[Xen-devel] [PATCH 4 of 7] libxl: add libxl__wait_for_offspring function

[Olaf Hering <olaf@xxxxxxxxx>]

# HG changeset patch
# User Olaf Hering <olaf@xxxxxxxxx>
# Date 1319707404 -7200
# Node ID f52460f64b6f58b480d0037a31c20606e9a4ef55
# Parent  1417042ea4ab7b43fed11535c6d79d88ded644dc
libxl: add libxl__wait_for_offspring function

libxl__wait_for_offspring() is a generic version of
libxl__wait_for_device_model().

Use libxl__wait_for_offspring for device model.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>

diff -r 1417042ea4ab -r f52460f64b6f tools/libxl/libxl_device.c
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -535,88 +535,12 @@ int libxl__wait_for_device_model(libxl__
                                                        void *userdata),
                                  void *check_callback_userdata)
 {
-    libxl_ctx *ctx = libxl__gc_owner(gc);
     char *path;
-    char *p;
-    unsigned int len;
-    int rc = 0;
-    struct xs_handle *xsh;
-    int nfds;
-    fd_set rfds;
-    struct timeval tv;
-    unsigned int num;
-    char **l = NULL;
-
-    xsh = xs_daemon_open();
-    if (xsh == NULL) {
-        LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "Unable to open xenstore 
connection");
-        goto err;
-    }
-
     path = libxl__sprintf(gc, "/local/domain/0/device-model/%d/state", domid);
-    xs_watch(xsh, path, path);
-    tv.tv_sec = LIBXL_DEVICE_MODEL_START_TIMEOUT;
-    tv.tv_usec = 0;
-    nfds = xs_fileno(xsh) + 1;
-    if (spawning && spawning->fd > xs_fileno(xsh))
-        nfds = spawning->fd + 1;
-
-    while (rc > 0 || (!rc && tv.tv_sec > 0)) {
-        if ( spawning ) {
-            rc = libxl__spawn_check(gc, spawning);
-            if ( rc ) {
-                LIBXL__LOG(ctx, LIBXL__LOG_ERROR,
-                           "Device Model died during startup");
-                rc = -1;
-                goto err_died;
-            }
-        }
-        p = xs_read(xsh, XBT_NULL, path, &len);
-        if ( NULL == p )
-            goto again;
-
-        if ( NULL != state && strcmp(p, state) )
-            goto again;
-
-        if ( NULL != check_callback ) {
-            rc = (*check_callback)(gc, domid, p, check_callback_userdata);
-            if ( rc > 0 )
-                goto again;
-        }
-
-        free(p);
-        xs_unwatch(xsh, path, path);
-        xs_daemon_close(xsh);
-        return rc;
-again:
-        free(p);
-        FD_ZERO(&rfds);
-        FD_SET(xs_fileno(xsh), &rfds);
-        if (spawning)
-            FD_SET(spawning->fd, &rfds);
-        rc = select(nfds, &rfds, NULL, NULL, &tv);
-        if (rc > 0) {
-            if (FD_ISSET(xs_fileno(xsh), &rfds)) {
-                l = xs_read_watch(xsh, &num);
-                if (l != NULL)
-                    free(l);
-                else
-                    goto again;
-            }
-            if (spawning && FD_ISSET(spawning->fd, &rfds)) {
-                unsigned char dummy;
-                if (read(spawning->fd, &dummy, sizeof(dummy)) != 1)
-                    LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_DEBUG,
-                                     "failed to read spawn status pipe");
-            }
-        }
-    }
-    LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "Device Model not ready");
-err_died:
-    xs_unwatch(xsh, path, path);
-    xs_daemon_close(xsh);
-err:
-    return -1;
+    return libxl__wait_for_offspring(gc, domid,
+                                     LIBXL_DEVICE_MODEL_START_TIMEOUT,
+                                     "Device Model", path, state, spawning,
+                                     check_callback, check_callback_userdata);
 }
 
 int libxl__wait_for_backend(libxl__gc *gc, char *be_path, char *state)
diff -r 1417042ea4ab -r f52460f64b6f tools/libxl/libxl_exec.c
--- a/tools/libxl/libxl_exec.c
+++ b/tools/libxl/libxl_exec.c
@@ -169,6 +169,99 @@ out:
     free(pid);
 }
 
+int libxl__wait_for_offspring(libxl__gc *gc,
+                                 uint32_t domid,
+                                 uint32_t timeout, char *what,
+                                 char *path, char *state,
+                                 libxl__spawn_starting *spawning,
+                                 int (*check_callback)(libxl__gc *gc,
+                                                       uint32_t domid,
+                                                       const char *state,
+                                                       void *userdata),
+                                 void *check_callback_userdata)
+{
+    libxl_ctx *ctx = libxl__gc_owner(gc);
+    char *p;
+    unsigned int len;
+    int rc = 0;
+    struct xs_handle *xsh;
+    int nfds;
+    fd_set rfds;
+    struct timeval tv;
+    unsigned int num;
+    char **l = NULL;
+
+    xsh = xs_daemon_open();
+    if (xsh == NULL) {
+        LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "Unable to open xenstore 
connection");
+        goto err;
+    }
+
+    xs_watch(xsh, path, path);
+    tv.tv_sec = timeout;
+    tv.tv_usec = 0;
+    nfds = xs_fileno(xsh) + 1;
+    if (spawning && spawning->fd > xs_fileno(xsh))
+        nfds = spawning->fd + 1;
+
+    while (rc > 0 || (!rc && tv.tv_sec > 0)) {
+        if ( spawning ) {
+            rc = libxl__spawn_check(gc, spawning);
+            if ( rc ) {
+                LIBXL__LOG(ctx, LIBXL__LOG_ERROR,
+                           "%s died during startup", what);
+                rc = -1;
+                goto err_died;
+            }
+        }
+        p = xs_read(xsh, XBT_NULL, path, &len);
+        if ( NULL == p )
+            goto again;
+
+        if ( NULL != state && strcmp(p, state) )
+            goto again;
+
+        if ( NULL != check_callback ) {
+            rc = (*check_callback)(gc, domid, p, check_callback_userdata);
+            if ( rc > 0 )
+                goto again;
+        }
+
+        free(p);
+        xs_unwatch(xsh, path, path);
+        xs_daemon_close(xsh);
+        return rc;
+again:
+        free(p);
+        FD_ZERO(&rfds);
+        FD_SET(xs_fileno(xsh), &rfds);
+        if (spawning)
+            FD_SET(spawning->fd, &rfds);
+        rc = select(nfds, &rfds, NULL, NULL, &tv);
+        if (rc > 0) {
+            if (FD_ISSET(xs_fileno(xsh), &rfds)) {
+                l = xs_read_watch(xsh, &num);
+                if (l != NULL)
+                    free(l);
+                else
+                    goto again;
+            }
+            if (spawning && FD_ISSET(spawning->fd, &rfds)) {
+                unsigned char dummy;
+                if (read(spawning->fd, &dummy, sizeof(dummy)) != 1)
+                    LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_DEBUG,
+                                     "failed to read spawn status pipe");
+            }
+        }
+    }
+    LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "%s not ready", what);
+err_died:
+    xs_unwatch(xsh, path, path);
+    xs_daemon_close(xsh);
+err:
+    return -1;
+}
+
 static int libxl__set_fd_flag(libxl__gc *gc, int fd, int flag)
 {
     int flags;
diff -r 1417042ea4ab -r f52460f64b6f tools/libxl/libxl_internal.h
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -330,6 +330,16 @@ _hidden int libxl__destroy_device_model(
 
 _hidden void libxl_spawner_record_pid(void *for_spawn, pid_t innerchild);
 
+_hidden int libxl__wait_for_offspring(libxl__gc *gc,
+                                 uint32_t domid,
+                                 uint32_t timeout, char *what,
+                                 char *path, char *state,
+                                 libxl__spawn_starting *spawning,
+                                 int (*check_callback)(libxl__gc *gc,
+                                                       uint32_t domid,
+                                                       const char *state,
+                                                       void *userdata),
+                                 void *check_callback_userdata);
   /* Logs errors.  A copy of "what" is taken.  Return values:
    *  < 0   error, for_spawn need not be detached
    *   +1   caller is the parent, must call detach on *for_spawn eventually
@@ -345,7 +355,7 @@ _hidden int libxl__spawn_check(libxl__gc
   /* Logs errors but also returns them.
    * for_spawn must actually be a  libxl__spawn_starting*  but
    * we take void* so you can pass this function directly to
-   * libxl__wait_for_device_model.  Caller must still call detach. */
+   * libxl__wait_for_offspring.  Caller must still call detach. */
 
  /* low-level stuff, for synchronous subprocesses etc. */
 

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