t*)xmalloc(sizeof(*p));
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p->data.val = 0;
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switch(argtype)
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{
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case TYPE_INT:
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p->data.val = strtol(val, &q, 0);
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if(q && *q)
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p->data.val = 0;
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break;
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case TYPE_NAME:
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p->data.ptr = xmalloc(strlen(val) + 1);
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strcpy(p->data.ptr, val);
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break;
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case TYPE_IP:
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p->data.ip = strtoip(val);
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break;
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case TYPE_BOOL:
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if(!strcasecmp("yes", val))
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p->data.val = stupid_true;
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else if(!strcasecmp("no", val))
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p->data.val = stupid_false;
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else
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p->data.val = 0;
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}
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p->argtype = argtype;
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if(p->data.val)
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{
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p->next = *cfg;
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*cfg = p;
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cp
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return p;
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}
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else
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{
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free(p);
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cp
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return NULL;
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}
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}
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/*
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Read exactly one line and strip the trailing newline if any. If the
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file was on EOF, return NULL. Otherwise, return all the data in a
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dynamically allocated buffer.
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If line is non-NULL, it will be used as an initial buffer, to avoid
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unnecessary mallocing each time this function is called. If buf is
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given, and buf needs to be expanded, the var pointed to by buflen
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will be increased.
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*/
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char *readline(FILE *fp, char **buf, size_t *buflen)
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{
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char *newline = NULL;
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char *p;
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char *line; /* The array that contains everything that has been read
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so far */
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char *idx; /* Read into this pointer, which points to an offset
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within line */
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size_t size, newsize; /* The size of the current array pointed to by
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line */
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size_t maxlen; /* Maximum number of characters that may be read with
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fgets. This is newsize - oldsize. */
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if(feof(fp))
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return NULL;
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if((buf != NULL) && (buflen != NULL))
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{
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size = *buflen;
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line = *buf;
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}
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else
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{
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size = 100;
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line = xmalloc(size);
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}
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maxlen = size;
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idx = line;
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*idx = 0;
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for(;;)
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{
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errno = 0;
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p = fgets(idx, maxlen, fp);
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if(p == NULL) /* EOF or error */
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{
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if(feof(fp))
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break;
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/* otherwise: error; let the calling function print an error
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message if applicable */
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free(line);
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return NULL;
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}
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newline = strchr(p, '\n');
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if(newline == NULL)
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/* We haven't yet read everything to the end of the line */
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{
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newsize = size << 1;
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line = xrealloc(line, newsize);
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idx = &line[size - 1];
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maxlen = newsize - size + 1;
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size = newsize;
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}
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else
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{
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*newline = '\0'; /* kill newline */
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break; /* yay */
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}
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}
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if((buf != NULL) && (buflen != NULL))
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{
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*buflen = size;
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*buf = line;
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}
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return line;
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}
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/*
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Parse a configuration file and put the results in the configuration tree
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starting at *base.
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*/
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int read_config_file(config_t **base, const char *fname)
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{
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int err = -2; /* Parse error */
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FILE *fp;
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char *buffer, *line;
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char *p, *q;
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int i, lineno = 0;
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config_t *cfg;
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size_t bufsize;
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cp
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if((fp = fopen (fname, "r")) == NULL)
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return -1;
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bufsize = 100;
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buffer = xmalloc(bufsize);
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for(;;)
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{
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if((line = readline(fp, &buffer, &bufsize)) == NULL)
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{
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err = -1;
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break;
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}
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if(feof(fp))
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{
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err = 0;
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break;
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}
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lineno++;
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if((p = strtok(line, "\t =")) == NULL)
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continue; /* no tokens on this line */
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if(p[0] == '#')
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continue; /* comment: ignore */
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for(i = 0; hazahaza[i].name != NULL; i++)
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if(!strcasecmp(hazahaza[i].name, p))
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break;
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if(!hazahaza[i].name)
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{
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syslog(LOG_ERR, _("Invalid variable name `%s' on line %d while reading config file %s"),
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p, lineno, fname);
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break;
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}
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if(((q = strtok(NULL, "\t\n\r =")) == NULL) || q[0] == '#')
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{
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fprintf(stderr, _("No value for variable `%s' on line %d while reading config file %s"),
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hazahaza[i].name, lineno, fname);
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break;
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}
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cfg = add_config_val(base, hazahaza[i].argtype, q);
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if(cfg == NULL)
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{
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fprintf(stderr, _("Invalid value for variable `%s' on line %d while reading config file %s"),
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hazahaza[i].name, lineno, fname);
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break;
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}
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cfg->which = hazahaza[i].which;
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if(!config)
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config = cfg;
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}
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free(buffer);
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fclose (fp);
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cp
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return err;
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}
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int read_server_config()
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{
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char *fname;
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int x;
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cp
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asprintf(&fname, "%s/tinc.conf", confbase);
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x = read_config_file(&config, fname);
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if(x == -1) /* System error */
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{
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fprintf(stderr, _("Failed to read `%s': %m\n"),
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fname);
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}
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free(fname);
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cp
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return x;
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}
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/*
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Look up the value of the config option type
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*/
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const config_t *get_config_val(config_t *p, which_t type)
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{
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cp
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for(; p != NULL; p = p->next)
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if(p->which == type)
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break;
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cp
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return p;
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}
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/*
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Remove the complete configuration tree.
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*/
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void clear_config(config_t **base)
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{
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config_t *p, *next;
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cp
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for(p = *base; p != NULL; p = next)
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{
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next = p->next;
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if(p->data.ptr && (p->argtype == TYPE_NAME))
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{
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free(p->data.ptr);
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}
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free(p);
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}
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*base = NULL;
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cp
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}
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int isadir(const char* f)
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{
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struct stat s;
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if(stat(f, &s) < 0)
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{
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fprintf(stderr, _("Couldn't stat `%s': %m\n"),
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f);
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return -1;
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}
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return S_ISDIR(s.st_mode);
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}
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int is_safe_path(const char *file)
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{
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char *p;
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struct stat s;
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p = strrchr(file, '/');
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assert(p); /* p has to contain a / */
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*p = '\0';
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if(stat(file, &s) < 0)
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{
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fprintf(stderr, _("Couldn't stat `%s': %m\n"),
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file);
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return 0;
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}
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if(s.st_uid != geteuid())
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{
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fprintf(stderr, _("`%s' is owned by UID %d instead of %d.\n"),
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file, s.st_uid, geteuid());
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return 0;
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}
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if(S_ISLNK(s.st_mode))
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{
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fprintf(stderr, _("Warning: `%s' is a symlink\n"),
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file);
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/* fixme: read the symlink and start again */
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}
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*p = '/';
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if(stat(file, &s) < 0 && errno != ENOENT)
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{
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fprintf(stderr, _("Couldn't stat `%s': %m\n"),
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file);
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return 0;
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}
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if(errno == ENOENT)
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return 1;
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if(s.st_uid != geteuid())
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{
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fprintf(stderr, _("`%s' is owned by UID %d instead of %d.\n"),
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file, s.st_uid, geteuid());
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return 0;
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}
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if(S_ISLNK(s.st_mode))
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{
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fprintf(stderr, _("Warning: `%s' is a symlink\n"),
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file);
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/* fixme: read the symlink and start again */
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}
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if(s.st_mode & 0007)
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{
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/* Accessible by others */
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fprintf(stderr, _("`%s' has unsecure permissions.\n"),
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file);
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return 0;
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}
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return 1;
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}
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FILE *ask_and_safe_open(const char* filename, const char* what)
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{
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FILE *r;
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char *directory;
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char *fn;
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int len;
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/* Check stdin and stdout */
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if(!isatty(0) || !isatty(1))
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{
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/* Argh, they are running us from a script or something. Write
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the files to the current directory and let them burn in hell
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for ever. */
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fn = xstrdup(filename);
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}
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else
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{
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/* Ask for a file and/or directory name. */
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fprintf(stdout, _("Please enter a file to save %s to [%s]: "),
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what, filename);
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fflush(stdout); /* Don't wait for a newline */
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if((fn = readline(stdin, NULL, NULL)) == NULL)
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{
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fprintf(stderr, _("Error while reading stdin: %m\n"));
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return NULL;
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}
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if(strlen(fn) == 0)
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/* User just pressed enter. */
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fn = xstrdup(filename);
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}
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if((strchr(fn, '/') == NULL) || (fn[0] != '/'))
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{
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/* The directory is a relative path or a filename. */
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char *p;
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directory = get_current_dir_name();
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len = strlen(fn) + strlen(directory) + 2; /* 1 for the / */
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p = xmalloc(len);
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snprintf(p, len, "%s/%s", directory, fn);
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free(fn);
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free(directory);
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fn = p;
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}
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if(isadir(fn) > 0) /* -1 is error */
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{
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char *p;
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len = strlen(fn) + strlen(filename) + 2; /* 1 for the / */
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p = xmalloc(len);
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snprintf(p, len, "%s/%s", fn, filename);
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free(fn);
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fn = p;
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}
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umask(0077); /* Disallow everything for group and other */
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/* Open it first to keep the inode busy */
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if((r = fopen(fn, "w")) == NULL)
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{
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fprintf(stderr, _("Error opening file `%s': %m\n"),
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fn);
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free(fn);
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return NULL;
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}
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/* Then check the file for nasty attacks */
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if(!is_safe_path(fn)) /* Do not permit any directories that are
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readable or writeable by other users. */
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{
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fprintf(stderr, _("The file `%s' (or any of the leading directories) has unsafe permissions.\n"
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"I will not create or overwrite this file.\n"),
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fn);
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fclose(r);
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free(fn);
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return NULL;
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}
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free(fn);
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return r;
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}
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