libxenlight: tests a lots more of xl return value inside the library

and in xl.

introducing a domain where the xenguest build function has fail, lead
to having xenstored receiving SIGBUS, since it's trying to access some
of the domain's memory, which haven't been properly allocated. (it
doesn't seems to be a way to make xenstored more robust to this though
since xc_map_foreign_range just succeed).

make xl a lot more robust regarding all those random errors possible.

Signed-off-by: Vincent Hanquez <vincent.hanquez@eu.citrix.com>

2 files changed, 49 insertions, 17 deletions

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index c2dcbcc52d..15299ea346 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -176,18 +176,24 @@ 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;
+    int i, ret;
+
+    ret = build_pre(ctx, domid, info, state);
+    if (ret) goto out;
 
-    build_pre(ctx, domid, info, state);
     if (info->hvm) {
-        build_hvm(ctx, domid, info, state);
+        ret = build_hvm(ctx, domid, info, state);
+        if (ret) goto out;
+
         vments = libxl_calloc(ctx, 5, sizeof(char *));
         vments[0] = "rtc/timeoffset";
         vments[1] = (info->u.hvm.timeoffset) ? info->u.hvm.timeoffset : "";
         vments[2] = "image/ostype";
         vments[3] = "hvm";
     } else {
-        build_pv(ctx, domid, info, state);
+        ret = build_pv(ctx, domid, info, state);
+        if (ret) goto out;
+
         vments = libxl_calloc(ctx, 9, sizeof(char *));
         i = 0;
         vments[i++] = "image/ostype";
@@ -203,8 +209,9 @@ int libxl_domain_build(struct libxl_ctx *ctx, libxl_domain_build_info *info, uin
             vments[i++] = (char*) info->u.pv.cmdline;
         }
     }
-    build_post(ctx, domid, info, state, vments, localents);
-    return 0;
+    ret = build_post(ctx, domid, info, state, vments, localents);
+out:
+    return ret;
 }
 
 int libxl_domain_restore(struct libxl_ctx *ctx, libxl_domain_build_info *info,
@@ -212,10 +219,14 @@ int libxl_domain_restore(struct libxl_ctx *ctx, libxl_domain_build_info *info,
                          libxl_device_model_info *dm_info)
 {
     char **vments = NULL, **localents = NULL;
-    int i;
+    int i, ret;
+
+    ret = build_pre(ctx, domid, info, state);
+    if (ret) goto out;
+
+    ret = restore_common(ctx, domid, info, state, fd);
+    if (ret) goto out;
 
-    build_pre(ctx, domid, info, state);
-    restore_common(ctx, domid, info, state, fd);
     if (info->hvm) {
         vments = libxl_calloc(ctx, 5, sizeof(char *));
         vments[0] = "rtc/timeoffset";
@@ -238,13 +249,15 @@ int libxl_domain_restore(struct libxl_ctx *ctx, libxl_domain_build_info *info,
             vments[i++] = (char*) info->u.pv.cmdline;
         }
     }
-    build_post(ctx, domid, info, state, vments, localents);
+    ret = build_post(ctx, domid, info, state, vments, localents);
+    if (ret) goto out;
+
     if (info->hvm)
         asprintf(&(dm_info->saved_state), "/var/lib/xen/qemu-save.%d", domid);
     else
         dm_info->saved_state = NULL;
-
-    return 0;
+out:
+    return ret;
 }
 
 int libxl_domain_resume(struct libxl_ctx *ctx, uint32_t domid)
diff --git a/tools/libxl/xl.c b/tools/libxl/xl.c
index 3be7acf0a4..2322ce4a67 100644
--- a/tools/libxl/xl.c
+++ b/tools/libxl/xl.c
@@ -750,6 +750,7 @@ static void create_domain(int debug, int daemonize, const char *config_file, con
     int num_disks = 0, num_vifs = 0, num_pcidevs = 0, num_vfbs = 0, num_vkbs = 0;
     int i, fd;
     int need_daemon = 1;
+    int ret;
     libxl_device_model_starting *dm_starting = 0;
     libxl_waiter *w1 = NULL, *w2 = NULL;
     memset(&dm_info, 0x00, sizeof(dm_info));
@@ -768,29 +769,47 @@ start:
     }
 
     libxl_ctx_set_log(&ctx, log_callback, NULL);
-    libxl_domain_make(&ctx, &info1, &domid);
+
+    ret = libxl_domain_make(&ctx, &info1, &domid);
+    if (ret) {
+        fprintf(stderr, "cannot make domain: %d\n", ret);
+        return;
+    }
 
     if (!restore_file || !need_daemon) {
         if (dm_info.saved_state) {
             free(dm_info.saved_state);
             dm_info.saved_state = NULL;
         }
-        libxl_domain_build(&ctx, &info2, domid, &state);
+        ret = libxl_domain_build(&ctx, &info2, domid, &state);
     } else {
         int restore_fd;
 
         restore_fd = open(restore_file, O_RDONLY);
-        libxl_domain_restore(&ctx, &info2, domid, restore_fd, &state, &dm_info);
+        ret = libxl_domain_restore(&ctx, &info2, domid, restore_fd, &state, &dm_info);
         close(restore_fd);
     }
 
+    if (ret) {
+        fprintf(stderr, "cannot (re-)build domain: %d\n", ret);
+        return;
+    }
+
     for (i = 0; i < num_disks; i++) {
         disks[i].domid = domid;
-        libxl_device_disk_add(&ctx, domid, &disks[i]);
+        ret = libxl_device_disk_add(&ctx, domid, &disks[i]);
+        if (ret) {
+            fprintf(stderr, "cannot add disk %d to domain: %d\n", i, ret);
+            return;
+        }
     }
     for (i = 0; i < num_vifs; i++) {
         vifs[i].domid = domid;
-        libxl_device_nic_add(&ctx, domid, &vifs[i]);
+        ret = libxl_device_nic_add(&ctx, domid, &vifs[i]);
+        if (ret) {
+            fprintf(stderr, "cannot add nic %d to domain: %d\n", i, ret);
+            return;
+        }
     }
     if (info1.hvm) {
         dm_info.domid = domid;