sockets.c

Android 一些工具

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>

#include "sysdeps.h"

#define  TRACE_TAG  TRACE_SOCKETS
#include "adb.h"

ADB_MUTEX_DEFINE( socket_list_lock );

static void local_socket_close_locked(asocket *s);

int sendfailmsg(int fd, const char *reason)
{
    char buf[9];
    int len;
    len = strlen(reason);
    if(len > 0xffff) len = 0xffff;
    snprintf(buf, sizeof buf, "FAIL%04x", len);
    if(writex(fd, buf, 8)) return -1;
    return writex(fd, reason, len);
}

//extern int online;

static unsigned local_socket_next_id = 1;

static asocket local_socket_list = {
    .next = &local_socket_list,
    .prev = &local_socket_list,
};

asocket *find_local_socket(unsigned id)
{
    asocket *s;
    asocket *result = NULL;

    adb_mutex_lock(&socket_list_lock);
    for(s = local_socket_list.next; s != &local_socket_list && !result; s = s->next) {
        if(s->id == id) result = s;
    }
    adb_mutex_unlock(&socket_list_lock);

    return result;
}

void install_local_socket(asocket *s)
{
    adb_mutex_lock(&socket_list_lock);

    s->id = local_socket_next_id++;

    s->next = &local_socket_list;
    s->prev = local_socket_list.prev;
    s->prev->next = s;
    s->next->prev = s;

    adb_mutex_unlock(&socket_list_lock);
}

void remove_socket(asocket *s)
{
    // socket_list_lock should already be held
    if (s->prev && s->next)
    {
        s->prev->next = s->next;
        s->next->prev = s->prev;
        s->next = 0;
        s->prev = 0;
        s->id = 0;
    }
}

void close_all_sockets(atransport *t)
{
    asocket *s;

        /* this is a little gross, but since s->close() *will* modify
        ** the list out from under you, your options are limited.
        */
    adb_mutex_lock(&socket_list_lock);
restart:
    for(s = local_socket_list.next; s != &local_socket_list; s = s->next){
        if(s->transport == t || (s->peer && s->peer->transport == t)) {
            local_socket_close_locked(s);
            goto restart;
        }
    }
    adb_mutex_unlock(&socket_list_lock);
}

static int local_socket_enqueue(asocket *s, apacket *p)
{
    D("LS(%d): enqueue %d\n", s->id, p->len);

    p->ptr = p->data;

        /* if there is already data queue'd, we will receive
        ** events when it's time to write.  just add this to
        ** the tail
        */
    if(s->pkt_first) {
        goto enqueue;
    }

        /* write as much as we can, until we
        ** would block or there is an error/eof
        */
    while(p->len > 0) {
        int r = adb_write(s->fd, p->ptr, p->len);
        if(r > 0) {
            p->len -= r;
            p->ptr += r;
            continue;
        }
        if((r == 0) || (errno != EAGAIN)) {
            D( "LS(%d): not ready, errno=%d: %s\n", s->id, errno, strerror(errno) );
            s->close(s);
            return 1; /* not ready (error) */
        } else {
            break;
        }
    }

    if(p->len == 0) {
        put_apacket(p);
        return 0; /* ready for more data */
    }

enqueue:
    p->next = 0;
    if(s->pkt_first) {
        s->pkt_last->next = p;
    } else {
        s->pkt_first = p;
    }
    s->pkt_last = p;

        /* make sure we are notified when we can drain the queue */
    fdevent_add(&s->fde, FDE_WRITE);

    return 1; /* not ready (backlog) */
}

static void local_socket_ready(asocket *s)
{
        /* far side is ready for data, pay attention to
           readable events */
    fdevent_add(&s->fde, FDE_READ);
//    D("LS(%d): ready()\n", s->id);
}

static void local_socket_close(asocket *s)
{
    adb_mutex_lock(&socket_list_lock);
    local_socket_close_locked(s);
    adb_mutex_unlock(&socket_list_lock);
}

static void local_socket_close_locked(asocket *s)
{
    apacket *p, *n;

    if(s->peer) {
        s->peer->peer = 0;
        // tweak to avoid deadlock
        if (s->peer->close == local_socket_close)
            local_socket_close_locked(s->peer);
        else
            s->peer->close(s->peer);
    }

        /* IMPORTANT: the remove closes the fd
        ** that belongs to this socket
        */
    fdevent_remove(&s->fde);

        /* dispose of any unwritten data */
    for(p = s->pkt_first; p; p = n) {
        D("LS(%d): discarding %d bytes\n", s->id, p->len);
        n = p->next;
        put_apacket(p);
    }

    D("LS(%d): closed\n", s->id);
    remove_socket(s);
    free(s);
}

static void local_socket_event_func(int fd, unsigned ev, void *_s)
{
    asocket *s = _s;

    if(ev & FDE_READ){
        apacket *p = get_apacket();
        unsigned char *x = p->data;
        size_t avail = MAX_PAYLOAD;
        int r;
        int is_eof = 0;

        while(avail > 0) {
            r = adb_read(fd, x, avail);
            if(r > 0) {
                avail -= r;
                x += r;
                continue;
            }
            if(r < 0) {
                if(errno == EAGAIN) break;
                if(errno == EINTR) continue;
            }

                /* r = 0 or unhandled error */
            is_eof = 1;
            break;
        }

        if((avail == MAX_PAYLOAD) || (s->peer == 0)) {
            put_apacket(p);
        } else {
            p->len = MAX_PAYLOAD - avail;

            r = s->peer->enqueue(s->peer, p);

            if(r < 0) {
                    /* error return means they closed us as a side-effect
                    ** and we must retutn immediately
                    */
                return;
            }

            if(r > 0) {
                    /* if the remote cannot accept further events,
                    ** we disable notification of READs.  They'll
                    ** be enabled again when we get a call to ready()
                    */
                fdevent_del(&s->fde, FDE_READ);
            }
        }

        if(is_eof) {
            s->close(s);
        }
        return;
    }

    if(ev & FDE_WRITE){
        apacket *p;

        while((p = s->pkt_first) != 0) {
            while(p->len > 0) {
                int r = adb_write(fd, p->ptr, p->len);
                if(r > 0) {
                    p->ptr += r;
                    p->len -= r;
                    continue;
                }
                if(r < 0) {
                    if(errno == EAGAIN) return;
                    if(errno == EINTR) continue;
                }
                s->close(s);
                return;
            }

            if(p->len == 0) {
                s->pkt_first = p->next;
                if(s->pkt_first == 0) s->pkt_last = 0;
                put_apacket(p);
            }
        }

            /* no more packets queued, so we can ignore
            ** writable events again and tell our peer
            ** to resume writing
            */
        fdevent_del(&s->fde, FDE_WRITE);
        s->peer->ready(s->peer);
        return;
    }

    if(ev & FDE_ERROR){
            /* this should be caught be the next read or write
            ** catching it here means we may skip the last few
            ** bytes of readable data.
            */
//        s->close(s);
        return;
    }
}

asocket *create_local_socket(int fd)
{
    asocket *s = calloc(1, sizeof(asocket));
    if(s == 0) fatal("cannot allocate socket");
    install_local_socket(s);
    s->fd = fd;
    s->enqueue = local_socket_enqueue;
    s->ready = local_socket_ready;
    s->close = local_socket_close;

    fdevent_install(&s->fde, fd, local_socket_event_func, s);
/*    fdevent_add(&s->fde, FDE_ERROR); */
    //fprintf(stderr, "Created local socket in create_local_socket \n");
    D("LS(%d): created (fd=%d)\n", s->id, s->fd);
    return s;
}

asocket *create_local_service_socket(const char *name)
{
    asocket *s;
    int fd;

#if !ADB_HOST
    if (!strcmp(name,"jdwp")) {
        return create_jdwp_service_socket();
    }
    if (!strcmp(name,"track-jdwp")) {
        return create_jdwp_tracker_service_socket();
    }
#endif
    fd = service_to_fd(name);
    if(fd < 0) return 0;

    s = create_local_socket(fd);
    D("LS(%d): bound to '%s'\n", s->id, name);
    return s;
}

#if ADB_HOST
static asocket *create_host_service_socket(const char *name, const char* serial)
{
    asocket *s;

    s = host_service_to_socket(name, serial);

    if (s != NULL) {
        D("LS(%d) bound to '%s'\n", s->id, name);
        return s;
    }

    return s;
}
#endif /* ADB_HOST */

/* a Remote socket is used to send/receive data to/from a given transport object
** it needs to be closed when the transport is forcibly destroyed by the user