src/machine/operation.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2016 Lennart Poettering
   6 ***/
   7
   8 #include <sys/wait.h>
   9
  10 #include "alloc-util.h"
  11 #include "fd-util.h"
  12 #include "operation.h"
  13 #include "process-util.h"
  14
  15 static int operation_done(sd_event_source *s, const siginfo_t *si, void *userdata) {
  16         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  17         Operation *o = userdata;
  18         int r;
  19
  20         assert(o);
  21         assert(si);
  22
  23         log_debug("Operating " PID_FMT " is now complete with code=%s status=%i",
  24                   o->pid,
  25                   sigchld_code_to_string(si->si_code), si->si_status);
  26
  27         o->pid = 0;
  28
  29         if (si->si_code != CLD_EXITED) {
  30                 r = sd_bus_error_setf(&error, SD_BUS_ERROR_FAILED, "Child died abnormally.");
  31                 goto fail;
  32         }
  33
  34         if (si->si_status == EXIT_SUCCESS)
  35                 r = 0;
  36         else if (read(o->errno_fd, &r, sizeof(r)) != sizeof(r)) { /* Try to acquire error code for failed operation */
  37                 r = sd_bus_error_setf(&error, SD_BUS_ERROR_FAILED, "Child failed.");
  38                 goto fail;
  39         }
  40
  41         if (o->done) {
  42                 /* A completion routine is set for this operation, call it. */
  43                 r = o->done(o, r, &error);
  44                 if (r < 0) {
  45                         if (!sd_bus_error_is_set(&error))
  46                                 sd_bus_error_set_errno(&error, r);
  47
  48                         goto fail;
  49                 }
  50
  51         } else {
  52                 /* The default operation when done is to simply return an error on failure or an empty success
  53                  * message on success. */
  54                 if (r < 0) {
  55                         sd_bus_error_set_errno(&error, r);
  56                         goto fail;
  57                 }
  58
  59                 r = sd_bus_reply_method_return(o->message, NULL);
  60                 if (r < 0)
  61                         log_error_errno(r, "Failed to reply to message: %m");
  62         }
  63
  64         operation_free(o);
  65         return 0;
  66
  67 fail:
  68         r = sd_bus_reply_method_error(o->message, &error);
  69         if (r < 0)
  70                 log_error_errno(r, "Failed to reply to message: %m");
  71
  72         operation_free(o);
  73         return 0;
  74 }
  75
  76 int operation_new(Manager *manager, Machine *machine, pid_t child, sd_bus_message *message, int errno_fd, Operation **ret) {
  77         Operation *o;
  78         int r;
  79
  80         assert(manager);
  81         assert(child > 1);
  82         assert(message);
  83         assert(errno_fd >= 0);
  84
  85         o = new0(Operation, 1);
  86         if (!o)
  87                 return -ENOMEM;
  88
  89         o->extra_fd = -1;
  90
  91         r = sd_event_add_child(manager->event, &o->event_source, child, WEXITED, operation_done, o);
  92         if (r < 0) {
  93                 free(o);
  94                 return r;
  95         }
  96
  97         o->pid = child;
  98         o->message = sd_bus_message_ref(message);
  99         o->errno_fd = errno_fd;
 100
 101         LIST_PREPEND(operations, manager->operations, o);
 102         manager->n_operations++;
 103         o->manager = manager;
 104
 105         if (machine) {
 106                 LIST_PREPEND(operations_by_machine, machine->operations, o);
 107                 o->machine = machine;
 108         }
 109
 110         log_debug("Started new operation " PID_FMT ".", child);
 111
 112         /* At this point we took ownership of both the child and the errno file descriptor! */
 113
 114         if (ret)
 115                 *ret = o;
 116
 117         return 0;
 118 }
 119
 120 Operation *operation_free(Operation *o) {
 121         if (!o)
 122                 return NULL;
 123
 124         sd_event_source_unref(o->event_source);
 125
 126         safe_close(o->errno_fd);
 127         safe_close(o->extra_fd);
 128
 129         if (o->pid > 1)
 130                 (void) sigkill_wait(o->pid);
 131
 132         sd_bus_message_unref(o->message);
 133
 134         if (o->manager) {
 135                 LIST_REMOVE(operations, o->manager->operations, o);
 136                 o->manager->n_operations--;
 137         }
 138
 139         if (o->machine)
 140                 LIST_REMOVE(operations_by_machine, o->machine->operations, o);
 141
 142         return mfree(o);
 143 }