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2a93d86f1a28f558853c6eb6d789a5301b06ebf6
MaxScale/server/core/modutil.cc
Johan Wikman 0ba779d5a2 Update 2.4.0 Change Date
2019-06-25 10:11:55 +03:00

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/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2023-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
/**
* @file modutil.c - Implementation of useful routines for modules
*/
#include <string.h>
#include <strings.h>
#include <array>
#include <iterator>
#include <mutex>
#include <functional>
#include <cctype>
#include <maxsql/mariadb.hh>
#include <maxbase/alloc.h>
#include <maxscale/buffer.hh>
#include <maxscale/modutil.hh>
#include <maxscale/poll.hh>
#include <maxscale/protocol/mysql.hh>
#include <maxscale/utils.h>
#include <maxscale/mysql_utils.hh>
/** These are used when converting MySQL wildcards to regular expressions */
static bool pattern_init = false;
static pcre2_code* re_percent = NULL;
static pcre2_code* re_single = NULL;
static pcre2_code* re_escape = NULL;
static const PCRE2_SPTR pattern_percent = (PCRE2_SPTR) "%";
static const PCRE2_SPTR pattern_single = (PCRE2_SPTR) "([^\\\\]|^)_";
static const PCRE2_SPTR pattern_escape = (PCRE2_SPTR) "[.]";
static const char* sub_percent = ".*";
static const char* sub_single = "$1.";
static const char* sub_escape = "\\.";
static void modutil_reply_routing_error(DCB* backend_dcb,
int error,
const char* state,
char* errstr,
uint32_t flags);
/**
* Check if a GWBUF structure is a MySQL COM_QUERY packet
*
* @param buf Buffer to check
* @return True if GWBUF is a COM_QUERY packet
*/
int modutil_is_SQL(GWBUF* buf)
{
unsigned char* ptr;
if (GWBUF_LENGTH(buf) < 5)
{
return 0;
}
ptr = GWBUF_DATA(buf);
return ptr[4] == 0x03; // COM_QUERY
}
/**
* Check if a GWBUF structure is a MySQL COM_STMT_PREPARE packet
*
* @param buf Buffer to check
* @return True if GWBUF is a COM_STMT_PREPARE packet
*/
int modutil_is_SQL_prepare(GWBUF* buf)
{
unsigned char* ptr;
if (GWBUF_LENGTH(buf) < 5)
{
return 0;
}
ptr = GWBUF_DATA(buf);
return ptr[4] == 0x16; // COM_STMT_PREPARE
}
/**
* Extract the SQL portion of a COM_QUERY packet
*
* NB This sets *sql to point into the packet and does not
* allocate any new storage. The string pointed to by *sql is
* not NULL terminated.
*
* This routine is very simplistic and does not deal with SQL text
* that spans multiple buffers.
*
* The length returned is the complete length of the SQL, which may
* be larger than the amount of data in this packet.
*
* @param buf The packet buffer
* @param sql Pointer that is set to point at the SQL data
* @param length Length of the SQL query data
* @return True if the packet is a COM_QUERY packet
*/
int modutil_extract_SQL(GWBUF* buf, char** sql, int* length)
{
unsigned char* ptr;
if (!modutil_is_SQL(buf) && !modutil_is_SQL_prepare(buf))
{
return 0;
}
ptr = GWBUF_DATA(buf);
*length = *ptr++;
*length += (*ptr++ << 8);
*length += (*ptr++ << 16);
ptr += 2; // Skip sequence id and COM_QUERY byte
*length = *length - 1;
*sql = (char*)ptr;
return 1;
}
/**
* Extract the SQL portion of a COM_QUERY packet
*
* NB This sets *sql to point into the packet and does not
* allocate any new storage. The string pointed to by *sql is
* not NULL terminated.
*
* The number of bytes pointed to *sql is returned in *length
*
* The remaining number of bytes required for the complete query string
* are returned in *residual
*
* @param buf The packet buffer
* @param sql Pointer that is set to point at the SQL data
* @param length Length of the SQL query data pointed to by sql
* @param residual Any remain part of the query in future packets
* @return True if the packet is a COM_QUERY packet
*/
int modutil_MySQL_Query(GWBUF* buf, char** sql, int* length, int* residual)
{
unsigned char* ptr;
if (!modutil_is_SQL(buf))
{
return 0;
}
ptr = GWBUF_DATA(buf);
*residual = *ptr++;
*residual += (*ptr++ << 8);
*residual += (*ptr++ << 16);
ptr += 2; // Skip sequence id and COM_QUERY byte
*residual = *residual - 1;
*length = GWBUF_LENGTH(buf) - 5;
*residual -= *length;
*sql = (char*)ptr;
return 1;
}
/**
* Calculate the length of MySQL packet and how much is missing from the GWBUF
* passed as parameter.
*
* This routine assumes that there is only one MySQL packet in the buffer.
*
* @param buf buffer list including the query, may consist of
* multiple buffers
* @param nbytes_missing pointer to missing bytecount
*
* @return the length of MySQL packet and writes missing bytecount to
* nbytes_missing.
*/
int modutil_MySQL_query_len(GWBUF* buf, int* nbytes_missing)
{
int len;
int buflen;
if (!modutil_is_SQL(buf))
{
len = 0;
goto retblock;
}
len = MYSQL_GET_PAYLOAD_LEN((uint8_t*)GWBUF_DATA(buf));
*nbytes_missing = len - 1;
buflen = gwbuf_length(buf);
*nbytes_missing -= buflen - 5;
retblock:
return len;
}
/**
* Replace the contents of a GWBUF with the new SQL statement passed as a text string.
* The routine takes care of the modification needed to the MySQL packet,
* returning a GWBUF chain that can be used to send the data to a MySQL server
*
* @param orig The original request in a GWBUF
* @param sql The SQL text to replace in the packet
* @return A newly formed GWBUF containing the MySQL packet.
*/
GWBUF* modutil_replace_SQL(GWBUF* orig, char* sql)
{
unsigned char* ptr;
int length, newlength;
GWBUF* addition;
if (!modutil_is_SQL(orig))
{
return NULL;
}
ptr = GWBUF_DATA(orig);
length = *ptr++;
length += (*ptr++ << 8);
length += (*ptr++ << 16);
ptr += 2; // Skip sequence id and COM_QUERY byte
newlength = strlen(sql);
if (length - 1 == newlength)
{
/* New SQL is the same length as old */
memcpy(ptr, sql, newlength);
}
else if (length - 1 > newlength)
{
/* New SQL is shorter */
memcpy(ptr, sql, newlength);
GWBUF_RTRIM(orig, (length - 1) - newlength);
ptr = GWBUF_DATA(orig);
*ptr++ = (newlength + 1) & 0xff;
*ptr++ = ((newlength + 1) >> 8) & 0xff;
*ptr++ = ((newlength + 1) >> 16) & 0xff;
}
else
{
memcpy(ptr, sql, length - 1);
addition = gwbuf_alloc(newlength - (length - 1));
memcpy(GWBUF_DATA(addition), &sql[length - 1], newlength - (length - 1));
ptr = GWBUF_DATA(orig);
*ptr++ = (newlength + 1) & 0xff;
*ptr++ = ((newlength + 1) >> 8) & 0xff;
*ptr++ = ((newlength + 1) >> 16) & 0xff;
addition->gwbuf_type = orig->gwbuf_type;
orig->next = addition;
}
return orig;
}
/**
* Extract the SQL from a COM_QUERY packet and return in a NULL terminated buffer.
* The buffer should be freed by the caller when it is no longer required.
*
* If the packet is not a COM_QUERY packet then the function will return NULL
*
* @param buf The buffer chain
* @return Null terminated string containing query text or NULL on error
*/
char* modutil_get_SQL(GWBUF* buf)
{
unsigned int len, length;
unsigned char* ptr;
char* dptr, * rval = NULL;
if (modutil_is_SQL(buf) || modutil_is_SQL_prepare(buf)
|| MYSQL_IS_COM_INIT_DB((uint8_t*)GWBUF_DATA(buf)))
{
ptr = GWBUF_DATA(buf);
length = *ptr++;
length += (*ptr++ << 8);
length += (*ptr++ << 16);
rval = (char*) MXS_MALLOC(length + 1);
if (rval)
{
dptr = rval;
ptr += 2; // Skip sequence id and COM_QUERY byte
len = GWBUF_LENGTH(buf) - 5;
while (buf && length > 0)
{
int clen = length > len ? len : length;
memcpy(dptr, ptr, clen);
dptr += clen;
length -= clen;
buf = buf->next;
if (buf)
{
ptr = GWBUF_DATA(buf);
len = GWBUF_LENGTH(buf);
}
}
*dptr = 0;
}
}
return rval;
}
/**
* Copy query string from GWBUF buffer to separate memory area.
*
* @param buf GWBUF buffer including the query
*
* @return Plain text query if the packet type is COM_QUERY. Otherwise return
* a string including the packet type.
*/
char* modutil_get_query(GWBUF* buf)
{
uint8_t* packet;
mxs_mysql_cmd_t packet_type;
size_t len;
char* query_str = NULL;
packet = GWBUF_DATA(buf);
packet_type = (mxs_mysql_cmd_t)packet[4];
switch (packet_type)
{
case MXS_COM_QUIT:
len = strlen("[Quit msg]") + 1;
if ((query_str = (char*)MXS_MALLOC(len + 1)) == NULL)
{
goto retblock;
}
memcpy(query_str, "[Quit msg]", len);
memset(&query_str[len], 0, 1);
break;
case MXS_COM_QUERY:
len = MYSQL_GET_PAYLOAD_LEN(packet) - 1; /*< distract 1 for packet type byte */
if (len < 1 || len > ~(size_t)0 - 1 || (query_str = (char*)MXS_MALLOC(len + 1)) == NULL)
{
if (len >= 1 && len <= ~(size_t)0 - 1)
{
mxb_assert(!query_str);
}
goto retblock;
}
memcpy(query_str, &packet[5], len);
memset(&query_str[len], 0, 1);
break;
default:
len = strlen(STRPACKETTYPE(packet_type)) + 1;
if (len < 1 || len > ~(size_t)0 - 1 || (query_str = (char*)MXS_MALLOC(len + 1)) == NULL)
{
if (len >= 1 && len <= ~(size_t)0 - 1)
{
mxb_assert(!query_str);
}
goto retblock;
}
memcpy(query_str, STRPACKETTYPE(packet_type), len);
memset(&query_str[len], 0, 1);
break;
} /*< switch */
retblock:
return query_str;
}
/**
* create a GWBUFF with a MySQL ERR packet
*
* @param packet_number MySQL protocol sequence number in the packet
* @param in_affected_rows MySQL affected rows
* @param mysql_errno The MySQL errno
* @param sqlstate_msg The MySQL State Message
* @param mysql_message The Error Message
* @return The allocated GWBUF or NULL on failure
*/
GWBUF* modutil_create_mysql_err_msg(int packet_number,
int affected_rows,
int merrno,
const char* statemsg,
const char* msg)
{
uint8_t* outbuf = NULL;
uint32_t mysql_payload_size = 0;
uint8_t mysql_packet_header[4];
uint8_t* mysql_payload = NULL;
uint8_t field_count = 0;
uint8_t mysql_err[2];
uint8_t mysql_statemsg[6];
unsigned int mysql_errno = 0;
const char* mysql_error_msg = NULL;
const char* mysql_state = NULL;
GWBUF* errbuf = NULL;
if (statemsg == NULL || msg == NULL)
{
return NULL;
}
mysql_errno = (unsigned int)merrno;
mysql_error_msg = msg;
mysql_state = statemsg;
field_count = 0xff;
gw_mysql_set_byte2(mysql_err, mysql_errno);
mysql_statemsg[0] = '#';
memcpy(mysql_statemsg + 1, mysql_state, 5);
mysql_payload_size = sizeof(field_count)
+ sizeof(mysql_err)
+ sizeof(mysql_statemsg)
+ strlen(mysql_error_msg);
/* allocate memory for packet header + payload */
errbuf = gwbuf_alloc(sizeof(mysql_packet_header) + mysql_payload_size);
mxb_assert(errbuf != NULL);
if (errbuf == NULL)
{
return NULL;
}
outbuf = GWBUF_DATA(errbuf);
/** write packet header and packet number */
gw_mysql_set_byte3(mysql_packet_header, mysql_payload_size);
mysql_packet_header[3] = packet_number;
/** write header */
memcpy(outbuf, mysql_packet_header, sizeof(mysql_packet_header));
mysql_payload = outbuf + sizeof(mysql_packet_header);
/** write field */
memcpy(mysql_payload, &field_count, sizeof(field_count));
mysql_payload = mysql_payload + sizeof(field_count);
/** write errno */
memcpy(mysql_payload, mysql_err, sizeof(mysql_err));
mysql_payload = mysql_payload + sizeof(mysql_err);
/** write sqlstate */
memcpy(mysql_payload, mysql_statemsg, sizeof(mysql_statemsg));
mysql_payload = mysql_payload + sizeof(mysql_statemsg);
/** write error message */
memcpy(mysql_payload, mysql_error_msg, strlen(mysql_error_msg));
return errbuf;
}
/**
* modutil_send_mysql_err_packet
*
* Send a MySQL protocol Generic ERR message, to the dcb
*
* @param dcb The DCB to send the packet
* @param packet_number MySQL protocol sequence number in the packet
* @param in_affected_rows MySQL affected rows
* @param mysql_errno The MySQL errno
* @param sqlstate_msg The MySQL State Message
* @param mysql_message The Error Message
* @return 0 for successful dcb write or 1 on failure
*
*/
int modutil_send_mysql_err_packet(DCB* dcb,
int packet_number,
int in_affected_rows,
int mysql_errno,
const char* sqlstate_msg,
const char* mysql_message)
{
GWBUF* buf;
buf = modutil_create_mysql_err_msg(packet_number,
in_affected_rows,
mysql_errno,
sqlstate_msg,
mysql_message);
return dcb->func.write(dcb, buf);
}
// Helper function for debug assertions
static bool only_one_packet(GWBUF* buffer)
{
mxb_assert(buffer);
uint8_t header[4] = {};
gwbuf_copy_data(buffer, 0, MYSQL_HEADER_LEN, header);
size_t packet_len = gw_mysql_get_byte3(header);
size_t buffer_len = gwbuf_length(buffer);
return packet_len + MYSQL_HEADER_LEN == buffer_len;
}
/**
* Return the first packet from a buffer.
*
* @param p_readbuf Pointer to pointer to GWBUF. If the GWBUF contains a
* complete packet, after the call it will have been updated
* to begin at the byte following the packet.
*
* @return Pointer to GWBUF if the buffer contained at least one complete packet,
* otherwise NULL.
*
* @attention The returned GWBUF is not necessarily contiguous.
*/
GWBUF* modutil_get_next_MySQL_packet(GWBUF** p_readbuf)
{
GWBUF* packet = NULL;
GWBUF* readbuf = *p_readbuf;
if (readbuf)
{
size_t totalbuflen = gwbuf_length(readbuf);
if (totalbuflen >= MYSQL_HEADER_LEN)
{
size_t packetlen;
if (GWBUF_LENGTH(readbuf) >= 3) // The length is in the 3 first bytes.
{
uint8_t* data = (uint8_t*)GWBUF_DATA((readbuf));
packetlen = MYSQL_GET_PAYLOAD_LEN(data) + 4;
}
else
{
// The header is split between two GWBUFs.
uint8_t data[3];
gwbuf_copy_data(readbuf, 0, 3, data);
packetlen = MYSQL_GET_PAYLOAD_LEN(data) + 4;
}
if (packetlen <= totalbuflen)
{
packet = gwbuf_split(p_readbuf, packetlen);
}
}
}
mxb_assert(!packet || only_one_packet(packet));
return packet;
}
/**
* @brief Calculate the length of the complete MySQL packets in the buffer
*
* @param buffer Buffer to inspect
* @return Length of the complete MySQL packets in bytes
*/
static size_t get_complete_packets_length(GWBUF* buffer)
{
uint8_t packet_len[3];
uint32_t buflen = GWBUF_LENGTH(buffer);
size_t offset = 0;
size_t total = 0;
GWBUF* tail = buffer ? buffer->tail : nullptr;
while (buffer && gwbuf_copy_data(buffer, offset, 3, packet_len) == 3)
{
uint32_t len = gw_mysql_get_byte3(packet_len) + MYSQL_HEADER_LEN;
if (len < buflen)
{
offset += len;
total += len;
buflen -= len;
}
/** The packet is spread across multiple buffers or a buffer ends with
* a complete packet. */
else
{
uint32_t read_len = len;
while (read_len >= buflen && buffer)
{
read_len -= buflen;
buffer = buffer->next;
buflen = buffer ? GWBUF_LENGTH(buffer) : 0;
}
// TODO: Fix GWBUF interface so that this function can be written without
// TODO: knowledge about the internals of GWBUF.
if (buffer)
{
buffer->tail = tail;
}
/** Either the buffer ended with a complete packet or the buffer
* contains more data than is required. */
if (read_len == 0 || (buffer && read_len < buflen))
{
total += len;
offset = read_len;
buflen -= read_len;
}
/** The buffer chain contains at least one incomplete packet */
else
{
mxb_assert(!buffer);
break;
}
}
}
return total;
}
/**
* @brief Split the buffer into complete and partial packets
*
* @param p_readbuf Buffer to split, set to NULL if no partial packets are left
* @return Head of the chain of complete packets or NULL if no complete packets
* are available
*/
GWBUF* modutil_get_complete_packets(GWBUF** p_readbuf)
{
size_t buflen;
/** At least 3 bytes are needed to calculate the packet length. */
if (p_readbuf == NULL || (*p_readbuf) == NULL || (buflen = gwbuf_length(*p_readbuf)) < 3)
{
return NULL;
}
size_t total = get_complete_packets_length(*p_readbuf);
GWBUF* complete = NULL;
if (buflen == total)
{
complete = *p_readbuf;
*p_readbuf = NULL;
}
else if (total > 0)
{
#ifdef SS_DEBUG
size_t before = gwbuf_length(*p_readbuf);
#endif
complete = gwbuf_split(p_readbuf, total);
#ifdef SS_DEBUG
mxb_assert(gwbuf_length(complete) == total);
mxb_assert(*p_readbuf == NULL || before - total == gwbuf_length(*p_readbuf));
#endif
}
return complete;
}
int modutil_count_signal_packets(GWBUF* reply, int n_found, bool* more_out, modutil_state* state)
{
enum
{
SKIP_NEXT = 0x1,
PS_OUT_PARAM = 0x2,
};
unsigned int len = gwbuf_length(reply);
int eof = 0;
int err = 0;
size_t offset = 0;
bool more = false;
bool only_ok = true;
uint64_t num_packets = 0;
uint8_t internal_state = state ? state->state : 0;
while (offset < len)
{
num_packets++;
uint8_t header[MYSQL_HEADER_LEN + 5]; // Maximum size of an EOF packet
gwbuf_copy_data(reply, offset, MYSQL_HEADER_LEN + 1, header);
unsigned int payloadlen = MYSQL_GET_PAYLOAD_LEN(header);
unsigned int pktlen = payloadlen + MYSQL_HEADER_LEN;
if (payloadlen == GW_MYSQL_MAX_PACKET_LEN)
{
only_ok = false;
internal_state |= SKIP_NEXT;
}
else if (internal_state & SKIP_NEXT)
{
only_ok = false;
internal_state &= ~SKIP_NEXT;
}
else
{
uint8_t command = MYSQL_GET_COMMAND(header);
if (command == MYSQL_REPLY_ERR)
{
/** Any errors in the packet stream mean that the result set
* generation was aborted due to an error. No more results will
* follow after this. */
*more_out = false;
return 2;
}
else if (command == MYSQL_REPLY_EOF && pktlen == MYSQL_EOF_PACKET_LEN)
{
eof++;
only_ok = false;
uint8_t status[2]; // Two byte server status
gwbuf_copy_data(reply, offset + MYSQL_HEADER_LEN + 1 + 2, sizeof(status), status);
more = gw_mysql_get_byte2(status) & SERVER_MORE_RESULTS_EXIST;
/**
* MySQL 5.6 and 5.7 have a "feature" that doesn't set
* the SERVER_MORE_RESULTS_EXIST flag in the last EOF packet of
* a result set if the SERVER_PS_OUT_PARAMS flag was set in
* the first result set. To handle this, we have to store
* the information from the first EOF packet until we process
* the second EOF packet.
*/
if (gw_mysql_get_byte2(status) & SERVER_PS_OUT_PARAMS)
{
internal_state |= PS_OUT_PARAM;
}
else if (internal_state & PS_OUT_PARAM)
{
more = true;
internal_state &= ~PS_OUT_PARAM;
}
}
else if (command == MYSQL_REPLY_OK && pktlen >= MYSQL_OK_PACKET_MIN_LEN
&& (eof + n_found) % 2 == 0)
{
// An OK packet that is not in the middle of a resultset stream
uint8_t data[payloadlen - 1];
gwbuf_copy_data(reply, offset + MYSQL_HEADER_LEN + 1, sizeof(data), data);
uint8_t* ptr = data;
ptr += mxq::leint_bytes(ptr);
ptr += mxq::leint_bytes(ptr);
uint16_t* status = (uint16_t*)ptr;
more = (*status) & SERVER_MORE_RESULTS_EXIST;
}
else
{
only_ok = false;
}
}
offset += pktlen;
if (offset >= GWBUF_LENGTH(reply) && reply->next)
{
len -= GWBUF_LENGTH(reply);
offset -= GWBUF_LENGTH(reply);
reply = reply->next;
}
}
int total = err + eof + n_found;
if (state)
{
state->state = internal_state;
}
*more_out = more;
// Treat complete multi-statement result sets that consist of only OK packets as a single result set
// TODO: Review this, it doesn't look very convincing.
if (only_ok && !more && num_packets > 1)
{
total = 2;
}
return total;
}
/**
* Create parse error and EPOLLIN event to event queue of the backend DCB.
* When event is notified the error message is processed as error reply and routed
* upstream to client.
*
* @param backend_dcb DCB where event is added
* @param errstr Plain-text string error
* @param flags GWBUF type flags
*/
void modutil_reply_parse_error(DCB* backend_dcb,
char* errstr,
uint32_t flags)
{
modutil_reply_routing_error(backend_dcb, 1064, "42000", errstr, flags);
}
/**
* Create authentication error and EPOLLIN event to event queue of the backend DCB.
* When event is notified the error message is processed as error reply and routed
* upstream to client.
*
* @param backend_dcb DCB where event is added
* @param errstr Plain-text string error
* @param flags GWBUF type flags
*/
void modutil_reply_auth_error(DCB* backend_dcb,
char* errstr,
uint32_t flags)
{
modutil_reply_routing_error(backend_dcb, 1045, "28000", errstr, flags);
}
/**
* Create error message and EPOLLIN event to event queue of the backend DCB.
* When event is notified the message is processed as error reply and routed
* upstream to client.
*
* @param backend_dcb DCB where event is added
* @param error SQL error number
* @param state SQL state
* @param errstr Plain-text string error
* @param flags GWBUF type flags
*/
static void modutil_reply_routing_error(DCB* backend_dcb,
int error,
const char* state,
char* errstr,
uint32_t flags)
{
GWBUF* buf;
buf = modutil_create_mysql_err_msg(1, 0, error, state, errstr);
MXS_FREE(errstr);
if (buf == NULL)
{
MXS_ERROR("Creating routing error message failed.");
return;
}
/** Set flags that help router to process reply correctly */
gwbuf_set_type(buf, flags);
/** Create an incoming event for backend DCB */
poll_add_epollin_event_to_dcb(backend_dcb, buf);
return;
}
/**
* Find the first occurrence of a character in a string. This function ignores
* escaped characters and all characters that are enclosed in single or double quotes.
* @param ptr Pointer to area of memory to inspect
* @param c Character to search for
* @param len Size of the memory area
* @return Pointer to the first non-escaped, non-quoted occurrence of the character.
* If the character is not found, NULL is returned.
*/
char* strnchr_esc(char* ptr, char c, int len)
{
char* p = (char*)ptr;
char* start = p;
bool quoted = false, escaped = false;
char qc = 0;
while (p < start + len)
{
if (escaped)
{
escaped = false;
}
else if (*p == '\\')
{
escaped = true;
}
else if ((*p == '\'' || *p == '"') && !quoted)
{
quoted = true;
qc = *p;
}
else if (quoted && *p == qc)
{
quoted = false;
}
else if (*p == c && !escaped && !quoted)
{
return p;
}
p++;
}
return NULL;
}
/**
* Find the first occurrence of a character in a string. This function ignores
* escaped characters and all characters that are enclosed in single or double quotes.
* MySQL style comment blocks and identifiers in backticks are also ignored.
* @param ptr Pointer to area of memory to inspect
* @param c Character to search for
* @param len Size of the memory area
* @return Pointer to the first non-escaped, non-quoted occurrence of the character.
* If the character is not found, NULL is returned.
*/
char* strnchr_esc_mysql(char* ptr, char c, int len)
{
char* p = (char*) ptr;
char* start = p, * end = start + len;
bool quoted = false, escaped = false, backtick = false, comment = false;
char qc = 0;
while (p < end)
{
if (escaped)
{
escaped = false;
}
else if ((!comment && !quoted && !backtick) || (comment && *p == '*')
|| (!comment && quoted && *p == qc) || (!comment && backtick && *p == '`'))
{
switch (*p)
{
case '\\':
escaped = true;
break;
case '\'':
case '"':
if (!quoted)
{
quoted = true;
qc = *p;
}
else if (*p == qc)
{
quoted = false;
}
break;
case '/':
if (p + 1 < end && *(p + 1) == '*')
{
comment = true;
p += 1;
}
break;
case '*':
if (comment && p + 1 < end && *(p + 1) == '/')
{
comment = false;
p += 1;
}
break;
case '`':
backtick = !backtick;
break;
case '#':
return NULL;
case '-':
if (p + 2 < end && *(p + 1) == '-'
&& isspace(*(p + 2)))
{
return NULL;
}
break;
default:
break;
}
if (*p == c && !escaped && !quoted && !comment && !backtick)
{
return p;
}
}
p++;
}
return NULL;
}
/**
* @brief Check if the string is the final part of a valid SQL statement
*
* This function checks whether the string pointed by @p start contains any
* tokens that are interpreted as executable commands.
* @param start String containing the statement
* @param len Length of the string
* @return True if statement contains no executable parts
*/
bool is_mysql_statement_end(const char* start, int len)
{
const char* ptr = start;
bool rval = false;
while (ptr < start + len && (isspace(*ptr) || *ptr == ';'))
{
ptr++;
}
if (ptr < start + len)
{
switch (*ptr)
{
case '-':
if (ptr < start + len - 2 && *(ptr + 1) == '-' && isspace(*(ptr + 2)))
{
rval = true;
}
break;
case '#':
rval = true;
break;
case '/':
if (ptr < start + len - 1 && *(ptr + 1) == '*')
{
rval = true;
}
break;
}
}
else
{
rval = true;
}
return rval;
}
/**
* @brief Check if the token is the END part of a BEGIN ... END block.
* @param ptr String with at least three non-whitespace characters in it
* @return True if the token is the final part of a BEGIN .. END block
*/
bool is_mysql_sp_end(const char* start, int len)
{
const char* ptr = start;
while (ptr < start + len && (isspace(*ptr) || *ptr == ';'))
{
ptr++;
}
return ptr < start + len - 3 && strncasecmp(ptr, "end", 3) == 0;
}
/**
* Create a COM_QUERY packet from a string.
* @param query Query to create.
* @return Pointer to GWBUF with the query or NULL if memory allocation failed
*/
GWBUF* modutil_create_query(const char* query)
{
mxb_assert(query);
size_t len = strlen(query) + 1; // Query plus the command byte
GWBUF* rval = gwbuf_alloc(len + MYSQL_HEADER_LEN);
if (rval)
{
uint8_t* ptr = (uint8_t*)rval->start;
*ptr++ = (len);
*ptr++ = (len) >> 8;
*ptr++ = (len) >> 16;
*ptr++ = 0x0;
*ptr++ = 0x03;
memcpy(ptr, query, strlen(query));
}
return rval;
}
/**
* Count the number of statements in a query.
* @param buffer Buffer to analyze.
* @return Number of statements.
*/
int modutil_count_statements(GWBUF* buffer)
{
char* start = ((char*)(buffer)->start + 5);
char* ptr = start;
char* end = ((char*)(buffer)->end);
int num = 1;
while (ptr < end && (ptr = strnchr_esc(ptr, ';', end - ptr)))
{
num++;
while (ptr < end && *ptr == ';')
{
ptr++;
}
}
ptr = end - 1;
if (ptr >= start && ptr < end)
{
while (ptr > start && isspace(*ptr))
{
ptr--;
}
if (*ptr == ';')
{
num--;
}
}
return num;
}
int modutil_count_packets(GWBUF* buffer)
{
int packets = 0;
size_t offset = 0;
uint8_t len[3];
while (gwbuf_copy_data(buffer, offset, 3, len) == 3)
{
++packets;
offset += gw_mysql_get_byte3(len) + MYSQL_HEADER_LEN;
}
return packets;
}
/**
* Initialize the PCRE2 patterns used when converting MySQL wildcards to PCRE syntax.
*/
void prepare_pcre2_patterns()
{
static std::mutex re_lock;
std::lock_guard<std::mutex> guard(re_lock);
if (!pattern_init)
{
int err;
size_t erroff;
PCRE2_UCHAR errbuf[MXS_STRERROR_BUFLEN];
if ((re_percent = pcre2_compile(pattern_percent,
PCRE2_ZERO_TERMINATED,
0,
&err,
&erroff,
NULL))
&& (re_single = pcre2_compile(pattern_single,
PCRE2_ZERO_TERMINATED,
0,
&err,
&erroff,
NULL))
&& (re_escape = pcre2_compile(pattern_escape,
PCRE2_ZERO_TERMINATED,
0,
&err,
&erroff,
NULL)))
{
assert(!pattern_init);
pattern_init = true;
}
else
{
pcre2_get_error_message(err, errbuf, sizeof(errbuf));
MXS_ERROR("Failed to compile PCRE2 pattern: %s", errbuf);
}
if (!pattern_init)
{
pcre2_code_free(re_percent);
pcre2_code_free(re_single);
pcre2_code_free(re_escape);
re_percent = NULL;
re_single = NULL;
re_escape = NULL;
}
}
}
/**
* Check if @c string matches @c pattern according to the MySQL wildcard rules.
* The wildcard character @c '%%' is replaced with @c '.*' and @c '_' is replaced
* with @c '.'. All Regular expression special characters are escaped before
* matching is made.
* @param pattern Wildcard pattern
* @param string String to match
* @return MXS_PCRE2_MATCH if the pattern matches, MXS_PCRE2_NOMATCH if it does
* not match and MXS_PCRE2_ERROR if an error occurred
* @see maxscale/pcre2.h
*/
mxs_pcre2_result_t modutil_mysql_wildcard_match(const char* pattern, const char* string)
{
prepare_pcre2_patterns();
mxs_pcre2_result_t rval = MXS_PCRE2_ERROR;
bool err = false;
PCRE2_SIZE matchsize = strlen(string) + 1;
PCRE2_SIZE tempsize = matchsize;
char* matchstr = (char*) MXS_MALLOC(matchsize);
char* tempstr = (char*) MXS_MALLOC(tempsize);
if (matchstr && tempstr)
{
pcre2_match_data* mdata_percent = pcre2_match_data_create_from_pattern(re_percent, NULL);
pcre2_match_data* mdata_single = pcre2_match_data_create_from_pattern(re_single, NULL);
pcre2_match_data* mdata_escape = pcre2_match_data_create_from_pattern(re_escape, NULL);
if (mdata_percent && mdata_single && mdata_escape)
{
if (mxs_pcre2_substitute(re_escape,
pattern,
sub_escape,
&matchstr,
&matchsize) == MXS_PCRE2_ERROR
|| mxs_pcre2_substitute(re_single,
matchstr,
sub_single,
&tempstr,
&tempsize) == MXS_PCRE2_ERROR
|| mxs_pcre2_substitute(re_percent,
tempstr,
sub_percent,
&matchstr,
&matchsize) == MXS_PCRE2_ERROR)
{
err = true;
}
if (!err)
{
int errcode;
rval = mxs_pcre2_simple_match(matchstr, string, PCRE2_CASELESS, &errcode);
if (rval == MXS_PCRE2_ERROR)
{
if (errcode != 0)
{
PCRE2_UCHAR errbuf[MXS_STRERROR_BUFLEN];
pcre2_get_error_message(errcode, errbuf, sizeof(errbuf));
MXS_ERROR("Failed to match pattern: %s", errbuf);
}
err = true;
}
}
}
else
{
err = true;
}
if (err)
{
MXS_ERROR("Fatal error when matching wildcard patterns.");
}
pcre2_match_data_free(mdata_percent);
pcre2_match_data_free(mdata_single);
pcre2_match_data_free(mdata_escape);
}
MXS_FREE(matchstr);
MXS_FREE(tempstr);
return rval;
}
static inline bool is_next(mxs::Buffer::iterator it, mxs::Buffer::iterator end, const std::string& str)
{
mxb_assert(it != end);
for (auto s_it = str.begin(); s_it != str.end(); ++s_it, ++it)
{
if (it == end || *it != *s_it)
{
return false;
}
}
return true;
}
// Class for fast char type lookups
class LUT
{
public:
LUT(const std::string& values)
{
for (const auto& a : values)
{
m_table[(uint8_t)a] = true;
}
}
LUT(std::function<bool(uint8_t)> is_type)
{
for (int i = 0; i <= std::numeric_limits<uint8_t>::max(); i++)
{
m_table[i] = is_type(i);
}
}
inline bool operator()(uint8_t c) const
{
return m_table[c];
}
private:
std::array<bool, 256> m_table = {};
};
// Optimized versions of standard functions that ignore the locale and use a lookup table
static const LUT is_space(::isspace);
static const LUT is_digit(::isdigit);
static const LUT is_alpha(::isalpha);
static const LUT is_alnum(::isalnum);
static const LUT is_xdigit(::isxdigit);
// For detection of characters that need special treatment, helps speed up processing of keywords etc.
static const LUT is_special([](uint8_t c) {
return isdigit(c) || isspace(c) || std::string("\"'`#-/\\").find(
c) != std::string::npos;
});
static std::pair<bool, mxs::Buffer::iterator> probe_number(mxs::Buffer::iterator it,
mxs::Buffer::iterator end)
{
mxb_assert(it != end);
mxb_assert(is_digit(*it));
std::pair<bool, mxs::Buffer::iterator> rval = std::make_pair(true, it);
bool is_hex = *it == '0';
bool allow_hex = false;
// Skip the first character, we know it's a number
it++;
while (it != end)
{
if (is_digit(*it) || (allow_hex && is_xdigit(*it)))
{
// Digit or hex-digit, skip it
}
else
{
// Non-digit character
if (is_hex && (*it == 'x' || *it == 'X'))
{
/** A hexadecimal literal, mark that we've seen the `x` so that
* if another one is seen, it is treated as a normal character */
is_hex = false;
allow_hex = true;
}
else if (*it == 'e')
{
// Possible scientific notation number
auto next_it = std::next(it);
if (next_it == end || (!is_digit(*next_it) && *next_it != '-'))
{
rval.first = false;
break;
}
// Skip over the minus if we have one
if (*next_it == '-')
{
it++;
}
}
else if (*it == '.')
{
// Possible decimal number
auto next_it = std::next(it);
if (next_it != end && !is_digit(*next_it))
{
/** No number after the period, not a decimal number.
* The fractional part of the number is optional in MariaDB. */
rval.first = false;
break;
}
mxb_assert(is_digit(*next_it));
}
else
{
// If we have a non-text character, we treat it as a number
rval.first = !is_alpha(*it);
break;
}
}
// Store the previous iterator
rval.second = it;
it++;
}
return rval;
}
static inline bool is_negation(const std::string& str, int i)
{
bool rval = false;
if (i > 0 && str[i - 1] == '-')
{
// Possibly a negative number
rval = true;
for (int j = i - 1; j >= 0; j--)
{
if (!is_space(str[j]))
{
/** If we find a previously converted value, we know that it
* is not a negation but a subtraction. */
rval = str[j] != '?';
break;
}
}
}
return rval;
}
mxs::Buffer::iterator find_char(mxs::Buffer::iterator it, const mxs::Buffer::iterator& end, char c)
{
for (; it != end; ++it)
{
if (*it == '\\')
{
if (++it == end)
{
break;
}
}
else if (*it == c)
{
return it;
}
}
return it;
}
namespace maxscale
{
std::string get_canonical(GWBUF* querybuf)
{
std::string rval;
int i = 0;
rval.resize(gwbuf_length(querybuf) - MYSQL_HEADER_LEN + 1);
mxs::Buffer buf(querybuf);
for (auto it = std::next(buf.begin(), MYSQL_HEADER_LEN + 1); // Skip packet header and command
it != buf.end(); ++it)
{
if (!is_special(*it))
{
// Normal character, no special handling required
rval[i++] = *it;
}
else if (*it == '\\')
{
// Jump over any escaped values
rval[i++] += *it++;
if (it != buf.end())
{
rval[i++] = *it;
}
else
{
// Query that ends with a backslash
break;
}
}
else if (is_space(*it))
{
if (i == 0 || is_space(rval[i - 1]))
{
// Leading or repeating whitespace, skip it
}
else
{
rval[i++] = ' ';
}
}
else if (*it == '/' && is_next(it, buf.end(), "/*"))
{
auto comment_start = std::next(it, 2);
if (comment_start == buf.end())
{
break;
}
else if (*comment_start != '!' && *comment_start != 'M')
{
// Non-executable comment
while (it != buf.end())
{
if (is_next(it, buf.end(), "*/"))
{
// Comment end marker, return to normal parsing
++it;
break;
}
++it;
}
if (it == buf.end())
{
break;
}
}
else
{
// Executable comment, treat it as normal SQL
rval[i++] = *it;
}
}
else if ((*it == '#' || *it == '-')
&& (is_next(it, buf.end(), "# ") || is_next(it, buf.end(), "-- ")))
{
// End-of-line comment, jump to the next line if one exists
while (it != buf.end())
{
if (*it == '\n')
{
break;
}
else if (*it == '\r')
{
if ((is_next(it, buf.end(), "\r\n")))
{
++it;
}
break;
}
++it;
}
if (it == buf.end())
{
break;
}
}
else if (is_digit(*it) && (i == 0 || (!is_alnum(rval[i - 1]) && rval[i - 1] != '_')))
{
auto num_end = probe_number(it, buf.end());
if (num_end.first)
{
if (is_negation(rval, i))
{
// Remove the sign
i--;
}
rval[i++] = '?';
it = num_end.second;
}
}
else if (*it == '\'' || *it == '"')
{
char c = *it;
if ((it = find_char(std::next(it), buf.end(), c)) == buf.end())
{
break;
}
rval[i++] = '?';
}
else if (*it == '`')
{
auto start = it;
if ((it = find_char(std::next(it), buf.end(), '`')) == buf.end())
{
break;
}
std::copy(start, it, &rval[i]);
i += std::distance(start, it);
rval[i++] = '`';
}
else
{
rval[i++] = *it;
}
mxb_assert(it != buf.end());
}
// Remove trailing whitespace
while (i > 0 && is_space(rval[i - 1]))
{
--i;
}
// Shrink the buffer so that the internal bookkeeping of std::string remains up to date
rval.resize(i);
buf.release();
return rval;
}
}
char* modutil_get_canonical(GWBUF* querybuf)
{
return MXS_STRDUP(maxscale::get_canonical(querybuf).c_str());
}
char* modutil_MySQL_bypass_whitespace(char* sql, size_t len)
{
char* i = sql;
char* end = i + len;
while (i != end)
{
if (isspace(*i))
{
++i;
}
else if (*i == '/') // Might be a comment
{
if ((i + 1 != end) && (*(i + 1) == '*')) // Indeed it was
{
i += 2;
while (i != end)
{
if (*i == '*') // Might be the end of the comment
{
++i;
if (i != end)
{
if (*i == '/') // Indeed it was
{
++i;
break; // Out of this inner while.
}
}
}
else
{
// It was not the end of the comment.
++i;
}
}
}
else
{
// Was not a comment, so we'll bail out.
break;
}
}
else if (*i == '-') // Might be the start of a comment to the end of line
{
bool is_comment = false;
if (i + 1 != end)
{
if (*(i + 1) == '-') // Might be, yes.
{
if (i + 2 != end)
{
if (isspace(*(i + 2))) // Yes, it is.
{
is_comment = true;
i += 3;
while ((i != end) && (*i != '\n'))
{
++i;
}
if (i != end)
{
mxb_assert(*i == '\n');
++i;
}
}
}
}
}
if (!is_comment)
{
break;
}
}
else if (*i == '#')
{
++i;
while ((i != end) && (*i != '\n'))
{
++i;
}
if (i != end)
{
mxb_assert(*i == '\n');
++i;
}
break;
}
else
{
// Neither whitespace not start of a comment, so we bail out.
break;
}
}
return i;
}
bool modutil_ignorable_ping(DCB* dcb)
{
static uint8_t com_ping_packet[] =
{
0x01, 0x00, 0x00, 0x00, 0x0e
};
GWBUF* buf = gwbuf_alloc_and_load(sizeof(com_ping_packet), com_ping_packet);
bool rval = false;
if (buf)
{
gwbuf_set_type(buf, GWBUF_TYPE_IGNORABLE);
if (dcb->func.write(dcb, buf))
{
rval = true;
}
}
return rval;
}
const char format_str[] = "COM_UNKNOWN(%02hhx)";
// The message always fits inside the buffer
thread_local char unknow_type[sizeof(format_str)] = "";
const char* STRPACKETTYPE(int p)
{
switch (p)
{
case MXS_COM_SLEEP:
return "COM_SLEEP";
case MXS_COM_QUIT:
return "COM_QUIT";
case MXS_COM_INIT_DB:
return "COM_INIT_DB";
case MXS_COM_QUERY:
return "COM_QUERY";
case MXS_COM_FIELD_LIST:
return "COM_FIELD_LIST";
case MXS_COM_CREATE_DB:
return "COM_CREATE_DB";
case MXS_COM_DROP_DB:
return "COM_DROP_DB";
case MXS_COM_REFRESH:
return "COM_REFRESH";
case MXS_COM_SHUTDOWN:
return "COM_SHUTDOWN";
case MXS_COM_STATISTICS:
return "COM_STATISTICS";
case MXS_COM_PROCESS_INFO:
return "COM_PROCESS_INFO";
case MXS_COM_CONNECT:
return "COM_CONNECT";
case MXS_COM_PROCESS_KILL:
return "COM_PROCESS_KILL";
case MXS_COM_DEBUG:
return "COM_DEBUG";
case MXS_COM_PING:
return "COM_PING";
case MXS_COM_TIME:
return "COM_TIME";
case MXS_COM_DELAYED_INSERT:
return "COM_DELAYED_INSERT";
case MXS_COM_CHANGE_USER:
return "COM_CHANGE_USER";
case MXS_COM_BINLOG_DUMP:
return "COM_BINLOG_DUMP";
case MXS_COM_TABLE_DUMP:
return "COM_TABLE_DUMP";
case MXS_COM_CONNECT_OUT:
return "COM_CONNECT_OUT";
case MXS_COM_REGISTER_SLAVE:
return "COM_REGISTER_SLAVE";
case MXS_COM_STMT_PREPARE:
return "COM_STMT_PREPARE";
case MXS_COM_STMT_EXECUTE:
return "COM_STMT_EXECUTE";
case MXS_COM_STMT_SEND_LONG_DATA:
return "COM_STMT_SEND_LONG_DATA";
case MXS_COM_STMT_CLOSE:
return "COM_STMT_CLOSE";
case MXS_COM_STMT_RESET:
return "COM_STMT_RESET";
case MXS_COM_SET_OPTION:
return "COM_SET_OPTION";
case MXS_COM_STMT_FETCH:
return "COM_STMT_FETCH";
case MXS_COM_DAEMON:
return "COM_DAEMON";
}
snprintf(unknow_type, sizeof(unknow_type), format_str, p);
return unknow_type;
}
namespace maxscale
{
std::string extract_sql(GWBUF* buffer, size_t len)
{
std::string rval;
uint8_t cmd = mxs_mysql_get_command(buffer);
if (cmd == MXS_COM_QUERY || cmd == MXS_COM_STMT_PREPARE)
{
mxs::Buffer buf(buffer);
size_t header_len = MYSQL_HEADER_LEN + 1;
size_t total_len = buf.length() - header_len;
// Skip the packet header and the command byte
std::copy_n(std::next(buf.begin(), header_len), MXS_MIN(total_len, len), std::back_inserter(rval));
buf.release();
}
return rval;
}
}
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