Add new file utils.c, Move ast_gethostbyname to utils.c

git-svn-id: http://svn.digium.com/svn/asterisk/trunk@2931 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 130 insertions, 0 deletions

diff --git a/utils.c b/utils.c
new file mode 100755
index 000000000..df068816b
--- /dev/null
+++ b/utils.c
@@ -0,0 +1,130 @@
+/*
+ * Asterisk -- A telephony toolkit for Linux.
+ *
+ * Utility functions
+ *
+ * Copyright (C) 2004, Digium
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License
+ */
+
+#include <asterisk/lock.h>
+#include <asterisk/utils.h>
+
+#if defined(__FreeBSD__)
+
+/* duh? ERANGE value copied from web... */
+#define ERANGE 34
+#undef gethostbyname
+
+int gethostbyname_r (const char *name, struct hostent *ret, char *buf,
+			size_t buflen, struct hostent **result, 
+			int *h_errnop) 
+{
+	int hsave;
+	struct hostent *ph;
+	static ast_mutex_t __mutex = AST_MUTEX_INITIALIZER;
+	ast_mutex_lock(&__mutex); /* begin critical area */
+	hsave = h_errno;
+
+	ph = gethostbyname(name);
+	*h_errnop = h_errno; /* copy h_errno to *h_herrnop */
+	if (ph == NULL) {
+		*result = NULL;
+	} else {
+		char **p, **q;
+		char *pbuf;
+		int nbytes=0;
+		int naddr=0, naliases=0;
+		/* determine if we have enough space in buf */
+
+		/* count how many addresses */
+		for (p = ph->h_addr_list; *p != 0; p++) {
+			nbytes += ph->h_length; /* addresses */
+			nbytes += sizeof(*p); /* pointers */
+			naddr++;
+		}
+		nbytes += sizeof(*p); /* one more for the terminating NULL */
+
+		/* count how many aliases, and total length of strings */
+		for (p = ph->h_aliases; *p != 0; p++) {
+			nbytes += (strlen(*p)+1); /* aliases */
+			nbytes += sizeof(*p);  /* pointers */
+			naliases++;
+		}
+		nbytes += sizeof(*p); /* one more for the terminating NULL */
+
+		/* here nbytes is the number of bytes required in buffer */
+		/* as a terminator must be there, the minimum value is ph->h_length */
+		if(nbytes > buflen) {
+			*result = NULL;
+			ast_mutex_unlock(&__mutex); /* end critical area */
+			return ERANGE; /* not enough space in buf!! */
+		}
+
+		/* There is enough space. Now we need to do a deep copy! */
+		/* Allocation in buffer:
+			from [0] to [(naddr-1) * sizeof(*p)]:
+			pointers to addresses
+			at [naddr * sizeof(*p)]:
+			NULL
+			from [(naddr+1) * sizeof(*p)] to [(naddr+naliases) * sizeof(*p)] :
+			pointers to aliases
+			at [(naddr+naliases+1) * sizeof(*p)]:
+			NULL
+			then naddr addresses (fixed length), and naliases aliases (asciiz).
+		*/
+
+		*ret = *ph;   /* copy whole structure (not its address!) */
+
+		/* copy addresses */
+		q = (char **)buf; /* pointer to pointers area (type: char **) */
+		ret->h_addr_list = q; /* update pointer to address list */
+		pbuf = buf + ((naddr+naliases+2)*sizeof(*p)); /* skip that area */
+		for (p = ph->h_addr_list; *p != 0; p++) {
+			memcpy(pbuf, *p, ph->h_length); /* copy address bytes */
+			*q++ = pbuf; /* the pointer is the one inside buf... */
+			pbuf += ph->h_length; /* advance pbuf */
+		}
+		*q++ = NULL; /* address list terminator */
+
+		/* copy aliases */
+		ret->h_aliases = q; /* update pointer to aliases list */
+		for (p = ph->h_aliases; *p != 0; p++) {
+			strcpy(pbuf, *p); /* copy alias strings */
+			*q++ = pbuf; /* the pointer is the one inside buf... */
+			pbuf += strlen(*p); /* advance pbuf */
+			*pbuf++ = 0; /* string terminator */
+		}
+		*q++ = NULL; /* terminator */
+
+		strcpy(pbuf, ph->h_name); /* copy alias strings */
+		ret->h_name = pbuf;
+		pbuf += strlen(ph->h_name); /* advance pbuf */
+		*pbuf++ = 0; /* string terminator */
+
+		*result = ret;  /* and let *result point to structure */
+
+	}
+	h_errno = hsave;  /* restore h_errno */
+	ast_mutex_unlock(&__mutex); /* end critical area */
+
+	return (*result != NULL);
+}
+
+
+#endif
+
+struct hostent *ast_gethostbyname(const char *host, struct ast_hostent *hp)
+{
+	int res;
+	int herrno;
+	struct hostent *result = NULL;
+
+	res = gethostbyname_r(host, &hp->hp, hp->buf, sizeof(hp->buf), &result, &herrno);
+
+	if (res || !hp->hp.h_addr_list || !hp->hp.h_addr_list[0])
+		return NULL;
+	return &hp->hp;
+}