process: Cancel all asynchronous jobs on reinit

If an asynchronous job is running over a reinit, the process can return
and run its callback function after the reinit. This becomes a problem
if the callback function accesses pointers that were only valid before
the reinit (eg. device structs).
If a reinit is requested explicitly stop all active asynchronous jobs
and clear their callback functions before the reinit.

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>

diff --git a/discover/device-handler.c b/discover/device-handler.c
index 78fb159a3026a2d515d05d0467eae27bd4e33938..3cf7edff082d9f6f880ccdd19c18fa698490cbce 100644 (file)
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -358,6 +358,9 @@ void device_handler_reinit(struct device_handler *handler)
                handler->pending_boot_is_default = false;
        }
 
+       /* Cancel any remaining async jobs */
+       process_stop_async_all();
+
        /* free unresolved boot options */
        list_for_each_entry_safe(&handler->unresolved_boot_options,
                        opt, tmp, list)

diff --git a/lib/process/process.c b/lib/process/process.c
index 93fd9c90b9bff4c8c67f0dcf02039d04c8adfd56..f7e5b8faa2d1af4595fb479fe3d39b429184ad90 100644 (file)
--- a/lib/process/process.c
+++ b/lib/process/process.c
@@ -440,8 +440,29 @@ int process_run_async(struct process *process)
 
 void process_stop_async(struct process *process)
 {
+       /* Avoid signalling an old pid */
+       if (process->cancelled)
+               return;
+
        pb_debug("process: sending SIGTERM to pid %d\n", process->pid);
        kill(process->pid, SIGTERM);
+       process->cancelled = true;
+}
+
+void process_stop_async_all(void)
+{
+       struct process_info *procinfo;
+       struct process *process = NULL;
+
+       pb_debug("process: cancelling all async jobs\n");
+
+       list_for_each_entry(&procset->async_list, procinfo, async_list) {
+               process = &procinfo->process;
+               /* Ignore the process completion - callbacks may use stale data */
+               process->exit_cb = NULL;
+               process->stdout_cb = NULL;
+               process_stop_async(process);
+       }
 }
 
 int process_run_simple_argv(void *ctx, const char *argv[])

diff --git a/lib/process/process.h b/lib/process/process.h
index 65fdba8d537beeb9e43efe9d3f3b08429d143530..f858b0edc11ce344f36e6644dfba157dd634237f 100644 (file)
--- a/lib/process/process.h
+++ b/lib/process/process.h
@@ -45,6 +45,7 @@ struct process {
 
        /* post-execution information */
        int                     exit_status;
+       bool                    cancelled;
 };
 
 /* Process management system init. process_init must be called before
@@ -77,6 +78,7 @@ int process_run_simple(void *ctx, const char *name, ...)
 int process_run_async(struct process *process);
 
 void process_stop_async(struct process *process);
+void process_stop_async_all(void);
 
 /* helper function to determine if a process exited cleanly, with a non-zero
  * exit status */