src/lxc/confile_utils.c

   1 /* liblxcapi
   2  *
   3  * Copyright © 2017 Christian Brauner <christian.brauner@ubuntu.com>.
   4  * Copyright © 2017 Canonical Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program 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
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <stdio.h>
  21 #include <string.h>
  22
  23 #include "utils.h"
  24
  25 int parse_idmaps(const char *idmap, char *type, unsigned long *nsid,
  26                  unsigned long *hostid, unsigned long *range)
  27 {
  28         int ret = -1;
  29         unsigned long tmp_hostid, tmp_nsid, tmp_range;
  30         char tmp_type;
  31         char *window, *slide;
  32         char *dup = NULL;
  33
  34         /* Duplicate string. */
  35         dup = strdup(idmap);
  36         if (!dup)
  37                 goto on_error;
  38
  39         /* A prototypical idmap entry would be: "u 1000 1000000 65536" */
  40
  41         /* align */
  42         slide = window = dup;
  43         /* skip whitespace */
  44         slide += strspn(slide, " \t\r");
  45         if (slide != window && *slide == '\0')
  46                 goto on_error;
  47
  48         /* Validate type. */
  49         if (*slide != 'u' && *slide != 'g')
  50                 goto on_error;
  51         /* Assign type. */
  52         tmp_type = *slide;
  53
  54         /* move beyond type */
  55         slide++;
  56         /* align */
  57         window = slide;
  58         /* Validate that only whitespace follows. */
  59         slide += strspn(slide, " \t\r");
  60         /* There must be whitespace. */
  61         if (slide == window)
  62                 goto on_error;
  63
  64         /* Mark beginning of nsuid. */
  65         window = slide;
  66         /* Validate that non-whitespace follows. */
  67         slide += strcspn(slide, " \t\r");
  68         /* There must be non-whitespace. */
  69         if (slide == window || *slide == '\0')
  70                 goto on_error;
  71         /* Mark end of nsuid. */
  72         *slide = '\0';
  73
  74         /* Parse nsuid. */
  75         if (lxc_safe_ulong(window, &tmp_nsid) < 0)
  76                 goto on_error;
  77
  78         /* Move beyond \0. */
  79         slide++;
  80         /* align */
  81         window = slide;
  82         /* Validate that only whitespace follows. */
  83         slide += strspn(slide, " \t\r");
  84         /* If there was only one whitespace then we whiped it with our \0 above.
  85          * So only ensure that we're not at the end of the string.
  86          */
  87         if (*slide == '\0')
  88                 goto on_error;
  89
  90         /* Mark beginning of hostid. */
  91         window = slide;
  92         /* Validate that non-whitespace follows. */
  93         slide += strcspn(slide, " \t\r");
  94         /* There must be non-whitespace. */
  95         if (slide == window || *slide == '\0')
  96                 goto on_error;
  97         /* Mark end of nsuid. */
  98         *slide = '\0';
  99
 100         /* Parse hostid. */
 101         if (lxc_safe_ulong(window, &tmp_hostid) < 0)
 102                 goto on_error;
 103
 104         /* Move beyond \0. */
 105         slide++;
 106         /* align */
 107         window = slide;
 108         /* Validate that only whitespace follows. */
 109         slide += strspn(slide, " \t\r");
 110         /* If there was only one whitespace then we whiped it with our \0 above.
 111          * So only ensure that we're not at the end of the string.
 112          */
 113         if (*slide == '\0')
 114                 goto on_error;
 115
 116         /* Mark beginning of range. */
 117         window = slide;
 118         /* Validate that non-whitespace follows. */
 119         slide += strcspn(slide, " \t\r");
 120         /* There must be non-whitespace. */
 121         if (slide == window)
 122                 goto on_error;
 123
 124         /* The range is the last valid entry we expect. So make sure that there
 125          * is not trailing garbage and if there is, error out.
 126          */
 127         if (*(slide + strspn(slide, " \t\r\n")) != '\0')
 128                 goto on_error;
 129         /* Mark end of range. */
 130         *slide = '\0';
 131
 132         /* Parse range. */
 133         if (lxc_safe_ulong(window, &tmp_range) < 0)
 134                 goto on_error;
 135
 136         *type = tmp_type;
 137         *nsid = tmp_nsid;
 138         *hostid = tmp_hostid;
 139         *range = tmp_range;
 140
 141         /* Yay, we survived. */
 142         ret = 0;
 143
 144 on_error:
 145         free(dup);
 146
 147         return ret;
 148 }