getservbyname_r.c raw

   1  #define _GNU_SOURCE
   2  #include <sys/socket.h>
   3  #include <netinet/in.h>
   4  #include <netdb.h>
   5  #include <inttypes.h>
   6  #include <errno.h>
   7  #include <string.h>
   8  #include <stdlib.h>
   9  #include "lookup.h"
  10  
  11  #define ALIGN (sizeof(struct { char a; char *b; }) - sizeof(char *))
  12  
  13  int getservbyname_r(const char *name, const char *prots,
  14  	struct servent *se, char *buf, size_t buflen, struct servent **res)
  15  {
  16  	struct service servs[MAXSERVS];
  17  	int cnt, proto, align;
  18  
  19  	*res = 0;
  20  
  21  	/* Don't treat numeric port number strings as service records. */
  22  	char *end = "";
  23  	strtoul(name, &end, 10);
  24  	if (!*end) return ENOENT;
  25  
  26  	/* Align buffer */
  27  	align = -(uintptr_t)buf & ALIGN-1;
  28  	if (buflen < 2*sizeof(char *)+align)
  29  		return ERANGE;
  30  	buf += align;
  31  
  32  	if (!prots) proto = 0;
  33  	else if (!strcmp(prots, "tcp")) proto = IPPROTO_TCP;
  34  	else if (!strcmp(prots, "udp")) proto = IPPROTO_UDP;
  35  	else return EINVAL;
  36  
  37  	cnt = __lookup_serv(servs, name, proto, 0, 0);
  38  	if (cnt<0) switch (cnt) {
  39  	case EAI_MEMORY:
  40  	case EAI_SYSTEM:
  41  		return ENOMEM;
  42  	default:
  43  		return ENOENT;
  44  	}
  45  
  46  	se->s_name = (char *)name;
  47  	se->s_aliases = (void *)buf;
  48  	se->s_aliases[0] = se->s_name;
  49  	se->s_aliases[1] = 0;
  50  	se->s_port = htons(servs[0].port);
  51  	se->s_proto = servs[0].proto == IPPROTO_TCP ? "tcp" : "udp";
  52  
  53  	*res = se;
  54  	return 0;
  55  }
  56