Re: [libvirt] [PATCH] Allocate buffer to hold xend response

> - if (VIR_ALLOC_N(*content, content_length) < 0 ) { > + if (content_length > XEND_RCV_BUF_MAX_LEN) { > + virXendError(VIR_ERR_INTERNAL_ERROR, > + _("Xend returned HTTP Content-Length of %d, " > + "which exceeds maximum of %d"), > + content_length, > + XEND_RCV_BUF_MAX_LEN); > + return -1; > + } > + > This is subtle enough that a comment might avoid trouble later. /* Allocate one byte beyond the end of the largest buffer we will read. Combined with the fact that VIR_ALLOC_N zeros the returned buffer, this guarantees that "content" will always be NUL-terminated. */

> + if (VIR_ALLOC_N(*content, content_length + 1) < 0 ) { > virReportOOMError(); > return -1; > } > @@ -380,7 +390,7 @@ xend_get(virConnectPtr xend, const char *path, > virXendError(VIR_ERR_GET_FAILED, > _("%d status from xen daemon: %s:%s"), > ret, path, > - content ? *content: "NULL"); > + content ? *content : "NULL"); > Oh! I've just noticed that testing "content" is wrong, since it will always be non-NULL. BTW, the parameter should be marked as such via "ATTRIBUTE_NONNULL (3)".

The test should examine "*content", i.e., *content ? *content : "NULL"); Then I remembered the NULLSTR macro. You can replace the above with this: NULLSTR(*content)); FYI, here's its definition: $ git grep -A2 ine.NULLSTR src/internal.h:# define NULLSTR(s) \ src/internal.h- ((void)verify_true(sizeof *(s) == sizeof (char)), \ src/internal.h- (s) ? (s) : "(null)")