[PATCH v2 1/2] util/getauxval: Ensure setting errno if not found

[Vivian Wang]

Sometimes zero is a valid value for getauxval (e.g. AT_EXECFD). Make
sure that we can distinguish between a valid zero value and a not found
entry by setting errno.

Assumes that getauxval from sys/auxv.h sets errno correctly.

Signed-off-by: Vivian Wang <uwu@dram.page>
---
 util/getauxval.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/util/getauxval.c b/util/getauxval.c
index b124107d61..fad16c406e 100644
--- a/util/getauxval.c
+++ b/util/getauxval.c
@@ -95,6 +95,7 @@ unsigned long qemu_getauxval(unsigned long type)
         }
     }
 
+    errno = ENOENT;
     return 0;
 }
 
@@ -104,7 +105,9 @@ unsigned long qemu_getauxval(unsigned long type)
 unsigned long qemu_getauxval(unsigned long type)
 {
     unsigned long aux = 0;
-    elf_aux_info(type, &aux, sizeof(aux));
+    int ret = elf_aux_info(type, &aux, sizeof(aux));
+    if (ret != 0)
+        errno = ret;
     return aux;
 }
 
@@ -112,6 +115,7 @@ unsigned long qemu_getauxval(unsigned long type)
 
 unsigned long qemu_getauxval(unsigned long type)
 {
+    errno = ENOSYS;
     return 0;
 }
 
-- 
2.45.1