src/shared/install-printf.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2013 Zbigniew Jędrzejewski-Szmek
   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 <stdio.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24
  25 #include "formats-util.h"
  26 #include "install-printf.h"
  27 #include "install.h"
  28 #include "macro.h"
  29 #include "specifier.h"
  30 #include "string-util.h"
  31 #include "unit-name.h"
  32 #include "user-util.h"
  33
  34 static int specifier_prefix_and_instance(char specifier, void *data, void *userdata, char **ret) {
  35         const UnitFileInstallInfo *i = userdata;
  36         _cleanup_free_ char *prefix = NULL;
  37         int r;
  38
  39         assert(i);
  40
  41         r = unit_name_to_prefix_and_instance(i->name, &prefix);
  42         if (r < 0)
  43                 return r;
  44
  45         if (endswith(prefix, "@") && i->default_instance) {
  46                 char *ans;
  47
  48                 ans = strjoin(prefix, i->default_instance);
  49                 if (!ans)
  50                         return -ENOMEM;
  51                 *ret = ans;
  52         } else {
  53                 *ret = prefix;
  54                 prefix = NULL;
  55         }
  56
  57         return 0;
  58 }
  59
  60 static int specifier_name(char specifier, void *data, void *userdata, char **ret) {
  61         const UnitFileInstallInfo *i = userdata;
  62         char *ans;
  63
  64         assert(i);
  65
  66         if (unit_name_is_valid(i->name, UNIT_NAME_TEMPLATE) && i->default_instance)
  67                 return unit_name_replace_instance(i->name, i->default_instance, ret);
  68
  69         ans = strdup(i->name);
  70         if (!ans)
  71                 return -ENOMEM;
  72         *ret = ans;
  73         return 0;
  74 }
  75
  76 static int specifier_prefix(char specifier, void *data, void *userdata, char **ret) {
  77         const UnitFileInstallInfo *i = userdata;
  78
  79         assert(i);
  80
  81         return unit_name_to_prefix(i->name, ret);
  82 }
  83
  84 static int specifier_instance(char specifier, void *data, void *userdata, char **ret) {
  85         const UnitFileInstallInfo *i = userdata;
  86         char *instance;
  87         int r;
  88
  89         assert(i);
  90
  91         r = unit_name_to_instance(i->name, &instance);
  92         if (r < 0)
  93                 return r;
  94
  95         if (isempty(instance)) {
  96                 instance = strdup(i->default_instance ?: "");
  97                 if (!instance)
  98                         return -ENOMEM;
  99         }
 100
 101         *ret = instance;
 102         return 0;
 103 }
 104
 105 static int specifier_user_name(char specifier, void *data, void *userdata, char **ret) {
 106         char *t;
 107
 108         /* If we are UID 0 (root), this will not result in NSS,
 109          * otherwise it might. This is good, as we want to be able to
 110          * run this in PID 1, where our user ID is 0, but where NSS
 111          * lookups are not allowed.
 112
 113          * We don't user getusername_malloc() here, because we don't want to look
 114          * at $USER, to remain consistent with specifer_user_id() below.
 115          */
 116
 117         t = uid_to_name(getuid());
 118         if (!t)
 119                 return -ENOMEM;
 120
 121         *ret = t;
 122         return 0;
 123 }
 124
 125 static int specifier_user_id(char specifier, void *data, void *userdata, char **ret) {
 126
 127         if (asprintf(ret, UID_FMT, getuid()) < 0)
 128                 return -ENOMEM;
 129
 130         return 0;
 131 }
 132
 133 int install_full_printf(UnitFileInstallInfo *i, const char *format, char **ret) {
 134
 135         /* This is similar to unit_full_printf() but does not support
 136          * anything path-related.
 137          *
 138          * %n: the full id of the unit                 (foo@bar.waldo)
 139          * %N: the id of the unit without the suffix   (foo@bar)
 140          * %p: the prefix                              (foo)
 141          * %i: the instance                            (bar)
 142
 143          * %U the UID of the running user
 144          * %u the username of running user
 145          * %m the machine ID of the running system
 146          * %H the host name of the running system
 147          * %b the boot ID of the running system
 148          * %v `uname -r` of the running system
 149          */
 150
 151         const Specifier table[] = {
 152                 { 'n', specifier_name,                NULL },
 153                 { 'N', specifier_prefix_and_instance, NULL },
 154                 { 'p', specifier_prefix,              NULL },
 155                 { 'i', specifier_instance,            NULL },
 156
 157                 { 'U', specifier_user_id,             NULL },
 158                 { 'u', specifier_user_name,           NULL },
 159
 160                 { 'm', specifier_machine_id,          NULL },
 161                 { 'H', specifier_host_name,           NULL },
 162                 { 'b', specifier_boot_id,             NULL },
 163                 { 'v', specifier_kernel_release,      NULL },
 164                 {}
 165         };
 166
 167         assert(i);
 168         assert(format);
 169         assert(ret);
 170
 171         return specifier_printf(format, table, i, ret);
 172 }