Line data    Source code

       1             : /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
       2             : 
       3             : /***
       4             :   This file is part of systemd.
       5             : 
       6             :   Copyright 2012 Lennart Poettering
       7             : 
       8             :   systemd is free software; you can redistribute it and/or modify it
       9             :   under the terms of the GNU Lesser General Public License as published by
      10             :   the Free Software Foundation; either version 2.1 of the License, or
      11             :   (at your option) any later version.
      12             : 
      13             :   systemd is distributed in the hope that it will be useful, but
      14             :   WITHOUT ANY WARRANTY; without even the implied warranty of
      15             :   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
      16             :   Lesser General Public License for more details.
      17             : 
      18             :   You should have received a copy of the GNU Lesser General Public License
      19             :   along with systemd; If not, see <http://www.gnu.org/licenses/>.
      20             : ***/
      21             : 
      22             : #include <string.h>
      23             : 
      24             : #include "macro.h"
      25             : #include "util.h"
      26             : #include "replace-var.h"
      27             : #include "def.h"
      28             : 
      29             : /*
      30             :  * Generic infrastructure for replacing @FOO@ style variables in
      31             :  * strings. Will call a callback for each replacement.
      32             :  */
      33             : 
      34          42 : static int get_variable(const char *b, char **r) {
      35             :         size_t k;
      36             :         char *t;
      37             : 
      38          42 :         assert(b);
      39          42 :         assert(r);
      40             : 
      41          42 :         if (*b != '@')
      42          30 :                 return 0;
      43             : 
      44          12 :         k = strspn(b + 1, UPPERCASE_LETTERS "_");
      45          12 :         if (k <= 0 || b[k+1] != '@')
      46          10 :                 return 0;
      47             : 
      48           2 :         t = strndup(b + 1, k);
      49           2 :         if (!t)
      50           0 :                 return -ENOMEM;
      51             : 
      52           2 :         *r = t;
      53           2 :         return 1;
      54             : }
      55             : 
      56           1 : char *replace_var(const char *text, char *(*lookup)(const char *variable, void*userdata), void *userdata) {
      57             :         char *r, *t;
      58             :         const char *f;
      59             :         size_t l;
      60             : 
      61           1 :         assert(text);
      62           1 :         assert(lookup);
      63             : 
      64           1 :         l = strlen(text);
      65           1 :         r = new(char, l+1);
      66           1 :         if (!r)
      67           0 :                 return NULL;
      68             : 
      69           1 :         f = text;
      70           1 :         t = r;
      71          44 :         while (*f) {
      72          84 :                 _cleanup_free_ char *v = NULL, *n = NULL;
      73             :                 char *a;
      74             :                 int k;
      75             :                 size_t skip, d, nl;
      76             : 
      77          42 :                 k = get_variable(f, &v);
      78          42 :                 if (k < 0)
      79           0 :                         goto oom;
      80          42 :                 if (k == 0) {
      81          40 :                         *(t++) = *(f++);
      82          40 :                         continue;
      83             :                 }
      84             : 
      85           2 :                 n = lookup(v, userdata);
      86           2 :                 if (!n)
      87           0 :                         goto oom;
      88             : 
      89           2 :                 skip = strlen(v) + 2;
      90             : 
      91           2 :                 d = t - r;
      92           2 :                 nl = l - skip + strlen(n);
      93           2 :                 a = realloc(r, nl + 1);
      94           2 :                 if (!a)
      95           0 :                         goto oom;
      96             : 
      97           2 :                 l = nl;
      98           2 :                 r = a;
      99           2 :                 t = r + d;
     100             : 
     101           2 :                 t = stpcpy(t, n);
     102           2 :                 f += skip;
     103             :         }
     104             : 
     105           1 :         *t = 0;
     106           1 :         return r;
     107             : 
     108             : oom:
     109           0 :         free(r);
     110           0 :         return NULL;
     111             : }