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/*
* MySQL port driver.
*
* Copyright (C) 2008, Brian Cully <bjc@kublai.com>
*/
#include <mysql.h>
#include <errno.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
const char *LOGPATH = "/tmp/mysqlerl.log";
const size_t BUFSIZE = 2048;
static FILE *logfile = NULL;
typedef u_int32_t msglen_t;
void
openlog()
{
logfile = fopen(LOGPATH, "a");
}
void
closelog()
{
fclose(logfile);
}
void
logmsg(const char *format, ...)
{
FILE *out = logfile;
va_list args;
if (logfile == NULL)
logfile = stderr;
va_start(args, format);
(void)vfprintf(logfile, format, args);
(void)fprintf(logfile, "\n");
va_end(args);
fflush(logfile);
}
int
restartable_read(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) {
logmsg("ERROR: EOF trying to read additional %d bytes from "
"standard input", buflen - rc);
return -1;
}
rc += readb;
}
return rc;
}
int
restartable_write(const 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;
}
char *
read_cmd()
{
char *buf;
msglen_t len;
logmsg("DEBUG: reading message length.");
if (restartable_read((char *)&len, sizeof(len)) == -1) {
logmsg("ERROR: couldn't read %d byte message prefix: %s.",
sizeof(len), strerror(errno));
exit(2);
}
len = ntohl(len);
buf = malloc(len);
if (buf == NULL) {
logmsg("ERROR: Couldn't malloc %d bytes: %s.", len,
strerror(errno));
exit(2);
}
memset(buf, 0, BUFSIZE);
logmsg("DEBUG: reading message body (len: %d).", len);
if (restartable_read(buf, len) == -1) {
logmsg("ERROR: couldn't read %d byte message: %s.",
len, strerror(errno));
exit(2);
}
return buf;
}
int
write_cmd(const char *cmd, msglen_t len)
{
msglen_t nlen;
nlen = htonl(len + 3);
restartable_write((char *)&nlen, sizeof(nlen));
restartable_write(" - ", 3);
restartable_write(cmd, len);
}
void
dispatch_db_cmd(MYSQL *dbh, const char *cmd)
{
msglen_t len, nlen;
logmsg("DEBUG: dispatch_cmd(\"%s\")", cmd);
write_cmd(cmd, strlen(cmd));
}
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, *cmd;
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];
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 ((cmd = read_cmd()) != NULL) {
dispatch_db_cmd(&dbh, cmd);
free(cmd);
}
mysql_close(&dbh);
logmsg("INFO: shutting down.");
closelog();
return 0;
}
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