[DTrace-devel] [PATCH v2 4/5 REVIEWED] module: use uintptr_t as type for kernel symbols withuot type info

[Kris Van Hees]

When a kernel symbol is known to exist (found in kallsyms) but no type
information can be found, a compilation error is reported.  That makes
it impossible to use casting to resolve missing type information for
symbols whose address is clearly known.  So, assign those symbol the
uintptr_t type.

Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>
---
 libdtrace/dt_module.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/libdtrace/dt_module.c b/libdtrace/dt_module.c
index bb8c030d..5d67bdc6 100644
--- a/libdtrace/dt_module.c
+++ b/libdtrace/dt_module.c
@@ -1759,20 +1759,31 @@ dtrace_symbol_type(dtrace_hdl_t *dtp, const GElf_Sym *symp,
 		tip->dtt_type = DT_FPTR_TYPE(dtp);
 	}
 
-	if (undefined) {
-		if (dmp->dm_extern == NULL)
-			return dt_set_errno(dtp, EDT_NOSYM);
+	if (!undefined)
+		goto out;
 
-		dt_ident_t *idp =
-		    dt_idhash_lookup(dmp->dm_extern, sip->name);
+	/*
+	 * Try externs for the module (if any).  If that fails, and we are
+	 * looking for a symbol in a kernel module, default to uintptr_t.
+	 */
+	if (dmp->dm_extern != NULL) {
+		dt_ident_t *idp	= dt_idhash_lookup(dmp->dm_extern, sip->name);
 
 		if (idp == NULL)
 			return dt_set_errno(dtp, EDT_NOSYM);
 
 		tip->dtt_ctfp = idp->di_ctfp;
 		tip->dtt_type = idp->di_type;
-	}
+	} else if (dmp->dm_flags & DT_DM_KERNEL) {
+		tip->dtt_ctfp = dmp->dm_ctfp;
+		tip->dtt_type = ctf_lookup_by_name(dmp->dm_ctfp, "uintptr_t");
+
+		if (tip->dtt_type == CTF_ERR)
+			return dt_set_errno(dtp, EDT_NOSYM);
+	} else
+		return dt_set_errno(dtp, EDT_NOSYM);
 
+out:
 	tip->dtt_object = dmp->dm_name;
 	return 0;
 }
-- 
2.40.1