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