cutils: Allow NULL endptr in parse_uint()

All the qemu_strto*() functions permit a NULL endptr, just like their
libc counterparts, leaving parse_uint() as the oddball that caused
SEGFAULT on NULL and required the user to call parse_uint_full()
instead.  Relax things for consistency, even though the testsuite is
the only impacted caller.  Add one more unit test to ensure even
parse_uint_full(NULL, 0, &value) works.  This also fixes our code to
uniformly favor EINVAL over ERANGE when both apply.

Also fixes a doc mismatch @v vs. a parameter named value.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-9-eblake@redhat.com>

1 files changed, 16 insertions, 2 deletions

diff --git a/tests/unit/test-cutils.c b/tests/unit/test-cutils.c
index 3664b4fffc..cd8fe7d940 100644
--- a/tests/unit/test-cutils.c
+++ b/tests/unit/test-cutils.c
@@ -270,14 +270,26 @@ static void test_parse_uint_full_correct(void)
 
 static void test_parse_uint_full_erange_junk(void)
 {
-    /* FIXME - inconsistent with qemu_strto* which favors EINVAL */
+    /* EINVAL has priority over ERANGE */
     uint64_t i = 999;
     const char *str = "-2junk";
     int r;
 
     r = parse_uint_full(str, 0, &i);
 
-    g_assert_cmpint(r, ==, -ERANGE /* FIXME -EINVAL */);
+    g_assert_cmpint(r, ==, -EINVAL);
+    g_assert_cmpuint(i, ==, 0);
+}
+
+static void test_parse_uint_full_null(void)
+{
+    uint64_t i = 999;
+    const char *str = NULL;
+    int r;
+
+    r = parse_uint_full(str, 0, &i);
+
+    g_assert_cmpint(r, ==, -EINVAL);
     g_assert_cmpuint(i, ==, 0);
 }
 
@@ -3328,6 +3340,8 @@ int main(int argc, char **argv)
                     test_parse_uint_full_correct);
     g_test_add_func("/cutils/parse_uint_full/erange_junk",
                     test_parse_uint_full_erange_junk);
+    g_test_add_func("/cutils/parse_uint_full/null",
+                    test_parse_uint_full_null);
 
     /* qemu_strtoi() tests */
     g_test_add_func("/cutils/qemu_strtoi/correct",