[Xen-devel] [PATCH 04/14]: libxenlight, avoid writing empty values to xenstore

[Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>]

Prevent segmentation fault caused by empty values
in key-value pairs for the /vm/ subdirectory
when creating a pv domain.

Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>

# HG changeset patch
# User Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
# Date 1259166041 18000
# Node ID ef6525f1ea939e2e283929428c1c78e53b90a819
# Parent  aba8d2df7e42c185f77a17e47b491385a65383f1
Prevent segmentation fault caused by empty values 
in key-value pairs for the /vm/ subdirectory 
when creating a pv domain.

Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>

diff -r aba8d2df7e42 -r ef6525f1ea93 libxl.c
--- a/libxl.c
+++ b/libxl.c
@@ -191,6 +191,7 @@ retry_transaction:
 int libxl_domain_build(struct libxl_ctx *ctx, libxl_domain_build_info *info, 
uint32_t domid, libxl_domain_build_state *state)
 {
     char **vments = NULL, **localents = NULL;
+    int i;
 
     build_pre(ctx, domid, info, state);
     if (info->hvm) {
@@ -203,14 +204,19 @@ int libxl_domain_build(struct libxl_ctx 
     } else {
         build_pv(ctx, domid, info, state);
         vments = libxl_calloc(ctx, 9, sizeof(char *));
-        vments[0] = "image/ostype";
-        vments[1] = "linux";
-        vments[2] = "image/kernel";
-        vments[3] = (char*) info->kernel;
-        vments[4] = "image/ramdisk";
-        vments[5] = (char*) info->u.pv.ramdisk;
-        vments[6] = "image/cmdline";
-        vments[7] = (char*) info->u.pv.cmdline;
+        i = 0;
+        vments[i++] = "image/ostype";
+        vments[i++] = "linux";
+        vments[i++] = "image/kernel";
+        vments[i++] = (char*) info->kernel;
+        if (info->u.pv.ramdisk) {
+            vments[i++] = "image/ramdisk";
+            vments[i++] = (char*) info->u.pv.ramdisk;
+        }
+        if (info->u.pv.cmdline) {
+            vments[i++] = "image/cmdline";
+            vments[i++] = (char*) info->u.pv.cmdline;
+        }
     }
     build_post(ctx, domid, info, state, vments, localents);
     return 0;

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