Introduce ast_parse_arg() , a generic function to parse strings

in a consistent way. This is meant to replace the custom code
which is repeated all over the place in the various files when
parsing config files, CLI entries and other string information.

Right now the code supports parsing int32, uint32 and sockaddr_in with
optional default values and bound checks. It contains minimal error
checking, but that can be easily extended as the need arises.

Being a new API i am introducing this only in trunk, though I believe
that once the interface has been ironed out it might become a
worthwhile addition to 1.4 as well - basically, the first time
we will need to fix a piece of argument parsing code, we might as
well bring in this change and use the new API instead.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@75379 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 119 insertions, 0 deletions

diff --git a/main/config.c b/main/config.c
index 2568dc728..e9ba97fcc 100644
--- a/main/config.c
+++ b/main/config.c
@@ -37,6 +37,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include <errno.h>
 #include <time.h>
 #include <sys/stat.h>
+#include <sys/socket.h>		/* for AF_INET */
 #define AST_INCLUDE_GLOB 1
 #ifdef AST_INCLUDE_GLOB
 #if defined(__Darwin__) || defined(__CYGWIN__)
@@ -1444,6 +1445,124 @@ int ast_destroy_realtime(const char *family, const char *keyfield, const char *l
 	return res;
 }
 
+/*! \brief Helper function to parse arguments
+ * See documentation in config.h
+ */
+int ast_parse_arg(const char *arg, enum ast_parse_flags flags,
+        void *p_result, ...)
+{
+	va_list ap;
+	int error = 0;
+
+	va_start(ap, p_result);
+	switch (flags & PARSE_TYPE) {
+	case PARSE_INT32:
+	    {
+		int32_t *result = p_result;
+		int32_t x, def = result ? *result : 0,
+			high = (int32_t)0x7fffffff,
+			low  = (int32_t)0x80000000;
+		/* optional argument: first default value, then range */
+		if (flags & PARSE_DEFAULT)
+			def = va_arg(ap, int32_t);
+		if (flags & (PARSE_IN_RANGE|PARSE_OUT_RANGE)) {
+			/* range requested, update bounds */
+			low = va_arg(ap, int32_t);
+			high = va_arg(ap, int32_t);
+		}
+		x = strtol(arg, NULL, 0);
+		error = (x < low) || (x > high);
+		if (flags & PARSE_OUT_RANGE)
+			error = !error;
+		if (result)
+			*result  = error ? def : x;
+		ast_debug(3,
+			"extract int from [%s] in [%d, %d] gives [%d](%d)\n",
+			arg, low, high,
+			result ? *result : x, error);
+		break;
+	    }
+
+	case PARSE_UINT32:
+	    {
+		uint32_t *result = p_result;
+		uint32_t x, def = result ? *result : 0,
+			low = 0, high = (uint32_t)~0;
+		/* optional argument: first default value, then range */
+		if (flags & PARSE_DEFAULT)
+			def = va_arg(ap, uint32_t);
+		if (flags & (PARSE_IN_RANGE|PARSE_OUT_RANGE)) {
+			/* range requested, update bounds */
+			low = va_arg(ap, uint32_t);
+			high = va_arg(ap, uint32_t);
+		}
+		x = strtoul(arg, NULL, 0);
+		error = (x < low) || (x > high);
+		if (flags & PARSE_OUT_RANGE)
+			error = !error;
+		if (result)
+			*result  = error ? def : x;
+		ast_debug(3,
+			"extract uint from [%s] in [%u, %u] gives [%u](%d)\n",
+			arg, low, high,
+			result ? *result : x, error);
+		break;
+	    }
+
+	case PARSE_INADDR:
+	    {
+		char *port, *buf;
+		struct sockaddr_in _sa_buf;	/* buffer for the result */
+		struct sockaddr_in *sa = p_result ?
+			(struct sockaddr_in *)p_result : &_sa_buf;
+		/* default is either the supplied value or the result itself */
+		struct sockaddr_in *def = (flags & PARSE_DEFAULT) ?
+			va_arg(ap, struct sockaddr_in *) : sa;
+		struct hostent *hp;
+		struct ast_hostent ahp;
+
+		bzero(&_sa_buf, sizeof(_sa_buf)); /* clear buffer */
+		/* duplicate the string to strip away the :port */
+		port = ast_strdupa(arg);
+		buf = strsep(&port, ":");
+		sa->sin_family = AF_INET;	/* assign family */
+		/*
+		 * honor the ports flag setting, assign default value
+		 * in case of errors or field unset.
+		 */
+		flags &= PARSE_PORT_MASK; /* the only flags left to process */
+		if (port) {
+			if (flags == PARSE_PORT_FORBID) {
+				error = 1;	/* port was forbidden */
+				sa->sin_port = def->sin_port;
+			} else if (flags == PARSE_PORT_IGNORE)
+				sa->sin_port = def->sin_port;
+			else /* accept or require */
+				sa->sin_port = htons(strtol(port, NULL, 0));
+		} else {
+			sa->sin_port = def->sin_port;
+			if (flags == PARSE_PORT_REQUIRE)
+				error = 1;
+		}
+		/* Now deal with host part, even if we have errors before. */
+		hp = ast_gethostbyname(buf, &ahp);
+		if (hp)	/* resolved successfully */
+			memcpy(&sa->sin_addr, hp->h_addr, sizeof(sa->sin_addr));
+		else {
+			error = 1;
+			sa->sin_addr = def->sin_addr;
+		}
+		ast_debug(3,
+			"extract inaddr from [%s] gives [%s:%d](%d)\n",
+			arg, ast_inet_ntoa(sa->sin_addr),
+			ntohs(sa->sin_port), error);
+	    	break;
+	    }
+	}
+	va_end(ap);
+	return error;
+}
+
 static int config_command(int fd, int argc, char **argv) 
 {
 	struct ast_config_engine *eng;