src/core/unit-printf.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 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 "systemd/sd-id128.h"
  23 #include "unit.h"
  24 #include "specifier.h"
  25 #include "path-util.h"
  26 #include "strv.h"
  27 #include "unit-name.h"
  28 #include "unit-printf.h"
  29 #include "macro.h"
  30 #include "cgroup-util.h"
  31 #include "special.h"
  32
  33 static char *specifier_prefix_and_instance(char specifier, void *data, void *userdata) {
  34         Unit *u = userdata;
  35         assert(u);
  36
  37         return unit_name_to_prefix_and_instance(u->id);
  38 }
  39
  40 static char *specifier_prefix(char specifier, void *data, void *userdata) {
  41         Unit *u = userdata;
  42         assert(u);
  43
  44         return unit_name_to_prefix(u->id);
  45 }
  46
  47 static char *specifier_prefix_unescaped(char specifier, void *data, void *userdata) {
  48         Unit *u = userdata;
  49         char *p, *r;
  50
  51         assert(u);
  52
  53         p = unit_name_to_prefix(u->id);
  54         if (!p)
  55                 return NULL;
  56
  57         r = unit_name_unescape(p);
  58         free(p);
  59
  60         return r;
  61 }
  62
  63 static char *specifier_instance_unescaped(char specifier, void *data, void *userdata) {
  64         Unit *u = userdata;
  65         assert(u);
  66
  67         if (u->instance)
  68                 return unit_name_unescape(u->instance);
  69
  70         return strdup("");
  71 }
  72
  73 static char *specifier_filename(char specifier, void *data, void *userdata) {
  74         Unit *u = userdata;
  75         assert(u);
  76
  77         if (u->instance)
  78                 return unit_name_path_unescape(u->instance);
  79
  80         return unit_name_to_path(u->id);
  81 }
  82
  83 static char *specifier_cgroup(char specifier, void *data, void *userdata) {
  84         Unit *u = userdata;
  85         assert(u);
  86
  87         return unit_default_cgroup_path(u);
  88 }
  89
  90 static char *specifier_cgroup_root(char specifier, void *data, void *userdata) {
  91         _cleanup_free_ char *p = NULL;
  92         Unit *u = userdata;
  93         const char *slice;
  94         int r;
  95
  96         assert(u);
  97
  98         slice = unit_slice_name(u);
  99         if (specifier == 'R' || !slice)
 100                 return strdup(u->manager->cgroup_root);
 101
 102         r = cg_slice_to_path(slice, &p);
 103         if (r < 0)
 104                 return NULL;
 105
 106         return strjoin(u->manager->cgroup_root, "/", p, NULL);
 107 }
 108
 109 static char *specifier_runtime(char specifier, void *data, void *userdata) {
 110         Unit *u = userdata;
 111         assert(u);
 112
 113         if (u->manager->running_as == SYSTEMD_USER) {
 114                 const char *e;
 115
 116                 e = getenv("XDG_RUNTIME_DIR");
 117                 if (e)
 118                         return strdup(e);
 119         }
 120
 121         return strdup("/run");
 122 }
 123
 124 static char *specifier_user_name(char specifier, void *data, void *userdata) {
 125         Unit *u = userdata;
 126         ExecContext *c;
 127         int r;
 128         const char *username;
 129         _cleanup_free_ char *tmp = NULL;
 130         uid_t uid;
 131         char *printed = NULL;
 132
 133         assert(u);
 134
 135         c = unit_get_exec_context(u);
 136
 137         if (c && c->user)
 138                 username = c->user;
 139         else
 140                 /* get USER env from env or our own uid */
 141                 username = tmp = getusername_malloc();
 142
 143         /* fish username from passwd */
 144         r = get_user_creds(&username, &uid, NULL, NULL, NULL);
 145         if (r < 0)
 146                 return NULL;
 147
 148         switch (specifier) {
 149                 case 'U':
 150                         if (asprintf(&printed, "%d", uid) < 0)
 151                                 return NULL;
 152                         break;
 153                 case 'u':
 154                         printed = strdup(username);
 155                         break;
 156         }
 157
 158         return printed;
 159 }
 160
 161 static char *specifier_user_home(char specifier, void *data, void *userdata) {
 162         Unit *u = userdata;
 163         ExecContext *c;
 164         int r;
 165         const char *username, *home;
 166
 167         assert(u);
 168
 169         c = unit_get_exec_context(u);
 170
 171         /* return HOME if set, otherwise from passwd */
 172         if (!c || !c->user) {
 173                 char *h;
 174
 175                 r = get_home_dir(&h);
 176                 if (r < 0)
 177                         return NULL;
 178
 179                 return h;
 180         }
 181
 182         username = c->user;
 183         r = get_user_creds(&username, NULL, NULL, &home, NULL);
 184         if (r < 0)
 185                return NULL;
 186
 187         return strdup(home);
 188 }
 189
 190 static char *specifier_user_shell(char specifier, void *data, void *userdata) {
 191         Unit *u = userdata;
 192         ExecContext *c;
 193         int r;
 194         const char *username, *shell;
 195         char *ret;
 196
 197         assert(u);
 198
 199         c = unit_get_exec_context(u);
 200
 201         if (c && c->user)
 202                 username = c->user;
 203         else
 204                 username = "root";
 205
 206         /* return /bin/sh for root, otherwise the value from passwd */
 207         r = get_user_creds(&username, NULL, NULL, NULL, &shell);
 208         if (r < 0) {
 209                 log_warning_unit(u->id,
 210                                  "Failed to determine shell: %s",
 211                                  strerror(-r));
 212                 return NULL;
 213         }
 214
 215         if (!path_is_absolute(shell)) {
 216                 log_warning_unit(u->id,
 217                                  "Shell %s is not absolute, ignoring.",
 218                                  shell);
 219         }
 220
 221         ret = strdup(shell);
 222         if (!ret)
 223                 log_oom();
 224
 225         return ret;
 226 }
 227
 228 char *unit_name_printf(Unit *u, const char* format) {
 229
 230         /*
 231          * This will use the passed string as format string and
 232          * replace the following specifiers:
 233          *
 234          * %n: the full id of the unit                 (foo@bar.waldo)
 235          * %N: the id of the unit without the suffix   (foo@bar)
 236          * %p: the prefix                              (foo)
 237          * %i: the instance                            (bar)
 238          */
 239
 240         const Specifier table[] = {
 241                 { 'n', specifier_string,              u->id },
 242                 { 'N', specifier_prefix_and_instance, NULL },
 243                 { 'p', specifier_prefix,              NULL },
 244                 { 'i', specifier_string,              u->instance },
 245                 { 0, NULL, NULL }
 246         };
 247
 248         assert(u);
 249         assert(format);
 250
 251         return specifier_printf(format, table, u);
 252 }
 253
 254 char *unit_full_printf(Unit *u, const char *format) {
 255
 256         /* This is similar to unit_name_printf() but also supports
 257          * unescaping. Also, adds a couple of additional codes:
 258          *
 259          * %f the the instance if set, otherwise the id
 260          * %c cgroup path of unit
 261          * %r where units in this slice are place in the cgroup tree
 262          * %R the root of this systemd's instance tree
 263          * %t the runtime directory to place sockets in (e.g. "/run" or $XDG_RUNTIME_DIR)
 264          * %U the UID of the configured user or running user
 265          * %u the username of the configured user or running user
 266          * %h the homedir of the configured user or running user
 267          * %s the shell of the configured user or running user
 268          * %m the machine ID of the running system
 269          * %H the host name of the running system
 270          * %b the boot ID of the running system
 271          * %v `uname -r` of the running system
 272          */
 273
 274         const Specifier table[] = {
 275                 { 'n', specifier_string,              u->id },
 276                 { 'N', specifier_prefix_and_instance, NULL },
 277                 { 'p', specifier_prefix,              NULL },
 278                 { 'P', specifier_prefix_unescaped,    NULL },
 279                 { 'i', specifier_string,              u->instance },
 280                 { 'I', specifier_instance_unescaped,  NULL },
 281
 282                 { 'f', specifier_filename,            NULL },
 283                 { 'c', specifier_cgroup,              NULL },
 284                 { 'r', specifier_cgroup_root,         NULL },
 285                 { 'R', specifier_cgroup_root,         NULL },
 286                 { 't', specifier_runtime,             NULL },
 287                 { 'U', specifier_user_name,           NULL },
 288                 { 'u', specifier_user_name,           NULL },
 289                 { 'h', specifier_user_home,           NULL },
 290                 { 's', specifier_user_shell,          NULL },
 291
 292                 { 'm', specifier_machine_id,          NULL },
 293                 { 'H', specifier_host_name,           NULL },
 294                 { 'b', specifier_boot_id,             NULL },
 295                 { 'v', specifier_kernel_release,      NULL },
 296                 {}
 297         };
 298
 299         assert(format);
 300
 301         return specifier_printf(format, table, u);
 302 }
 303
 304 char **unit_full_printf_strv(Unit *u, char **l) {
 305         size_t n;
 306         char **r, **i, **j;
 307
 308         /* Applies unit_full_printf to every entry in l */
 309
 310         assert(u);
 311
 312         n = strv_length(l);
 313         r = new(char*, n+1);
 314         if (!r)
 315                 return NULL;
 316
 317         for (i = l, j = r; *i; i++, j++) {
 318                 *j = unit_full_printf(u, *i);
 319                 if (!*j)
 320                         goto fail;
 321         }
 322
 323         *j = NULL;
 324         return r;
 325
 326 fail:
 327         for (j--; j >= r; j--)
 328                 free(*j);
 329
 330         free(r);
 331
 332         return NULL;
 333 }