diff options
| author | Simon McVittie <simon.mcvittie@collabora.co.uk> | 2015-11-26 10:37:48 +0000 |
|---|---|---|
| committer | Simon McVittie <smcv@debian.org> | 2015-11-27 10:03:06 +0000 |
| commit | 420f3474ed4c0427d71eb88f42bf464eeab31ff2 (patch) | |
| tree | e73292d0ec53c6fa39a3238443fedc486e758a7e | |
| parent | 7c7f4a5110330255ee630c50a08fc159a15981d0 (diff) | |
Do not attempt to call child_setup on Windows
child_setup() is defined to be called after fork() and before exec(),
but Windows' process model does not have fork(): the equivalent of
those two operations is a single CreateProcess() call. This means
that there is no point at which we could call child_setup() and
have it affect only the child's process-global state. At the point
where it is currently executed, it affects the parent's process-global
state instead, which would be actively harmful if we used any
child_setup() function that was not a no-op on Windows.
The equivalent function in GLib, g_spawn_async_with_pipes(), documents
child_setup() as unused on Windows. Do the same here.
In practice, our only use of child_setup() outside tests
is #ifdef DBUS_UNIX anyway, so this change has no practical effect
right now.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=85857
Reviewed-by: Ralf Habacker <ralf.habacker@freenet.de>
| -rw-r--r-- | dbus/dbus-spawn-win.c | 15 | ||||
| -rw-r--r-- | dbus/dbus-spawn.c | 11 |
2 files changed, 10 insertions, 16 deletions
diff --git a/dbus/dbus-spawn-win.c b/dbus/dbus-spawn-win.c index c58bf3cd..43fafd5a 100644 --- a/dbus/dbus-spawn-win.c +++ b/dbus/dbus-spawn-win.c @@ -69,8 +69,6 @@ struct DBusBabysitter #endif char *log_name; - DBusSpawnChildSetupFunc child_setup; - void *user_data; int argc; char **argv; @@ -588,12 +586,6 @@ babysitter (void *parameter) PING(); _dbus_babysitter_ref (sitter); - if (sitter->child_setup) - { - PING(); - (*sitter->child_setup) (sitter->user_data); - } - _dbus_verbose ("babysitter: spawning %s\n", sitter->log_name); PING(); @@ -648,8 +640,8 @@ _dbus_spawn_async_with_babysitter (DBusBabysitter **sitter_p, const char *log_name, char **argv, char **envp, - DBusSpawnChildSetupFunc child_setup, - void *user_data, + DBusSpawnChildSetupFunc child_setup _DBUS_GNUC_UNUSED, + void *user_data _DBUS_GNUC_UNUSED, DBusError *error) { DBusBabysitter *sitter; @@ -669,9 +661,6 @@ _dbus_spawn_async_with_babysitter (DBusBabysitter **sitter_p, return FALSE; } - sitter->child_setup = child_setup; - sitter->user_data = user_data; - sitter->log_name = _dbus_strdup (log_name); if (sitter->log_name == NULL && log_name != NULL) { diff --git a/dbus/dbus-spawn.c b/dbus/dbus-spawn.c index ddd254dc..e591e690 100644 --- a/dbus/dbus-spawn.c +++ b/dbus/dbus-spawn.c @@ -1188,9 +1188,14 @@ babysit (pid_t grandchild_pid, } /** - * Spawns a new process. The child_setup - * function is passed the given user_data and is run in the child - * just before calling exec(). + * Spawns a new process. + * + * On Unix platforms, the child_setup function is passed the given + * user_data and is run in the child after fork() but before calling exec(). + * This can be used to change uid, resource limits and so on. + * On Windows, this functionality does not fit the multi-processing model + * (Windows does the equivalent of fork() and exec() in a single API call), + * and the child_setup function and its user_data are ignored. * * Also creates a "babysitter" which tracks the status of the * child process, advising the parent if the child exits. |