[Xen-devel] [PATCH 1/4] libxl: Use libxl_strdup instead of strdup on libxl_version_info

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

The change is simple replace of raw strdup with a libxl variant.
The benefit of that is the libxl variant has the extra
behaviour of abort-on-alloc-fail - and will improve error handling.

libxl_version_info is a bit odd - it is a public function and as libxl.h
mentions - the callers of libxl_ public function needs to call the appropiate
_dispose() function.

"However libxl_get_version_info() is special and returns a cached
result from the ctx which cannot and should not be freed (as evidenced
by it returning a const struct). This data is freed in libxl_ctx_free()
by calling libxl_version_info_dispose(). This is why none of the callers
remember to free -- they shouldn't be doing so." (Ian Campbell)

So the patch makes sure to use the NOGC.

Suggested-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 tools/libxl/libxl.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 2bde0f5..548e2e2 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -5258,6 +5258,7 @@ libxl_numainfo *libxl_get_numainfo(libxl_ctx *ctx, int 
*nr)
 
 const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
 {
+    GC_INIT(ctx);
     union {
         xen_extraversion_t xen_extra;
         xen_compile_info_t xen_cc;
@@ -5270,26 +5271,26 @@ const libxl_version_info* 
libxl_get_version_info(libxl_ctx *ctx)
     libxl_version_info *info = &ctx->version_info;
 
     if (info->xen_version_extra != NULL)
-        return info;
+        goto out;
 
     xen_version = xc_version(ctx->xch, XENVER_version, NULL);
     info->xen_version_major = xen_version >> 16;
     info->xen_version_minor = xen_version & 0xFF;
 
     xc_version(ctx->xch, XENVER_extraversion, &u.xen_extra);
-    info->xen_version_extra = strdup(u.xen_extra);
+    info->xen_version_extra = libxl__strdup(NOGC, u.xen_extra);
 
     xc_version(ctx->xch, XENVER_compile_info, &u.xen_cc);
-    info->compiler = strdup(u.xen_cc.compiler);
-    info->compile_by = strdup(u.xen_cc.compile_by);
-    info->compile_domain = strdup(u.xen_cc.compile_domain);
-    info->compile_date = strdup(u.xen_cc.compile_date);
+    info->compiler = libxl__strdup(NOGC, u.xen_cc.compiler);
+    info->compile_by = libxl__strdup(NOGC, u.xen_cc.compile_by);
+    info->compile_domain = libxl__strdup(NOGC, u.xen_cc.compile_domain);
+    info->compile_date = libxl__strdup(NOGC, u.xen_cc.compile_date);
 
     xc_version(ctx->xch, XENVER_capabilities, &u.xen_caps);
-    info->capabilities = strdup(u.xen_caps);
+    info->capabilities = libxl__strdup(NOGC, u.xen_caps);
 
     xc_version(ctx->xch, XENVER_changeset, &u.xen_chgset);
-    info->changeset = strdup(u.xen_chgset);
+    info->changeset = libxl__strdup(NOGC, u.xen_chgset);
 
     xc_version(ctx->xch, XENVER_platform_parameters, &u.p_parms);
     info->virt_start = u.p_parms.virt_start;
@@ -5297,8 +5298,10 @@ const libxl_version_info* 
libxl_get_version_info(libxl_ctx *ctx)
     info->pagesize = xc_version(ctx->xch, XENVER_pagesize, NULL);
 
     xc_version(ctx->xch, XENVER_commandline, &u.xen_commandline);
-    info->commandline = strdup(u.xen_commandline);
+    info->commandline = libxl__strdup(NOGC, u.xen_commandline);
 
+ out:
+    GC_FREE;
     return info;
 }
 
-- 
2.1.0


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