Subversion Repositories planix.SVN

/* posix */
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>

/* bsd extensions */
#include <sys/uio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#include "priv.h"

int h_errno;

enum
{
        Nname= 6,
};

/*
 *  for inet addresses only
 */
struct hostent*
gethostbyname(const char *name)
{
        int i, t, fd, m;
        char *p, *bp;
        int nn, na;
        unsigned long x;
        static struct hostent h;
        static char buf[1024];
        static char *nptr[Nname+1];
        static char *aptr[Nname+1];
        static char addr[Nname][4];

        h.h_name = 0;
        t = _sock_ipattr(name);

        /* connect to server */
        fd = open("/net/cs", O_RDWR);
        if(fd < 0){
                _syserrno();
                h_errno = NO_RECOVERY;
                return 0;
        }

        /* construct the query, always expect an ip# back */
        switch(t){
        case Tsys:
                snprintf(buf, sizeof buf, "!sys=%s ip=*", name);
                break;
        case Tdom:
                snprintf(buf, sizeof buf, "!dom=%s ip=*", name);
                break;
        case Tip:
                snprintf(buf, sizeof buf, "!ip=%s", name);
                break;
        }

        /* query the server */
        if(write(fd, buf, strlen(buf)) < 0){
                _syserrno();
                h_errno = TRY_AGAIN;
                return 0;
        }
        lseek(fd, 0, 0);
        for(i = 0; i < sizeof(buf)-1; i += m){
                m = read(fd, buf+i, sizeof(buf) - 1 - i);
                if(m <= 0)
                        break;
                buf[i+m++] = ' ';
        }
        close(fd);
        buf[i] = 0;

        /* parse the reply */
        nn = na = 0;
        for(bp = buf;;){
                p = strchr(bp, '=');
                if(p == 0)
                        break;
                *p++ = 0;
                if(strcmp(bp, "dom") == 0){
                        if(h.h_name == 0)
                                h.h_name = p;
                        if(nn < Nname)
                                nptr[nn++] = p;
                } else if(strcmp(bp, "sys") == 0){
                        if(nn < Nname)
                                nptr[nn++] = p;
                } else if(strcmp(bp, "ip") == 0){
                        x = inet_addr(p);
                        x = ntohl(x);
                        if(na < Nname){
                                addr[na][0] = x>>24;
                                addr[na][1] = x>>16;
                                addr[na][2] = x>>8;
                                addr[na][3] = x;
                                aptr[na] = addr[na];
                                na++;
                        }
                }
                while(*p && *p != ' ')
                        p++;
                if(*p)
                        *p++ = 0;
                bp = p;
        }
        if(nn+na == 0){
                h_errno = HOST_NOT_FOUND;
                return 0;
        }

        nptr[nn] = 0;
        aptr[na] = 0;
        h.h_aliases = nptr;
        h.h_addr_list = aptr;
        h.h_length = 4;
        h.h_addrtype = AF_INET;
        if(h.h_name == 0)
                h.h_name = nptr[0];
        if(h.h_name == 0)
                h.h_name = aptr[0];

        return &h;
}