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unix.c

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/*
 * Copyright (c) 1995-2004, Index Data
 * See the file LICENSE for details.
 *
 * $Id: unix.c,v 1.7 2004/11/18 15:18:14 heikki Exp $
 * UNIX socket COMSTACK. By Morten Bøgeskov.
 */
/**
 * \file unix.c
 * \brief Implements UNIX domain socket COMSTACK
 */

#ifndef WIN32

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>

#include <grp.h>
#include <pwd.h>
#include <sys/types.h>

#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>

#include <yaz/comstack.h>
#include <yaz/unix.h>
#include <yaz/nmem.h>

#ifndef YAZ_SOCKLEN_T
#define YAZ_SOCKLEN_T int
#endif

static int unix_close(COMSTACK h);
static int unix_put(COMSTACK h, char *buf, int size);
static int unix_get(COMSTACK h, char **buf, int *bufsize);
static int unix_connect(COMSTACK h, void *address);
static int unix_more(COMSTACK h);
static int unix_rcvconnect(COMSTACK h);
static int unix_bind(COMSTACK h, void *address, int mode);
static int unix_listen(COMSTACK h, char *raddr, int *addrlen,
            int (*check_ip)(void *cd, const char *a, int len, int type),
            void *cd);
static int unix_set_blocking(COMSTACK p, int blocking);

static COMSTACK unix_accept(COMSTACK h);
static char *unix_addrstr(COMSTACK h);
static void *unix_straddr(COMSTACK h, const char *str);

#ifndef SUN_LEN
#define SUN_LEN(ptr) ((size_t) (((struct sockaddr_un *) 0)->sun_path) \
                  + strlen ((ptr)->sun_path))
#endif
#if 0
#define TRC(x) x
#else
#define TRC(X)
#endif

/* this state is used for both SSL and straight TCP/IP */
typedef struct unix_state
{
    char *altbuf; /* alternate buffer for surplus data */
    int altsize;  /* size as xmalloced */
    int altlen;   /* length of data or 0 if none */

    int written;  /* -1 if we aren't writing */
    int towrite;  /* to verify against user input */
    int (*complete)(const unsigned char *buf, int len); /* length/comple. */
    struct sockaddr_un addr;  /* returned by cs_straddr */
    int uid;
    int gid;
    int umask;
    char buf[128]; /* returned by cs_addrstr */
} unix_state;

static int unix_init (void)
{
    return 1;
}

/*
 * This function is always called through the cs_create() macro.
 * s >= 0: socket has already been established for us.
 */
COMSTACK unix_type(int s, int blocking, int protocol, void *vp)
{
    COMSTACK p;
    unix_state *state;
    int new_socket;

    if (!unix_init ())
      return 0;
    if (s < 0)
    {
      if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
          return 0;
      new_socket = 1;
    }
    else
      new_socket = 0;
    if (!(p = (struct comstack *)xmalloc(sizeof(struct comstack))))
      return 0;
    if (!(state = (struct unix_state *)(p->cprivate =
                              xmalloc(sizeof(unix_state)))))
      return 0;

    if (!((p->blocking = blocking)&1))
    {
      if (fcntl(s, F_SETFL, O_NONBLOCK) < 0)
          return 0;
#ifndef MSG_NOSIGNAL
      signal (SIGPIPE, SIG_IGN);
#endif
    }

    p->io_pending = 0;
    p->iofile = s;
    p->type = unix_type;
    p->protocol = (enum oid_proto) protocol;

    p->f_connect = unix_connect;
    p->f_rcvconnect = unix_rcvconnect;
    p->f_get = unix_get;
    p->f_put = unix_put;
    p->f_close = unix_close;
    p->f_more = unix_more;
    p->f_bind = unix_bind;
    p->f_listen = unix_listen;
    p->f_accept = unix_accept;
    p->f_addrstr = unix_addrstr;
    p->f_straddr = unix_straddr;
    p->f_set_blocking = unix_set_blocking;

    p->state = new_socket ? CS_ST_UNBND : CS_ST_IDLE; /* state of line */
    p->event = CS_NONE;
    p->cerrno = 0;
    p->stackerr = 0;

    state->altbuf = 0;
    state->altsize = state->altlen = 0;
    state->towrite = state->written = -1;
    if (protocol == PROTO_WAIS)
      state->complete = completeWAIS;
    else
      state->complete = cs_complete_auto;

    p->timeout = COMSTACK_DEFAULT_TIMEOUT;
    TRC(fprintf(stderr, "Created new UNIX comstack\n"));

    return p;
}


static int unix_strtoaddr_ex(const char *str, struct sockaddr_un *add)
{
    char *cp;
    if (!unix_init ())
      return 0;
    TRC(fprintf(stderr, "unix_strtoaddress: %s\n", str ? str : "NULL"));
    add->sun_family = AF_UNIX;
    strncpy(add->sun_path, str, sizeof(add->sun_path));
    cp = strchr (add->sun_path, ':');
    if (cp)
      *cp = '\0';
    return 1;
}

static void *unix_straddr(COMSTACK h, const char *str)
{
    unix_state *sp = (unix_state *)h->cprivate;
    char * s = strdup(str);
    char * f = s;
    const char * file = NULL;
    char * eol;

    sp->uid = sp->gid = sp->umask = -1;

    if ((eol = strchr(s, ',')))
    {
      do
      {
          if ((eol = strchr(s, ',')))
            *eol++ = '\0';
          if (sp->uid  == -1 && strncmp(s, "user=",  5) == 0)
          {
            char * arg = s + 5;
            if (strspn(arg, "0123456789") == strlen(arg))
            {
                sp->uid = atoi(arg);
            }
            else
            {
                struct passwd * pw = getpwnam(arg);
                if(pw == NULL)
                {
                  printf("No such user\n");
                  free(f);
                  return 0;
                }
                sp->uid = pw->pw_uid;
            }
          }
          else if (sp->gid == -1 && strncmp(s, "group=", 6) == 0)
          {
            char * arg = s + 6;
            if (strspn(arg, "0123456789") == strlen(arg))
            {
                sp->gid = atoi(arg);
            }
            else
            {
                struct group * gr = getgrnam(arg);
                if (gr == NULL)
                {
                  printf("No such group\n");
                  free(f);
                  return 0;
                }
                sp->gid = gr->gr_gid;
            }
          }
          else if (sp->umask == -1 && strncmp(s, "umask=", 6) == 0)
          {
            char * end;
            char * arg = s + 6;
            
            sp->umask = strtol(arg, &end, 8);
            if (errno == EINVAL ||
                *end)
            {
                printf("Invalid umask\n");
                free(f);
                return 0;
            }
          }
          else if (file == NULL && strncmp(s, "file=", 5) == 0)
          {
            char * arg = s + 5;
            file = arg;
          }
          else
          {
            printf("invalid or double argument: %s\n", s);
            free(f);
            return 0;
          }
      } while((s = eol));
    }
    else
    {
      file = str;
    }
    if(! file)
    {
      errno = EINVAL;
      return 0;
    }

    TRC(fprintf(stderr, "unix_straddr: %s\n", str ? str : "NULL"));

    if (!unix_strtoaddr_ex (file, &sp->addr))
    {
      free(f);
      return 0;
    }
    free(f);
    return &sp->addr;
}

struct sockaddr_un *unix_strtoaddr(const char *str)
{
    static struct sockaddr_un add;

    TRC(fprintf(stderr, "unix_strtoaddr: %s\n", str ? str : "NULL"));

    if (!unix_strtoaddr_ex (str, &add))
      return 0;
    return &add;
}

static int unix_more(COMSTACK h)
{
    unix_state *sp = (unix_state *)h->cprivate;

    return sp->altlen && (*sp->complete)((unsigned char *) sp->altbuf,
                               sp->altlen);
}

/*
 * connect(2) will block (sometimes) - nothing we can do short of doing
 * weird things like spawning subprocesses or threading or some weird junk
 * like that.
 */
static int unix_connect(COMSTACK h, void *address)
{
    struct sockaddr_un *add = (struct sockaddr_un *)address;
    int r;

    TRC(fprintf(stderr, "unix_connect\n"));
    h->io_pending = 0;
    if (h->state != CS_ST_UNBND)
    {
      h->cerrno = CSOUTSTATE;
      return -1;
    }
    r = connect(h->iofile, (struct sockaddr *) add, SUN_LEN(add));
    if (r < 0)
    {
      if (yaz_errno() == EINPROGRESS)
      {
          h->event = CS_CONNECT;
          h->state = CS_ST_CONNECTING;
          h->io_pending = CS_WANT_WRITE|CS_WANT_READ;
          return 1;
      }
      h->cerrno = CSYSERR;
      return -1;
    }
    h->event = CS_CONNECT;
    h->state = CS_ST_CONNECTING;

    return unix_rcvconnect (h);
}

/*
 * nop
 */
static int unix_rcvconnect(COMSTACK h)
{
    TRC(fprintf(stderr, "unix_rcvconnect\n"));

    if (h->state == CS_ST_DATAXFER)
      return 0;
    if (h->state != CS_ST_CONNECTING)
    {
      h->cerrno = CSOUTSTATE;
      return -1;
    }
    h->event = CS_DATA;
    h->state = CS_ST_DATAXFER;
    return 0;
}

static int unix_bind(COMSTACK h, void *address, int mode)
{
    unix_state *sp = (unix_state *)h->cprivate;
    struct sockaddr *addr = (struct sockaddr *)address;
    const char * path = ((struct sockaddr_un *)addr)->sun_path;
    struct stat stat_buf;

    TRC (fprintf (stderr, "unix_bind\n"));

    if(stat(path, &stat_buf) != -1) {
      struct sockaddr_un socket_unix;
      int socket_out = -1;
      if(! S_ISSOCK(stat_buf.st_mode)) {
          h->cerrno = CSYSERR;
          yaz_set_errno(EEXIST); /* Not a socket (File exists) */
          return -1;
      }
      if((socket_out = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
          h->cerrno = CSYSERR;
          return -1;
      }
      socket_unix.sun_family = AF_UNIX;
      strncpy(socket_unix.sun_path, path, sizeof(socket_unix.sun_path));
      if(connect(socket_out, (struct sockaddr *) &socket_unix, SUN_LEN(&socket_unix)) < 0) {
          if(yaz_errno() == ECONNREFUSED) {
            TRC (fprintf (stderr, "Socket exists but nobody is listening\n"));
          } else {
            h->cerrno = CSYSERR;
            return -1;
          }
      } else {
          close(socket_out);
          h->cerrno = CSYSERR;
          yaz_set_errno(EADDRINUSE);
          return -1;
      }
      unlink(path);
    }

    if (bind(h->iofile, (struct sockaddr *) addr, SUN_LEN((struct sockaddr_un *)addr)))
    {
      h->cerrno = CSYSERR;
      return -1;
    }
    chown(path, sp->uid, sp->gid);
    chmod(path, sp->umask != -1 ? sp->umask : 0666);
    if (mode == CS_SERVER && listen(h->iofile, 3) < 0)
    {
      h->cerrno = CSYSERR;
      return -1;
    }
    h->state = CS_ST_IDLE;
    h->event = CS_LISTEN;
    return 0;
}

static int unix_listen(COMSTACK h, char *raddr, int *addrlen,
                    int (*check_ip)(void *cd, const char *a, int len, int t),
                void *cd)
{
    struct sockaddr_un addr;
    YAZ_SOCKLEN_T len = sizeof(addr);

    TRC(fprintf(stderr, "unix_listen pid=%d\n", getpid()));
    if (h->state != CS_ST_IDLE)
    {
      h->cerrno = CSOUTSTATE;
      return -1;
    }
    h->newfd = accept(h->iofile, (struct sockaddr*)&addr, &len);
    if (h->newfd < 0)
    {
      if (
          yaz_errno() == EWOULDBLOCK
#ifdef EAGAIN
#if EAGAIN != EWOULDBLOCK
          || yaz_errno() == EAGAIN
#endif
#endif
          )
          h->cerrno = CSNODATA;
      else
          h->cerrno = CSYSERR;
      return -1;
    }
    if (addrlen && (size_t) (*addrlen) >= sizeof(struct sockaddr_un))
      memcpy(raddr, &addr, *addrlen = sizeof(struct sockaddr_un));
    else if (addrlen)
      *addrlen = 0;
    h->state = CS_ST_INCON;
    return 0;
}

static COMSTACK unix_accept(COMSTACK h)
{
    COMSTACK cnew;
    unix_state *state, *st = (unix_state *)h->cprivate;

    TRC(fprintf(stderr, "unix_accept\n"));
    if (h->state == CS_ST_INCON)
    {
      if (!(cnew = (COMSTACK)xmalloc(sizeof(*cnew))))
      {
          h->cerrno = CSYSERR;
          close(h->newfd);
          h->newfd = -1;
          return 0;
      }
      memcpy(cnew, h, sizeof(*h));
      cnew->iofile = h->newfd;
      cnew->io_pending = 0;
      if (!(state = (unix_state *)
            (cnew->cprivate = xmalloc(sizeof(unix_state)))))
      {
          h->cerrno = CSYSERR;
          if (h->newfd != -1)
          {
            close(h->newfd);
            h->newfd = -1;
          }
          return 0;
      }
      if (!(cnew->blocking&1) && 
            (fcntl(cnew->iofile, F_SETFL, O_NONBLOCK) < 0)
          )
      {
          h->cerrno = CSYSERR;
          if (h->newfd != -1)
          {
            close(h->newfd);
            h->newfd = -1;
          }
          xfree (cnew);
          xfree (state);
          return 0;
      }
      h->newfd = -1;
      state->altbuf = 0;
      state->altsize = state->altlen = 0;
      state->towrite = state->written = -1;
      state->complete = st->complete;
      memcpy(&state->addr, &st->addr, sizeof(state->addr));
      cnew->state = CS_ST_ACCEPT;
      cnew->event = CS_NONE;
      h->state = CS_ST_IDLE;

      h = cnew;
    }
    if (h->state == CS_ST_ACCEPT)
    {
    }
    else
    {
      h->cerrno = CSOUTSTATE;
      return 0;
    }
    h->io_pending = 0;
    h->state = CS_ST_DATAXFER;
    h->event = CS_DATA;
    return h;
}

#define CS_UNIX_BUFCHUNK 4096

/*
 * Return: -1 error, >1 good, len of buffer, ==1 incomplete buffer,
 * 0=connection closed.
 */
static int unix_get(COMSTACK h, char **buf, int *bufsize)
{
    unix_state *sp = (unix_state *)h->cprivate;
    char *tmpc;
    int tmpi, berlen, rest, req, tomove;
    int hasread = 0, res;

    TRC(fprintf(stderr, "unix_get: bufsize=%d\n", *bufsize));
    if (sp->altlen) /* switch buffers */
    {
      TRC(fprintf(stderr, "  %d bytes in altbuf (0x%x)\n", sp->altlen,
                (unsigned) sp->altbuf));
      tmpc = *buf;
      tmpi = *bufsize;
      *buf = sp->altbuf;
      *bufsize = sp->altsize;
      hasread = sp->altlen;
      sp->altlen = 0;
      sp->altbuf = tmpc;
      sp->altsize = tmpi;
    }
    h->io_pending = 0;
    while (!(berlen = (*sp->complete)((unsigned char *)*buf, hasread)))
    {
      if (!*bufsize)
      {
          if (!(*buf = (char *)xmalloc(*bufsize = CS_UNIX_BUFCHUNK)))
            return -1;
      }
      else if (*bufsize - hasread < CS_UNIX_BUFCHUNK)
          if (!(*buf =(char *)xrealloc(*buf, *bufsize *= 2)))
            return -1;
      res = recv(h->iofile, *buf + hasread, CS_UNIX_BUFCHUNK, 0);
      TRC(fprintf(stderr, "  recv res=%d, hasread=%d\n", res, hasread));
      if (res < 0)
      {
          if (yaz_errno() == EWOULDBLOCK
#ifdef EAGAIN
#if EAGAIN != EWOULDBLOCK
            || yaz_errno() == EAGAIN
#endif
#endif
            || yaz_errno() == EINPROGRESS
            )
          {
            h->io_pending = CS_WANT_READ;
            break;
          }
          else if (yaz_errno() == 0)
            continue;
          else
            return -1;
      }
      else if (!res)
          return hasread;
      hasread += res;
    }
    TRC (fprintf (stderr, "  Out of read loop with hasread=%d, berlen=%d\n",
              hasread, berlen));
    /* move surplus buffer (or everything if we didn't get a BER rec.) */
    if (hasread > berlen)
    {
      tomove = req = hasread - berlen;
      rest = tomove % CS_UNIX_BUFCHUNK;
      if (rest)
          req += CS_UNIX_BUFCHUNK - rest;
      if (!sp->altbuf)
      {
          if (!(sp->altbuf = (char *)xmalloc(sp->altsize = req)))
            return -1;
      } else if (sp->altsize < req)
          if (!(sp->altbuf =(char *)xrealloc(sp->altbuf, sp->altsize = req)))
            return -1;
      TRC(fprintf(stderr, "  Moving %d bytes to altbuf(0x%x)\n", tomove,
                (unsigned) sp->altbuf));
      memcpy(sp->altbuf, *buf + berlen, sp->altlen = tomove);
    }
    if (berlen < CS_UNIX_BUFCHUNK - 1)
      *(*buf + berlen) = '\0';
    return berlen ? berlen : 1;
}



/*
 * Returns 1, 0 or -1
 * In nonblocking mode, you must call again with same buffer while
 * return value is 1.
 */
static int unix_put(COMSTACK h, char *buf, int size)
{
    int res;
    struct unix_state *state = (struct unix_state *)h->cprivate;

    TRC(fprintf(stderr, "unix_put: size=%d\n", size));
    h->io_pending = 0;
    h->event = CS_DATA;
    if (state->towrite < 0)
    {
      state->towrite = size;
      state->written = 0;
    }
    else if (state->towrite != size)
    {
      h->cerrno = CSWRONGBUF;
      return -1;
    }
    while (state->towrite > state->written)
    {
      if ((res =
           send(h->iofile, buf + state->written, size -
              state->written,
#ifdef MSG_NOSIGNAL
              MSG_NOSIGNAL
#else
              0
#endif
             )) < 0)
      {
          if (
            yaz_errno() == EWOULDBLOCK
#ifdef EAGAIN
#if EAGAIN != EWOULDBLOCK
            || yaz_errno() == EAGAIN
#endif
#endif
            )
          {
            TRC(fprintf(stderr, "  Flow control stop\n"));
            h->io_pending = CS_WANT_WRITE;
            return 1;
          }
          h->cerrno = CSYSERR;
          return -1;
      }
      state->written += res;
      TRC(fprintf(stderr, "  Wrote %d, written=%d, nbytes=%d\n",
                res, state->written, size));
    }
    state->towrite = state->written = -1;
    TRC(fprintf(stderr, "  Ok\n"));
    return 0;
}

static int unix_close(COMSTACK h)
{
    unix_state *sp = (struct unix_state *)h->cprivate;

    TRC(fprintf(stderr, "unix_close\n"));
    if (h->iofile != -1)
    {
      close(h->iofile);
    }
    if (sp->altbuf)
      xfree(sp->altbuf);
    xfree(sp);
    xfree(h);
    return 0;
}

static char *unix_addrstr(COMSTACK h)
{
    unix_state *sp = (struct unix_state *)h->cprivate;
    char *buf = sp->buf;
    sprintf(buf, "unix:%s", sp->addr.sun_path);
    return buf;
}

static int unix_set_blocking(COMSTACK p, int blocking)
{
    unsigned long flag;

    if (p->blocking == blocking)
      return 1;
    flag = fcntl(p->iofile, F_GETFL, 0);
    if(!blocking)
      flag = flag & ~O_NONBLOCK;
    else
      flag = flag | O_NONBLOCK;
    if (fcntl(p->iofile, F_SETFL, flag) < 0)
      return 0;
    p->blocking = blocking;
    return 1;
}
#endif

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