src/shared/specifier.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <stdbool.h>
  22 #include <stddef.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/utsname.h>
  26
  27 #include "sd-id128.h"
  28
  29 #include "alloc-util.h"
  30 #include "hostname-util.h"
  31 #include "macro.h"
  32 #include "specifier.h"
  33 #include "string-util.h"
  34
  35 /*
  36  * Generic infrastructure for replacing %x style specifiers in
  37  * strings. Will call a callback for each replacement.
  38  *
  39  */
  40
  41 int specifier_printf(const char *text, const Specifier table[], void *userdata, char **_ret) {
  42         char *ret, *t;
  43         const char *f;
  44         bool percent = false;
  45         size_t l;
  46         int r;
  47
  48         assert(text);
  49         assert(table);
  50
  51         l = strlen(text);
  52         ret = new(char, l+1);
  53         if (!ret)
  54                 return -ENOMEM;
  55
  56         t = ret;
  57
  58         for (f = text; *f; f++, l--) {
  59
  60                 if (percent) {
  61                         if (*f == '%')
  62                                 *(t++) = '%';
  63                         else {
  64                                 const Specifier *i;
  65
  66                                 for (i = table; i->specifier; i++)
  67                                         if (i->specifier == *f)
  68                                                 break;
  69
  70                                 if (i->lookup) {
  71                                         _cleanup_free_ char *w = NULL;
  72                                         char *n;
  73                                         size_t k, j;
  74
  75                                         r = i->lookup(i->specifier, i->data, userdata, &w);
  76                                         if (r < 0) {
  77                                                 free(ret);
  78                                                 return r;
  79                                         }
  80
  81                                         j = t - ret;
  82                                         k = strlen(w);
  83
  84                                         n = new(char, j + k + l + 1);
  85                                         if (!n) {
  86                                                 free(ret);
  87                                                 return -ENOMEM;
  88                                         }
  89
  90                                         memcpy(n, ret, j);
  91                                         memcpy(n + j, w, k);
  92
  93                                         free(ret);
  94
  95                                         ret = n;
  96                                         t = n + j + k;
  97                                 } else {
  98                                         *(t++) = '%';
  99                                         *(t++) = *f;
 100                                 }
 101                         }
 102
 103                         percent = false;
 104                 } else if (*f == '%')
 105                         percent = true;
 106                 else
 107                         *(t++) = *f;
 108         }
 109
 110         *t = 0;
 111         *_ret = ret;
 112         return 0;
 113 }
 114
 115 /* Generic handler for simple string replacements */
 116
 117 int specifier_string(char specifier, void *data, void *userdata, char **ret) {
 118         char *n;
 119
 120         n = strdup(strempty(data));
 121         if (!n)
 122                 return -ENOMEM;
 123
 124         *ret = n;
 125         return 0;
 126 }
 127
 128 int specifier_machine_id(char specifier, void *data, void *userdata, char **ret) {
 129         sd_id128_t id;
 130         char *n;
 131         int r;
 132
 133         r = sd_id128_get_machine(&id);
 134         if (r < 0)
 135                 return r;
 136
 137         n = new(char, 33);
 138         if (!n)
 139                 return -ENOMEM;
 140
 141         *ret = sd_id128_to_string(id, n);
 142         return 0;
 143 }
 144
 145 int specifier_boot_id(char specifier, void *data, void *userdata, char **ret) {
 146         sd_id128_t id;
 147         char *n;
 148         int r;
 149
 150         r = sd_id128_get_boot(&id);
 151         if (r < 0)
 152                 return r;
 153
 154         n = new(char, 33);
 155         if (!n)
 156                 return -ENOMEM;
 157
 158         *ret = sd_id128_to_string(id, n);
 159         return 0;
 160 }
 161
 162 int specifier_host_name(char specifier, void *data, void *userdata, char **ret) {
 163         char *n;
 164
 165         n = gethostname_malloc();
 166         if (!n)
 167                 return -ENOMEM;
 168
 169         *ret = n;
 170         return 0;
 171 }
 172
 173 int specifier_kernel_release(char specifier, void *data, void *userdata, char **ret) {
 174         struct utsname uts;
 175         char *n;
 176         int r;
 177
 178         r = uname(&uts);
 179         if (r < 0)
 180                 return -errno;
 181
 182         n = strdup(uts.release);
 183         if (!n)
 184                 return -ENOMEM;
 185
 186         *ret = n;
 187         return 0;
 188 }