common/bltins/mkservice.c

	mkservice.c revision 34f9b3eef6fdadbda0a846aa4d68691ac40eace5
/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1982-2009 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                  David Korn <dgk@research.att.com>                   *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * mkservice varname pathname
 * eloop [-t timeout]
 * Written by David Korn
 * AT&T Labs
 */

static const char mkservice_usage[] =
"[-?\n@(#)$Id: mkservice (AT&T Research) 2001-06-13 $\n]"
USAGE_LICENSE
"[+NAME? mkservice - create a shell server ]"
"[+DESCRIPTION?\bmkservice\b creates a tcp or udp server that is "
    "implemented by shell functions.]"
"[+?The \aservice_path\a must be of the form \b/dev/tcp/localhost/\b\aportno\a "
    "or \b/dev/udp/localhost/\b\aportno\a depending on whether the "
    "\btcp\b or \budp\b protocol is used.  \aportno\a is the port "
    "number that the service will use.]"
"[+?The shell variable \avarname\a is associated with the service.  This "
    "variable can have subvariables that keeps the state of all "
    "active connections.  The functions \avarname\a\b.accept\b, "
    "\avarname\a\b.action\b and \avarname\a\b.close\b implement the "
    "service as follows:]{"
    "[+accept?This function is invoked when a client tries to connect "
        "to the service.  It is called with an argument which "
        "is the file descriptor number associated with the "
        "accepted connection.  If the function returns a non-zero "
        "value, this connection will be closed.]"
    "[+action?This function is invoked when there is data waiting "
        "to be read from one of the active connections.  It is "
        "called with the file descriptor number that has data "
        "to be read.  If the function returns a non-zero "
        "value, this connection will be closed.]"
    "[+close?This function is invoked when the connection is closed.]"
    "}"
"[+?If \avarname\a is unset, then all active connection, and the service "
    "itself will be closed.]"
""
"\n"
"\nvarname service_path\n"
"\n"
"[+EXIT STATUS?]{"
        "[+0?Success.]"
        "[+>0?An error occurred.]"
"}"
"[+SEE ALSO?\beloop\b(1)]"
;


static const char eloop_usage[] =
"[-?\n@(#)$Id: eloop (AT&T Research) 2001-06-13 $\n]"
USAGE_LICENSE
"[+NAME? eloop - process event loop]"
"[+DESCRIPTION?\beloop\b causes the shell to block waiting for events "
    "to process.  By default, \beloop\b does not return.]"
"[t]#[timeout?\atimeout\a is the number of milliseconds to wait "
    "without receiving any events to process.]"
"\n"
"\n\n"
"\n"
"[+EXIT STATUS?If no timeout is specified, \beloop\b will not return "
    "unless interrupted.  Otherwise]{"
        "[+0?The specified timeout interval occurred.]"
        "[+>0?An error occurred.]"
"}"
"[+SEE ALSO?\bmkservice\b(1)]"
;


#include    "defs.h"

#include    <cmd.h>
#include    <error.h>
#include    <nval.h>
#include    <sys/socket.h>
#include    <netinet/in.h>

#define ACCEPT  0
#define ACTION  1
#define CLOSE   2

#ifndef O_SERVICE
#   define O_SERVICE    O_NOCTTY
#endif

static const char*  disctab[] =
{
    "accept",
    "action",
    "close",
    0
};

typedef struct Service_s Service_t;

struct Service_s
{
    Namfun_t    fun;
    short       fd;
    int     refcount;
    int     (*acceptf)(Service_t*,int);
    int     (*actionf)(Service_t*,int,int);
    int     (*errorf)(Service_t*,int,const char*, ...);
    void        *context;
    Namval_t*   node;
    Namval_t*   disc[elementsof(disctab)-1];
};

static short        *file_list;
static Sfio_t       **poll_list;
static Service_t    **service_list;
static int      npoll;
static int      nready;
static int      ready;
static int      (*covered_fdnotify)(int, int);

static int fdclose(Service_t *sp, register int fd)
{
    register int i;
    service_list[fd] = 0;
    if(sp->fd==fd)
        sp->fd = -1;
    for(i=0; i < npoll; i++)
    {
        if(file_list[i]==fd)
        {
            file_list[i] = file_list[npoll--];
            if(sp->actionf)
                (*sp->actionf)(sp, fd, 1);
            return(1);
        }
    }
    return(0);
}

static int fdnotify(int fd1, int fd2)
{
    Service_t *sp;
    if (covered_fdnotify)
        (*covered_fdnotify)(fd1, fd2);
    if(fd2!=SH_FDCLOSE)
    {
        register int i;
        service_list[fd2] = service_list[fd1];
        service_list[fd1] = 0;
        for(i=0; i < npoll; i++)
        {
            if(file_list[i]==fd1)
            {
                file_list[i] = fd2;
                return(0);
            }
        }
    }
    else if(sp = service_list[fd1])
    {
        fdclose(sp,fd1);
        if(--sp->refcount==0)
            nv_unset(sp->node);
    }
    return(0);
}

static void process_stream(Sfio_t* iop)
{
    int r=0, fd = sffileno(iop);
    Service_t * sp = service_list[fd];
    if(fd==sp->fd)  /* connection socket */
    {
        struct sockaddr addr;
        socklen_t addrlen = sizeof(addr);
        fd = accept(fd, &addr, &addrlen);
        service_list[fd] = sp;
        sp->refcount++;
        file_list[npoll++] = fd;
        if(fd>=0)
        {
            if(sp->acceptf)
                r = (*sp->acceptf)(sp,fd);
        }
    }
    else if(sp->actionf)
    {
        service_list[fd] = 0;
        r = (*sp->actionf)(sp, fd, 0);
        service_list[fd] = sp;
        if(r<0)
            close(fd);
    }
}

static int waitnotify(int fd, long timeout, int rw)
{
    Sfio_t *special=0, **pstream;
    register int    i;

    if (fd >= 0)
        special = sh_fd2sfio(fd);
    while(1)
    {
        pstream = poll_list;
        while(ready < nready)
            process_stream(pstream[ready++]);
        if(special)
            *pstream++ = special;
        for(i=0; i < npoll; i++)
        {
            if(service_list[file_list[i]])
                *pstream++ = sh_fd2sfio(file_list[i]);
        }
#if 1
        for(i=0; i < pstream-poll_list; i++)
            sfset(poll_list[i],SF_WRITE,0);
#endif
        nready = ready = 0;
        errno = 0;
#ifdef DEBUG
        sfprintf(sfstderr,"before poll npoll=%d",pstream-poll_list);
        for(i=0; i < pstream-poll_list; i++)
            sfprintf(sfstderr," %d",sffileno(poll_list[i]));
        sfputc(sfstderr,'\n');
#endif
        nready  = sfpoll(poll_list,pstream-poll_list,timeout);
#ifdef DEBUG
        sfprintf(sfstderr,"after poll nready=%d",nready);
        for(i=0; i < nready; i++)
            sfprintf(sfstderr," %d",sffileno(poll_list[i]));
        sfputc(sfstderr,'\n');
#endif
#if 1
        for(i=0; i < pstream-poll_list; i++)
            sfset(poll_list[i],SF_WRITE,1);
#endif
        if(nready<=0)
            return(errno? -1: 0);
        if(special && poll_list[0]==special)
        {
            ready = 1;
            return(fd);
        }
    }
}

static int service_init(void)
{
    file_list =  newof(NULL,short,n,0);
    poll_list =  newof(NULL,Sfio_t*,n,0);
    service_list =  newof(NULL,Service_t*,n,0);
    covered_fdnotify = sh_fdnotify(fdnotify);
    sh_waitnotify(waitnotify);
    return(1);
}

void service_add(Service_t *sp)
{
    static int init;
    if (!init)
        init = service_init();
    service_list[sp->fd] = sp;
    file_list[npoll++] = sp->fd;
}

static int Accept(register Service_t *sp, int accept_fd)
{
    register Namval_t*  nq = sp->disc[ACCEPT];
    int         fd;

    fd = fcntl(accept_fd, F_DUPFD, 10);
    if (fd >= 0)
    {
        close(accept_fd);
        if (nq)
        {
            char*   av[3];
            char    buff[20];

            av[1] = buff;
            av[2] = 0;
            sfsprintf(buff, sizeof(buff), "%d", fd);
            if (sh_fun(nq, sp->node, av))
            {
                close(fd);
                return -1;
            }
        }
    }
    sfsync(NiL);
    return fd;
}

static int Action(Service_t *sp, int fd, int close)
{
    register Namval_t*  nq;
    int         r=0;

    if(close)
        nq = sp->disc[CLOSE];
    else
        nq = sp->disc[ACTION];
    if (nq)
    {
        char*   av[3];
        char    buff[20];

        av[1] = buff;
        av[2] = 0;
        sfsprintf(buff, sizeof(buff), "%d", fd);
        r=sh_fun(nq, sp->node, av);
    }
    sfsync(NiL);
    return r > 0 ? -1 : 1;
}

static int Error(Service_t *sp, int level, const char* arg, ...)
{
    va_list         ap;

    va_start(ap, arg);
    if(sp->node)
        nv_unset(sp->node);
    free((void*)sp);
        errorv(NiL, ERROR_exit(1), ap);
        va_end(ap);
    return 0;
}

static char* setdisc(Namval_t* np, const char* event, Namval_t* action, Namfun_t* fp)
{
    register Service_t* sp = (Service_t*)fp;
    register const char*    cp;
    register int        i;
    register int        n = strlen(event) - 1;
    register Namval_t*  nq;

    for (i = 0; cp = disctab[i]; i++)
    {
        if (memcmp(event, cp, n))
            continue;
        if (action == np)
            action = sp->disc[i];
        else
        {
            if (nq = sp->disc[i])
                free((void*)nq);
            if (action)
                sp->disc[i] = action;
            else
                sp->disc[i] = 0;
        }
        return action ? (char*)action : "";
    }
    /* try the next level */
    return nv_setdisc(np, event, action, fp);
}

static void putval(Namval_t* np, const char* val, int flag, Namfun_t* fp)
{
    register Service_t* sp = (Service_t*)fp;
    if (!val)
        fp = nv_stack(np, NiL);
    nv_putv(np, val, flag, fp);
    if (!val)
    {
        register int i;
        for(i=0; i< sh.lim.open_max; i++)
        {
            if(service_list[i]==sp)
            {
                close(i);
                if(--sp->refcount<=0)
                    break;
            }
        }
        free((void*)fp);
        return;
    }
}

static const Namdisc_t servdisc =
{
    sizeof(Service_t),
    putval,
    0,
    0,
    setdisc
};

int b_mkservice(int argc, char** argv, void* extra)
{
    register char*      var;
    register char*      path;
    register Namval_t*  np;
    register Service_t* sp;
    register int        fd;

    NOT_USED(argc);
    NOT_USED(extra);
    for (;;)
    {
        switch (optget(argv, mkservice_usage))
        {
        case 0:
            break;
        case ':':
            error(2, opt_info.arg);
            continue;
        case '?':
            error(ERROR_usage(2), opt_info.arg);
            continue;
        }
        break;
    }
    argv += opt_info.index;
    if (error_info.errors || !(var = *argv++) || !(path = *argv++) || *argv)
        error(ERROR_usage(2), optusage(NiL));
    if (!(sp = newof(0, Service_t, 1, 0)))
        error(ERROR_exit(1), "out of space");
    sp->acceptf = Accept;
    sp->actionf = Action;
    sp->errorf = Error;
    sp->refcount = 1;
    sp->context = extra;
    sp->node = 0;
    sp->fun.disc = &servdisc;
    if((fd = sh_open(path, O_SERVICE|O_RDWR))<=0)
    {
        free((void*)sp);
        error(ERROR_exit(1), "%s: cannot start service", path);
    }
    if((sp->fd = fcntl(fd, F_DUPFD, 10))>=10)
        close(fd);
    else
        sp->fd = fd;
    np = nv_open(var,sh.var_tree,NV_ARRAY|NV_VARNAME|NV_NOASSIGN);
    sp->node = np;
    nv_putval(np, path, 0);
    nv_stack(np, (Namfun_t*)sp);
    service_add(sp);
    return(0);
}

int b_eloop(int argc, char** argv, void* extra)
{
    register long   timeout = -1;
    NOT_USED(argc);
    NOT_USED(extra);
    for (;;)
    {
        switch (optget(argv, eloop_usage))
        {
        case 0:
            break;
        case 't':
            timeout = opt_info.num;
            continue;
        case ':':
            error(2, opt_info.arg);
            continue;
        case '?':
            error(ERROR_usage(2), opt_info.arg);
            continue;
        }
        break;
    }
    argv += opt_info.index;
    if (error_info.errors  || *argv)
        error(ERROR_usage(2), optusage(NiL));
    while(1)
    {
        if(waitnotify(-1, timeout, 0)==0)
            break;
        sfprintf(sfstderr,"interrupted\n");
    }
    return(errno != 0);
}