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#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <ctype.h>
#include "dietfeatures.h"
#include <netdb.h>
#include <arpa/inet.h>
static int netfd=-1;
static char* netmap;
static unsigned int netlen;
static char* aliases[10];
static char *cur;
/* loopback 127.0.0.0 lo # comment */
struct netent *getnetent(void) {
static struct netent ne;
char *last;
int aliasidx;
if (netfd<0) {
netfd=open(_PATH_NETWORKS,O_RDONLY);
if (netfd<0) return 0;
fcntl (netfd, F_SETFD, FD_CLOEXEC);
netlen=lseek(netfd,0,SEEK_END);
netmap=mmap(0,netlen,PROT_READ|PROT_WRITE,MAP_PRIVATE,netfd,0);
if ((long)netmap==(-1)) goto error;
cur=netmap;
}
last=netmap+netlen;
again:
ne.n_name=0;
ne.n_aliases=aliases; aliases[0]=0;
ne.n_addrtype=AF_INET;
ne.n_net=0;
if (cur>=last) return 0;
if (*cur=='#' || *cur=='\n') goto parseerror;
/* first, the primary name */
if (!isalpha(*cur)) goto parseerror;
ne.n_name=cur;
ne.n_aliases=aliases;
while (cur<last && isalnum(*cur)) cur++;
if (cur>=last) return 0;
if (*cur=='\n') goto parseerror;
*cur=0; cur++;
/* second, the ip */
while (cur<last && isblank(*cur)) cur++;
{
const char *tmp=cur;
char save;
while (cur<last && (isdigit(*cur) || *cur=='.')) ++cur;
save=*cur; *cur=0;
if (inet_aton(tmp,(struct in_addr*)&ne.n_net)==0) goto parseerror;
*cur=save;
}
if (cur>=last) return 0;
/* now the aliases */
for (aliasidx=0;aliasidx<10;++aliasidx) {
while (cur<last && isblank(*cur)) ++cur;
aliases[aliasidx]=cur;
while (cur<last && isalpha(*cur)) ++cur;
if (*cur=='\n') { *cur++=0; ++aliasidx; break; }
if (cur>=last || !isblank(*cur)) break;
*cur++=0;
}
aliases[aliasidx]=0;
return ≠
parseerror:
while (cur<last && *cur!='\n') cur++;
cur++;
goto again;
error:
if (netmap!=(char*)-1) munmap(netmap,netlen);
if (netfd!=-1) close(netfd);
netmap=(char*)-1;
netfd=-1;
errno=ENOMEM;
return 0;
}
struct netent *getnetbyaddr(unsigned long net, int type) {
struct netent *s;
for (s=getnetent(); s; s=getnetent()) {
if (net==s->n_net && type==s->n_addrtype)
return s;
}
return 0;
}
void endnetent(void) {
if (netmap!=(char*)-1) munmap(netmap,netlen);
if (netfd!=-1) close(netfd);
netmap=(char*)-1;
netfd=-1;
}
void setnetent(int stayopen) {
(void)stayopen;
endnetent();
}
struct netent *getnetbyname(const char *name) {
struct netent *s;
setnetent(0);
for (s=getnetent(); s; s=getnetent()) {
char **tmp;
#if 0
write(1,"found ",6);
write(1,s->s_name,strlen(s->s_name));
write(1,"/",1);
write(1,s->s_proto,strlen(s->s_proto));
write(1,"\n",1);
if (!strcmp(s->s_name,"ssh")) {
write(2,"ssh!\n",5);
}
#endif
if (!strcmp(name,s->n_name))
return s;
tmp=s->n_aliases;
while (*tmp)
if (!strcmp(name,*tmp++)) return s;
}
return 0;
}
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