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af45b39d887ad4ec4a806d352009cdc28238f21f
android_development/emulator/qemud/qemud.c
David 'Digit' Turner af45b39d88 This adds a new helper program (qemu-props) to support the emulated system. 
Its purpose is to contact the 'boot-properties' service during the
boot process and to set the list of system properties read from the
emulator program through it.

It must be launched from /system/etc/init.goldfish.rc as root.

It depends on the 'boot-properties' service being implemented by the
emulator (in a later patch). If not available, it will simply timeout.

This also fixes a potential crash in qemud which can happen in the following case:

- client sends a command to a service
- the service responds with one or more message
- the service immediately closes the connection before the client can read the data

what happened is that the FDHandler object was buffering out-going packets to the
client, but the Multiplexer acted on the disconnection immediately. This resulted
in:

- client_free() being called
-   fdhandler_shutdown() being called
-     the FDHandler being placed on the 'closing' list to be able to send
      buffered packets later. And 'receiver_close' being called
-       client_fd_close() being called, which would call client_free()
        recursively
-         the second client_free() call would free the object
-  the first client_free() call would try to free the object again
-  ==> dlmalloc() detects a double-free and immediately aborts.

the fixes simply avoids the calle to receiver_close() in fdhandler_shutdown()
since this function is called from an explicit shutdown request from the multiplexer,
it doesn't correspond to the case where the client has closed the connection itself.
2009-05-26 17:07:25 +02:00

1717 lines
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#include <stdint.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <termios.h>
#include <cutils/sockets.h>
/*
* the qemud daemon program is only used within Android as a bridge
* between the emulator program and the emulated system. it really works as
* a simple stream multiplexer that works as follows:
*
* - qemud is started by init following instructions in
* /system/etc/init.goldfish.rc (i.e. it is never started on real devices)
*
* - qemud communicates with the emulator program through a single serial
* port, whose name is passed through a kernel boot parameter
* (e.g. android.qemud=ttyS1)
*
* - qemud binds one unix local stream socket (/dev/socket/qemud, created
* by init through /system/etc/init.goldfish.rc).
*
*
* emulator <==serial==> qemud <---> /dev/socket/qemud <-+--> client1
* |
* +--> client2
*
* - the special channel index 0 is used by the emulator and qemud only.
* other channel numbers correspond to clients. More specifically,
* connection are created like this:
*
* * the client connects to /dev/socket/qemud
*
* * the client sends the service name through the socket, as
* <service-name>
*
* * qemud creates a "Client" object internally, assigns it an
* internal unique channel number > 0, then sends a connection
* initiation request to the emulator (i.e. through channel 0):
*
* connect:<id>:<name>
*
* where <name> is the service name, and <id> is a 2-hexchar
* number corresponding to the channel number.
*
* * in case of success, the emulator responds through channel 0
* with:
*
* ok:connect:<id>
*
* after this, all messages between the client and the emulator
* are passed in pass-through mode.
*
* * if the emulator refuses the service connection, it will
* send the following through channel 0:
*
* ko:connect:<id>:reason-for-failure
*
* * If the client closes the connection, qemud sends the following
* to the emulator:
*
* disconnect:<id>
*
* The same message is the opposite direction if the emulator
* chooses to close the connection.
*
* * any command sent through channel 0 to the emulator that is
* not properly recognized will be answered by:
*
* ko:unknown command
*
*
* Internally, the daemon maintains a "Client" object for each client
* connection (i.e. accepting socket connection).
*/
/* name of the single control socket used by the daemon */
#define CONTROL_SOCKET_NAME "qemud"
#define DEBUG 1
#define T_ACTIVE 0 /* set to 1 to dump traffic */
#if DEBUG
# define LOG_TAG "qemud"
# include <cutils/log.h>
# define D(...) LOGD(__VA_ARGS__)
#else
# define D(...) ((void)0)
# define T(...) ((void)0)
#endif
#if T_ACTIVE
# define T(...) D(__VA_ARGS__)
#else
# define T(...) ((void)0)
#endif
/** UTILITIES
**/
static void
fatal( const char* fmt, ... )
{
va_list args;
va_start(args, fmt);
fprintf(stderr, "PANIC: ");
vfprintf(stderr, fmt, args);
fprintf(stderr, "\n" );
va_end(args);
exit(1);
}
static void*
xalloc( size_t sz )
{
void* p;
if (sz == 0)
return NULL;
p = malloc(sz);
if (p == NULL)
fatal( "not enough memory" );
return p;
}
#define xnew(p) (p) = xalloc(sizeof(*(p)))
static void*
xalloc0( size_t sz )
{
void* p = xalloc(sz);
memset( p, 0, sz );
return p;
}
#define xnew0(p) (p) = xalloc0(sizeof(*(p)))
#define xfree(p) (free((p)), (p) = NULL)
static void*
xrealloc( void* block, size_t size )
{
void* p = realloc( block, size );
if (p == NULL && size > 0)
fatal( "not enough memory" );
return p;
}
#define xrenew(p,count) (p) = xrealloc((p),sizeof(*(p))*(count))
static int
hex2int( const uint8_t* data, int len )
{
int result = 0;
while (len > 0) {
int c = *data++;
unsigned d;
result <<= 4;
do {
d = (unsigned)(c - '0');
if (d < 10)
break;
d = (unsigned)(c - 'a');
if (d < 6) {
d += 10;
break;
}
d = (unsigned)(c - 'A');
if (d < 6) {
d += 10;
break;
}
return -1;
}
while (0);
result |= d;
len -= 1;
}
return result;
}
static void
int2hex( int value, uint8_t* to, int width )
{
int nn = 0;
static const char hexchars[16] = "0123456789abcdef";
for ( --width; width >= 0; width--, nn++ ) {
to[nn] = hexchars[(value >> (width*4)) & 15];
}
}
static int
fd_read(int fd, void* to, int len)
{
int ret;
do {
ret = read(fd, to, len);
} while (ret < 0 && errno == EINTR);
return ret;
}
static int
fd_write(int fd, const void* from, int len)
{
int ret;
do {
ret = write(fd, from, len);
} while (ret < 0 && errno == EINTR);
return ret;
}
static void
fd_setnonblock(int fd)
{
int ret, flags;
do {
flags = fcntl(fd, F_GETFD);
} while (flags < 0 && errno == EINTR);
if (flags < 0) {
fatal( "%s: could not get flags for fd %d: %s",
__FUNCTION__, fd, strerror(errno) );
}
do {
ret = fcntl(fd, F_SETFD, flags | O_NONBLOCK);
} while (ret < 0 && errno == EINTR);
if (ret < 0) {
fatal( "%s: could not set fd %d to non-blocking: %s",
__FUNCTION__, fd, strerror(errno) );
}
}
static int
fd_accept(int fd)
{
struct sockaddr from;
socklen_t fromlen = sizeof(from);
int ret;
do {
ret = accept(fd, &from, &fromlen);
} while (ret < 0 && errno == EINTR);
return ret;
}
/** FD EVENT LOOP
**/
/* A Looper object is used to monitor activity on one or more
* file descriptors (e.g sockets).
*
* - call looper_add() to register a function that will be
* called when events happen on the file descriptor.
*
* - call looper_enable() or looper_disable() to enable/disable
* the set of monitored events for a given file descriptor.
*
* - call looper_del() to unregister a file descriptor.
* this does *not* close the file descriptor.
*
* Note that you can only provide a single function to handle
* all events related to a given file descriptor.
* You can call looper_enable/_disable/_del within a function
* callback.
*/
/* the current implementation uses Linux's epoll facility
* the event mask we use are simply combinations of EPOLLIN
* EPOLLOUT, EPOLLHUP and EPOLLERR
*/
#include <sys/epoll.h>
#define MAX_CHANNELS 16
#define MAX_EVENTS (MAX_CHANNELS+1) /* each channel + the serial fd */
/* the event handler function type, 'user' is a user-specific
* opaque pointer passed to looper_add().
*/
typedef void (*EventFunc)( void* user, int events );
/* bit flags for the LoopHook structure.
*
* HOOK_PENDING means that an event happened on the
* corresponding file descriptor.
*
* HOOK_CLOSING is used to delay-close monitored
* file descriptors.
*/
enum {
HOOK_PENDING = (1 << 0),
HOOK_CLOSING = (1 << 1),
};
/* A LoopHook structure is used to monitor a given
* file descriptor and record its event handler.
*/
typedef struct {
int fd;
int wanted; /* events we are monitoring */
int events; /* events that occured */
int state; /* see HOOK_XXX constants */
void* ev_user; /* user-provided handler parameter */
EventFunc ev_func; /* event handler callback */
} LoopHook;
/* Looper is the main object modeling a looper object
*/
typedef struct {
int epoll_fd;
int num_fds;
int max_fds;
struct epoll_event* events;
LoopHook* hooks;
} Looper;
/* initialize a looper object */
static void
looper_init( Looper* l )
{
l->epoll_fd = epoll_create(4);
l->num_fds = 0;
l->max_fds = 0;
l->events = NULL;
l->hooks = NULL;
}
/* finalize a looper object */
static void
looper_done( Looper* l )
{
xfree(l->events);
xfree(l->hooks);
l->max_fds = 0;
l->num_fds = 0;
close(l->epoll_fd);
l->epoll_fd = -1;
}
/* return the LoopHook corresponding to a given
* monitored file descriptor, or NULL if not found
*/
static LoopHook*
looper_find( Looper* l, int fd )
{
LoopHook* hook = l->hooks;
LoopHook* end = hook + l->num_fds;
for ( ; hook < end; hook++ ) {
if (hook->fd == fd)
return hook;
}
return NULL;
}
/* grow the arrays in the looper object */
static void
looper_grow( Looper* l )
{
int old_max = l->max_fds;
int new_max = old_max + (old_max >> 1) + 4;
int n;
xrenew( l->events, new_max );
xrenew( l->hooks, new_max );
l->max_fds = new_max;
/* now change the handles to all events */
for (n = 0; n < l->num_fds; n++) {
struct epoll_event ev;
LoopHook* hook = l->hooks + n;
ev.events = hook->wanted;
ev.data.ptr = hook;
epoll_ctl( l->epoll_fd, EPOLL_CTL_MOD, hook->fd, &ev );
}
}
/* register a file descriptor and its event handler.
* no event mask will be enabled
*/
static void
looper_add( Looper* l, int fd, EventFunc func, void* user )
{
struct epoll_event ev;
LoopHook* hook;
if (l->num_fds >= l->max_fds)
looper_grow(l);
hook = l->hooks + l->num_fds;
hook->fd = fd;
hook->ev_user = user;
hook->ev_func = func;
hook->state = 0;
hook->wanted = 0;
hook->events = 0;
fd_setnonblock(fd);
ev.events = 0;
ev.data.ptr = hook;
epoll_ctl( l->epoll_fd, EPOLL_CTL_ADD, fd, &ev );
l->num_fds += 1;
}
/* unregister a file descriptor and its event handler
*/
static void
looper_del( Looper* l, int fd )
{
LoopHook* hook = looper_find( l, fd );
if (!hook) {
D( "%s: invalid fd: %d", __FUNCTION__, fd );
return;
}
/* don't remove the hook yet */
hook->state |= HOOK_CLOSING;
epoll_ctl( l->epoll_fd, EPOLL_CTL_DEL, fd, NULL );
}
/* enable monitoring of certain events for a file
* descriptor. This adds 'events' to the current
* event mask
*/
static void
looper_enable( Looper* l, int fd, int events )
{
LoopHook* hook = looper_find( l, fd );
if (!hook) {
D("%s: invalid fd: %d", __FUNCTION__, fd );
return;
}
if (events & ~hook->wanted) {
struct epoll_event ev;
hook->wanted |= events;
ev.events = hook->wanted;
ev.data.ptr = hook;
epoll_ctl( l->epoll_fd, EPOLL_CTL_MOD, fd, &ev );
}
}
/* disable monitoring of certain events for a file
* descriptor. This ignores events that are not
* currently enabled.
*/
static void
looper_disable( Looper* l, int fd, int events )
{
LoopHook* hook = looper_find( l, fd );
if (!hook) {
D("%s: invalid fd: %d", __FUNCTION__, fd );
return;
}
if (events & hook->wanted) {
struct epoll_event ev;
hook->wanted &= ~events;
ev.events = hook->wanted;
ev.data.ptr = hook;
epoll_ctl( l->epoll_fd, EPOLL_CTL_MOD, fd, &ev );
}
}
/* wait until an event occurs on one of the registered file
* descriptors. Only returns in case of error !!
*/
static void
looper_loop( Looper* l )
{
for (;;) {
int n, count;
do {
count = epoll_wait( l->epoll_fd, l->events, l->num_fds, -1 );
} while (count < 0 && errno == EINTR);
if (count < 0) {
D("%s: error: %s", __FUNCTION__, strerror(errno) );
return;
}
if (count == 0) {
D("%s: huh ? epoll returned count=0", __FUNCTION__);
continue;
}
/* mark all pending hooks */
for (n = 0; n < count; n++) {
LoopHook* hook = l->events[n].data.ptr;
hook->state = HOOK_PENDING;
hook->events = l->events[n].events;
}
/* execute hook callbacks. this may change the 'hooks'
* and 'events' array, as well as l->num_fds, so be careful */
for (n = 0; n < l->num_fds; n++) {
LoopHook* hook = l->hooks + n;
if (hook->state & HOOK_PENDING) {
hook->state &= ~HOOK_PENDING;
hook->ev_func( hook->ev_user, hook->events );
}
}
/* now remove all the hooks that were closed by
* the callbacks */
for (n = 0; n < l->num_fds;) {
LoopHook* hook = l->hooks + n;
if (!(hook->state & HOOK_CLOSING)) {
n++;
continue;
}
hook[0] = l->hooks[l->num_fds-1];
l->num_fds -= 1;
}
}
}
#if T_ACTIVE
char*
quote( const void* data, int len )
{
const char* p = data;
const char* end = p + len;
int count = 0;
int phase = 0;
static char* buff = NULL;
for (phase = 0; phase < 2; phase++) {
if (phase != 0) {
xfree(buff);
buff = xalloc(count+1);
}
count = 0;
for (p = data; p < end; p++) {
int c = *p;
if (c == '\\') {
if (phase != 0) {
buff[count] = buff[count+1] = '\\';
}
count += 2;
continue;
}
if (c >= 32 && c < 127) {
if (phase != 0)
buff[count] = c;
count += 1;
continue;
}
if (c == '\t') {
if (phase != 0) {
memcpy(buff+count, "<TAB>", 5);
}
count += 5;
continue;
}
if (c == '\n') {
if (phase != 0) {
memcpy(buff+count, "<LN>", 4);
}
count += 4;
continue;
}
if (c == '\r') {
if (phase != 0) {
memcpy(buff+count, "<CR>", 4);
}
count += 4;
continue;
}
if (phase != 0) {
buff[count+0] = '\\';
buff[count+1] = 'x';
buff[count+2] = "0123456789abcdef"[(c >> 4) & 15];
buff[count+3] = "0123456789abcdef"[ (c) & 15];
}
count += 4;
}
}
buff[count] = 0;
return buff;
}
#endif /* T_ACTIVE */
/** PACKETS
**
** We need a way to buffer data before it can be sent to the
** corresponding file descriptor. We use linked list of Packet
** objects to do this.
**/
typedef struct Packet Packet;
#define MAX_PAYLOAD 4000
struct Packet {
Packet* next;
int len;
int channel;
uint8_t data[ MAX_PAYLOAD ];
};
/* we expect to alloc/free a lot of packets during
* operations so use a single linked list of free packets
* to keep things speedy and simple.
*/
static Packet* _free_packets;
/* Allocate a packet */
static Packet*
packet_alloc(void)
{
Packet* p = _free_packets;
if (p != NULL) {
_free_packets = p->next;
} else {
xnew(p);
}
p->next = NULL;
p->len = 0;
p->channel = -1;
return p;
}
/* Release a packet. This takes the address of a packet
* pointer that will be set to NULL on exit (avoids
* referencing dangling pointers in case of bugs)
*/
static void
packet_free( Packet* *ppacket )
{
Packet* p = *ppacket;
if (p) {
p->next = _free_packets;
_free_packets = p;
*ppacket = NULL;
}
}
/** PACKET RECEIVER
**
** Simple abstraction for something that can receive a packet
** from a FDHandler (see below) or something else.
**
** Send a packet to it with 'receiver_post'
**
** Call 'receiver_close' to indicate that the corresponding
** packet source was closed.
**/
typedef void (*PostFunc) ( void* user, Packet* p );
typedef void (*CloseFunc)( void* user );
typedef struct {
PostFunc post;
CloseFunc close;
void* user;
} Receiver;
/* post a packet to a receiver. Note that this transfers
* ownership of the packet to the receiver.
*/
static __inline__ void
receiver_post( Receiver* r, Packet* p )
{
if (r->post)
r->post( r->user, p );
else
packet_free(&p);
}
/* tell a receiver the packet source was closed.
* this will also prevent further posting to the
* receiver.
*/
static __inline__ void
receiver_close( Receiver* r )
{
if (r->close) {
r->close( r->user );
r->close = NULL;
}
r->post = NULL;
}
/** FD HANDLERS
**
** these are smart listeners that send incoming packets to a receiver
** and can queue one or more outgoing packets and send them when
** possible to the FD.
**
** note that we support clean shutdown of file descriptors,
** i.e. we try to send all outgoing packets before destroying
** the FDHandler.
**/
typedef struct FDHandler FDHandler;
typedef struct FDHandlerList FDHandlerList;
struct FDHandler {
int fd;
FDHandlerList* list;
char closing;
Receiver receiver[1];
/* queue of outgoing packets */
int out_pos;
Packet* out_first;
Packet** out_ptail;
FDHandler* next;
FDHandler** pref;
};
struct FDHandlerList {
/* the looper that manages the fds */
Looper* looper;
/* list of active FDHandler objects */
FDHandler* active;
/* list of closing FDHandler objects.
* these are waiting to push their
* queued packets to the fd before
* freeing themselves.
*/
FDHandler* closing;
};
/* remove a FDHandler from its current list */
static void
fdhandler_remove( FDHandler* f )
{
f->pref[0] = f->next;
if (f->next)
f->next->pref = f->pref;
}
/* add a FDHandler to a given list */
static void
fdhandler_prepend( FDHandler* f, FDHandler** list )
{
f->next = list[0];
f->pref = list;
list[0] = f;
if (f->next)
f->next->pref = &f->next;
}
/* initialize a FDHandler list */
static void
fdhandler_list_init( FDHandlerList* list, Looper* looper )
{
list->looper = looper;
list->active = NULL;
list->closing = NULL;
}
/* close a FDHandler (and free it). Note that this will not
* perform a graceful shutdown, i.e. all packets in the
* outgoing queue will be immediately free.
*
* this *will* notify the receiver that the file descriptor
* was closed.
*
* you should call fdhandler_shutdown() if you want to
* notify the FDHandler that its packet source is closed.
*/
static void
fdhandler_close( FDHandler* f )
{
/* notify receiver */
receiver_close(f->receiver);
/* remove the handler from its list */
fdhandler_remove(f);
/* get rid of outgoing packet queue */
if (f->out_first != NULL) {
Packet* p;
while ((p = f->out_first) != NULL) {
f->out_first = p->next;
packet_free(&p);
}
}
/* get rid of file descriptor */
if (f->fd >= 0) {
looper_del( f->list->looper, f->fd );
close(f->fd);
f->fd = -1;
}
f->list = NULL;
xfree(f);
}
/* Ask the FDHandler to cleanly shutdown the connection,
* i.e. send any pending outgoing packets then auto-free
* itself.
*/
static void
fdhandler_shutdown( FDHandler* f )
{
if (f->out_first != NULL && !f->closing)
{
/* move the handler to the 'closing' list */
f->closing = 1;
fdhandler_remove(f);
fdhandler_prepend(f, &f->list->closing);
/* prevent later fdhandler_close() to
* call the receiver's close.
*/
f->receiver->close = NULL;
return;
}
fdhandler_close(f);
}
/* Enqueue a new packet that the FDHandler will
* send through its file descriptor.
*/
static void
fdhandler_enqueue( FDHandler* f, Packet* p )
{
Packet* first = f->out_first;
p->next = NULL;
f->out_ptail[0] = p;
f->out_ptail = &p->next;
if (first == NULL) {
f->out_pos = 0;
looper_enable( f->list->looper, f->fd, EPOLLOUT );
}
}
/* FDHandler file descriptor event callback for read/write ops */
static void
fdhandler_event( FDHandler* f, int events )
{
int len;
/* in certain cases, it's possible to have both EPOLLIN and
* EPOLLHUP at the same time. This indicates that there is incoming
* data to read, but that the connection was nonetheless closed
* by the sender. Be sure to read the data before closing
* the receiver to avoid packet loss.
*/
if (events & EPOLLIN) {
Packet* p = packet_alloc();
int len;
if ((len = fd_read(f->fd, p->data, MAX_PAYLOAD)) < 0) {
D("%s: can't recv: %s", __FUNCTION__, strerror(errno));
packet_free(&p);
} else if (len > 0) {
p->len = len;
p->channel = -101; /* special debug value, not used */
receiver_post( f->receiver, p );
}
}
if (events & (EPOLLHUP|EPOLLERR)) {
/* disconnection */
D("%s: disconnect on fd %d", __FUNCTION__, f->fd);
fdhandler_close(f);
return;
}
if (events & EPOLLOUT && f->out_first) {
Packet* p = f->out_first;
int avail, len;
avail = p->len - f->out_pos;
if ((len = fd_write(f->fd, p->data + f->out_pos, avail)) < 0) {
D("%s: can't send: %s", __FUNCTION__, strerror(errno));
} else {
f->out_pos += len;
if (f->out_pos >= p->len) {
f->out_pos = 0;
f->out_first = p->next;
packet_free(&p);
if (f->out_first == NULL) {
f->out_ptail = &f->out_first;
looper_disable( f->list->looper, f->fd, EPOLLOUT );
}
}
}
}
}
/* Create a new FDHandler that monitors read/writes */
static FDHandler*
fdhandler_new( int fd,
FDHandlerList* list,
Receiver* receiver )
{
FDHandler* f = xalloc0(sizeof(*f));
f->fd = fd;
f->list = list;
f->receiver[0] = receiver[0];
f->out_first = NULL;
f->out_ptail = &f->out_first;
f->out_pos = 0;
fdhandler_prepend(f, &list->active);
looper_add( list->looper, fd, (EventFunc) fdhandler_event, f );
looper_enable( list->looper, fd, EPOLLIN );
return f;
}
/* event callback function to monitor accepts() on server sockets.
* the convention used here is that the receiver will receive a
* dummy packet with the new client socket in p->channel
*/
static void
fdhandler_accept_event( FDHandler* f, int events )
{
if (events & EPOLLIN) {
/* this is an accept - send a dummy packet to the receiver */
Packet* p = packet_alloc();
D("%s: accepting on fd %d", __FUNCTION__, f->fd);
p->data[0] = 1;
p->len = 1;
p->channel = fd_accept(f->fd);
if (p->channel < 0) {
D("%s: accept failed ?: %s", __FUNCTION__, strerror(errno));
packet_free(&p);
return;
}
receiver_post( f->receiver, p );
}
if (events & (EPOLLHUP|EPOLLERR)) {
/* disconnecting !! */
D("%s: closing accept fd %d", __FUNCTION__, f->fd);
fdhandler_close(f);
return;
}
}
/* Create a new FDHandler used to monitor new connections on a
* server socket. The receiver must expect the new connection
* fd in the 'channel' field of a dummy packet.
*/
static FDHandler*
fdhandler_new_accept( int fd,
FDHandlerList* list,
Receiver* receiver )
{
FDHandler* f = xalloc0(sizeof(*f));
f->fd = fd;
f->list = list;
f->receiver[0] = receiver[0];
fdhandler_prepend(f, &list->active);
looper_add( list->looper, fd, (EventFunc) fdhandler_accept_event, f );
looper_enable( list->looper, fd, EPOLLIN );
listen( fd, 5 );
return f;
}
/** SERIAL CONNECTION STATE
**
** The following is used to handle the framing protocol
** used on the serial port connection.
**/
/* each packet is made of a 6 byte header followed by a payload
* the header looks like:
*
* offset size description
* 0 2 a 2-byte hex string for the channel number
* 4 4 a 4-char hex string for the size of the payload
* 6 n the payload itself
*/
#define HEADER_SIZE 6
#define CHANNEL_OFFSET 0
#define LENGTH_OFFSET 2
#define CHANNEL_SIZE 2
#define LENGTH_SIZE 4
#define CHANNEL_CONTROL 0
/* The Serial object receives data from the serial port,
* extracts the payload size and channel index, then sends
* the resulting messages as a packet to a generic receiver.
*
* You can also use serial_send to send a packet through
* the serial port.
*/
typedef struct Serial {
FDHandler* fdhandler; /* used to monitor serial port fd */
Receiver receiver[1]; /* send payload there */
int in_len; /* current bytes in input packet */
int in_datalen; /* payload size, or 0 when reading header */
int in_channel; /* extracted channel number */
Packet* in_packet; /* used to read incoming packets */
} Serial;
/* a callback called when the serial port's fd is closed */
static void
serial_fd_close( Serial* s )
{
fatal("unexpected serial port close !!");
}
static void
serial_dump( Packet* p, const char* funcname )
{
T("%s: %03d bytes: '%s'",
funcname, p->len, quote(p->data, p->len));
}
/* a callback called when a packet arrives from the serial port's FDHandler.
*
* This will essentially parse the header, extract the channel number and
* the payload size and store them in 'in_datalen' and 'in_channel'.
*
* After that, the payload is sent to the receiver once completed.
*/
static void
serial_fd_receive( Serial* s, Packet* p )
{
int rpos = 0, rcount = p->len;
Packet* inp = s->in_packet;
int inpos = s->in_len;
serial_dump( p, __FUNCTION__ );
while (rpos < rcount)
{
int avail = rcount - rpos;
/* first, try to read the header */
if (s->in_datalen == 0) {
int wanted = HEADER_SIZE - inpos;
if (avail > wanted)
avail = wanted;
memcpy( inp->data + inpos, p->data + rpos, avail );
inpos += avail;
rpos += avail;
if (inpos == HEADER_SIZE) {
s->in_datalen = hex2int( inp->data + LENGTH_OFFSET, LENGTH_SIZE );
s->in_channel = hex2int( inp->data + CHANNEL_OFFSET, CHANNEL_SIZE );
if (s->in_datalen <= 0) {
D("ignoring %s packet from serial port",
s->in_datalen ? "empty" : "malformed");
s->in_datalen = 0;
}
//D("received %d bytes packet for channel %d", s->in_datalen, s->in_channel);
inpos = 0;
}
}
else /* then, populate the packet itself */
{
int wanted = s->in_datalen - inpos;
if (avail > wanted)
avail = wanted;
memcpy( inp->data + inpos, p->data + rpos, avail );
inpos += avail;
rpos += avail;
if (inpos == s->in_datalen) {
if (s->in_channel < 0) {
D("ignoring %d bytes addressed to channel %d",
inpos, s->in_channel);
} else {
inp->len = inpos;
inp->channel = s->in_channel;
receiver_post( s->receiver, inp );
s->in_packet = inp = packet_alloc();
}
s->in_datalen = 0;
inpos = 0;
}
}
}
s->in_len = inpos;
packet_free(&p);
}
/* send a packet to the serial port.
* this assumes that p->len and p->channel contain the payload's
* size and channel and will add the appropriate header.
*/
static void
serial_send( Serial* s, Packet* p )
{
Packet* h = packet_alloc();
//D("sending to serial %d bytes from channel %d: '%.*s'", p->len, p->channel, p->len, p->data);
/* insert a small header before this packet */
h->len = HEADER_SIZE;
int2hex( p->len, h->data + LENGTH_OFFSET, LENGTH_SIZE );
int2hex( p->channel, h->data + CHANNEL_OFFSET, CHANNEL_SIZE );
serial_dump( h, __FUNCTION__ );
serial_dump( p, __FUNCTION__ );
fdhandler_enqueue( s->fdhandler, h );
fdhandler_enqueue( s->fdhandler, p );
}
/* initialize serial reader */
static void
serial_init( Serial* s,
int fd,
FDHandlerList* list,
Receiver* receiver )
{
Receiver recv;
recv.user = s;
recv.post = (PostFunc) serial_fd_receive;
recv.close = (CloseFunc) serial_fd_close;
s->receiver[0] = receiver[0];
s->fdhandler = fdhandler_new( fd, list, &recv );
s->in_len = 0;
s->in_datalen = 0;
s->in_channel = 0;
s->in_packet = packet_alloc();
}
/** CLIENTS
**/
typedef struct Client Client;
typedef struct Multiplexer Multiplexer;
/* A Client object models a single qemud client socket
* connection in the emulated system.
*
* the client first sends the name of the system service
* it wants to contact (no framing), then waits for a 2
* byte answer from qemud.
*
* the answer is either "OK" or "KO" to indicate
* success or failure.
*
* In case of success, the client can send messages
* to the service.
*
* In case of failure, it can disconnect or try sending
* the name of another service.
*/
struct Client {
Client* next;
Client** pref;
int channel;
char registered;
FDHandler* fdhandler;
Multiplexer* multiplexer;
};
struct Multiplexer {
Client* clients;
int last_channel;
Serial serial[1];
Looper looper[1];
FDHandlerList fdhandlers[1];
};
static int multiplexer_open_channel( Multiplexer* mult, Packet* p );
static void multiplexer_close_channel( Multiplexer* mult, int channel );
static void multiplexer_serial_send( Multiplexer* mult, int channel, Packet* p );
static void
client_dump( Client* c, Packet* p, const char* funcname )
{
T("%s: client %p (%d): %3d bytes: '%s'",
funcname, c, c->fdhandler->fd,
p->len, quote(p->data, p->len));
}
/* destroy a client */
static void
client_free( Client* c )
{
/* remove from list */
c->pref[0] = c->next;
if (c->next)
c->next->pref = c->pref;
c->channel = -1;
c->registered = 0;
/* gently ask the FDHandler to shutdown to
* avoid losing queued outgoing packets */
if (c->fdhandler != NULL) {
fdhandler_shutdown(c->fdhandler);
c->fdhandler = NULL;
}
xfree(c);
}
/* a function called when a client socket receives data */
static void
client_fd_receive( Client* c, Packet* p )
{
client_dump(c, p, __FUNCTION__);
if (c->registered) {
/* the client is registered, just send the
* data through the serial port
*/
multiplexer_serial_send(c->multiplexer, c->channel, p);
return;
}
if (c->channel > 0) {
/* the client is waiting registration results.
* this should not happen because the client
* should wait for our 'ok' or 'ko'.
* close the connection.
*/
D("%s: bad client sending data before end of registration",
__FUNCTION__);
BAD_CLIENT:
packet_free(&p);
client_free(c);
return;
}
/* the client hasn't registered a service yet,
* so this must be the name of a service, call
* the multiplexer to start registration for
* it.
*/
D("%s: attempting registration for service '%.*s'",
__FUNCTION__, p->len, p->data);
c->channel = multiplexer_open_channel(c->multiplexer, p);
if (c->channel < 0) {
D("%s: service name too long", __FUNCTION__);
goto BAD_CLIENT;
}
D("%s: -> received channel id %d", __FUNCTION__, c->channel);
packet_free(&p);
}
/* a function called when the client socket is closed. */
static void
client_fd_close( Client* c )
{
T("%s: client %p (%d)", __FUNCTION__, c, c->fdhandler->fd);
/* no need to shutdown the FDHandler */
c->fdhandler = NULL;
/* tell the emulator we're out */
if (c->channel > 0)
multiplexer_close_channel(c->multiplexer, c->channel);
/* free the client */
client_free(c);
}
/* a function called when the multiplexer received a registration
* response from the emulator for a given client.
*/
static void
client_registration( Client* c, int registered )
{
Packet* p = packet_alloc();
/* sends registration status to client */
if (!registered) {
D("%s: registration failed for client %d", __FUNCTION__, c->channel);
memcpy( p->data, "KO", 2 );
p->len = 2;
} else {
D("%s: registration succeeded for client %d", __FUNCTION__, c->channel);
memcpy( p->data, "OK", 2 );
p->len = 2;
}
client_dump(c, p, __FUNCTION__);
fdhandler_enqueue(c->fdhandler, p);
/* now save registration state
*/
c->registered = registered;
if (!registered) {
/* allow the client to try registering another service */
c->channel = -1;
}
}
/* send data to a client */
static void
client_send( Client* c, Packet* p )
{
client_dump(c, p, __FUNCTION__);
fdhandler_enqueue(c->fdhandler, p);
}
/* Create new client socket handler */
static Client*
client_new( Multiplexer* mult,
int fd,
FDHandlerList* pfdhandlers,
Client** pclients )
{
Client* c;
Receiver recv;
xnew(c);
c->multiplexer = mult;
c->next = NULL;
c->pref = &c->next;
c->channel = -1;
c->registered = 0;
recv.user = c;
recv.post = (PostFunc) client_fd_receive;
recv.close = (CloseFunc) client_fd_close;
c->fdhandler = fdhandler_new( fd, pfdhandlers, &recv );
/* add to client list */
c->next = *pclients;
c->pref = pclients;
*pclients = c;
if (c->next)
c->next->pref = &c->next;
return c;
}
/** GLOBAL MULTIPLEXER
**/
/* find a client by its channel */
static Client*
multiplexer_find_client( Multiplexer* mult, int channel )
{
Client* c = mult->clients;
for ( ; c != NULL; c = c->next ) {
if (c->channel == channel)
return c;
}
return NULL;
}
/* handle control messages coming from the serial port
* on CONTROL_CHANNEL.
*/
static void
multiplexer_handle_control( Multiplexer* mult, Packet* p )
{
/* connection registration success */
if (p->len == 13 && !memcmp(p->data, "ok:connect:", 11)) {
int channel = hex2int(p->data+11, 2);
Client* client = multiplexer_find_client(mult, channel);
/* note that 'client' can be NULL if the corresponding
* socket was closed before the emulator response arrived.
*/
if (client != NULL) {
client_registration(client, 1);
} else {
D("%s: NULL client: '%.*s'", __FUNCTION__, p->len, p->data+11);
}
goto EXIT;
}
/* connection registration failure */
if (p->len == 13 && !memcmp(p->data, "ko:connect:",11)) {
int channel = hex2int(p->data+11, 2);
Client* client = multiplexer_find_client(mult, channel);
if (client != NULL)
client_registration(client, 0);
goto EXIT;
}
/* emulator-induced client disconnection */
if (p->len == 13 && !memcmp(p->data, "disconnect:",11)) {
int channel = hex2int(p->data+11, 2);
Client* client = multiplexer_find_client(mult, channel);
if (client != NULL)
client_free(client);
goto EXIT;
}
/* A message that begins with "X00" is a probe sent by
* the emulator used to detect which version of qemud it runs
* against (in order to detect 1.0/1.1 system images. Just
* silently ignore it there instead of printing an error
* message.
*/
if (p->len >= 3 && !memcmp(p->data,"X00",3)) {
goto EXIT;
}
D("%s: unknown control message (%d bytes): '%.*s'",
__FUNCTION__, p->len, p->len, p->data);
EXIT:
packet_free(&p);
}
/* a function called when an incoming packet comes from the serial port */
static void
multiplexer_serial_receive( Multiplexer* mult, Packet* p )
{
Client* client;
T("%s: channel=%d '%.*s'", __FUNCTION__, p->channel, p->len, p->data);
if (p->channel == CHANNEL_CONTROL) {
multiplexer_handle_control(mult, p);
return;
}
client = multiplexer_find_client(mult, p->channel);
if (client != NULL) {
client_send(client, p);
return;
}
D("%s: discarding packet for unknown channel %d", __FUNCTION__, p->channel);
packet_free(&p);
}
/* a function called when the serial reader closes */
static void
multiplexer_serial_close( Multiplexer* mult )
{
fatal("unexpected close of serial reader");
}
/* a function called to send a packet to the serial port */
static void
multiplexer_serial_send( Multiplexer* mult, int channel, Packet* p )
{
p->channel = channel;
serial_send( mult->serial, p );
}
/* a function used by a client to allocate a new channel id and
* ask the emulator to open it. 'service' must be a packet containing
* the name of the service in its payload.
*
* returns -1 if the service name is too long.
*
* notice that client_registration() will be called later when
* the answer arrives.
*/
static int
multiplexer_open_channel( Multiplexer* mult, Packet* service )
{
Packet* p = packet_alloc();
int len, channel;
/* find a free channel number, assume we don't have many
* clients here. */
{
Client* c;
TRY_AGAIN:
channel = (++mult->last_channel) & 0xff;
for (c = mult->clients; c != NULL; c = c->next)
if (c->channel == channel)
goto TRY_AGAIN;
}
len = snprintf((char*)p->data, sizeof p->data, "connect:%.*s:%02x", service->len, service->data, channel);
if (len >= (int)sizeof(p->data)) {
D("%s: weird, service name too long (%d > %d)", __FUNCTION__, len, sizeof(p->data));
packet_free(&p);
return -1;
}
p->channel = CHANNEL_CONTROL;
p->len = len;
serial_send(mult->serial, p);
return channel;
}
/* used to tell the emulator a channel was closed by a client */
static void
multiplexer_close_channel( Multiplexer* mult, int channel )
{
Packet* p = packet_alloc();
int len = snprintf((char*)p->data, sizeof(p->data), "disconnect:%02x", channel);
if (len > (int)sizeof(p->data)) {
/* should not happen */
return;
}
p->channel = CHANNEL_CONTROL;
p->len = len;
serial_send(mult->serial, p);
}
/* this function is used when a new connection happens on the control
* socket.
*/
static void
multiplexer_control_accept( Multiplexer* m, Packet* p )
{
/* the file descriptor for the new socket connection is
* in p->channel. See fdhandler_accept_event() */
int fd = p->channel;
Client* client = client_new( m, fd, m->fdhandlers, &m->clients );
D("created client %p listening on fd %d", client, fd);
/* free dummy packet */
packet_free(&p);
}
static void
multiplexer_control_close( Multiplexer* m )
{
fatal("unexpected multiplexer control close");
}
static void
multiplexer_init( Multiplexer* m, const char* serial_dev )
{
int fd, control_fd;
Receiver recv;
/* initialize looper and fdhandlers list */
looper_init( m->looper );
fdhandler_list_init( m->fdhandlers, m->looper );
/* open the serial port */
do {
fd = open(serial_dev, O_RDWR);
} while (fd < 0 && errno == EINTR);
if (fd < 0) {
fatal( "%s: could not open '%s': %s", __FUNCTION__, serial_dev,
strerror(errno) );
}
// disable echo on serial lines
if ( !memcmp( serial_dev, "/dev/ttyS", 9 ) ) {
struct termios ios;
tcgetattr( fd, &ios );
ios.c_lflag = 0; /* disable ECHO, ICANON, etc... */
tcsetattr( fd, TCSANOW, &ios );
}
/* initialize the serial reader/writer */
recv.user = m;
recv.post = (PostFunc) multiplexer_serial_receive;
recv.close = (CloseFunc) multiplexer_serial_close;
serial_init( m->serial, fd, m->fdhandlers, &recv );
/* open the qemud control socket */
recv.user = m;
recv.post = (PostFunc) multiplexer_control_accept;
recv.close = (CloseFunc) multiplexer_control_close;
fd = android_get_control_socket(CONTROL_SOCKET_NAME);
if (fd < 0) {
fatal("couldn't get fd for control socket '%s'", CONTROL_SOCKET_NAME);
}
fdhandler_new_accept( fd, m->fdhandlers, &recv );
/* initialize clients list */
m->clients = NULL;
}
/** MAIN LOOP
**/
static Multiplexer _multiplexer[1];
int main( void )
{
Multiplexer* m = _multiplexer;
/* extract the name of our serial device from the kernel
* boot options that are stored in /proc/cmdline
*/
#define KERNEL_OPTION "android.qemud="
{
char buff[1024];
int fd, len;
char* p;
char* q;
fd = open( "/proc/cmdline", O_RDONLY );
if (fd < 0) {
D("%s: can't open /proc/cmdline !!: %s", __FUNCTION__,
strerror(errno));
exit(1);
}
len = fd_read( fd, buff, sizeof(buff)-1 );
close(fd);
if (len < 0) {
D("%s: can't read /proc/cmdline: %s", __FUNCTION__,
strerror(errno));
exit(1);
}
buff[len] = 0;
p = strstr( buff, KERNEL_OPTION );
if (p == NULL) {
D("%s: can't find '%s' in /proc/cmdline",
__FUNCTION__, KERNEL_OPTION );
exit(1);
}
p += sizeof(KERNEL_OPTION)-1; /* skip option */
q = p;
while ( *q && *q != ' ' && *q != '\t' )
q += 1;
snprintf( buff, sizeof(buff), "/dev/%.*s", q-p, p );
multiplexer_init( m, buff );
}
D( "entering main loop");
looper_loop( m->looper );
D( "unexpected termination !!" );
return 0;
}
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