# HG changeset patch
# User Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>
# Date 1319033430 -7200
# Node ID 52c8717d2e0841e08e3569ca7bdac0b8309b6cf2
# Parent a2a3c4d7333ec15b818b3403f148ad61c254ea82
libxl: handle the return value of wait_for_dev_destroy select and pass it to
caller function.
Handle the return value of the select call inside wait_for_dev_destroy
properly, and return 0 if a device is removed, or ERROR_* if a timeout or error
happened. Use the return value of wait_for_dev_destroy inside
libxl__device_remove to properly return from that function.
This patch should be applied after Ian Campbell's v3 "libxl: rationalise
libxl_device_* APIs".
Signed-off-by: Roger Pau Monne <roger.pau@xxxxxxxxxxxxx>
diff -r a2a3c4d7333e -r 52c8717d2e08 tools/libxl/libxl.h
--- a/tools/libxl/libxl.h Tue Oct 18 13:36:43 2011 +0100
+++ b/tools/libxl/libxl.h Wed Oct 19 16:10:30 2011 +0200
@@ -221,6 +221,7 @@ enum {
ERROR_INVAL = -6,
ERROR_BADFAIL = -7,
ERROR_GUEST_TIMEDOUT = -8,
+ ERROR_TIMEDOUT = -9,
};
#define LIBXL_VERSION 0
diff -r a2a3c4d7333e -r 52c8717d2e08 tools/libxl/libxl_device.c
--- a/tools/libxl/libxl_device.c Tue Oct 18 13:36:43 2011 +0100
+++ b/tools/libxl/libxl_device.c Wed Oct 19 16:10:30 2011 +0200
@@ -367,6 +367,10 @@ int libxl__device_disk_dev_number(const
return -1;
}
+/*
+ * Returns 0 if a device is removed, ERROR_* if an error
+ * or timeout occurred.
+ */
static int wait_for_dev_destroy(libxl__gc *gc, struct timeval *tv)
{
libxl_ctx *ctx = libxl__gc_owner(gc);
@@ -375,22 +379,41 @@ static int wait_for_dev_destroy(libxl__g
fd_set rfds;
char **l1 = NULL;
+start:
rc = 1;
nfds = xs_fileno(ctx->xsh) + 1;
FD_ZERO(&rfds);
FD_SET(xs_fileno(ctx->xsh), &rfds);
- if (select(nfds, &rfds, NULL, NULL, tv) > 0) {
- l1 = xs_read_watch(ctx->xsh, &n);
- if (l1 != NULL) {
- char *state = libxl__xs_read(gc, XBT_NULL, l1[XS_WATCH_PATH]);
- if (!state || atoi(state) == 6) {
- xs_unwatch(ctx->xsh, l1[0], l1[1]);
- xs_rm(ctx->xsh, XBT_NULL, l1[XS_WATCH_TOKEN]);
- LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "Destroyed device backend at
%s", l1[XS_WATCH_TOKEN]);
- rc = 0;
+ switch (select(nfds, &rfds, NULL, NULL, tv)) {
+ case -1:
+ if (errno == EINTR)
+ goto start;
+ rc = ERROR_FAIL;
+ break;
+ case 0:
+ rc = ERROR_TIMEDOUT;
+ break;
+ default:
+ l1 = xs_read_watch(ctx->xsh, &n);
+ if (l1 != NULL) {
+ char *state = libxl__xs_read(gc, XBT_NULL,
+ l1[XS_WATCH_PATH]);
+ if (!state || atoi(state) == 6) {
+ xs_unwatch(ctx->xsh, l1[0], l1[1]);
+ xs_rm(ctx->xsh, XBT_NULL, l1[XS_WATCH_TOKEN]);
+ LIBXL__LOG(ctx, LIBXL__LOG_DEBUG,
+ "Destroyed device backend at %s",
+ l1[XS_WATCH_TOKEN]);
+ rc = 0;
+ } else {
+ /* State is not "disconnected", continue waiting... */
+ goto start;
+ }
+ free(l1);
+ } else {
+ rc = ERROR_FAIL;
}
- free(l1);
- }
+ break;
}
return rc;
}
@@ -436,7 +459,9 @@ retry_transaction:
struct timeval tv;
tv.tv_sec = LIBXL_DESTROY_TIMEOUT;
tv.tv_usec = 0;
- (void)wait_for_dev_destroy(gc, &tv);
+ rc = wait_for_dev_destroy(gc, &tv);
+ if (rc < 0) /* an error or timeout occurred, clear watches */
+ xs_unwatch(ctx->xsh, state_path, be_path);
xs_rm(ctx->xsh, XBT_NULL, libxl__device_frontend_path(gc, dev));
} else {
rc = 1; /* Caller must wait_for_dev_destroy */
@@ -542,7 +567,8 @@ int libxl__devices_destroy(libxl__gc *gc
tv.tv_sec = LIBXL_DESTROY_TIMEOUT;
tv.tv_usec = 0;
while (n_watches > 0) {
- if (wait_for_dev_destroy(gc, &tv)) {
+ if (wait_for_dev_destroy(gc, &tv) < 0) {
+ /* function returned ERROR_* */
break;
} else {
n_watches--;
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