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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"
struct lib9p_srvconn {
/* immutable */
struct lib9p_srv *srv;
cid_t reader;
int fd;
/* mutable */
uint32_t max_msg_size;
enum lib9p_version version;
unsigned int refcount;
};
struct lib9p_srvreq {
struct lib9p_srvconn *conn;
uint8_t *msg;
};
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(),
.max_msg_size = CONFIG_9P_MAX_MSG_SIZE,
.version = LIB9P_VER_UNINITIALIZED,
.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: %m", -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 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.max_msg_size) {
struct lib9p_ctx ctx = {
.version = conn.version,
.max_msg_size = conn.max_msg_size,
};
if (initialized)
lib9p_errorf(&ctx, LINUX_EMSGSIZE, "T-message larger than negotiated limit (%zu > %zu)", goal, conn.max_msg_size);
else
lib9p_errorf(&ctx, LINUX_EMSGSIZE, "T-message larger than server limit (%zu > %zu)", goal, conn.max_msg_size);
marshal_error(&ctx, 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: %m", -r);
goto close;
} else if (r == 0) {
fprintf(stderr, "error: read: unexpected EOF");
goto close;
}
done += r;
}
/* Handle the message... */
if (conn.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(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));
}
static inline uint16_t min_u16(uint16_t a, b) {
return (a < b) ? a : b;
}
/* We have special code for marshaling Rerror because we don't ever
* want to produce an error because the err_msg is too long for the
* `ctx->max_msg_size`! */
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 = ctx->err_msg,
},
};
if (host.ename.len + ctx->Rerror_overhead > ctx->max_msg_size)
host.ename.len = ctx->max_msg_size - overhead;
lib9p_marshal(ctx, tag, host, net);
}
ERANGE for reply too large
EPROTONOSUPPORT for version errors
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