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#include <unistd.h>
#include <fcntl.h>
#include <netdb.h>
#include <sys/mman.h>
#include <errno.h>
#include <netinet/in.h>
#include <string.h>
#include <ctype.h>
#include <netdb.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include "dietfeatures.h"
static char* hostmap=0;
static unsigned int hostlen;
static char *cur;
/* ::1 localhost6 alias1 alias2 # internet protocol, pseudo protocol number */
struct hostent* gethostent_r(char* buf, int len) {
char *dest;
struct hostent* pe=(struct hostent*)buf;
char* last;
char* max=buf+len;
int aliasidx;
if (!hostmap) {
int hostfd=open(_PATH_HOSTS,O_RDONLY);
if (hostfd<0) return 0;
hostlen=lseek(hostfd,0,SEEK_END);
hostmap=mmap(0,hostlen,PROT_READ|PROT_WRITE,MAP_PRIVATE,hostfd,0);
if ((long)hostmap==(-1)) { close(hostfd); hostmap=0; goto error; }
close(hostfd); hostfd=-1;
cur=hostmap;
}
last=hostmap+hostlen;
again:
if ((size_t)len<sizeof(struct hostent)+11*sizeof(char*)) goto nospace;
dest=buf+sizeof(struct hostent);
pe->h_name=0;
pe->h_aliases=(char**)dest; pe->h_aliases[0]=0; dest+=10*sizeof(char*);
pe->h_addr_list=(char**)dest; dest+=2*sizeof(char**);
if (cur>=last) return 0;
if (*cur=='#' || *cur=='\n') goto parseerror;
/* first, the ip number */
pe->h_name=cur;
while (cur<last && !isspace(*cur)) cur++;
if (cur>=last) return 0;
if (*cur=='\n') goto parseerror;
{
char save=*cur;
*cur=0;
pe->h_addr_list[0]=dest;
pe->h_addr_list[1]=0;
if (max-dest<16) goto nospace;
if (inet_pton(AF_INET6,pe->h_name,dest)>0) {
pe->h_addrtype=AF_INET6;
pe->h_length=16;
dest+=16;
} else if (inet_pton(AF_INET,pe->h_name,dest)>0) {
pe->h_addrtype=AF_INET;
pe->h_length=4;
dest+=4;
} else {
*cur=save;
goto parseerror;
}
*cur=save;
}
++cur;
/* now the aliases */
for (aliasidx=0;aliasidx<9;++aliasidx) {
while (cur<last && isblank(*cur)) ++cur;
pe->h_aliases[aliasidx]=cur;
while (cur<last && !isspace(*cur)) ++cur;
{
char *from=pe->h_aliases[aliasidx];
int len=cur-from;
if (max-dest<len+2) goto nospace;
pe->h_aliases[aliasidx]=dest;
memmove(dest,from,(size_t)(cur-from));
dest+=len;
*dest=0; ++dest;
}
if (*cur=='\n') { ++cur; ++aliasidx; break; }
if (cur>=last || !isblank(*cur)) break;
cur++;
}
pe->h_aliases[aliasidx]=0;
pe->h_name=pe->h_aliases[0];
pe->h_aliases++;
return pe;
parseerror:
while (cur<last && *cur!='\n') cur++;
cur++;
goto again;
nospace:
errno=ERANGE;
goto __error;
error:
errno=ENOMEM;
__error:
if (hostmap!=(char*)-1) munmap(hostmap,hostlen);
hostmap=(char*)-1;
return 0;
}
void sethostent(int stayopen) {
(void)stayopen;
cur=hostmap;
}
void endhostent(void) {
if (hostmap!=(char*)-1) munmap(hostmap,hostlen);
hostmap=0;
}
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