src/basic/verbs.c

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