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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <sys/wait.h>
#include <unistd.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "operation.h"
#include "process-util.h"
static int read_operation_errno(const siginfo_t *si, Operation *o) {
int r;
assert(si);
assert(o);
if (si->si_code != CLD_EXITED)
return log_debug_errno(SYNTHETIC_ERRNO(ESHUTDOWN), "Child died abnormally");
if (si->si_status == EXIT_SUCCESS)
r = 0;
else {
ssize_t n = read(o->errno_fd, &r, sizeof(r));
if (n < 0)
return log_debug_errno(errno, "Failed to read operation's errno: %m");
if (n != sizeof(r))
return log_debug_errno(SYNTHETIC_ERRNO(EIO), "Received unexpectedly short message when reading operation's errno");
}
return r;
}
static int operation_done(sd_event_source *s, const siginfo_t *si, void *userdata) {
Operation *o = ASSERT_PTR(userdata);
int r;
assert(si);
log_debug("Operation " PID_FMT " is now complete with code=%s status=%i",
o->pid,
sigchld_code_to_string(si->si_code), si->si_status);
o->pid = 0;
r = read_operation_errno(si, o);
if (r < 0)
log_debug_errno(r, "Operation failed: %m");
/* If a completion routine (o->done) is set for this operation, call it. It sends a response, but can return an error in which case it expect us to reply.
* Otherwise, the default action is to simply return an error on failure or an empty success message on success. */
if (o->message) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
if (o->done)
r = o->done(o, r, &error);
if (r < 0) {
if (!sd_bus_error_is_set(&error))
sd_bus_error_set_errno(&error, r);
r = sd_bus_reply_method_error(o->message, &error);
if (r < 0)
log_error_errno(r, "Failed to reply to dbus message: %m");
} else if (!o->done) {
/* when o->done set it's responsible for sending reply in a happy-path case */
r = sd_bus_reply_method_return(o->message, NULL);
if (r < 0)
log_error_errno(r, "Failed to reply to dbus message: %m");
}
} else if (o->link) {
if (o->done)
r = o->done(o, r, /* error = */ NULL);
if (r < 0)
(void) sd_varlink_error_errno(o->link, r);
else if (!o->done)
/* when o->done set it's responsible for sending reply in a happy-path case */
(void) sd_varlink_reply(o->link, NULL);
} else
assert_not_reached();
operation_free(o);
return 0;
}
int operation_new(Manager *manager, Machine *machine, pid_t child, sd_bus_message *message, sd_varlink *link, int errno_fd, Operation **ret) {
Operation *o;
int r;
assert(manager);
assert(child > 1);
assert(errno_fd >= 0);
assert(message || link);
assert(!(message && link));
o = new0(Operation, 1);
if (!o)
return -ENOMEM;
o->extra_fd = -EBADF;
r = sd_event_add_child(manager->event, &o->event_source, child, WEXITED, operation_done, o);
if (r < 0) {
free(o);
return r;
}
o->pid = child;
o->message = sd_bus_message_ref(message);
o->link = sd_varlink_ref(link);
o->errno_fd = errno_fd;
LIST_PREPEND(operations, manager->operations, o);
manager->n_operations++;
o->manager = manager;
if (machine) {
LIST_PREPEND(operations_by_machine, machine->operations, o);
o->machine = machine;
}
log_debug("Started new operation " PID_FMT ".", child);
/* At this point we took ownership of both the child and the errno file descriptor! */
if (ret)
*ret = o;
return 0;
}
Operation *operation_free(Operation *o) {
if (!o)
return NULL;
sd_event_source_unref(o->event_source);
safe_close(o->errno_fd);
safe_close(o->extra_fd);
if (o->pid > 1)
(void) sigkill_wait(o->pid);
sd_bus_message_unref(o->message);
sd_varlink_unref(o->link);
if (o->manager) {
LIST_REMOVE(operations, o->manager->operations, o);
o->manager->n_operations--;
}
if (o->machine)
LIST_REMOVE(operations_by_machine, o->machine->operations, o);
return mfree(o);
}
_noreturn_ void report_errno_and_exit(int errno_fd, int r) {
if (r >= 0)
_exit(EXIT_SUCCESS);
assert(errno_fd >= 0);
ssize_t n = write(errno_fd, &r, sizeof(r));
if (n < 0)
log_debug_errno(errno, "Failed to write operation's errno: %m");
if (n != sizeof(r))
log_debug_errno(SYNTHETIC_ERRNO(EIO), "Sent unexpectedly short message");
_exit(EXIT_FAILURE);
}
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