nserve: Add ncmd.h

* nserver/src/nserve.c (sanitize, check_cmd): Move functions ...
* nserver/src/ncmd.c (sanitize, check_cmd): ... here.
* nserver/src/nserve.h (CMD_MIN_SIZE, CMD_MAX_SIZE): Move constants...
* nserver/src/ncmd.h (CMD_MIN_SIZE, CMD_MAX_SIZE): ... here.
(sanitize, check_cmd): New function declarations.

1 files changed, 42 insertions, 0 deletions

diff --git a/nserver/src/ncmd.c b/nserver/src/ncmd.c
new file mode 100644
index 0000000..05785ba
--- /dev/null
+++ b/nserver/src/ncmd.c
@@ -0,0 +1,42 @@
+#include <ncmd.h>
+
+int sanitize(char *cmd)
+{
+    check(cmd != NULL, "cmd is NULL");
+
+    size_t len = strlen(cmd);
+    check(len > 0, "cmd empty");
+
+    // strip newline character at the end.
+    cmd[len - 1] = '\0';
+
+    return 0;
+ error:
+    return -1;
+}
+
+char *check_cmd(char *cmd)
+{
+    char *err = NULL;
+
+    check(cmd != NULL, "cmd is NULL");
+
+    int rc = sanitize(cmd);
+    check(rc != -1, "sanitize failed");
+
+    size_t len = strlen(cmd);
+    if (len >= CMD_MIN_SIZE && len <= CMD_MAX_SIZE) {
+        return NULL;
+    }
+
+    if (len == 0) {
+        err = "closing connection\n";
+    } else {
+        err = "command size invalid\n";
+    }
+
+    return err;
+ error:
+    err = "internal error\n";
+    return err;
+}