[PATCH 3 of 9] libxl: add printf attribute to libxl_xs_write and fixup resulting warnings

[Ian Campbell <ian.campbell@citrix.com>]

There is an unfortunate warning for the empty format string by default
which I workaround by adding -Wno-format-zero-length.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

diff -r 24a1b866b2d1 -r 8545cbf7f513 tools/libxl/Makefile
--- a/tools/libxl/Makefile	Mon Jul 12 14:56:37 2010 +0100
+++ b/tools/libxl/Makefile	Mon Jul 12 14:56:37 2010 +0100
@@ -11,7 +11,7 @@
 XLUMAJOR = 1.0
 XLUMINOR = 0
 
-CFLAGS += -Werror
+CFLAGS += -Werror -Wno-format-zero-length
 CFLAGS += -I. -fPIC
 CFLAGS += $(CFLAGS_libxenctrl) $(CFLAGS_libxenguest) $(CFLAGS_libxenstore) $(CFLAGS_libblktapctl)
 
diff -r 24a1b866b2d1 -r 8545cbf7f513 tools/libxl/libxl.c
--- a/tools/libxl/libxl.c	Mon Jul 12 14:56:37 2010 +0100
+++ b/tools/libxl/libxl.c	Mon Jul 12 14:56:37 2010 +0100
@@ -523,7 +523,7 @@
         path = libxl_sprintf(ctx, "/local/domain/0/device-model/%d/state", domid);
         state = libxl_xs_read(ctx, XBT_NULL, path);
         if (state != NULL && !strcmp(state, "paused")) {
-            libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "/local/domain/0/device-model/%d/command", domid), "continue", strlen("continue"));
+            libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "/local/domain/0/device-model/%d/command", domid), "continue");
             libxl_wait_for_device_model(ctx, domid, "running", NULL, NULL);
         }
     }
@@ -2663,7 +2663,7 @@
     }
 
     if (domid != 0)
-        libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/static-max", dompath), "%lu", max_memkb);
+        libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/static-max", dompath), "%"PRIu32, max_memkb);
 
     return 0;
 }
@@ -2702,14 +2702,14 @@
     videoram_s = libxl_xs_read(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/videoram", dompath));
     videoram = videoram_s ? atoi(videoram_s) : 0;
 
-    libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/target", dompath), "%lu", target_memkb);
+    libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/target", dompath), "%"PRIu32, target_memkb);
 
     rc = xc_domain_getinfolist(ctx->xch, domid, 1, &info);
     if (rc != 1 || info.domain != domid)
         return rc;
     xcinfo2xlinfo(&info, &ptr);
     uuid = libxl_uuid2string(ctx, ptr.uuid);
-    libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "/vm/%s/memory", uuid), "%lu", target_memkb / 1024);
+    libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "/vm/%s/memory", uuid), "%"PRIu32, target_memkb / 1024);
 
     if (enforce || !domid)
         memorykb = target_memkb;
diff -r 24a1b866b2d1 -r 8545cbf7f513 tools/libxl/libxl_dom.c
--- a/tools/libxl/libxl_dom.c	Mon Jul 12 14:56:37 2010 +0100
+++ b/tools/libxl/libxl_dom.c	Mon Jul 12 14:56:37 2010 +0100
@@ -247,7 +247,7 @@
         return 1;
     }
     path = libxl_sprintf(si->ctx, "%s/control/shutdown", libxl_xs_get_dompath(si->ctx, si->domid));
-    libxl_xs_write(si->ctx, XBT_NULL, path, "suspend", strlen("suspend"));
+    libxl_xs_write(si->ctx, XBT_NULL, path, "suspend");
     if (si->hvm) {
         unsigned long hvm_pvdrv, hvm_s_state;
         xc_get_hvm_param(si->ctx->xch, si->domid, HVM_PARAM_CALLBACK_IRQ, &hvm_pvdrv);
@@ -275,7 +275,7 @@
     }
     if (!strcmp(state, "suspend")) {
         XL_LOG(si->ctx, XL_LOG_ERROR, "guest didn't suspend in time");
-        libxl_xs_write(si->ctx, XBT_NULL, path, "", 1);
+        libxl_xs_write(si->ctx, XBT_NULL, path, "");
     }
     return 1;
 }
@@ -338,7 +338,7 @@
     char *filename = libxl_sprintf(ctx, "/var/lib/xen/qemu-save.%d", domid);
 
     XL_LOG(ctx, XL_LOG_DEBUG, "Saving device model state to %s", filename);
-    libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "/local/domain/0/device-model/%d/command", domid), "save", strlen("save"));
+    libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "/local/domain/0/device-model/%d/command", domid), "save");
     libxl_wait_for_device_model(ctx, domid, "paused", NULL, NULL);
 
     c = libxl_write_exactly(ctx, fd, QEMU_SIGNATURE, strlen(QEMU_SIGNATURE),
diff -r 24a1b866b2d1 -r 8545cbf7f513 tools/libxl/libxl_internal.h
--- a/tools/libxl/libxl_internal.h	Mon Jul 12 14:56:37 2010 +0100
+++ b/tools/libxl/libxl_internal.h	Mon Jul 12 14:56:37 2010 +0100
@@ -117,7 +117,7 @@
 int libxl_xs_writev(struct libxl_ctx *ctx, xs_transaction_t t,
                     char *dir, char **kvs);
 int libxl_xs_write(struct libxl_ctx *ctx, xs_transaction_t t,
-                   char *path, char *fmt, ...);
+                   char *path, char *fmt, ...) PRINTF_ATTRIBUTE(4, 5);
 char *libxl_xs_get_dompath(struct libxl_ctx *ctx, uint32_t domid); // logs errs
 char *libxl_xs_read(struct libxl_ctx *ctx, xs_transaction_t t, char *path);
 char **libxl_xs_directory(struct libxl_ctx *ctx, xs_transaction_t t, char *path, unsigned int *nb);