Move C code into c_src

8 files changed, 1040 insertions, 0 deletions

diff --git a/c_src/Makefile b/c_src/Makefile
new file mode 100644
index 0000000..29eec47
--- /dev/null
+++ b/c_src/Makefile
@@ -0,0 +1,29 @@
+ERLPREFIX =	/usr/local
+ERLINTERFACE = 	erl_interface-3.7.6
+ERLINCS =	-I$(ERLPREFIX)/lib/erlang/lib/$(ERLINTERFACE)/include
+ERLLIBS =	-L$(ERLPREFIX)/lib/erlang/lib/$(ERLINTERFACE)/lib \
+		-lerl_interface -lei
+
+MYSQLPREFIX =	/usr/local/mysql
+MYSQLINCS =	-I$(MYSQLPREFIX)/include
+#MYSQLLIBS =	-L$(MYSQLPREFIX)/lib -lmysqlclient
+MYSQLLIBS =	$(MYSQLPREFIX)/lib/libmysqlclient.a
+
+CFLAGS =	-g -Wall -Werror $(MYSQLINCS) $(ERLINCS)
+LDFLAGS =	$(MYSQLLIBS) $(ERLLIBS)
+
+PRIVDIR =	../priv
+
+BINS =	$(PRIVDIR)/mysqlerl
+OBJS =	io.o log.o msg.o mysqlerl.o
+
+all:	$(BINS)
+
+clean:
+	rm -rf *.o $(BINS)
+
+$(PRIVDIR)/mysqlerl: $(PRIVDIR) $(OBJS)
+	$(CC) -o $@ $(OBJS) $(LDFLAGS)
+
+$(PRIVDIR):
+	mkdir -p $(PRIVDIR)
diff --git a/c_src/io.c b/c_src/io.c
new file mode 100644
index 0000000..565b1ac
--- /dev/null
+++ b/c_src/io.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2008, Brian Cully <bjc@kublai.com>
+ */
+
+#include "io.h"
+#include "log.h"
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+int
+restartable_read(unsigned char *buf, size_t buflen)
+{
+  ssize_t rc, readb;
+
+  rc = 0;
+  READLOOP:
+  while (rc < buflen) {
+    readb = read(STDIN_FILENO, buf + rc, buflen - rc);
+    if (readb == -1) {
+      if (errno == EAGAIN || errno == EINTR)
+        goto READLOOP;
+
+      return -1;
+    } else if (readb == 0) {
+      return -1;
+    }
+
+    rc += readb;
+  }
+
+  return rc;
+}
+
+int
+restartable_write(const unsigned char *buf, size_t buflen)
+{
+  ssize_t rc, wroteb;
+
+  rc = 0;
+  WRITELOOP:
+  while (rc < buflen) {
+    wroteb = write(STDOUT_FILENO, buf + rc, buflen - rc);
+    if (wroteb == -1) {
+      if (errno == EAGAIN || errno == EINTR)
+        goto WRITELOOP;
+
+      return -1;
+    }
+
+    rc += wroteb;
+  }
+
+  return rc;
+}
diff --git a/c_src/io.h b/c_src/io.h
new file mode 100644
index 0000000..bf4e086
--- /dev/null
+++ b/c_src/io.h
@@ -0,0 +1,13 @@
+/*
+ * Copyright (C) 2008, Brian Cully <bjc@kublai.com>
+ */
+
+#ifndef _IO_H
+#define _IO_H
+
+#include <sys/types.h>
+
+int restartable_read(unsigned char *buf, size_t buflen);
+int restartable_write(const unsigned char *buf, size_t buflen);
+
+#endif
diff --git a/c_src/log.c b/c_src/log.c
new file mode 100644
index 0000000..80aa755
--- /dev/null
+++ b/c_src/log.c
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2008, Brian Cully <bjc@kublai.com>
+ */
+
+#include "log.h"
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <time.h>
+#include <unistd.h>
+
+const char *LOGPATH = "/tmp/mysqlerl.log";
+static FILE *logfile = NULL;
+
+void
+openlog()
+{
+  logfile = fopen(LOGPATH, "a");
+}
+
+void
+closelog()
+{
+  fclose(logfile);
+}
+
+void
+logmsg(const char *format, ...)
+{
+  FILE *out = logfile;
+  char timebuf[32] = "\0";
+  struct tm now_tm;
+  time_t now_time;
+  va_list args;
+
+  va_start(args, format);
+
+  if (logfile == NULL)
+    out = stderr;
+
+  if (time(&now_time) == (time_t)-1) {
+    (void)fprintf(out, "LOGERROR - Failed to fetch time: ");
+  } else {
+    (void)localtime_r(&now_time, &now_tm);
+    if (strftime(timebuf, sizeof(timebuf), "%Y%m%d %H:%M:%S ", &now_tm) == 0) {
+      (void)fprintf(out, "LOGERROR - Failed to parse time (now: %d): ",
+                    (int)now_time);
+    } else {
+      (void)fprintf(out, "%s", timebuf);
+    }
+  }
+  (void)fprintf(out, "[%d]: ", getpid());
+  (void)vfprintf(out, format, args);
+  (void)fprintf(out, "\n");
+
+  fflush(out);
+
+  va_end(args);
+}
+
diff --git a/c_src/log.h b/c_src/log.h
new file mode 100644
index 0000000..ae9a9bd
--- /dev/null
+++ b/c_src/log.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright (C) 2008, Brian Cully <bjc@kublai.com>
+ */
+
+#ifndef _LOG_H
+#define _LOG_H
+
+void openlog();
+void closelog();
+void logmsg(const char *format, ...);
+
+#endif
diff --git a/c_src/msg.c b/c_src/msg.c
new file mode 100644
index 0000000..65926b4
--- /dev/null
+++ b/c_src/msg.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2008, Brian Cully <bjc@kublai.com>
+ */
+
+#include "msg.h"
+
+#include "io.h"
+#include "log.h"
+
+#include <string.h>
+
+ETERM *
+read_msg()
+{
+  ETERM *msg;
+  unsigned char *buf;
+  msglen_t len;
+
+  if (restartable_read((unsigned char *)&len, sizeof(len)) == -1) {
+    if (errno == 0) {
+      logmsg("INFO: got end of file from Erlang process, shutting down.");
+      exit(0);
+    }
+
+    logmsg("ERROR: couldn't read %d byte message prefix: %s.",
+           sizeof(len), strerror(errno));
+
+    exit(2);
+  }
+
+  len = ntohl(len);
+  buf = (unsigned char *)malloc(len);
+  if (buf == NULL) {
+    logmsg("ERROR: Couldn't malloc %d bytes: %s.", len,
+           strerror(errno));
+
+    exit(2);
+  }
+
+  if (restartable_read(buf, len) == -1) {
+    logmsg("ERROR: couldn't read %d byte message: %s.",
+           len, strerror(errno));
+
+    free(buf);
+    exit(2);
+  }
+
+  msg = erl_decode(buf);
+  free(buf);
+
+  return msg;
+}
+
+int
+write_msg(ETERM *msg)
+{
+  unsigned char *buf;
+  msglen_t nlen, buflen;
+
+  buflen = erl_term_len(msg);
+  buf = (unsigned char *)malloc(buflen);
+  erl_encode(msg, buf);
+  erl_free_term(msg);
+
+  nlen = htonl(buflen);
+  if (restartable_write((unsigned char *)&nlen, sizeof(nlen)) == -1) {
+    free(buf);
+    return -1;
+  }
+  if (restartable_write(buf, buflen) == -1) {
+    free(buf);
+    return -1;
+  }
+  free(buf);
+
+  return 0;
+}
diff --git a/c_src/msg.h b/c_src/msg.h
new file mode 100644
index 0000000..6db2aa8
--- /dev/null
+++ b/c_src/msg.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2008, Brian Cully <bjc@kublai.com>
+ */
+
+#ifndef _MSG_H
+#define _MSG_H
+
+#include <erl_interface.h>
+#include <ei.h>
+#include <stdlib.h>
+
+typedef u_int32_t msglen_t;
+
+ETERM *read_msg();
+int write_msg(ETERM *msg);
+
+#endif
diff --git a/c_src/mysqlerl.c b/c_src/mysqlerl.c
new file mode 100644
index 0000000..5c67517
--- /dev/null
+++ b/c_src/mysqlerl.c
@@ -0,0 +1,775 @@
+/*
+ * MySQL port driver.
+ *
+ * Copyright (C) 2008, Brian Cully <bjc@kublai.com>
+ */
+
+#include "io.h"
+#include "log.h"
+#include "msg.h"
+
+#include <errno.h>
+#include <mysql.h>
+#include <string.h>
+
+const char *CONNECT_MSG      = "sql_connect";
+const char *QUERY_MSG        = "sql_query";
+const char *PARAM_QUERY_MSG  = "sql_param_query";
+const char *SELECT_COUNT_MSG = "sql_select_count";
+const char *SELECT_MSG       = "sql_select";
+const char *FIRST_MSG        = "sql_first";
+const char *LAST_MSG         = "sql_last";
+const char *NEXT_MSG         = "sql_next";
+const char *PREV_MSG         = "sql_prev";
+
+const char *NULL_SQL      = "null";
+const char *NUMERIC_SQL   = "sql_numeric";
+const char *DECIMAL_SQL   = "sql_decimal";
+const char *FLOAT_SQL     = "sql_float";
+const char *CHAR_SQL      = "sql_char";
+const char *VARCHAR_SQL   = "sql_varchar";
+const char *TIMESTAMP_SQL = "sql_timestamp";
+const char *INTEGER_SQL   = "sql_integer";
+
+const char *SELECT_ABSOLUTE = "absolute";
+const char *SELECT_RELATIVE = "relative";
+const char *SELECT_NEXT     = "next";
+
+my_bool TRUTHY = 1;
+my_bool FALSY  = 0;
+
+MYSQL dbh;
+MYSQL_BIND *r_bind = NULL;
+MYSQL_FIELD *fields = NULL;
+MYSQL_STMT *sth = NULL;
+MYSQL_RES *results = NULL;
+my_ulonglong numrows = 0;
+my_ulonglong resultoffset = 0; // The index of the next row to read.
+unsigned int numfields = 0;
+
+void
+set_mysql_results(MYSQL_STMT *handle)
+{
+  int i;
+
+  /* Clear any old statement handles. */
+  if (sth) {
+    numrows = 0;
+    mysql_stmt_close(sth);
+  }
+  sth = handle;
+
+  /* Get result metadata. */
+  if (results) {
+    mysql_free_result(results);
+  }
+  results = mysql_stmt_result_metadata(sth);
+
+  /* Buffer results. */
+  if (r_bind) {
+    for (i = 0; i < numfields; i++) {
+      free(r_bind[i].buffer);
+      free(r_bind[i].is_null);
+      free(r_bind[i].length);
+      free(r_bind[i].error);
+    }
+    free(r_bind);
+  }
+
+  numfields = mysql_num_fields(results);
+  fields = mysql_fetch_fields(results);
+
+  r_bind = malloc(numfields * sizeof(MYSQL_BIND));
+  memset(r_bind, 0, numfields * sizeof(MYSQL_BIND));
+  for (i = 0; i < numfields; i++) {
+    r_bind[i].buffer_type   = fields[i].type;
+    r_bind[i].buffer_length = fields[i].length;
+    r_bind[i].buffer        = malloc(fields[i].length);
+    r_bind[i].is_null       = malloc(sizeof(*r_bind[i].is_null));
+    r_bind[i].length        = malloc(sizeof(*r_bind[i].length));
+    r_bind[i].error         = malloc(sizeof(*r_bind[i].error));
+  }
+  mysql_stmt_bind_result(sth, r_bind);
+
+  mysql_stmt_store_result(sth);
+
+  resultoffset = 0;
+  numrows = mysql_stmt_num_rows(sth);
+}
+
+ETERM *
+make_cols()
+{
+  ETERM **cols, *rc;
+  unsigned int i;
+
+  cols = (ETERM **)malloc(numfields * sizeof(ETERM *));
+  if (cols == NULL) {
+    logmsg("ERROR: Couldn't allocate %d bytes for columns: %s",
+           strerror(errno));
+    exit(3);
+  }
+
+  for (i = 0; i < numfields; i++)
+    cols[i] = erl_mk_string(fields[i].name);
+
+  rc = erl_mk_list(cols, numfields);
+
+  for (i = 0; i < numfields; i++)
+    erl_free_term(cols[i]);
+  free(cols);
+
+  return rc;
+}
+
+ETERM *
+make_row()
+{
+  ETERM **rowtup, *rc;
+  unsigned int i;
+
+  rowtup = (ETERM **)malloc(numfields * sizeof(ETERM *));
+  if (rowtup == NULL) {
+    logmsg("ERROR: Couldn't allocate %d bytes for row: %s",
+           strerror(errno));
+    exit(3);
+  }
+
+  for (i = 0; i < numfields; i++) {
+    if (*r_bind[i].is_null)
+      rowtup[i] = erl_mk_atom("null");
+    else
+      rowtup[i] = erl_mk_estring(r_bind[i].buffer, *r_bind[i].length);
+  }
+
+  rc = erl_mk_tuple(rowtup, numfields);
+  if (rc == NULL) {
+    logmsg("ERROR: couldn't allocate %d-tuple", numfields);
+    exit(3);
+  }
+
+  for (i = 0; i < numfields; i++)
+    erl_free_term(rowtup[i]);
+  free(rowtup);
+
+  return rc;
+}
+
+ETERM *
+make_rows(my_ulonglong count)
+{
+  ETERM **rows, *rc;
+  unsigned int i;
+
+  rows = (ETERM **)malloc(numrows * sizeof(ETERM *));
+  if (rows == NULL) {
+    logmsg("ERROR: Couldn't allocate %d bytes for rows: %s",
+           strerror(errno));
+    exit(3);
+  }
+
+  for (i = 0; i < count; i++) {
+    ETERM *rt;
+
+    switch (mysql_stmt_fetch(sth)) {
+    case 0:
+      rt = make_row();
+      rows[i] = erl_format("~w", rt);
+      erl_free_term(rt);
+      break;
+    case MYSQL_NO_DATA:
+      logmsg("ERROR: No data waiting");
+      exit(3);
+    case MYSQL_DATA_TRUNCATED:
+      logmsg("ERROR: Data truncated");
+      exit(3);
+    default:
+      logmsg("ERROR: Couldn't fetch a row (%d): %s",
+             mysql_stmt_errno(sth), mysql_stmt_error(sth));
+      exit(3);
+    }
+  }
+
+  rc = erl_mk_list(rows, count);
+
+  for (i = 0; i < count; i++)
+    erl_free_term(rows[i]);
+  free(rows);
+
+  return rc;
+}
+
+ETERM *
+handle_mysql_result()
+{
+  ETERM *ecols, *erows, *resp;
+
+  ecols = make_cols(fields);
+  erows = make_rows(numrows);
+  resultoffset = numrows;
+
+  resp = erl_format("{selected, ~w, ~w}", ecols, erows);
+
+  erl_free_term(ecols);
+  erl_free_term(erows);
+
+  return resp;
+}
+
+void
+handle_connect(ETERM *msg)
+{
+  ETERM *resp, *tmp;
+  char *host, *db_name, *user, *passwd;
+  int port;
+
+  tmp     = erl_element(2, msg);
+  host    = erl_iolist_to_string(tmp);
+  erl_free_term(tmp);
+
+  tmp     = erl_element(3, msg);
+  port    = ERL_INT_VALUE(tmp);
+  erl_free_term(tmp);
+
+  tmp     = erl_element(4, msg);
+  db_name = erl_iolist_to_string(tmp);
+  erl_free_term(tmp);
+
+  tmp     = erl_element(5, msg);
+  user    = erl_iolist_to_string(tmp);
+  erl_free_term(tmp);
+
+  tmp     = erl_element(6, msg);
+  passwd  = erl_iolist_to_string(tmp);
+  erl_free_term(tmp);
+
+  /* TODO: handle options, passed in next. */
+
+  logmsg("INFO: Connecting to %s on %s:%d as %s", db_name, host, port, user);
+  if (mysql_real_connect(&dbh, host, user, passwd,
+                         db_name, port, NULL, 0) == NULL) {
+    logmsg("ERROR: Failed to connect to database %s as %s: %s.",
+           db_name, user, mysql_error(&dbh));
+    exit(2);
+  }
+
+  resp = erl_format("ok");
+  write_msg(resp);
+  erl_free_term(resp);
+}
+
+void
+handle_query(ETERM *cmd)
+{
+  ETERM *query, *resp;
+  MYSQL_STMT *handle;
+  char *q;
+
+  query = erl_element(2, cmd);
+  q = erl_iolist_to_string(query);
+  erl_free_term(query);
+
+  handle = mysql_stmt_init(&dbh);
+  if (mysql_stmt_prepare(handle, q, strlen(q))) {
+    resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                      mysql_stmt_errno(handle), mysql_stmt_error(handle));
+  } else if (mysql_stmt_execute(handle)) {
+    resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                      mysql_stmt_errno(handle), mysql_stmt_error(handle));
+  } else {
+    set_mysql_results(handle);
+    if (results) {
+      resp = handle_mysql_result(results);
+    } else {
+      if (mysql_num_fields(results) == 0)
+        resp = erl_format("{updated, ~i}", numrows);
+      else
+        resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                          mysql_stmt_errno(handle), mysql_stmt_error(handle));
+    }
+  }
+
+  erl_free(q);
+  mysql_stmt_close(handle);
+
+  write_msg(resp);
+  erl_free_term(resp);
+}
+
+int
+bind_string(MYSQL_BIND *bind, const ETERM *erl_value, unsigned long len)
+{
+  char *val;
+  unsigned long slen;
+
+  val = erl_iolist_to_string(erl_value);
+  if (!val) {
+    logmsg("ERROR: bind_string val is NULL");
+    return -1;
+  }
+
+  slen = strlen(val);
+
+  bind->buffer_type = MYSQL_TYPE_BLOB;
+  bind->buffer_length = len;
+
+  bind->length = malloc(sizeof(unsigned long));
+  memcpy(bind->length, &slen, sizeof(unsigned long));
+
+  bind->buffer = malloc((slen + 1) * sizeof(char));
+  memcpy(bind->buffer, val, slen);
+
+  free(val);
+  return 0;
+}
+
+/*
+ * http://dev.mysql.com/doc/refman/5.1/en/mysql-stmt-execute.html
+ *
+ * 6 >  odbc:param_query(Ref,
+ *                       "INSERT INTO EMPLOYEE (NR, FIRSTNAME, "
+ *                       "LASTNAME, GENDER) VALUES(?, ?, ?, ?)",
+ *                       [{sql_integer,[2,3,4,5,6,7,8]},
+ *                        {{sql_varchar, 20},
+ *                         ["John", "Monica", "Ross", "Rachel",
+ *                          "Piper", "Prue", "Louise"]},
+ *                        {{sql_varchar, 20},
+ *                         ["Doe","Geller","Geller", "Green",
+ *                          "Halliwell", "Halliwell", "Lane"]},
+ *                        {{sql_char, 1}, ["M","F","M","F","T","F","F"]}]).
+ * {updated, 7}
+ */
+void
+handle_param_query(ETERM *msg)
+{
+  ETERM *query, *params, *p, *tmp, *resp;
+  MYSQL_STMT *handle;
+  MYSQL_BIND *bind;
+  char *q;
+  int param_count, i;
+
+  query = erl_element(2, msg);
+  q = erl_iolist_to_string(query);
+  erl_free_term(query);
+
+  params = erl_element(3, msg);
+  erl_free_term(params);
+
+  handle = mysql_stmt_init(&dbh);
+  if (mysql_stmt_prepare(handle, q, strlen(q))) {
+    resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                      mysql_stmt_errno(handle), mysql_stmt_error(handle));
+  } else {
+    param_count = mysql_stmt_param_count(handle);
+    if (param_count != erl_length(params)) {
+      resp = erl_format("{error, {mysql_error, -1, [expected_params, %d, got_params, %d]}}", param_count, erl_length(params));
+    } else {
+      bind = malloc(param_count * sizeof(MYSQL_BIND));
+      if (bind == NULL) {
+        logmsg("ERROR: Couldn't allocate %d bytes for bind params.",
+               param_count * sizeof(MYSQL_BIND));
+        exit(3);
+      }
+      memset(bind, 0, param_count * sizeof(MYSQL_BIND));
+
+      for (i = 0, tmp = params;
+           i < param_count && (p = erl_hd(tmp)) != NULL;
+           i++, tmp = erl_tl(tmp)) {
+        ETERM *type, *value;
+
+        type = erl_element(1, p);
+        value = erl_element(2, p);
+
+        if (ERL_IS_TUPLE(type)) {
+          // Parameter Type + Size: {Type, Size}
+          ETERM *t_type, *t_size;
+          char *t;
+          unsigned long size;
+
+          t_size = erl_element(2, type);
+          size = ERL_INT_VALUE(t_size);
+          bind[i].buffer_length = size;
+          erl_free_term(t_size);
+
+          t_type = erl_element(1, type);
+          t = (char *)ERL_ATOM_PTR(t_type);
+          bind[i].length = malloc(sizeof(unsigned long));
+          if (strncmp(t, NUMERIC_SQL, strlen(NUMERIC_SQL)) == 0) {
+            int val;
+
+            bind[i].buffer_type = MYSQL_TYPE_LONG;
+            *bind[i].length = sizeof(int);
+            bind[i].buffer = malloc(*bind[i].length);
+            memset(bind[i].buffer, 0, *bind[i].length);
+
+            val = ERL_INT_VALUE(value);
+            memcpy(bind[i].buffer, &val, *bind[i].length);
+          } else if (strncmp(t, DECIMAL_SQL, strlen(DECIMAL_SQL)) == 0) {
+            char *val;
+
+            bind[i].buffer_type = MYSQL_TYPE_STRING;
+            *bind[i].length = bind[i].buffer_length * sizeof(char);
+            bind[i].buffer = malloc(*bind[i].length);
+            memset(bind[i].buffer, 0, *bind[i].length);
+
+            val = erl_iolist_to_string(value);
+            if (val) {
+              memcpy(bind[i].buffer, val, *bind[i].length);
+              free(val);
+            }
+          } else if (strncmp(t, FLOAT_SQL, strlen(FLOAT_SQL)) == 0) {
+            float val;
+
+            bind[i].buffer_type = MYSQL_TYPE_FLOAT;
+            *bind[i].length = sizeof(float);
+            bind[i].buffer = malloc(*bind[i].length);
+            memset(bind[i].buffer, 0, *bind[i].length);
+
+            val = ERL_FLOAT_VALUE(value);
+            memcpy(bind[i].buffer, &val, *bind[i].length);
+          } else if (strncmp(t, CHAR_SQL, strlen(CHAR_SQL)) == 0) {
+            char *val;
+
+            bind[i].buffer_type = MYSQL_TYPE_STRING;
+            *bind[i].length = bind[i].buffer_length * sizeof(char);
+            bind[i].buffer = malloc(*bind[i].length);
+            memset(bind[i].buffer, 0, *bind[i].length);
+
+            val = erl_iolist_to_string(value);
+            if (val) {
+              memcpy(bind[i].buffer, val, *bind[i].length);
+              free(val);
+            }
+          } else if (strncmp(t, VARCHAR_SQL, strlen(VARCHAR_SQL)) == 0) {
+            (void)bind_string(&bind[i], value, size);
+          } else {
+            logmsg("ERROR: Unknown sized type: {%s, %d}", t,
+                   bind[i].buffer_length);
+            exit(3);
+          }
+          erl_free_term(t_type);
+        } else {
+          char *t;
+
+          t = (char *)ERL_ATOM_PTR(type);
+          if (strncmp(t, TIMESTAMP_SQL, strlen(TIMESTAMP_SQL)) == 0) {
+            bind[i].buffer_type = MYSQL_TYPE_TIMESTAMP;
+            *bind[i].length = sizeof(MYSQL_TIME);
+            bind[i].buffer = malloc(*bind[i].length);
+            memset(bind[i].buffer, 0, *bind[i].length);
+
+            memcpy(bind[i].buffer, value, *bind[i].length);
+          } else if (strncmp(t, INTEGER_SQL, strlen(INTEGER_SQL)) == 0) {
+            int val;
+
+            bind[i].buffer_type = MYSQL_TYPE_LONG;
+            *bind[i].length = sizeof(int);
+            bind[i].buffer = malloc(*bind[i].length);
+            memset(bind[i].buffer, 0, *bind[i].length);
+
+            val = ERL_INT_VALUE(value);
+            memcpy(bind[i].buffer, &val, *bind[i].length);
+          } else {
+            logmsg("ERROR: Unknown type: %s", t);
+            exit(3);
+          }
+        }
+
+        if (ERL_IS_ATOM(value)
+            && strncmp((char *)ERL_ATOM_PTR(value),
+                       NULL_SQL, strlen(NULL_SQL)) == 0)
+          bind[i].is_null = &TRUTHY;
+        else
+          bind[i].is_null = &FALSY;
+
+        erl_free_term(value);
+        erl_free_term(type);
+      }
+      erl_free_term(params);
+
+      if (mysql_stmt_bind_param(handle, bind)) {
+        resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                          mysql_stmt_errno(handle), mysql_stmt_error(handle));
+      } else {
+        if (mysql_stmt_execute(handle)) {
+          resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                            mysql_stmt_errno(handle), mysql_stmt_error(handle));
+        } else {
+          set_mysql_results(handle);
+          if (results) {
+            resp = handle_mysql_result();
+          } else {
+            if (mysql_num_fields(results) == 0)
+              resp = erl_format("{updated, ~i}", numrows);
+            else
+              resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                                mysql_stmt_errno(handle), mysql_stmt_error(handle));
+          }
+        }
+      }
+
+      for (i = 0; i < param_count; i++) {
+        free(bind[i].length);
+        free(bind[i].buffer);
+      }
+      free(bind);
+    }
+  }
+  erl_free(q);
+
+  mysql_stmt_close(handle);
+
+  write_msg(resp);
+  erl_free_term(resp);
+}
+
+void
+handle_select_count(ETERM *msg)
+{
+  ETERM *query, *resp;
+  MYSQL_STMT *handle;
+  char *q;
+
+  query = erl_element(2, msg);
+  q = erl_iolist_to_string(query);
+  erl_free_term(query);
+
+  handle = mysql_stmt_init(&dbh);
+  if (mysql_stmt_prepare(handle, q, strlen(q))) {
+    resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                      mysql_stmt_errno(handle), mysql_stmt_error(handle));
+  } else if (mysql_stmt_execute(handle)) {
+    resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                      mysql_stmt_errno(handle), mysql_stmt_error(handle));
+  } else {
+    set_mysql_results(handle);
+    if (results) {
+      resp = erl_format("{ok, ~i}", mysql_stmt_affected_rows(handle));
+    } else if (mysql_num_fields(results) == 0) {
+      resp = erl_format("{ok, ~i}", mysql_stmt_affected_rows(handle));
+    } else {
+      resp = erl_format("{error, {mysql_error, ~i, ~s}}",
+                        mysql_stmt_errno(handle), mysql_stmt_error(handle));
+    }
+  }
+  erl_free(q);
+
+  write_msg(resp);
+  erl_free_term(resp);
+}
+
+void
+handle_first(ETERM *msg)
+{
+  ETERM *ecols, *erows, *resp;
+
+  if (results == NULL) {
+    logmsg("ERROR: got first message w/o cursor.");
+    exit(2);
+  }
+
+  mysql_stmt_data_seek(sth, resultoffset);
+  resultoffset = 1;
+
+  ecols = make_cols(fields);
+  erows = make_rows(1);
+  resp = erl_format("{selected, ~w, ~w}", ecols, erows);
+  erl_free_term(erows);
+
+  erl_free_term(ecols);
+  write_msg(resp);
+  erl_free_term(resp);
+}
+
+void
+handle_last(ETERM *msg)
+{
+  ETERM *ecols, *erows, *resp;
+
+  if (results == NULL) {
+    logmsg("ERROR: got last message w/o cursor.");
+    exit(2);
+  }
+
+  mysql_stmt_data_seek(sth, numrows - 1);
+  resultoffset = numrows;
+
+  ecols = make_cols(fields);
+  erows = make_rows(1);
+  resp = erl_format("{selected, ~w, ~w}", ecols, erows);
+  erl_free_term(erows);
+
+  erl_free_term(ecols);
+  write_msg(resp);
+  erl_free_term(resp);
+}
+
+void
+handle_next(ETERM *msg)
+{
+  ETERM *ecols, *erows, *resp;
+
+  if (results == NULL) {
+    logmsg("ERROR: got next message w/o cursor.");
+    exit(2);
+  }
+
+  ecols = make_cols(fields);
+  if (resultoffset == numrows) {
+    resp = erl_format("{selected, ~w, []}", ecols);
+  } else {
+    mysql_stmt_data_seek(sth, resultoffset);
+    resultoffset++;
+    erows = make_rows(1);
+    resp = erl_format("{selected, ~w, ~w}", ecols, erows);
+    erl_free_term(erows);
+  }
+
+  erl_free_term(ecols);
+  write_msg(resp);
+  erl_free_term(resp);
+}
+
+void
+handle_prev(ETERM *msg)
+{
+  ETERM *ecols, *erows, *resp;
+
+  if (results == NULL) {
+    logmsg("ERROR: got prev message w/o cursor.");
+    exit(2);
+  }
+
+  ecols = make_cols(fields);
+  if (resultoffset <= 1) {
+    resp = erl_format("{selected, ~w, []}", ecols);
+  } else {
+    resultoffset--;
+    mysql_stmt_data_seek(sth, resultoffset - 1);
+    erows = make_rows(1);
+    resp = erl_format("{selected, ~w, ~w}", ecols, erows);
+    erl_free_term(erows);
+  }
+
+  erl_free_term(ecols);
+  write_msg(resp);
+  erl_free_term(resp);
+}
+
+void
+handle_select(ETERM *msg)
+{
+  ETERM *epos, *ecount, *ecols, *erows, *resp;
+  my_ulonglong pos, count;
+
+  epos   = erl_element(2, msg);
+  ecount = erl_element(3, msg);
+  pos    = ERL_INT_UVALUE(epos);
+  count  = ERL_INT_UVALUE(ecount);
+  erl_free_term(epos);
+  erl_free_term(ecount);
+
+  if (results == NULL) {
+    logmsg("ERROR: select message w/o cursor.");
+    exit(2);
+  }
+
+  if (ERL_IS_TUPLE(epos)) {
+    char *pos_type;
+    unsigned int pos_count;
+
+    pos_type = ERL_ATOM_PTR(erl_element(1, epos));
+    pos_count = ERL_INT_UVALUE(erl_element(2, epos));
+    if (strncmp(pos_type, SELECT_ABSOLUTE, strlen(SELECT_ABSOLUTE)) == 0) {
+      resultoffset = pos_count - 1;
+    } else if (strncmp(pos_type, SELECT_RELATIVE, strlen(SELECT_RELATIVE)) == 0) {
+      resultoffset += pos_count - 1;
+    } else {
+      resp = erl_format("{error, unknown_position, ~w}", epos);
+      write_msg(resp);
+      erl_free_term(resp);
+
+      return;
+    }
+  } else {
+    if (strncmp((char *)ERL_ATOM_PTR(epos), SELECT_NEXT, strlen(SELECT_NEXT)) == 0) {
+      handle_next(NULL);
+      return;
+    } else {
+      resp = erl_format("{error, unknown_position, ~w}", epos);
+      write_msg(resp);
+      erl_free_term(resp);
+
+      return;
+    }
+  }
+
+  mysql_stmt_data_seek(sth, resultoffset);
+
+  ecols = make_cols();
+  erows = make_rows(count);
+  resultoffset += count;
+  resp = erl_format("{selected, ~w, ~w}", ecols, erows);
+  erl_free_term(erows);
+
+  erl_free_term(ecols);
+  write_msg(resp);
+  erl_free_term(resp);
+}
+
+void
+dispatch_db_cmd(ETERM *msg)
+{
+  ETERM *tag;
+  char *tag_name;
+
+  tag = erl_element(1, msg);
+  tag_name = (char *)ERL_ATOM_PTR(tag);
+  if (strncmp(tag_name, CONNECT_MSG, strlen(CONNECT_MSG)) == 0)
+    handle_connect(msg);
+  else if (strncmp(tag_name, QUERY_MSG, strlen(QUERY_MSG)) == 0)
+    handle_query(msg);
+  else if (strncmp(tag_name, PARAM_QUERY_MSG, strlen(PARAM_QUERY_MSG)) == 0)
+    handle_param_query(msg);
+  else if (strncmp(tag_name, SELECT_COUNT_MSG, strlen(SELECT_COUNT_MSG)) == 0)
+    handle_select_count(msg);
+  else if (strncmp(tag_name, SELECT_MSG, strlen(SELECT_MSG)) == 0)
+    handle_select(msg);
+  else if (strncmp(tag_name, FIRST_MSG, strlen(FIRST_MSG)) == 0)
+    handle_first(msg);
+  else if (strncmp(tag_name, LAST_MSG, strlen(LAST_MSG)) == 0)
+    handle_last(msg);
+  else if (strncmp(tag_name, NEXT_MSG, strlen(NEXT_MSG)) == 0)
+    handle_next(msg);
+  else if (strncmp(tag_name, PREV_MSG, strlen(PREV_MSG)) == 0)
+    handle_prev(msg);
+  else {
+    logmsg("WARNING: message type %s unknown.", (char *)ERL_ATOM_PTR(tag));
+    erl_free_term(tag);
+    exit(3);
+  }
+
+  erl_free_term(tag);
+}
+
+int
+main(int argc, char *argv[])
+{
+  ETERM *msg;
+
+  openlog();
+  logmsg("INFO: starting up.");
+  erl_init(NULL, 0);
+
+  mysql_init(&dbh);
+  while ((msg = read_msg()) != NULL) {
+    dispatch_db_cmd(msg);
+    erl_free_term(msg);
+  }
+  mysql_close(&dbh);
+
+  logmsg("INFO: shutting down.");
+  closelog();
+
+  return 0;
+}