DB integration: initial support. user login by DB.

src/db.c

@@ -0,0 +1,129 @@
+#include "db.h"
+#include <libpq-fe.h>
+#include <string.h>
+
+#define UNUSED(x) (void)(x)
+#define Q_LEN 128
+
+static PGconn *conn = NULL;
+static PGresult *res = NULL;
+
+// #define USR_NOT_FOUND "User with such credentials is not found!"
+
+static void clearRes() {
+  PQclear(res);
+  res = NULL;
+}
+
+static int terminate(int code) {
+  if (code != 0)
+    fprintf(stderr, "%s\n", PQerrorMessage(conn));
+
+  if (res != NULL)
+    PQclear(res);
+
+  if (conn != NULL)
+    PQfinish(conn);
+
+  return code;
+}
+
+static int exit_query(int code) {
+  if (code != 0)
+    fprintf(stderr, "%s\n", PQerrorMessage(conn));
+
+  if (res != NULL)
+    PQclear(res);
+
+  return code;
+}
+
+static void processNotice(void *arg, const char *message) {
+  UNUSED(arg);
+  UNUSED(message);
+
+  // do nothing
+}
+
+int init_connection() {
+  // TODO: get from external configs
+  conn = PQconnectdb("user=postgres password=dobro host=127.0.0.1 dbname=bbs");
+
+  if (PQstatus(conn) != CONNECTION_OK)
+    return terminate(1);
+
+  int server_ver = PQserverVersion(conn);
+  char *user = PQuser(conn);
+  char *db_name = PQdb(conn);
+
+  printf("Connection established! server version: %d, user: %s, db: %s\n", server_ver,
+         user, db_name);
+  return exit_query(0);
+}
+
+int db_user_auth(i_auth_t *credentials, o_auth_t *response) {
+  char query[Q_LEN];
+  response->is_logged = 0;
+  sprintf(query,
+          "SELECT username, password, privileges "
+          "FROM users "
+          "WHERE username= '%s'",
+          credentials->name);
+  res = PQexec(conn, query);
+
+  if (PQresultStatus(res) != PGRES_TUPLES_OK && !PQntuples(res))
+    return exit_query(1);
+
+  const char *pass = PQgetvalue(res, 0, 1);
+  if (!strcmp(pass, credentials->pass)) {
+    response->is_logged = 1;
+    response->privileges = PQgetvalue(res, 0, 2)[0];
+    return exit_query(0);
+  }
+  return exit_query(2);
+}
+
+/*s
+
+int f_main() {
+  int libpq_ver = PQlibVersion();
+  printf("Version of libpq: %d\n", libpq_ver);
+
+  conn = PQconnectdb("user=postgres password=dobro host=127.0.0.1 dbname=bbs");
+  if (PQstatus(conn) != CONNECTION_OK)
+    terminate(1);
+
+  PQsetNoticeProcessor(conn, processNotice, NULL);
+
+  int server_ver = PQserverVersion(conn);
+  char *user = PQuser(conn);
+  char *db_name = PQdb(conn);
+
+  printf("Server version: %d\n", server_ver);
+  printf("User: %s\n", user);
+  printf("Database name: %s\n", db_name);
+
+  res = PQexec(conn, "SELECT id, username, privileges, email "
+                     "FROM users");
+  if (PQresultStatus(res) != PGRES_TUPLES_OK)
+    terminate(1);
+
+  int nrows = PQntuples(res);
+  for (int i = 0; i < nrows; i++) {
+    char *id = PQgetvalue(res, i, 0);
+    char *name = PQgetvalue(res, i, 1);
+    char *privileges = PQgetvalue(res, i, 2);
+    char *email = PQgetvalue(res, i, 3);
+    printf("Id: %s, Name: %s, Privileges: %d, Email: %s, \n", id, name,
+           privileges[0], email);
+  }
+
+  printf("Total: %d rows\n", nrows);
+
+  clearRes();
+  terminate(0);
+
+  return 0;
+}
+
+*/