src/machine/operation.c

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