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         UnitFileInstallInfo *i = userdata;
  36
  37         assert(i);
  38
  39         return unit_name_to_prefix_and_instance(i->name, ret);
  40 }
  41
  42 static int specifier_prefix(char specifier, void *data, void *userdata, char **ret) {
  43         UnitFileInstallInfo *i = userdata;
  44
  45         assert(i);
  46
  47         return unit_name_to_prefix(i->name, ret);
  48 }
  49
  50 static int specifier_instance(char specifier, void *data, void *userdata, char **ret) {
  51         const UnitFileInstallInfo *i = userdata;
  52         char *instance;
  53         int r;
  54
  55         assert(i);
  56
  57         r = unit_name_to_instance(i->name, &instance);
  58         if (r < 0)
  59                 return r;
  60
  61         if (isempty(instance)) {
  62                 instance = strdup(i->default_instance ?: "");
  63                 if (!instance)
  64                         return -ENOMEM;
  65         }
  66
  67         *ret = instance;
  68         return 0;
  69 }
  70
  71 static int specifier_user_name(char specifier, void *data, void *userdata, char **ret) {
  72         char *t;
  73
  74         /* If we are UID 0 (root), this will not result in NSS,
  75          * otherwise it might. This is good, as we want to be able to
  76          * run this in PID 1, where our user ID is 0, but where NSS
  77          * lookups are not allowed. */
  78
  79         t = getusername_malloc();
  80         if (!t)
  81                 return -ENOMEM;
  82
  83         *ret = t;
  84         return 0;
  85 }
  86
  87 static int specifier_user_id(char specifier, void *data, void *userdata, char **ret) {
  88
  89         if (asprintf(ret, UID_FMT, getuid()) < 0)
  90                 return -ENOMEM;
  91
  92         return 0;
  93 }
  94
  95 int install_full_printf(UnitFileInstallInfo *i, const char *format, char **ret) {
  96
  97         /* This is similar to unit_full_printf() but does not support
  98          * anything path-related.
  99          *
 100          * %n: the full id of the unit                 (foo@bar.waldo)
 101          * %N: the id of the unit without the suffix   (foo@bar)
 102          * %p: the prefix                              (foo)
 103          * %i: the instance                            (bar)
 104
 105          * %U the UID of the running user
 106          * %u the username of running user
 107          * %m the machine ID of the running system
 108          * %H the host name of the running system
 109          * %b the boot ID of the running system
 110          * %v `uname -r` of the running system
 111          */
 112
 113         const Specifier table[] = {
 114                 { 'n', specifier_string,              i->name },
 115                 { 'N', specifier_prefix_and_instance, NULL },
 116                 { 'p', specifier_prefix,              NULL },
 117                 { 'i', specifier_instance,            NULL },
 118
 119                 { 'U', specifier_user_id,             NULL },
 120                 { 'u', specifier_user_name,           NULL },
 121
 122                 { 'm', specifier_machine_id,          NULL },
 123                 { 'H', specifier_host_name,           NULL },
 124                 { 'b', specifier_boot_id,             NULL },
 125                 { 'v', specifier_kernel_release,      NULL },
 126                 {}
 127         };
 128
 129         assert(i);
 130         assert(format);
 131         assert(ret);
 132
 133         return specifier_printf(format, table, i, ret);
 134 }