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#include <assert.h>
#include <stdio.h> /* for fprintf(), stderr */
#include <string.h> /* for strerror() */
#include <libcr/coroutine.h>
#include <libcr_ipc/chan.h>
#include <libnetio/netio.h>
#include <lib9p/9p.h>
#include <lib9p/srv.h>
#include "internal.h"
/* The hierarchy of concepts is:
*
* server -> connection -> session -> request
*
*/
struct lib9p_srv_sess {
/* immutable */
struct lib9p_srv *srv;
int connfd;
cid_t reader; /* the lib9p_srv_read_cr() coroutine for this session */
/* mutable */
struct lib9p_ctx ctx;
unsigned int refcount;
};
struct lib9p_srv_req {
struct lib9p_srv_sess *sess;
uint8_t *msg;
};
static void marshal_error(struct lib9p_ctx *ctx, uint16_t tag, uint8_t *net) {
struct lib9p_msg_Rerror host = {
.ename = {
.len = strnlen(ctx->err_msg, CONFIG_9P_MAX_ERR_SIZE),
.utf8 = (uint8_t*)ctx->err_msg,
},
.errno = ctx->err_num,
};
lib9p_marshal(ctx, LIB9P_TYP_Rerror, tag, &host, net);
}
void handle_message(struct lib9p_srvconn *conn, uint8_t *net);
COROUTINE lib9p_srv_read_cr(void *_srv) {
uint8_t buf[CONFIG_9P_MAX_MSG_SIZE];
struct lib9p_srv *srv = _srv;
assert(srv);
cr_begin();
for (;;) {
struct lib9p_srvconn conn = {
.srv = srv,
.reader = cr_getcid(),
.ctx = {
.version = LIB9P_VER_UNINITIALIZED,
.max_msg_size = CONFIG_9P_MAX_MSG_SIZE,
},
.refcount = 1,
};
conn.fd = netio_accept(srv->sockfd);
if (conn.fd < 0) {
fprintf(stderr, "error: accept: %s", strerror(-conn.fd));
continue;
}
for (;;) {
/* Read the message size. */
size_t goal = 4, done = 0;
while (done < goal) {
ssize_t r = netio_read(conn.fd, &buf[done], sizeof(buf)-done);
if (r < 0) {
fprintf(stderr, "error: read: %s", strerror(-r));
goto close;
} else if (r == 0) {
if (done != 0)
fprintf(stderr, "error: read: unexpected EOF");
goto close;
}
done += r;
}
goal = decode_u32le(buf);
if (goal < 7) {
/* We can't even respond with an Rerror becuase we wouldn't know what tag to use! */
fprintf(stderr, "error: T-message is impossibly small");
goto close;
}
if (goal > conn.ctx.max_msg_size) {
lib9p_errorf(&conn.ctx, LINUX_EMSGSIZE, "T-message larger than %s limit (%zu > %zu)",
conn.ctx.version ? "negotiated" : "server", goal, conn.ctx.max_msg_size);
uint16_t tag = decode_u16le(&buf[5]);
marshal_error(&conn.ctx, tag, buf);
netio_write(conn.fd, buf, decode_u32le(buf));
continue;
}
/* Read the rest of the message. */
while (done < goal) {
ssize_t r = netio_read(conn.fd, &buf[done], sizeof(buf)-done);
if (r < 0) {
fprintf(stderr, "error: read: %s", strerror(-r));
goto close;
} else if (r == 0) {
fprintf(stderr, "error: read: unexpected EOF");
goto close;
}
done += r;
}
/* Handle the message... */
if (conn.ctx.version == LIB9P_VER_UNINITIALIZED) {
/* ...synchronously if we haven't negotiated the protocol yet, ... */
handle_message(&conn, buf);
} else {
/* ...asynchronously if we have. */
cr_chan_send(&srv->reqch, buf);
cr_pause_and_yield();
}
}
close:
netio_close(conn.fd, true, (--conn.refcount) == 0);
if (conn.refcount) {
cr_pause_and_yield();
assert(conn.refcount == 0);
netio_close(conn.fd, false, true);
}
}
cr_end();
}
COROUTINE lib9p_srv_write_cr(void *_srv) {
uint8_t net[CONFIG_9P_MAX_MSG_SIZE];
lib9p_srv *srv = _srv;
assert(srv);
cr_begin();
for (;;) {
struct lib9p_srvreq req;
cr_chan_recv(&srv->reqch, &req);
memcpy(net, req.msg, decode_u32le(req.msg));
req.conn->refcount++;
cr_unpause(req.conn->reader);
handle_message(&req.conn, net);
if ((--req.conn->refcount) == 0)
cr_unpause(req.conn->reader);
}
cr_end();
}
void handle_message(struct lib9p_srvconn *conn, uint8_t *net) {
uint8_t host[CONFIG_9P_MAX_MSG_SIZE];
struct lib9p_ctx ctx = {
.version = req.conn->version,
.max_msg_size = req.conn->max_msg_size,
};
size_t host_size = lib9p_unmarshal_size(&ctx, net);
if (host_size == (size_t)-1)
goto write;
if (host_size > sizeof(host)) {
lib9p_errorf(&ctx, LINUX_EMSGSIZE, "unmarshalled payload larger than server limit (%zu > %zu)", host_size, sizeof(host));
goto write;
}
uint16_t tag;
uint8_t typ = lib9p_unmarshal(&ctx, net, &tag, host);
if (typ == (uint8_t)-1)
goto write;
if (typ % 2 != 0) {
lib9p_errorf(&ctx, LINUX_EOPNOTSUPP, "expected a T-message but got an R-message");
goto write;
}
TODO;
write:
if (ctx.err_num || ctx.err_msg[0])
marshal_error(&ctx, net);
else
TODO;
netio_write(req.conn->fd, net, decode_u32le(net));
}
void _version(struct lib9p_srv_req *ctx, struct lib9p_msg_Tversion *req, struct lib9p_msg_Rversion *resp) {
enum lib9p_version version = LIB9P_VER_unknown;
if (req->version.len >= 6 &&
req->version.utf8[0] == '9' &&
req->version.utf8[1] == 'P' &&
'0' <= req->version.utf8[2] && req->version.utf8[2] <= '9' &&
'0' <= req->version.utf8[3] && req->version.utf8[3] <= '9' &&
'0' <= req->version.utf8[4] && req->version.utf8[4] <= '9' &&
'0' <= req->version.utf8[5] && req->version.utf8[5] <= '9' &&
(req->version.utf8[6] == '\0' || req->version.utf8[6] == '.')) {
if (strcmp(&req->version.utf8[6], ".u") == 0)
version = LIB9P_VER_9P2000_u;
//else if (strcmp(&req->version.utf8[6], ".e") == 0)
// version = LIB9P_VER_9P2000_e;
else
version = LIB9P_VER_9P2000;
}
struct lib9p_ctx empty_ctx = {
.version = version,
.max_msg_size = CONFIG_9P_MAX_MSG_SIZE,
};
struct lib9p_msg_Rerror empty_error = { 0 };
assert(!lib9p_marshal(&empty_ctx, LIB9P_TYP_Rerror, 0, &empty_error, ctx->net));
uint32_t min_msg_size = decode_u32le(ctx->net);
assert(CONFIG_9P_MAX_MSG_SIZE >= min_msg_size);
if (req->max_msg_size < min_msg_size) {
lib9p_errorf(&ctx->ctx, LINUX_EDOM, "requested max_msg_size is less than minimum for %s (%"PRIu32" < %"PRIu32")",
version, req->max_msg_size, min_msg_size);
return;
}
resp->version = lib9p_version_str(version);
resp->max_msg_size = (CONFIG_9P_MAX_MSG_SIZE < req->max_msg_size)
? CONFIG_9P_MAX_MSG_SIZE
: req->max_msg_size;
}
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