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/*
* MySQL port driver.
*
* Copyright (C) 2008, Brian Cully <bjc@kublai.com>
*/
#include "io.h"
#include "log.h"
#include "msg.h"
#include <mysql.h>
#include <string.h>
const char *QUERY_MSG = "sql_query";
void
handle_sql_query(MYSQL *dbh, ETERM *cmd)
{
ETERM *query, *resp;
char *q;
query = erl_element(2, cmd);
q = erl_iolist_to_string(query);
erl_free_term(query);
logmsg("DEBUG: got query msg: %s.", q);
if (mysql_query(dbh, q)) {
resp = erl_format("{error, {mysql_error, ~i, ~s}}",
mysql_errno(dbh), mysql_error(dbh));
} else {
MYSQL_RES *result;
result = mysql_store_result(dbh);
if (result) {
MYSQL_FIELD *fields;
unsigned int i, num_fields, num_rows;
ETERM **cols, *ecols, **rows, *erows;
num_fields = mysql_num_fields(result);
fields = mysql_fetch_fields(result);
cols = (ETERM **)malloc(num_fields * sizeof(ETERM *));
for (i = 0; i < num_fields; i++) {
logmsg("DEBUG: cols[%d]: %s", i, fields[i].name);
cols[i] = erl_mk_string(fields[i].name);
}
ecols = erl_mk_list(cols, num_fields);
num_rows = mysql_num_rows(result);
rows = (ETERM **)malloc(num_rows * sizeof(ETERM *));
for (i = 0; i < num_rows; i++) {
ETERM **rowtup, *rt;
unsigned long *lengths;
MYSQL_ROW row;
unsigned int j;
row = mysql_fetch_row(result);
lengths = mysql_fetch_lengths(result);
rowtup = (ETERM **)malloc(num_fields * sizeof(ETERM *));
for (j = 0; j < num_fields; j++) {
logmsg("DEBUG: rows[%d][%d] (%d): '%s'", i, j, lengths[j], row[j]);
if (row[j])
rowtup[j] = erl_mk_estring(row[j], lengths[j]);
else
rowtup[j] = erl_mk_atom("NULL");
logmsg("DEBUG: rowtup[%d]: %d", j, rowtup[j]);
}
logmsg("DEBUG: making tuple of %d", num_fields);
rt = erl_mk_tuple(rowtup, num_fields);
if (rt == NULL) {
logmsg("ERROR: couldn't allocate %d-tuple", num_fields);
exit(3);
}
logmsg("DEBUG: copying rt");
rows[i] = erl_format("~w", rt);
logmsg("DEBUG: freeing row fields");
for (j = 0; j < num_fields; j++)
erl_free_term(rowtup[j]);
free(rowtup);
erl_free_term(rt);
}
logmsg("DEBUG: making row list");
erows = erl_mk_list(rows, num_rows);
logmsg("DEBUG: preparing response");
resp = erl_format("{selected, ~w, ~w}",
ecols, erows);
for (i = 0; i < num_fields; i++)
erl_free_term(cols[i]);
free(cols);
erl_free_term(ecols);
for (i = 0; i < num_rows; i++)
erl_free_term(rows[i]);
free(rows);
erl_free_term(erows);
} else {
if (mysql_field_count(dbh) == 0)
resp = erl_format("{num_rows, ~i}", mysql_affected_rows(dbh));
else
resp = erl_format("{error, {mysql_error, ~i, ~s}}",
mysql_errno(dbh), mysql_error(dbh));
}
}
erl_free(q);
logmsg("DEBUG: prepping buffers and sending.");
write_msg(resp);
erl_free_term(resp);
}
void
dispatch_db_cmd(MYSQL *dbh, ETERM *msg)
{
ETERM *tag;
tag = erl_element(1, msg);
if (strncmp((char *)ERL_ATOM_PTR(tag),
QUERY_MSG, strlen(QUERY_MSG)) == 0) {
handle_sql_query(dbh, msg);
} else {
logmsg("WARNING: message type %s unknown.", (char *)ERL_ATOM_PTR(tag));
erl_free_term(tag);
exit(3);
}
erl_free_term(tag);
}
void
usage()
{
fprintf(stderr, "Usage: mysqlerl host port db_name user passwd\n");
exit(1);
}
int
main(int argc, char *argv[])
{
MYSQL dbh;
char *host, *port, *db_name, *user, *passwd;
ETERM *msg;
openlog();
logmsg("INFO: starting up.");
if (argc < 6)
usage();
host = argv[1];
port = argv[2];
db_name = argv[3];
user = argv[4];
passwd = argv[5];
erl_init(NULL, 0);
mysql_init(&dbh);
if (mysql_real_connect(&dbh, host, user, passwd,
db_name, atoi(port), NULL, 0) == NULL) {
logmsg("ERROR: Failed to connect to database %s: %s (%s:%s).",
db_name, mysql_error(&dbh), user, passwd);
exit(2);
}
while ((msg = read_msg()) != NULL) {
dispatch_db_cmd(&dbh, msg);
erl_free_term(msg);
}
mysql_close(&dbh);
logmsg("INFO: shutting down.");
closelog();
return 0;
}
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