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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>
static int servicesfd=-1;
static char* servicesmap;
static unsigned int serviceslen;
static char* aliases[10];
static char *cur;
/* nameserver 42/tcp name # IEN 116 */
struct servent *getservent(void) {
static struct servent se;
char *last;
int aliasidx;
if (servicesfd<0) {
servicesfd=open(_PATH_SERVICES,O_RDONLY);
if (servicesfd<0) return 0;
serviceslen=lseek(servicesfd,0,SEEK_END);
servicesmap=mmap(0,serviceslen,PROT_READ|PROT_WRITE,MAP_PRIVATE,servicesfd,0);
if ((long)servicesmap==(-1)) goto error;
cur=servicesmap;
}
last=servicesmap+serviceslen;
again:
se.s_name=0;
se.s_aliases=aliases; aliases[0]=0;
se.s_port=0;
se.s_proto=0;
if (cur>=last) return 0;
if (*cur=='#' || *cur=='\n') goto parseerror;
/* first, the primary name */
if (!isalpha(*cur)) goto parseerror;
se.s_name=cur;
se.s_aliases=aliases;
while (cur<last && isalnum(*cur)) cur++;
if (cur>=last) return 0;
if (*cur=='\n') goto parseerror;
*cur=0; cur++;
/* second, the port */
while (cur<last && isblank(*cur)) cur++;
while (cur<last && isdigit(*cur)) {
se.s_port=se.s_port*10+*cur-'0';
cur++;
}
se.s_port=htons(se.s_port);
if (cur>=last) return 0;
/* third, "/tcp" or "/udp" */
if (*cur!='/') goto parseerror;
cur++;
se.s_proto=cur;
while (cur<last && isalpha(*cur)) ++cur;
if (cur>=last) return 0;
if (*cur=='\n') { *cur++=0; return &se; }
*cur=0; cur++;
/* 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 &se;
parseerror:
while (cur<last && *cur!='\n') cur++;
cur++;
goto again;
error:
if (servicesmap!=(char*)-1) munmap(servicesmap,serviceslen);
if (servicesfd!=-1) close(servicesfd);
servicesmap=(char*)-1;
servicesfd=-1;
errno=ENOMEM;
return 0;
}
void setservent(int stayopen) {
cur=servicesmap;
}
struct servent *getservbyname(const char *name, const char *proto) {
struct servent *s;
setservent(0);
for (s=getservent(); s; s=getservent()) {
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(name,"auth")) {
tmp=s->s_aliases;
write(1," aka ",5);
while (*tmp) {
write(1,*tmp,strlen(*tmp));
write(1,", ",2);
++tmp;
}
write(1,"\n",1);
}
#endif
if (!strcmp(name,s->s_name) && !strcmp(proto,s->s_proto))
return s;
tmp=s->s_aliases;
while (*tmp)
if (!strcmp(name,*tmp++)) return s;
}
return 0;
}
struct servent *getservbyport(int port, const char *proto) {
struct servent *s;
for (s=getservent(); s; s=getservent()) {
if (port==s->s_port && !strcmp(proto,s->s_proto))
return s;
}
return 0;
}
void endservent(void) {
if (servicesmap!=(char*)-1) munmap(servicesmap,serviceslen);
if (servicesfd!=-1) close(servicesfd);
servicesmap=(char*)-1;
servicesfd=-1;
}
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