nss/nss_files/files-parse.c

   1 /* Common code for file-based database parsers in nss_files module.
   2 Copyright (C) 1996 Free Software Foundation, Inc.
   3 This file is part of the GNU C Library.
   4
   5 The GNU C Library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 The GNU C Library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #include <ctype.h>
  21 #include <errno.h>
  22 #include <string.h>
  23 #include <stdlib.h>
  24
  25 /* These symbols are defined by the including source file:
  26
  27    ENTNAME -- database name of the structure and functions (hostent, pwent).
  28    STRUCTURE -- struct name, define only if not ENTNAME (passwd, group).
  29    DATABASE -- string of the database file's name ("hosts", "passwd").
  30
  31    ENTDATA -- if defined, `struct ENTDATA' is used by the parser to store
  32               things pointed to by the resultant `struct STRUCTURE'.
  33
  34    NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
  35
  36    Also see files-XXX.c.  */
  37
  38 #define CONCAT(a,b) CONCAT1(a,b)
  39 #define CONCAT1(a,b) a##b
  40
  41 #ifndef STRUCTURE
  42 #define STRUCTURE ENTNAME
  43 #endif
  44
  45
  46 struct parser_data
  47   {
  48 #ifdef ENTDATA
  49     struct ENTDATA entdata;
  50 #define ENTDATA_DECL(data) struct ENTDATA *const entdata = &data->entdata;
  51 #else
  52 #define ENTDATA_DECL(data)
  53 #endif
  54     char linebuffer[0];
  55   };
  56
  57 #ifdef ENTDATA
  58 /* The function can't be exported, because the entdata structure
  59    is defined only in files-foo.c.  */
  60 #define parser_stclass static inline
  61 #else
  62 /* Export the line parser function so it can be used in nss_db.  */
  63 #define parser_stclass /* Global */
  64 #define parse_line CONCAT(_nss_files_parse_,ENTNAME)
  65 #endif
  66
  67
  68 #ifdef EXTERN_PARSER
  69
  70 /* The parser is defined in a different module.  */
  71 extern int parse_line (char *line, struct STRUCTURE *result,
  72                        struct parser_data *data, int datalen);
  73
  74 #define LINE_PARSER(EOLSET, BODY) /* Do nothing */
  75
  76 #else
  77
  78 /* Define a line parsing function.  */
  79
  80 #define LINE_PARSER(EOLSET, BODY)                                             \
  81 parser_stclass int                                                            \
  82 parse_line (char *line, struct STRUCTURE *result,                             \
  83             struct parser_data *data, int datalen)                            \
  84 {                                                                             \
  85   ENTDATA_DECL (data)                                                         \
  86   char *p = strpbrk (line, EOLSET "\n");                                      \
  87   if (p)                                                                      \
  88     *p = '\0';                                                                \
  89   BODY;                                                                       \
  90   TRAILING_LIST_PARSER;                                                       \
  91   return 1;                                                                   \
  92 }
  93
  94
  95 #define STRING_FIELD(variable, terminator_p, swallow)                         \
  96   {                                                                           \
  97     variable = line;                                                          \
  98     while (*line != '\0' && !terminator_p (*line))                            \
  99       ++line;                                                                 \
 100     if (*line != '\0')                                                        \
 101       {                                                                       \
 102         *line = '\0';                                                         \
 103         do                                                                    \
 104           ++line;                                                             \
 105         while (swallow && terminator_p (*line));                              \
 106       }                                                                       \
 107   }
 108
 109 #define INT_FIELD(variable, terminator_p, swallow, base, convert)             \
 110   {                                                                           \
 111     char *endp;                                                               \
 112     variable = convert (strtol (line, &endp, base));                          \
 113     if (endp == line)                                                         \
 114       return 0;                                                               \
 115     else if (terminator_p (*endp))                                            \
 116       do                                                                      \
 117         ++endp;                                                               \
 118       while (swallow && terminator_p (*endp));                                \
 119     else if (*endp != '\0')                                                   \
 120       return 0;                                                               \
 121     line = endp;                                                              \
 122   }
 123
 124 #define ISCOLON(c) ((c) == ':')
 125
 126
 127 #ifndef TRAILING_LIST_MEMBER
 128 #define TRAILING_LIST_PARSER /* Nothing to do.  */
 129 #else
 130
 131 #define TRAILING_LIST_PARSER                                                  \
 132 {                                                                             \
 133   char **list = parse_list (line, data, datalen);                             \
 134   if (list)                                                                   \
 135     result->TRAILING_LIST_MEMBER = list;                                      \
 136   else                                                                        \
 137     return 0;                                                                 \
 138 }
 139
 140 static inline char **
 141 parse_list (char *line, struct parser_data *data, int datalen)
 142 {
 143   char *eol, **list, **p;
 144
 145   if (line >= data->linebuffer && line < (char *) data + datalen)
 146     /* Find the end of the line buffer, we will use the space in DATA after
 147        it for storing the vector of pointers.  */
 148     eol = strchr (line, '\0') + 1;
 149   else
 150     /* LINE does not point within DATA->linebuffer, so that space is
 151        not being used for scratch space right now.  We can use all of
 152        it for the pointer vector storage.  */
 153     eol = data->linebuffer;
 154   /* Adjust the pointer so it is aligned for storing pointers.  */
 155   eol += __alignof__ (char *) - 1;
 156   eol -= (eol - (char *) 0) % __alignof__ (char *);
 157   /* We will start the storage here for the vector of pointers.  */
 158   list = (char **) eol;
 159
 160   p = list;
 161   while (1)
 162     {
 163       char *elt;
 164
 165       if ((char *) &p[1] - (char *) data > datalen)
 166         {
 167           /* We cannot fit another pointer in the buffer.  */
 168           errno = ERANGE;
 169           return NULL;
 170         }
 171       if (*line == '\0')
 172         break;
 173
 174       elt = line;
 175       while (1)
 176         {
 177           if (TRAILING_LIST_SEPARATOR_P (*line))
 178             {
 179               *p++ = elt;
 180               *line = '\0';
 181               do
 182                 ++line;
 183               while (TRAILING_LIST_SEPARATOR_P (*line));
 184               elt = line;
 185             }
 186           else if (*line == '\0' || *line == '\n')
 187             {
 188               /* End of the line.  */
 189               if (line > elt)
 190                 /* Last element.  */
 191                 *p++ = elt;
 192               *line = '\0';
 193               break;
 194             }
 195           else
 196             ++line;
 197         }
 198     }
 199   *p = NULL;
 200
 201   return list;
 202 }
 203
 204 #endif  /* EXTERN_PARSER */
 205
 206
 207 #define LOOKUP_NAME(nameelt, aliaselt)                                        \
 208 {                                                                             \
 209   char **ap;                                                                  \
 210   if (! strcmp (name, result->nameelt))                                       \
 211     break;                                                                    \
 212   for (ap = result->aliaselt; *ap; ++ap)                                      \
 213     if (! strcmp (name, *ap))                                                 \
 214       break;                                                                  \
 215   if (*ap)                                                                    \
 216     break;                                                                    \
 217 }
 218
 219 #endif
 220
 221 /* This is defined by db-*.c to include "../nss_db/db-XXX.c" instead.  */
 222 #ifndef GENERIC
 223 #define GENERIC "files-XXX.c"
 224 #endif