[Xen-devel] [PATCH V9 01/12] introduce an API to async exec scripts

[Yang Hongyang <yanghy@xxxxxxxxxxxxxx>]

introduce an API to async exec scripts.it will be used
for both device and netbuffer.

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
---
 tools/libxl/libxl_internal.c | 82 ++++++++++++++++++++++++++++++++++++++++++++
 tools/libxl/libxl_internal.h | 21 ++++++++++++
 2 files changed, 103 insertions(+)

diff --git a/tools/libxl/libxl_internal.c b/tools/libxl/libxl_internal.c
index 6c94d3e..e47eb90 100644
--- a/tools/libxl/libxl_internal.c
+++ b/tools/libxl/libxl_internal.c
@@ -375,6 +375,88 @@ out:
     return rc;
 }
 
+static void libxl_async_exec_timeout(libxl__egc *egc,
+                                     libxl__ev_time *ev,
+                                     const struct timeval *requested_abs)
+{
+    libxl_async_exec *async_exec = CONTAINER_OF(ev, *async_exec, time);
+
+    STATE_AO_GC(async_exec->ao);
+
+    libxl__ev_time_deregister(gc, &async_exec->time);
+    assert(libxl__ev_child_inuse(&async_exec->child));
+
+    LOG(DEBUG, "killing hotplug script %s because of timeout",
+        async_exec->args[0]);
+
+    if (kill(async_exec->child.pid, SIGKILL)) {
+        LOGEV(ERROR, errno, "unable to kill hotplug script %s [%ld]",
+              async_exec->args[0],
+              (unsigned long)async_exec->child.pid);
+    }
+
+    return;
+}
+
+static void libxl_async_exec_done(libxl__egc *egc,
+                                  libxl__ev_child *child,
+                                  pid_t pid, int status)
+{
+    libxl_async_exec *async_exec = CONTAINER_OF(child, *async_exec, child);
+
+    STATE_AO_GC(async_exec->ao);
+
+    libxl__ev_time_deregister(gc, &async_exec->time);
+
+    if (status && !async_exec->allow_fail) {
+        libxl_report_child_exitstatus(CTX, LIBXL__LOG_ERROR,
+                                      async_exec->args[0],
+                                      pid, status);
+    }
+
+    async_exec->finish_cb(async_exec->opaque, status);
+}
+
+int libxl_async_exec_script(libxl__gc *gc, libxl_async_exec *async_exec)
+{
+    pid_t pid;
+
+    /* Convenience aliases */
+    libxl__ev_child *const child = &async_exec->child;
+    char * const *args = async_exec->args;
+    char * const *env = async_exec->env;
+    const int stdinfd = async_exec->stdinfd;
+    const int stdoutfd = async_exec->stdoutfd;
+    const int stderrfd = async_exec->stderrfd;
+
+    /* Set hotplug timeout */
+    if (libxl__ev_time_register_rel(gc, &async_exec->time,
+                                    libxl_async_exec_timeout,
+                                    async_exec->timeout * 1000)) {
+        LOG(ERROR, "unable to register timeout for "
+            "script %s", args[0]);
+        return ERROR_FAIL;
+    }
+
+    LOG(DEBUG, "Calling script: %s ", args[0]);
+
+    /* Fork and exec netbuf script */
+    pid = libxl__ev_child_fork(gc, child, libxl_async_exec_done);
+    if (pid == -1) {
+        LOG(ERROR, "unable to fork for script %s", args[0]);
+        return ERROR_FAIL;
+    }
+
+    if (!pid) {
+        /* child: Launch netbuf script */
+        libxl__exec(gc, stdinfd, stdoutfd, stderrfd, args[0], args, env);
+        /* notreached */
+        abort();
+    }
+
+    return 0;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index c2b73c4..eddafaf 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -2030,6 +2030,27 @@ _hidden const char *libxl__xen_script_dir_path(void);
 _hidden const char *libxl__lock_dir_path(void);
 _hidden const char *libxl__run_dir_path(void);
 
+/*----- asynchronous function -----*/
+typedef struct libxl_async_exec {
+    char **env;
+    char **args;
+    void *opaque;
+    void (*finish_cb)(void *opaque, int status);
+    /* unit: second */
+    int timeout;
+    bool allow_fail;
+    int stdinfd;
+    int stdoutfd;
+    int stderrfd;
+
+    libxl__ev_time time;
+    libxl__ev_child child;
+    libxl__ao *ao;
+} libxl_async_exec;
+
+_hidden extern int libxl_async_exec_script(libxl__gc *gc,
+                                           libxl_async_exec *async_exec);
+
 /*----- device addition/removal -----*/
 
 typedef struct libxl__ao_device libxl__ao_device;
-- 
1.8.3.2


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