lib/parse_ini.c

   1 /*****************************************************************************
   2 *
   3 * Nagios-plugins parse_ini library
   4 *
   5 * License: GPL
   6 * Copyright (c) 2007 Nagios Plugins Development Team
   7 *
   8 * Last Modified: $Date$
   9 *
  10 *
  11 * This program is free software: you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License as published by
  13 * the Free Software Foundation, either version 3 of the License, or
  14 * (at your option) any later version.
  15 *
  16 * This program is distributed in the hope that it will be useful,
  17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 * GNU General Public License for more details.
  20 *
  21 * You should have received a copy of the GNU General Public License
  22 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23 *
  24 * $Id$
  25 *
  26 *****************************************************************************/
  27
  28 #include "common.h"
  29 #include "utils_base.h"
  30 #include "parse_ini.h"
  31 #include <ctype.h>
  32
  33 #include <sys/types.h>
  34 #include <sys/stat.h>
  35 #include <unistd.h>
  36
  37 /* TODO: die like N::P if config file is not found */
  38
  39 /* np_ini_info contains the result of parsing a "locator" in the format
  40  * [stanza_name][@config_filename] (check_foo@/etc/foo.ini, for example)
  41  */
  42 typedef struct {
  43         char *file;
  44         char *stanza;
  45 } np_ini_info;
  46
  47 /* eat all characters from a FILE pointer until n is encountered */
  48 #define GOBBLE_TO(f, c, n) do { (c)=fgetc((f)); } while((c)!=EOF && (c)!=(n))
  49
  50 /* internal function that returns the constructed defaults options */
  51 static int read_defaults(FILE *f, const char *stanza, np_arg_list **opts);
  52 /* internal function that converts a single line into options format */
  53 static int add_option(FILE *f, np_arg_list **optlst);
  54 /* internal function to find default file */
  55 static char* default_file(void);
  56 /* internal function to stat() files */
  57 static int test_file(const char* env, int len, const char* file, char* temp_file);
  58
  59 /* parse_locator decomposes a string of the form
  60  *      [stanza][@filename]
  61  * into its seperate parts
  62  */
  63 static void parse_locator(const char *locator, const char *def_stanza, np_ini_info *i){
  64         size_t locator_len=0, stanza_len=0;
  65
  66         /* if locator is NULL we'll use default values */
  67         if(locator){
  68                 locator_len=strlen(locator);
  69                 stanza_len=strcspn(locator, "@");
  70         }
  71         /* if a non-default stanza is provided */
  72         if(stanza_len>0){
  73                 i->stanza=(char*)malloc(sizeof(char)*(stanza_len+1));
  74                 strncpy(i->stanza, locator, stanza_len);
  75                 i->stanza[stanza_len]='\0';
  76         } else { /* otherwise we use the default stanza */
  77                 i->stanza=strdup(def_stanza);
  78         }
  79         /* if there is no @file part */
  80         if(stanza_len==locator_len){
  81                 i->file=default_file();
  82         } else {
  83                 i->file=strdup(&(locator[stanza_len+1]));
  84         }
  85
  86         if(i->file==NULL || i->stanza==NULL){
  87                 die(STATE_UNKNOWN, _("malloc() failed!\n"));
  88         }
  89 }
  90
  91 /* this is the externally visible function used by extra_opts */
  92 np_arg_list* np_get_defaults(const char *locator, const char *default_section){
  93         FILE *inifile=NULL;
  94         np_arg_list *defaults=NULL;
  95         np_ini_info i;
  96
  97         parse_locator(locator, default_section, &i);
  98         /* if a file was specified or if we're using the default file */
  99         if(i.file != NULL && strlen(i.file) > 0){
 100                 if(strcmp(i.file, "-")==0){
 101                         inifile=stdin;
 102                 } else {
 103                         inifile=fopen(i.file, "r");
 104                 }
 105                 if(inifile==NULL) die(STATE_UNKNOWN, _("Can't read config file"));
 106                 if(read_defaults(inifile, i.stanza, &defaults)==FALSE)
 107                         die(STATE_UNKNOWN, _("Invalid section '%s' in config file '%s'\n"), i.stanza, i.file);
 108
 109                 free(i.file);
 110                 if(inifile!=stdin) fclose(inifile);
 111         }
 112         free(i.stanza);
 113         return defaults;
 114 }
 115
 116 /* read_defaults is where the meat of the parsing takes place.
 117  *
 118  * note that this may be called by a setuid binary, so we need to
 119  * be extra careful about user-supplied input (i.e. avoiding possible
 120  * format string vulnerabilities, etc)
 121  */
 122 static int read_defaults(FILE *f, const char *stanza, np_arg_list **opts){
 123         int c, status=FALSE;
 124         size_t i, stanza_len;
 125         enum { NOSTANZA, WRONGSTANZA, RIGHTSTANZA } stanzastate=NOSTANZA;
 126
 127         stanza_len=strlen(stanza);
 128
 129         /* our little stanza-parsing state machine.  */
 130         while((c=fgetc(f))!=EOF){
 131                 /* gobble up leading whitespace */
 132                 if(isspace(c)) continue;
 133                 switch(c){
 134                         /* globble up coment lines */
 135                         case '#':
 136                                 GOBBLE_TO(f, c, '\n');
 137                                 break;
 138                         /* start of a stanza.  check to see if it matches */
 139                         case '[':
 140                                 stanzastate=WRONGSTANZA;
 141                                 for(i=0; i<stanza_len; i++){
 142                                         c=fgetc(f);
 143                                         /* Strip leading whitespace */
 144                                         if(i==0) for(c; isspace(c); c=fgetc(f));
 145                                         /* nope, read to the end of the line */
 146                                         if(c!=stanza[i]) {
 147                                                 GOBBLE_TO(f, c, '\n');
 148                                                 break;
 149                                         }
 150                                 }
 151                                 /* if it matched up to here and the next char is ']'... */
 152                                 if(i==stanza_len){
 153                                         c=fgetc(f);
 154                                         /* Strip trailing whitespace */
 155                                         for(c; isspace(c); c=fgetc(f));
 156                                         if(c==']') stanzastate=RIGHTSTANZA;
 157                                 }
 158                                 break;
 159                         /* otherwise, we're in the body of a stanza or a parse error */
 160                         default:
 161                                 switch(stanzastate){
 162                                         /* we never found the start of the first stanza, so
 163                                          * we're dealing with a config error
 164                                          */
 165                                         case NOSTANZA:
 166                                                 die(STATE_UNKNOWN, _("Config file error"));
 167                                                 break;
 168                                         /* we're in a stanza, but for a different plugin */
 169                                         case WRONGSTANZA:
 170                                                 GOBBLE_TO(f, c, '\n');
 171                                                 break;
 172                                         /* okay, this is where we start taking the config */
 173                                         case RIGHTSTANZA:
 174                                                 ungetc(c, f);
 175                                                 if(add_option(f, opts)){
 176                                                         die(STATE_UNKNOWN, _("Config file error"));
 177                                                 }
 178                                                 status=TRUE;
 179                                                 break;
 180                                 }
 181                                 break;
 182                 }
 183         }
 184         return status;
 185 }
 186
 187 /*
 188  * read one line of input in the format
 189  *      ^option[[:space:]]*(=[[:space:]]*value)?
 190  * and creates it as a cmdline argument
 191  *      --option[=value]
 192  * appending it to the linked list optbuf.
 193  */
 194 static int add_option(FILE *f, np_arg_list **optlst){
 195         np_arg_list *opttmp=*optlst, *optnew;
 196         char *linebuf=NULL, *lineend=NULL, *optptr=NULL, *optend=NULL;
 197         char *eqptr=NULL, *valptr=NULL, *spaceptr=NULL, *valend=NULL;
 198         short done_reading=0, equals=0, value=0;
 199         size_t cfg_len=0, read_sz=8, linebuf_sz=0, read_pos=0;
 200         size_t opt_len=0, val_len=0;
 201
 202         /* read one line from the file */
 203         while(!done_reading){
 204                 /* grow if necessary */
 205                 if(linebuf==NULL || read_pos+read_sz >= linebuf_sz){
 206                         linebuf_sz=(linebuf_sz>0)?linebuf_sz<<1:read_sz;
 207                         linebuf=realloc(linebuf, linebuf_sz);
 208                         if(linebuf==NULL) die(STATE_UNKNOWN, _("malloc() failed!\n"));
 209                 }
 210                 if(fgets(&linebuf[read_pos], read_sz, f)==NULL) done_reading=1;
 211                 else {
 212                         read_pos=strlen(linebuf);
 213                         if(linebuf[read_pos-1]=='\n') {
 214                                 linebuf[--read_pos]='\0';
 215                                 done_reading=1;
 216                         }
 217                 }
 218         }
 219         lineend=&linebuf[read_pos];
 220         /* all that to read one line.  isn't C fun? :) now comes the parsing :/ */
 221
 222         /* skip leading whitespace */
 223         for(optptr=linebuf; optptr<lineend && isspace(*optptr); optptr++);
 224         /* continue to '=' or EOL, watching for spaces that might precede it */
 225         for(eqptr=optptr; eqptr<lineend && *eqptr!='='; eqptr++){
 226                 if(isspace(*eqptr) && optend==NULL) optend=eqptr;
 227                 else optend=NULL;
 228         }
 229         if(optend==NULL) optend=eqptr;
 230         --optend;
 231         /* ^[[:space:]]*=foo is a syntax error */
 232         if(optptr==eqptr) die(STATE_UNKNOWN, _("Config file error\n"));
 233         /* continue from '=' to start of value or EOL */
 234         for(valptr=eqptr+1; valptr<lineend && isspace(*valptr); valptr++);
 235         /* continue to the end of value (FIXME: watching for trailing comments) */
 236         for(valend=valptr; valend<lineend; valend++)
 237                 /* FIXME: N::P doesn't allow comments here. Remove next line and parse_ini won't either */
 238                 if(*valend=='#') break;
 239         --valend;
 240         /* Finally trim off trailing spaces */
 241         for(valend; isspace(*valend); valend--);
 242         /* calculate the length of "--foo" */
 243         opt_len=1+optend-optptr;
 244         /* 1-character params needs only one dash */
 245         if(opt_len==1)
 246                 cfg_len=1+(opt_len);
 247         else
 248                 cfg_len=2+(opt_len);
 249         /* if valptr<lineend then we have to also allocate space for "=bar" */
 250         if(valptr<lineend) {
 251                 equals=value=1;
 252                 val_len=1+valend-valptr;
 253                 cfg_len+=1+val_len;
 254         }
 255         /* if valptr==valend then we have "=" but no "bar" */
 256         else if(valptr==lineend) {
 257                 equals=1;
 258                 cfg_len+=1;
 259         }
 260         /* A line with no equal sign isn't valid */
 261         if(equals==0) die(STATE_UNKNOWN, _("Config file error\n"));
 262
 263         /* okay, now we have all the info we need, so we create a new np_arg_list
 264          * element and set the argument...
 265          */
 266         optnew=(np_arg_list *)malloc(sizeof(np_arg_list));
 267         optnew->next=NULL;
 268
 269         read_pos=0;
 270         optnew->arg=(char *)malloc(cfg_len+1);
 271         /* 1-character params needs only one dash */
 272         if(opt_len==1) {
 273                 strncpy(&optnew->arg[read_pos], "-", 1);
 274                 read_pos+=1;
 275         } else {
 276                 strncpy(&optnew->arg[read_pos], "--", 2);
 277                 read_pos+=2;
 278         }
 279         strncpy(&optnew->arg[read_pos], optptr, opt_len); read_pos+=opt_len;
 280         if(value) {
 281                 optnew->arg[read_pos++]='=';
 282                 strncpy(&optnew->arg[read_pos], valptr, val_len); read_pos+=val_len;
 283         }
 284         optnew->arg[read_pos]='\0';
 285
 286         /* ...and put that to the end of the list */
 287         if(*optlst==NULL) {
 288                 *optlst=optnew;
 289         }       else {
 290                 while(opttmp->next!=NULL) {
 291                         opttmp=opttmp->next;
 292                 }
 293                 opttmp->next = optnew;
 294         }
 295
 296         free(linebuf);
 297         return 0;
 298 }
 299
 300 static char* default_file(void){
 301         struct stat sb;
 302         char *np_env=NULL, *default_file=NULL;
 303         char temp_file[MAX_INPUT_BUFFER];
 304         size_t len;
 305
 306         if((np_env=getenv("NAGIOS_CONFIG_PATH"))!=NULL) {
 307                 /* skip any starting colon... */
 308                 while(*np_env==':') np_env++;
 309                 /* Look for NP_DEFAULT_INI_FILENAME1 and NP_DEFAULT_INI_FILENAME2 in
 310                  * every PATHs defined (colon-separated).
 311                  */
 312                 while((len=strcspn(np_env,":"))>0){
 313                         /* Test NP_DEFAULT_INI_FILENAME[1-2] in current np_env token */
 314                         if(test_file(np_env,len,NP_DEFAULT_INI_FILENAME1,temp_file)==1 ||
 315                            test_file(np_env,len,NP_DEFAULT_INI_FILENAME2,temp_file)==1){
 316                                 default_file=strdup(temp_file);
 317                                 break;
 318                         }
 319
 320                         /* Move on to the next token */
 321                         np_env+=len;
 322                         while(*np_env==':') np_env++;
 323                 } /* while(...) */
 324         } /* if(getenv("NAGIOS_CONFIG_PATH")) */
 325
 326         /* Look for NP_DEFAULT_INI_FILENAME1 in NP_DEFAULT_INI_NAGIOS_PATH[1-4] */
 327         if(!default_file){
 328                 if(test_file(NP_DEFAULT_INI_NAGIOS_PATH1,strlen(NP_DEFAULT_INI_NAGIOS_PATH1),NP_DEFAULT_INI_FILENAME1,temp_file)==1 ||
 329                    test_file(NP_DEFAULT_INI_NAGIOS_PATH2,strlen(NP_DEFAULT_INI_NAGIOS_PATH2),NP_DEFAULT_INI_FILENAME1,temp_file)==1 ||
 330                    test_file(NP_DEFAULT_INI_NAGIOS_PATH3,strlen(NP_DEFAULT_INI_NAGIOS_PATH3),NP_DEFAULT_INI_FILENAME1,temp_file)==1 ||
 331                    test_file(NP_DEFAULT_INI_NAGIOS_PATH4,strlen(NP_DEFAULT_INI_NAGIOS_PATH4),NP_DEFAULT_INI_FILENAME1,temp_file)==1)
 332                         default_file=strdup(temp_file);
 333         }
 334
 335         /* Look for NP_DEFAULT_INI_FILENAME2 in NP_DEFAULT_INI_PATH[1-3] */
 336         if(!default_file){
 337                 if(test_file(NP_DEFAULT_INI_PATH1,strlen(NP_DEFAULT_INI_PATH1),NP_DEFAULT_INI_FILENAME2,temp_file)==1 ||
 338                    test_file(NP_DEFAULT_INI_PATH2,strlen(NP_DEFAULT_INI_PATH2),NP_DEFAULT_INI_FILENAME2,temp_file)==1 ||
 339                    test_file(NP_DEFAULT_INI_PATH3,strlen(NP_DEFAULT_INI_PATH3),NP_DEFAULT_INI_FILENAME2,temp_file)==1)
 340                         default_file=strdup(temp_file);
 341         }
 342
 343         /* Return default_file or empty string (should return NULL if we want plugins
 344          * to die there)...
 345          */
 346         if(default_file)
 347                 return default_file;
 348         return "";
 349 }
 350
 351 /* put together len bytes from env and the filename and test for its
 352  * existence. Returns 1 if found, 0 if not and -1 if test wasn't performed.
 353  */
 354 static int test_file(const char* env, int len, const char* file, char* temp_file){
 355         struct stat sb;
 356
 357         /* test if len + filelen + '/' + '\0' fits in temp_file */
 358         if((len+strlen(file)+2)>MAX_INPUT_BUFFER)       return -1;
 359
 360         strncpy(temp_file,env,len);
 361         temp_file[len]='\0';
 362         strncat(temp_file,"/",len+1);
 363         strncat(temp_file,file,len+strlen(file)+1);
 364
 365         if(stat(temp_file, &sb) != -1) return 1;
 366         return 0;
 367 }
 368