Move fetch_env_ulong() from vfd_swmr.c to vfd_swmr_common.c for eventual

reuse by the zoo writer.

1 files changed, 29 insertions, 0 deletions

diff --git a/test/vfd_swmr_common.c b/test/vfd_swmr_common.c
index 7afd984..c79610d 100644
--- a/test/vfd_swmr_common.c
+++ b/test/vfd_swmr_common.c
@@ -191,3 +191,32 @@ vfd_swmr_create_fapl(bool writer, bool only_meta_pages, bool use_vfd_swmr)
     }
     return fapl;
 }
+
+/* Fetch a variable from the environment and parse it for unsigned long
+ * content.  Return 0 if the variable is not present, -1 if it is present
+ * but it does not parse and compare less than `limit`, 1 if it's present,
+ * parses, and is in-bounds.
+ */
+int
+fetch_env_ulong(const char *varname, unsigned long limit, unsigned long *valp)
+{
+    char *end;
+    unsigned long ul;
+    char *tmp;
+
+    if ((tmp = getenv(varname)) == NULL)
+        return 0;
+
+    errno = 0;
+    ul = strtoul(tmp, &end, 0);
+    if ((ul == ULONG_MAX && errno != 0) || end == tmp || *end != '\0') {
+        fprintf(stderr, "could not parse %s: %s\n", varname, strerror(errno));
+        return -1;
+    }
+    if (ul > limit) {
+        fprintf(stderr, "%s (%lu) out of range\n", varname, ul);
+        return -1;
+    }
+    *valp = ul;
+    return 1;
+}