src/machine/operation.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2016 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <sys/wait.h>
  21
  22 #include "alloc-util.h"
  23 #include "fd-util.h"
  24 #include "operation.h"
  25 #include "process-util.h"
  26
  27 static int operation_done(sd_event_source *s, const siginfo_t *si, void *userdata) {
  28         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  29         Operation *o = userdata;
  30         int r;
  31
  32         assert(o);
  33         assert(si);
  34
  35         log_debug("Operating " PID_FMT " is now complete with code=%s status=%i",
  36                   o->pid,
  37                   sigchld_code_to_string(si->si_code), si->si_status);
  38
  39         o->pid = 0;
  40
  41         if (si->si_code != CLD_EXITED) {
  42                 r = sd_bus_error_setf(&error, SD_BUS_ERROR_FAILED, "Child died abnormally.");
  43                 goto fail;
  44         }
  45
  46         if (si->si_status == EXIT_SUCCESS)
  47                 r = 0;
  48         else if (read(o->errno_fd, &r, sizeof(r)) != sizeof(r)) { /* Try to acquire error code for failed operation */
  49                 r = sd_bus_error_setf(&error, SD_BUS_ERROR_FAILED, "Child failed.");
  50                 goto fail;
  51         }
  52
  53         if (o->done) {
  54                 /* A completion routine is set for this operation, call it. */
  55                 r = o->done(o, r, &error);
  56                 if (r < 0) {
  57                         if (!sd_bus_error_is_set(&error))
  58                                 sd_bus_error_set_errno(&error, r);
  59
  60                         goto fail;
  61                 }
  62
  63         } else {
  64                 /* The default operation when done is to simply return an error on failure or an empty success
  65                  * message on success. */
  66                 if (r < 0) {
  67                         sd_bus_error_set_errno(&error, r);
  68                         goto fail;
  69                 }
  70
  71                 r = sd_bus_reply_method_return(o->message, NULL);
  72                 if (r < 0)
  73                         log_error_errno(r, "Failed to reply to message: %m");
  74         }
  75
  76         operation_free(o);
  77         return 0;
  78
  79 fail:
  80         r = sd_bus_reply_method_error(o->message, &error);
  81         if (r < 0)
  82                 log_error_errno(r, "Failed to reply to message: %m");
  83
  84         operation_free(o);
  85         return 0;
  86 }
  87
  88 int operation_new(Manager *manager, Machine *machine, pid_t child, sd_bus_message *message, int errno_fd, Operation **ret) {
  89         Operation *o;
  90         int r;
  91
  92         assert(manager);
  93         assert(child > 1);
  94         assert(message);
  95         assert(errno_fd >= 0);
  96
  97         o = new0(Operation, 1);
  98         if (!o)
  99                 return -ENOMEM;
 100
 101         o->extra_fd = -1;
 102
 103         r = sd_event_add_child(manager->event, &o->event_source, child, WEXITED, operation_done, o);
 104         if (r < 0) {
 105                 free(o);
 106                 return r;
 107         }
 108
 109         o->pid = child;
 110         o->message = sd_bus_message_ref(message);
 111         o->errno_fd = errno_fd;
 112
 113         LIST_PREPEND(operations, manager->operations, o);
 114         manager->n_operations++;
 115         o->manager = manager;
 116
 117         if (machine) {
 118                 LIST_PREPEND(operations_by_machine, machine->operations, o);
 119                 o->machine = machine;
 120         }
 121
 122         log_debug("Started new operation " PID_FMT ".", child);
 123
 124         /* At this point we took ownership of both the child and the errno file descriptor! */
 125
 126         if (ret)
 127                 *ret = o;
 128
 129         return 0;
 130 }
 131
 132 Operation *operation_free(Operation *o) {
 133         if (!o)
 134                 return NULL;
 135
 136         sd_event_source_unref(o->event_source);
 137
 138         safe_close(o->errno_fd);
 139         safe_close(o->extra_fd);
 140
 141         if (o->pid > 1)
 142                 (void) sigkill_wait(o->pid);
 143
 144         sd_bus_message_unref(o->message);
 145
 146         if (o->manager) {
 147                 LIST_REMOVE(operations, o->manager->operations, o);
 148                 o->manager->n_operations--;
 149         }
 150
 151         if (o->machine)
 152                 LIST_REMOVE(operations_by_machine, o->machine->operations, o);
 153
 154         return mfree(o);
 155 }