src/basic/verbs.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2014 Lennart Poettering
   4 ***/
   5
   6 #include <errno.h>
   7 #include <getopt.h>
   8 #include <stdbool.h>
   9 #include <stddef.h>
  10 #include <string.h>
  11
  12 #include "env-util.h"
  13 #include "log.h"
  14 #include "macro.h"
  15 #include "process-util.h"
  16 #include "string-util.h"
  17 #include "verbs.h"
  18 #include "virt.h"
  19
  20 /* Wraps running_in_chroot() which is used in various places, but also adds an environment variable check so external
  21  * processes can reliably force this on.
  22  */
  23 bool running_in_chroot_or_offline(void) {
  24         int r;
  25
  26         /* Added to support use cases like rpm-ostree, where from %post scripts we only want to execute "preset", but
  27          * not "start"/"restart" for example.
  28          *
  29          * See doc/ENVIRONMENT.md for docs.
  30          */
  31         r = getenv_bool("SYSTEMD_OFFLINE");
  32         if (r < 0 && r != -ENXIO)
  33                 log_debug_errno(r, "Failed to parse $SYSTEMD_OFFLINE: %m");
  34         else if (r >= 0)
  35                 return r > 0;
  36
  37         /* We've had this condition check for a long time which basically checks for legacy chroot case like Fedora's
  38          * "mock", which is used for package builds.  We don't want to try to start systemd services there, since
  39          * without --new-chroot we don't even have systemd running, and even if we did, adding a concept of background
  40          * daemons to builds would be an enormous change, requiring considering things like how the journal output is
  41          * handled, etc.  And there's really not a use case today for a build talking to a service.
  42          *
  43          * Note this call itself also looks for a different variable SYSTEMD_IGNORE_CHROOT=1.
  44          */
  45         r = running_in_chroot();
  46         if (r < 0)
  47                 log_debug_errno(r, "running_in_chroot(): %m");
  48
  49         return r > 0;
  50 }
  51
  52 int dispatch_verb(int argc, char *argv[], const Verb verbs[], void *userdata) {
  53         const Verb *verb;
  54         const char *name;
  55         unsigned i;
  56         int left, r;
  57
  58         assert(verbs);
  59         assert(verbs[0].dispatch);
  60         assert(argc >= 0);
  61         assert(argv);
  62         assert(argc >= optind);
  63
  64         left = argc - optind;
  65         name = argv[optind];
  66
  67         for (i = 0;; i++) {
  68                 bool found;
  69
  70                 /* At the end of the list? */
  71                 if (!verbs[i].dispatch) {
  72                         if (name)
  73                                 log_error("Unknown operation %s.", name);
  74                         else
  75                                 log_error("Requires operation parameter.");
  76                         return -EINVAL;
  77                 }
  78
  79                 if (name)
  80                         found = streq(name, verbs[i].verb);
  81                 else
  82                         found = verbs[i].flags & VERB_DEFAULT;
  83
  84                 if (found) {
  85                         verb = &verbs[i];
  86                         break;
  87                 }
  88         }
  89
  90         assert(verb);
  91
  92         if (!name)
  93                 left = 1;
  94
  95         if (verb->min_args != VERB_ANY &&
  96             (unsigned) left < verb->min_args) {
  97                 log_error("Too few arguments.");
  98                 return -EINVAL;
  99         }
 100
 101         if (verb->max_args != VERB_ANY &&
 102             (unsigned) left > verb->max_args) {
 103                 log_error("Too many arguments.");
 104                 return -EINVAL;
 105         }
 106
 107         if ((verb->flags & VERB_ONLINE_ONLY) && running_in_chroot_or_offline()) {
 108                 if (name)
 109                         log_info("Running in chroot, ignoring request: %s", name);
 110                 else
 111                         log_info("Running in chroot, ignoring request.");
 112                 return 0;
 113         }
 114
 115         if (verb->flags & VERB_MUST_BE_ROOT) {
 116                 r = must_be_root();
 117                 if (r < 0)
 118                         return r;
 119         }
 120
 121         if (name)
 122                 return verb->dispatch(left, argv + optind, userdata);
 123         else {
 124                 char* fake[2] = {
 125                         (char*) verb->verb,
 126                         NULL
 127                 };
 128
 129                 return verb->dispatch(1, fake, userdata);
 130         }
 131 }