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proxy_request.c
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proxy_request.c
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/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
#include "proxy.h"
#define PARSER_MAXLEN USHRT_MAX-1
// Find the starting offsets of each token; ignoring length.
// This creates a fast small (<= cacheline) index into the request,
// where we later scan or directly feed data into API's.
static int _process_tokenize(mcp_parser_t *pr, const size_t max) {
const char *s = pr->request;
int len = pr->endlen;
// since multigets can be huge, we can't purely judge reqlen against this
// limit, but we also can't index past it since the tokens are shorts.
if (len > PARSER_MAXLEN) {
len = PARSER_MAXLEN;
}
const char *end = s + len;
int curtoken = 0;
int state = 0;
while (s != end) {
switch (state) {
case 0:
// scanning for first non-space to find a token.
if (*s != ' ') {
pr->tokens[curtoken] = s - pr->request;
if (++curtoken == max) {
s++;
state = 2;
break;
}
state = 1;
}
s++;
break;
case 1:
// advance over a token
if (*s != ' ') {
s++;
} else {
state = 0;
}
break;
case 2:
// hit max tokens before end of the line.
// keep advancing so we can place endcap token.
if (*s == ' ') {
goto endloop;
}
s++;
break;
}
}
endloop:
// endcap token so we can quickly find the length of any token by looking
// at the next one.
pr->tokens[curtoken] = s - pr->request;
pr->ntokens = curtoken;
P_DEBUG("%s: cur_tokens: %d\n", __func__, curtoken);
return 0;
}
static int _process_token_len(mcp_parser_t *pr, size_t token) {
const char *s = pr->request + pr->tokens[token];
const char *e = pr->request + pr->tokens[token+1];
// start of next token is after any space delimiters, so back those out.
while (*(e-1) == ' ') {
e--;
}
return e - s;
}
static int _process_request_key(mcp_parser_t *pr) {
pr->klen = _process_token_len(pr, pr->keytoken);
// advance the parser in case of multikey.
pr->parsed = pr->tokens[pr->keytoken] + pr->klen + 1;
if (pr->request[pr->parsed-1] == ' ') {
P_DEBUG("%s: request_key found extra space\n", __func__);
pr->has_space = true;
} else {
pr->has_space = false;
}
return 0;
}
// Just for ascii multiget: search for next "key" beyond where we stopped
// tokenizing before.
// Returns the offset for the next key.
size_t _process_request_next_key(mcp_parser_t *pr) {
const char *cur = pr->request + pr->parsed;
int remain = pr->endlen - pr->parsed;
// chew off any leading whitespace.
while (remain) {
if (*cur == ' ') {
remain--;
cur++;
pr->parsed++;
} else {
break;
}
}
const char *s = memchr(cur, ' ', remain);
if (s != NULL) {
pr->klen = s - cur;
pr->parsed += s - cur;
} else {
pr->klen = remain;
pr->parsed += remain;
}
return cur - pr->request;
}
// for fast testing of existence of meta flags.
// meta has all flags as final tokens
static int _process_request_metaflags(mcp_parser_t *pr, int token) {
if (pr->ntokens <= token) {
pr->t.meta.flags = 0; // no flags found.
return 0;
}
const char *cur = pr->request + pr->tokens[token];
const char *end = pr->request + pr->endlen;
// We blindly convert flags into bits, since the range of possible
// flags is deliberately < 64.
int state = 0;
while (cur != end) {
switch (state) {
case 0:
if (*cur == ' ') {
cur++;
} else {
if (*cur < 65 || *cur > 122) {
return -1;
}
P_DEBUG("%s: setting meta flag: %d\n", __func__, *cur - 65);
pr->t.meta.flags |= (uint64_t)1 << (*cur - 65);
state = 1;
}
break;
case 1:
if (*cur != ' ') {
cur++;
} else {
state = 0;
}
break;
}
}
// not too great hack for noreply detection: this can be flattened out
// once a few other contexts are fixed and we detect the noreply from the
// coroutine start instead.
if (pr->t.meta.flags & ((uint64_t)1 << 48)) {
pr->noreply = true;
}
return 0;
}
// All meta commands are of form: "cm key f l a g S100"
static int _process_request_meta(mcp_parser_t *pr) {
_process_tokenize(pr, PARSER_MAX_TOKENS);
if (pr->ntokens < 2) {
P_DEBUG("%s: not enough tokens for meta command: %d\n", __func__, pr->ntokens);
return -1;
}
pr->keytoken = 1;
_process_request_key(pr);
// pass the first flag token.
return _process_request_metaflags(pr, 2);
}
// ms <key> <datalen> <flags>*\r\n
static int _process_request_mset(mcp_parser_t *pr) {
_process_tokenize(pr, PARSER_MAX_TOKENS);
if (pr->ntokens < 3) {
P_DEBUG("%s: not enough tokens for meta set command: %d\n", __func__, pr->ntokens);
return -1;
}
pr->keytoken = 1;
_process_request_key(pr);
const char *cur = pr->request + pr->tokens[2];
errno = 0;
char *n = NULL;
int vlen = strtol(cur, &n, 10);
if ((errno == ERANGE) || (cur == n)) {
return -1;
}
if (vlen < 0 || vlen > (INT_MAX - 2)) {
return -1;
}
vlen += 2;
pr->vlen = vlen;
// pass the first flag token
return _process_request_metaflags(pr, 3);
}
// gat[s] <exptime> <key>*\r\n
static int _process_request_gat(mcp_parser_t *pr) {
_process_tokenize(pr, 3);
if (pr->ntokens < 3) {
P_DEBUG("%s: not enough tokens for GAT: %d\n", __func__, pr->ntokens);
return -1;
}
pr->keytoken = 2;
_process_request_key(pr);
return 0;
}
#define NOREPLYSTR "noreply"
#define NOREPLYLEN sizeof(NOREPLYSTR)-1
// given a tokenized parser for a normal ASCII command, checks for noreply
// mode.
static int _process_request_noreply(mcp_parser_t *pr) {
if (pr->tokens[pr->ntokens] - pr->tokens[pr->ntokens-1] >= NOREPLYLEN
&& strncmp(NOREPLYSTR, pr->request + pr->tokens[pr->ntokens-1], NOREPLYLEN) == 0) {
pr->noreply = true;
}
return 0;
}
// we need t find the bytes supplied immediately so we can read the request
// from the client properly.
// set <key> <flags> <exptime> <bytes> [noreply]\r\n
static int _process_request_storage(mcp_parser_t *pr, size_t max) {
_process_tokenize(pr, max);
if (pr->ntokens < 5) {
P_DEBUG("%s: not enough tokens to storage command: %d\n", __func__, pr->ntokens);
return -1;
}
pr->keytoken = 1;
_process_request_key(pr);
errno = 0;
char *n = NULL;
const char *cur = pr->request + pr->tokens[4];
int vlen = strtol(cur, &n, 10);
if ((errno == ERANGE) || (cur == n)) {
return -1;
}
if (vlen < 0 || vlen > (INT_MAX - 2)) {
return -1;
}
vlen += 2;
pr->vlen = vlen;
return _process_request_noreply(pr);
}
// common request with key: <cmd> <key> <args>
static int _process_request_simple(mcp_parser_t *pr, const int min, const int max) {
_process_tokenize(pr, max);
if (pr->ntokens < min) {
P_DEBUG("%s: not enough tokens for simple request: %d\n", __func__, pr->ntokens);
return -1;
}
pr->keytoken = 1; // second token is usually the key... stupid GAT.
_process_request_key(pr);
return _process_request_noreply(pr);
}
// TODO: return code ENUM with error types.
// FIXME: the mcp_parser_t bits have ended up being more fragile than I hoped.
// careful zero'ing is required. revisit?
// I think this mostly refers to recursive work (maybe just multiget?)
// Is a parser object run throgh process_request() twice, ever?
int process_request(mcp_parser_t *pr, const char *command, size_t cmdlen) {
// we want to "parse in place" as much as possible, which allows us to
// forward an unmodified request without having to rebuild it.
const char *cm = command;
size_t cl = 0;
// min command length is 2, plus the "\r\n"
if (cmdlen < 4) {
return -1;
}
// Commands can end with bare '\n's. Depressingly I intended to be strict
// with a \r\n requirement but never did this and need backcompat.
// In this case we _know_ \n is at cmdlen because we can't enter this
// function otherwise.
if (cm[cmdlen-2] == '\r') {
pr->endlen = cmdlen - 2;
} else {
pr->endlen = cmdlen - 1;
}
const char *s = memchr(command, ' ', pr->endlen);
if (s != NULL) {
cl = s - command;
} else {
cl = pr->endlen;
}
pr->keytoken = 0;
pr->has_space = false;
pr->parsed = cl;
pr->request = command;
pr->reqlen = cmdlen;
int token_max = PARSER_MAX_TOKENS;
int cmd = -1;
int type = CMD_TYPE_GENERIC;
int ret = 0;
switch (cl) {
case 0:
case 1:
// falls through with cmd as -1. should error.
break;
case 2:
if (cm[0] == 'm') {
type = CMD_TYPE_META;
switch (cm[1]) {
case 'g':
cmd = CMD_MG;
ret = _process_request_meta(pr);
break;
case 's':
cmd = CMD_MS;
ret = _process_request_mset(pr);
break;
case 'd':
cmd = CMD_MD;
ret = _process_request_meta(pr);
break;
case 'n':
// TODO: do we route/handle NOP's at all?
// they should simply reflect to the client.
cmd = CMD_MN;
break;
case 'a':
cmd = CMD_MA;
ret = _process_request_meta(pr);
break;
case 'e':
cmd = CMD_ME;
// TODO: not much special processing here; binary keys
ret = _process_request_meta(pr);
break;
}
}
break;
case 3:
if (cm[0] == 'g') {
if (cm[1] == 'e' && cm[2] == 't') {
cmd = CMD_GET;
type = CMD_TYPE_GET;
token_max = 2; // don't chew through multigets.
ret = _process_request_simple(pr, 2, 2);
}
if (cm[1] == 'a' && cm[2] == 't') {
type = CMD_TYPE_GET;
cmd = CMD_GAT;
token_max = 2; // don't chew through multigets.
ret = _process_request_gat(pr);
}
} else if (cm[0] == 's' && cm[1] == 'e' && cm[2] == 't') {
cmd = CMD_SET;
ret = _process_request_storage(pr, token_max);
} else if (cm[0] == 'a' && cm[1] == 'd' && cm[2] == 'd') {
cmd = CMD_ADD;
ret = _process_request_storage(pr, token_max);
} else if (cm[0] == 'c' && cm[1] == 'a' && cm[2] == 's') {
cmd = CMD_CAS;
ret = _process_request_storage(pr, token_max);
}
break;
case 4:
if (strncmp(cm, "gets", 4) == 0) {
cmd = CMD_GETS;
type = CMD_TYPE_GET;
token_max = 2; // don't chew through multigets.
ret = _process_request_simple(pr, 2, 2);
} else if (strncmp(cm, "incr", 4) == 0) {
cmd = CMD_INCR;
ret = _process_request_simple(pr, 3, 4);
} else if (strncmp(cm, "decr", 4) == 0) {
cmd = CMD_DECR;
ret = _process_request_simple(pr, 3, 4);
} else if (strncmp(cm, "gats", 4) == 0) {
cmd = CMD_GATS;
type = CMD_TYPE_GET;
ret = _process_request_gat(pr);
} else if (strncmp(cm, "quit", 4) == 0) {
cmd = CMD_QUIT;
}
break;
case 5:
if (strncmp(cm, "touch", 5) == 0) {
cmd = CMD_TOUCH;
ret = _process_request_simple(pr, 3, 4);
} else if (strncmp(cm, "stats", 5) == 0) {
cmd = CMD_STATS;
// Don't process a key; fetch via arguments.
_process_tokenize(pr, token_max);
} else if (strncmp(cm, "watch", 5) == 0) {
cmd = CMD_WATCH;
_process_tokenize(pr, token_max);
}
break;
case 6:
if (strncmp(cm, "delete", 6) == 0) {
cmd = CMD_DELETE;
ret = _process_request_simple(pr, 2, 4);
} else if (strncmp(cm, "append", 6) == 0) {
cmd = CMD_APPEND;
ret = _process_request_storage(pr, token_max);
}
break;
case 7:
if (strncmp(cm, "replace", 7) == 0) {
cmd = CMD_REPLACE;
ret = _process_request_storage(pr, token_max);
} else if (strncmp(cm, "prepend", 7) == 0) {
cmd = CMD_PREPEND;
ret = _process_request_storage(pr, token_max);
} else if (strncmp(cm, "version", 7) == 0) {
cmd = CMD_VERSION;
_process_tokenize(pr, token_max);
}
break;
}
// TODO: log more specific error code.
if (cmd == -1 || ret != 0) {
return -1;
}
pr->command = cmd;
pr->cmd_type = type;
return 0;
}
// FIXME (v2): any reason to pass in command/cmdlen separately?
mcp_request_t *mcp_new_request(lua_State *L, mcp_parser_t *pr, const char *command, size_t cmdlen) {
// reserving an upvalue for key.
mcp_request_t *rq = lua_newuserdatauv(L, sizeof(mcp_request_t) + MCP_REQUEST_MAXLEN + KEY_MAX_LENGTH, 1);
// TODO (v2): memset only the non-data part? as the rest gets memcpy'd
// over.
memset(rq, 0, sizeof(mcp_request_t));
memcpy(&rq->pr, pr, sizeof(*pr));
memcpy(rq->request, command, cmdlen);
rq->pr.request = rq->request;
rq->pr.reqlen = cmdlen;
luaL_getmetatable(L, "mcp.request");
lua_setmetatable(L, -2);
// at this point we should know if we have to bounce through _nread to
// get item data or not.
return rq;
}
// fill a preallocated request object.
void mcp_set_request(mcp_parser_t *pr, mcp_request_t *rq, const char *command, size_t cmdlen) {
memset(rq, 0, sizeof(mcp_request_t));
memcpy(&rq->pr, pr, sizeof(*pr));
memcpy(rq->request, command, cmdlen);
rq->pr.request = rq->request;
rq->pr.reqlen = cmdlen;
}
// Replaces a token inside a request and re-parses.
// Note that this has some optimization opportunities. Delaying until
// required.
// We should not guarantee order when updating meta flags, which would allow
// blanking tokens and appending new ones.
// TODO (v2): much of the length is the key, avoid copying it.
int mcp_request_render(mcp_request_t *rq, int idx, const char flag, const char *tok, size_t len) {
char temp[MCP_REQUEST_MAXLEN+1];
char *p = temp;
mcp_parser_t *pr = &rq->pr;
if (pr->reqlen + len + 2 > MCP_REQUEST_MAXLEN) {
return -1;
}
// Cannot add/append tokens yet.
if (idx >= pr->ntokens) {
return -1;
}
memcpy(p, pr->request, pr->tokens[idx]);
p += pr->tokens[idx];
if (flag) {
*p = flag;
p++;
}
if (tok) {
memcpy(p, tok, len);
p += len;
}
// Add a space and copy more tokens if there were more.
if (idx+1 < pr->ntokens) {
if (flag || len != 0) {
// Only pre-space if not deleting the token.
*p = ' ';
p++;
}
memcpy(p, &pr->request[pr->tokens[idx+1]], pr->tokens[pr->ntokens] - pr->tokens[idx+1]);
p += pr->tokens[pr->ntokens] - pr->tokens[idx+1];
} else {
// If we removed something from the end we might've left some spaces.
while (*(p-1) == ' ') {
p--;
}
}
memcpy(p, "\r\n\0", 3);
p += 2;
memcpy(rq->request, temp, p - temp);
// Hold the vlen/vbuf and restore after re-parsing. Since we can only edit
// the command line, not the value here, we would otherwise allow sending
// arbitrary memory over the network if someone modifies a SET.
void *vbuf = pr->vbuf;
int vlen = pr->vlen;
memset(pr, 0, sizeof(mcp_parser_t)); // TODO: required?
int ret = process_request(pr, rq->request, p - temp);
if (ret != 0) {
return ret;
}
pr->vbuf = vbuf;
pr->vlen = vlen;
return 0;
}
int mcp_request_append(mcp_request_t *rq, const char flag, const char *tok, size_t len) {
mcp_parser_t *pr = &rq->pr;
const char *start = pr->request;
char *p = (char *)pr->request + pr->reqlen - 2; // start at the \r
assert(*p == '\r');
if (pr->reqlen + len + 2 > MCP_REQUEST_MAXLEN) {
return -1;
}
*p = ' ';
p++;
if (flag) {
*p = flag;
p++;
}
if (tok) {
memcpy(p, tok, len);
p += len;
}
memcpy(p, "\r\n\0", 3);
p += 2;
// See note on mcp_request_render()
void *vbuf = pr->vbuf;
int vlen = pr->vlen;
memset(pr, 0, sizeof(mcp_parser_t)); // TODO: required?
int ret = process_request(pr, rq->request, p - start);
if (ret != 0) {
return ret;
}
pr->vbuf = vbuf;
pr->vlen = vlen;
return 0;
}
void mcp_request_attach(mcp_request_t *rq, io_pending_proxy_t *p) {
mcp_parser_t *pr = &rq->pr;
char *r = (char *) pr->request;
size_t len = pr->reqlen;
// The stringified request. This is also referencing into the coroutine
// stack, which should be safe from gc.
p->iov[0].iov_base = r;
p->iov[0].iov_len = len;
p->iovcnt = 1;
p->iovbytes = len;
if (pr->vlen != 0) {
p->iov[1].iov_base = pr->vbuf;
p->iov[1].iov_len = pr->vlen;
p->iovcnt = 2;
p->iovbytes += pr->vlen;
}
}
// second argument is optional, for building set requests.
// TODO: append the \r\n for the VAL?
int mcplib_request(lua_State *L) {
LIBEVENT_THREAD *t = PROXY_GET_THR(L);
size_t len = 0;
size_t vlen = 0;
mcp_parser_t pr = {0};
const char *cmd = luaL_checklstring(L, 1, &len);
const char *val = NULL;
int type = lua_type(L, 2);
if (type == LUA_TSTRING) {
val = luaL_optlstring(L, 2, NULL, &vlen);
if (vlen < 2 || memcmp(val+vlen-2, "\r\n", 2) != 0) {
proxy_lua_error(L, "value passed to mcp.request must end with \\r\\n");
}
} else if (type == LUA_TUSERDATA) {
// vlen for requests and responses include the "\r\n" already.
mcp_resp_t *r = luaL_testudata(L, 2, "mcp.response");
if (r != NULL) {
if (r->resp.value) {
val = r->resp.value;
vlen = r->resp.vlen_read; // paranoia, so we can't overread into memory.
}
} else {
mcp_request_t *rq = luaL_testudata(L, 2, "mcp.request");
if (rq->pr.vbuf) {
val = rq->pr.vbuf;
vlen = rq->pr.vlen;
}
}
}
// FIXME (v2): if we inline the userdata we can avoid memcpy'ing the parser
// structure from the stack? but causes some code duplication.
if (process_request(&pr, cmd, len) != 0) {
proxy_lua_error(L, "failed to parse request");
return 0;
}
mcp_request_t *rq = mcp_new_request(L, &pr, cmd, len);
if (val != NULL) {
rq->pr.vlen = vlen;
rq->pr.vbuf = malloc(vlen);
if (rq->pr.vbuf == NULL) {
// Note: without *c we can't tick the appropriate counter.
// However, in practice raw malloc's are nearly never going to
// fail.
// TODO(v2): we can stack values into the request objects or use
// the slabber memory, so this isn't necessary anyway.
proxy_lua_error(L, "failed to allocate value memory for request object");
}
memcpy(rq->pr.vbuf, val, vlen);
// Note: Not enforcing the memory limit here is deliberate:
// - if we're over the memory limit, it'll get caught very soon after
// this, but we won't be causing some lua to bail mid-flight, which is
// more graceful to the end user.
pthread_mutex_lock(&t->proxy_limit_lock);
t->proxy_buffer_memory_used += rq->pr.vlen;
pthread_mutex_unlock(&t->proxy_limit_lock);
}
// rq is now created, parsed, and on the stack.
return 1;
}
int mcplib_request_key(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, -1, "mcp.request");
lua_pushlstring(L, MCP_PARSER_KEY(rq->pr), rq->pr.klen);
return 1;
}
// NOTE: I've mixed up const/non-const strings in the request. During parsing
// we want it to be const, but after that's done the request is no longer
// const. It might be better to just remove the const higher up the chain, but
// I'd rather not. So for now these functions will be dumping the const to
// modify the string.
int mcplib_request_ltrimkey(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, -2, "mcp.request");
int totrim = luaL_checkinteger(L, -1);
char *key = (char *) MCP_PARSER_KEY(rq->pr);
if (totrim > rq->pr.klen) {
proxy_lua_error(L, "ltrimkey cannot zero out key");
return 0;
} else {
memset(key, ' ', totrim);
rq->pr.klen -= totrim;
rq->pr.tokens[rq->pr.keytoken] += totrim;
}
return 1;
}
int mcplib_request_rtrimkey(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, -2, "mcp.request");
int totrim = luaL_checkinteger(L, -1);
char *key = (char *) MCP_PARSER_KEY(rq->pr);
if (totrim > rq->pr.klen) {
proxy_lua_error(L, "rtrimkey cannot zero out key");
return 0;
} else {
memset(key + (rq->pr.klen - totrim), ' ', totrim);
rq->pr.klen -= totrim;
// don't need to change the key token.
}
return 1;
}
// Virtual table operations on the request.
int mcplib_request_token(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, 1, "mcp.request");
int argc = lua_gettop(L);
if (argc == 1) {
lua_pushnil(L);
return 1;
}
int token = luaL_checkinteger(L, 2);
if (token < 1 || token > rq->pr.ntokens) {
// maybe an error?
lua_pushnil(L);
return 1;
}
size_t vlen = 0;
if (argc > 2) {
// overwriting a token.
size_t newlen = 0;
const char *newtok = lua_tolstring(L, 3, &newlen);
if (mcp_request_render(rq, token-1, 0, newtok, newlen) != 0) {
proxy_lua_error(L, "token(): request malformed after edit");
return 0;
}
return 0;
} else {
// fetching a token.
const char *start = rq->pr.request + rq->pr.tokens[token-1];
vlen = _process_token_len(&rq->pr, token-1);
P_DEBUG("%s: pushing token of len: %lu\n", __func__, vlen);
lua_pushlstring(L, start, vlen);
return 1;
}
return 0;
}
int mcplib_request_ntokens(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, 1, "mcp.request");
lua_pushinteger(L, rq->pr.ntokens);
return 1;
}
int mcplib_request_command(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, -1, "mcp.request");
lua_pushinteger(L, rq->pr.command);
return 1;
}
int mcplib_request_has_flag(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, 1, "mcp.request");
size_t len = 0;
const char *flagstr = luaL_checklstring(L, 2, &len);
if (len != 1) {
proxy_lua_error(L, "has_flag(): meta flag must be a single character");
return 0;
}
if (flagstr[0] < 65 || flagstr[0] > 122) {
proxy_lua_error(L, "has_flag(): invalid flag, must be A-Z,a-z");
return 0;
}
uint64_t flagbit = (uint64_t)1 << (flagstr[0] - 65);
if (rq->pr.t.meta.flags & flagbit) {
lua_pushboolean(L, 1);
} else {
lua_pushboolean(L, 0);
}
return 1;
}
// req:flag_token("F") -> (bool, nil|token)
// req:flag_token("O", "Onewopauqe") -> (bool, oldtoken)
int mcplib_request_flag_token(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, 1, "mcp.request");
size_t len = 0;
const char *flagstr = luaL_checklstring(L, 2, &len);
bool replace = false;
if (len != 1) {
proxy_lua_error(L, "has_flag(): meta flag must be a single character");
return 0;
}
if (flagstr[0] < 65 || flagstr[0] > 122) {
proxy_lua_error(L, "has_flag(): invalid flag, must be A-Z,a-z");
return 0;
}
if (lua_isstring(L, 3)) {
// overwriting a flag/token with the third argument.
replace = true;
}
uint64_t flagbit = (uint64_t)1 << (flagstr[0] - 65);
int ret = 1;
if (rq->pr.t.meta.flags & flagbit) {
// The flag definitely exists, but sadly we need to scan for the
// actual flag to see if it has a token.
lua_pushboolean(L, 1);
for (int x = rq->pr.keytoken+1; x < rq->pr.ntokens; x++) {
const char *s = rq->pr.request + rq->pr.tokens[x];
if (s[0] == flagstr[0]) {
size_t vlen = _process_token_len(&rq->pr, x);
if (vlen > 1) {
// strip the flag off the token and return.
lua_pushlstring(L, s+1, vlen-1);
ret = 2;
}
// Have something to replace the flag/token with.
if (replace) {
size_t newlen = 0;
const char *newtok = lua_tolstring(L, 3, &newlen);
if (mcp_request_render(rq, x, 0, newtok, newlen) != 0) {
proxy_lua_error(L, "token(): request malformed after edit");
return 0;
}
}
break;
}
}
} else {
lua_pushboolean(L, 0);
}
return ret;
}
// these functions take token as string or number
// if number, internally convert it to avoid creating garbage
static inline char _mcp_request_get_arg_flag(lua_State *L, int idx) {
size_t len = 0;
const char *flagstr = luaL_checklstring(L, idx, &len);
if (len != 1) {
proxy_lua_error(L, "request: meta flag must be a single character");
return 0;
}
if (flagstr[0] < 65 || flagstr[0] > 122) {
proxy_lua_error(L, "request: invalid flag, must be A-Z,a-z");
return 0;
}
return flagstr[0];
}
// *tostring must be large enough to hold a 64bit number as a string.
static inline const char * _mcp_request_check_flag_token(lua_State *L, int idx, char *tostring, size_t *tlen) {
const char *token = NULL;
*tlen = 0;
if (lua_isstring(L, idx)) {
token = lua_tolstring(L, idx, tlen);
} else if (lua_isnumber(L, idx)) {
int isnum = 0;
lua_Integer n = lua_tointegerx(L, idx, &isnum);
if (isnum) {
char *end = itoa_64(n, tostring);
token = tostring;
*tlen = end - tostring;
} else {
proxy_lua_error(L, "request: invalid flag argument");
return NULL;
}
} else if (lua_isnoneornil(L, idx)) {
// no token, just add the flag.
} else {
proxy_lua_error(L, "request: invalid flag argument");
return NULL;
}
return token;
}
// req:flag_add("F", token) -> (bool)
// if token is "example", appends "Fexample" to request
int mcplib_request_flag_add(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, 1, "mcp.request");
char flag = _mcp_request_get_arg_flag(L, 2);
char tostring[30];
uint64_t flagbit = (uint64_t)1 << (flag - 65);
if (rq->pr.t.meta.flags & flagbit) {
// fail, flag already exists.
lua_pushboolean(L, 0);
return 1;
}
size_t tlen = 0;
const char *token = _mcp_request_check_flag_token(L, 3, tostring, &tlen);
if (mcp_request_append(rq, flag, token, tlen) == 0) {
lua_pushboolean(L, 1);
} else {
lua_pushboolean(L, 0);
}
return 1;
}
// req:flag_set("F", token) -> (bool) [overwrites if exists]
// if token is "example", appends "Fexample" to request
int mcplib_request_flag_set(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, 1, "mcp.request");
char flag = _mcp_request_get_arg_flag(L, 2);
char tostring[30];
int x = mcp_request_find_flag_index(rq, flag);
size_t tlen = 0;
const char *token = _mcp_request_check_flag_token(L, 3, tostring, &tlen);
if (x > 0) {
// TODO: do nothing if:
// flag exists in request, without token, and we're not setting a
// token.
if (mcp_request_render(rq, x, flag, token, tlen) != 0) {
lua_pushboolean(L, 0);
return 1;
}
} else {
if (mcp_request_append(rq, flag, token, tlen) != 0) {
lua_pushboolean(L, 0);
return 1;
}
}
lua_pushboolean(L, 1);
return 1;
}
// allows replacing a flag with a different flag
// req:flag_replace("F", "N", token) -> (bool)
// if token is "example", appends "Nexample" to request
int mcplib_request_flag_replace(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, 1, "mcp.request");
char flag = _mcp_request_get_arg_flag(L, 2);
char newflag = _mcp_request_get_arg_flag(L, 3);
char tostring[30];
int x = mcp_request_find_flag_index(rq, flag);
size_t tlen = 0;
const char *token = _mcp_request_check_flag_token(L, 4, tostring, &tlen);
if (x > 0) {
if (mcp_request_render(rq, x, newflag, token, tlen) != 0) {
lua_pushboolean(L, 0);
return 1;
}
} else {
if (mcp_request_append(rq, newflag, token, tlen) != 0) {
lua_pushboolean(L, 0);
return 1;
}
}
lua_pushboolean(L, 1);
return 1;
}
// req:flag_del("F") -> (bool)
// remove a flag if exists
int mcplib_request_flag_del(lua_State *L) {
mcp_request_t *rq = luaL_checkudata(L, 1, "mcp.request");
char flag = _mcp_request_get_arg_flag(L, 2);
int x = mcp_request_find_flag_index(rq, flag);
if (x > 0) {
if (mcp_request_render(rq, x, 0, NULL, 0) != 0) {
lua_pushboolean(L, 0);
return 1;
}
} else {
// nothing there, didn't delete anything.
lua_pushboolean(L, 0);
return 1;
}
lua_pushboolean(L, 1);
return 1;