src/backend/tsearch/ts_utils.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * ts_utils.c
   4  *              various support functions
   5  *
   6  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
   7  *
   8  *
   9  * IDENTIFICATION
  10  *        src/backend/tsearch/ts_utils.c
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14
  15 #include "postgres.h"
  16
  17 #include <ctype.h>
  18
  19 #include "miscadmin.h"
  20 #include "tsearch/ts_locale.h"
  21 #include "tsearch/ts_public.h"
  22
  23
  24 /*
  25  * Given the base name and extension of a tsearch config file, return
  26  * its full path name.  The base name is assumed to be user-supplied,
  27  * and is checked to prevent pathname attacks.  The extension is assumed
  28  * to be safe.
  29  *
  30  * The result is a palloc'd string.
  31  */
  32 char *
  33 get_tsearch_config_filename(const char *basename,
  34                                                         const char *extension)
  35 {
  36         char            sharepath[MAXPGPATH];
  37         char       *result;
  38
  39         /*
  40          * We limit the basename to contain a-z, 0-9, and underscores.  This may
  41          * be overly restrictive, but we don't want to allow access to anything
  42          * outside the tsearch_data directory, so for instance '/' *must* be
  43          * rejected, and on some platforms '\' and ':' are risky as well. Allowing
  44          * uppercase might result in incompatible behavior between case-sensitive
  45          * and case-insensitive filesystems, and non-ASCII characters create other
  46          * interesting risks, so on the whole a tight policy seems best.
  47          */
  48         if (strspn(basename, "abcdefghijklmnopqrstuvwxyz0123456789_") != strlen(basename))
  49                 ereport(ERROR,
  50                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
  51                                  errmsg("invalid text search configuration file name \"%s\"",
  52                                                 basename)));
  53
  54         get_share_path(my_exec_path, sharepath);
  55         result = palloc(MAXPGPATH);
  56         snprintf(result, MAXPGPATH, "%s/tsearch_data/%s.%s",
  57                          sharepath, basename, extension);
  58
  59         return result;
  60 }
  61
  62 /*
  63  * Reads a stop-word file. Each word is run through 'wordop'
  64  * function, if given.  wordop may either modify the input in-place,
  65  * or palloc a new version.
  66  */
  67 void
  68 readstoplist(const char *fname, StopList *s, char *(*wordop) (const char *))
  69 {
  70         char      **stop = NULL;
  71
  72         s->len = 0;
  73         if (fname && *fname)
  74         {
  75                 char       *filename = get_tsearch_config_filename(fname, "stop");
  76                 tsearch_readline_state trst;
  77                 char       *line;
  78                 int                     reallen = 0;
  79
  80                 if (!tsearch_readline_begin(&trst, filename))
  81                         ereport(ERROR,
  82                                         (errcode(ERRCODE_CONFIG_FILE_ERROR),
  83                                          errmsg("could not open stop-word file \"%s\": %m",
  84                                                         filename)));
  85
  86                 while ((line = tsearch_readline(&trst)) != NULL)
  87                 {
  88                         char       *pbuf = line;
  89
  90                         /* Trim trailing space */
  91                         while (*pbuf && !t_isspace(pbuf))
  92                                 pbuf += pg_mblen(pbuf);
  93                         *pbuf = '\0';
  94
  95                         /* Skip empty lines */
  96                         if (*line == '\0')
  97                         {
  98                                 pfree(line);
  99                                 continue;
 100                         }
 101
 102                         if (s->len >= reallen)
 103                         {
 104                                 if (reallen == 0)
 105                                 {
 106                                         reallen = 64;
 107                                         stop = (char **) palloc(sizeof(char *) * reallen);
 108                                 }
 109                                 else
 110                                 {
 111                                         reallen *= 2;
 112                                         stop = (char **) repalloc(stop, sizeof(char *) * reallen);
 113                                 }
 114                         }
 115
 116                         if (wordop)
 117                         {
 118                                 stop[s->len] = wordop(line);
 119                                 if (stop[s->len] != line)
 120                                         pfree(line);
 121                         }
 122                         else
 123                                 stop[s->len] = line;
 124
 125                         (s->len)++;
 126                 }
 127
 128                 tsearch_readline_end(&trst);
 129                 pfree(filename);
 130         }
 131
 132         s->stop = stop;
 133
 134         /* Sort to allow binary searching */
 135         if (s->stop && s->len > 0)
 136                 qsort(s->stop, s->len, sizeof(char *), pg_qsort_strcmp);
 137 }
 138
 139 bool
 140 searchstoplist(StopList *s, char *key)
 141 {
 142         return (s->stop && s->len > 0 &&
 143                         bsearch(&key, s->stop, s->len,
 144                                         sizeof(char *), pg_qsort_strcmp));
 145 }