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