path: root/package/network/utils/nftables/patches/201-make-nftables-usable-with-mini-gmp.patch

From d559314e3e3debe1ff8c2c1372701df6154a53ef Mon Sep 17 00:00:00 2001
From: Steven Barth <steven@midlink.org>
Date: Mon, 15 Dec 2014 10:13:39 +0100
Subject: [PATCH 2/3] build: make nftables usable with mini-gmp

libgmp usually compiles to >400KB which can put a burden on embedded
device firmware especially if libgmp isn't used for other purposes.
mini-gmp in contrast adds only ~30KB to the nft-binary itself.

However mini-gmp does not support gmp_sscanf and gmp_printf.

This patch:
* Adds a configure flag --without-libgmp to select mini-gmp
* Replaces the single gmp_sscanf occurence with mpz_set_str
* Replaces calls to gmp_printf outside of pr_debug with
  a minimalistic mpz_printf usable to format one mpz_t
* Replaces gmp_vasprintf in erec_vcreate with vasprintf
  and rewrites the single user of the gmp format-flags
* Changes the parser token VERSION to IPHDRVERSION to avoid
  clashes with the VERSION-define in config.h

Signed-off-by: Steven Barth <cyrus@openwrt.org>
---
 configure.ac         | 17 ++++++++++++++---
 include/expression.h |  2 +-
 include/gmputil.h    | 10 ++++++++++
 include/utils.h      |  3 +--
 src/Makefile.am      |  4 ++++
 src/ct.c             |  2 +-
 src/datatype.c       |  8 +++-----
 src/erec.c           |  6 +++++-
 src/evaluate.c       |  8 ++++++--
 src/gmputil.c        | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/parser_bison.y   |  6 +++---
 src/scanner.l        |  2 +-
 12 files changed, 102 insertions(+), 20 deletions(-)

diff --git a/configure.ac b/configure.ac
index b55b2b1..1e3729d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -73,8 +73,18 @@ AM_CONDITIONAL([BUILD_PDF], [test "$DBLATEX" == "found"])
 PKG_CHECK_MODULES([LIBMNL], [libmnl >= 1.0.3])
 PKG_CHECK_MODULES([LIBNFTNL], [libnftnl >= 1.0.2])
 
-AC_CHECK_LIB([gmp], [__gmpz_init], ,
-	     AC_MSG_ERROR([No suitable version of libgmp found]))
+AC_ARG_WITH([libgmp], [AS_HELP_STRING([--without-libgmp],
+            [Disable libgmp support (use builtin mini-gmp)])], [],
+            [with_libgmp=yes])
+AS_IF([test "x$with_libgmp" != xno], [
+AC_CHECK_LIB([gmp],[__gmpz_init], , AC_MSG_ERROR([No suitable version of libgmp found]))
+])
+AM_CONDITIONAL([BUILD_MINIGMP], [test "x$with_libgmp" == xno])
+
+
+AS_IF([test "x$with_libgmp" != xyes -a "x$CONFIG_DEBUG" = xy], [
+AC_MSG_ERROR([--without-libgmp MUST be used with --disable-debug])
+])
 
 AC_ARG_WITH([cli], [AS_HELP_STRING([--without-cli],
             [disable interactive CLI (libreadline support)])],
@@ -130,4 +140,5 @@ AC_OUTPUT
 echo "
 nft configuration:
   cli support:			${with_cli}
-  enable debugging:		${with_debug}"
+  enable debugging:		${with_debug}
+  use shared libgmp:		${with_libgmp}"
diff --git a/include/expression.h b/include/expression.h
index 4b96879..7477c3e 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -2,7 +2,7 @@
 #define NFTABLES_EXPRESSION_H
 
 #include <stdbool.h>
-#include <gmp.h>
+#include <gmputil.h>
 #include <linux/netfilter/nf_tables.h>
 
 #include <nftables.h>
diff --git a/include/gmputil.h b/include/gmputil.h
index 63eb0ba..b9ced6d 100644
--- a/include/gmputil.h
+++ b/include/gmputil.h
@@ -1,9 +1,17 @@
 #ifndef NFTABLES_GMPUTIL_H
 #define NFTABLES_GMPUTIL_H
 
+#include <config.h>
+
+#ifdef HAVE_LIBGMP
 #include <gmp.h>
+#else
+#include <mini-gmp.h>
+#endif
+
 #include <asm/byteorder.h>
 
+
 enum mpz_word_order {
 	MPZ_MSWF		= 1,
 	MPZ_LSWF		= -1,
@@ -48,4 +56,6 @@ extern void mpz_import_data(mpz_t rop, const void *data,
 			    unsigned int len);
 extern void mpz_switch_byteorder(mpz_t rop, unsigned int len);
 
+extern int mpz_printf(const char *format, const mpz_t value);
+
 #endif /* NFTABLES_GMPUTIL_H */
diff --git a/include/utils.h b/include/utils.h
index 15b2e39..3c436ba 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -9,14 +9,13 @@
 #include <unistd.h>
 #include <assert.h>
 #include <list.h>
-#include <gmp.h>
 
 #define BITS_PER_BYTE	8
 
 #ifdef DEBUG
 #define pr_debug(fmt, arg...) gmp_printf(fmt, ##arg)
 #else
-#define pr_debug(fmt, arg...) ({ if (false) gmp_printf(fmt, ##arg); 0; })
+#define pr_debug(fmt, arg...) ({ if (false) {}; 0; })
 #endif
 
 #define __fmtstring(x, y)	__attribute__((format(printf, x, y)))
diff --git a/src/Makefile.am b/src/Makefile.am
index 378424d..099052a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -51,4 +51,8 @@ if BUILD_CLI
 nft_SOURCES +=	cli.c
 endif
 
+if BUILD_MINIGMP
+nft_SOURCES +=	mini-gmp.c
+endif
+
 nft_LDADD	= ${LIBMNL_LIBS} ${LIBNFTNL_LIBS}
diff --git a/src/ct.c b/src/ct.c
index 2eb85ea..759e65d 100644
--- a/src/ct.c
+++ b/src/ct.c
@@ -110,7 +110,7 @@ static void ct_label_type_print(const struct expr *expr)
 		return;
 	}
 	/* can happen when connlabel.conf is altered after rules were added */
-	gmp_printf("0x%Zx", expr->value);
+	mpz_printf("0x%Zx", expr->value);
 }
 
 static struct error_record *ct_label_type_parse(const struct expr *sym,
diff --git a/src/datatype.c b/src/datatype.c
index 4519d87..40ce898 100644
--- a/src/datatype.c
+++ b/src/datatype.c
@@ -186,7 +186,7 @@ void symbol_table_print(const struct symbol_table *tbl,
 
 static void invalid_type_print(const struct expr *expr)
 {
-	gmp_printf("0x%Zx [invalid type]", expr->value);
+	mpz_printf("0x%Zx [invalid type]", expr->value);
 }
 
 const struct datatype invalid_type = {
@@ -268,18 +268,16 @@ static void integer_type_print(const struct expr *expr)
 
 	if (expr->dtype->basefmt != NULL)
 		fmt = expr->dtype->basefmt;
-	gmp_printf(fmt, expr->value);
+	mpz_printf(fmt, expr->value);
 }
 
 static struct error_record *integer_type_parse(const struct expr *sym,
 					       struct expr **res)
 {
 	mpz_t v;
-	int len;
 
 	mpz_init(v);
-	if (gmp_sscanf(sym->identifier, "%Zu%n", v, &len) != 1 ||
-	    (int)strlen(sym->identifier) != len) {
+	if (mpz_set_str(v, sym->identifier, 0)) {
 		mpz_clear(v);
 		return error(&sym->location, "Could not parse %s",
 			     sym->dtype->desc);
diff --git a/src/erec.c b/src/erec.c
index 82543e6..810e9bf 100644
--- a/src/erec.c
+++ b/src/erec.c
@@ -44,6 +44,7 @@ static void erec_destroy(struct error_record *erec)
 	xfree(erec);
 }
 
+__attribute__((format(printf, 3, 0)))
 struct error_record *erec_vcreate(enum error_record_types type,
 				  const struct location *loc,
 				  const char *fmt, va_list ap)
@@ -55,10 +56,13 @@ struct error_record *erec_vcreate(enum error_record_types type,
 	erec->num_locations	= 0;
 	erec_add_location(erec, loc);
 
-	gmp_vasprintf(&erec->msg, fmt, ap);
+	if (vasprintf(&erec->msg, fmt, ap) < 0)
+		erec->msg = NULL;
+
 	return erec;
 }
 
+__attribute__((format(printf, 3, 4)))
 struct error_record *erec_create(enum error_record_types type,
 				 const struct location *loc,
 				 const char *fmt, ...)
diff --git a/src/evaluate.c b/src/evaluate.c
index 0732660..3cb5cca 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -232,9 +232,13 @@ static int expr_evaluate_value(struct eval_ctx *ctx, struct expr **expr)
 	case TYPE_INTEGER:
 		mpz_init_bitmask(mask, ctx->ectx.len);
 		if (mpz_cmp((*expr)->value, mask) > 0) {
+			char *valstr = mpz_get_str(NULL, 10, (*expr)->value);
+			char *rangestr = mpz_get_str(NULL, 10, mask);
 			expr_error(ctx->msgs, *expr,
-				   "Value %Zu exceeds valid range 0-%Zu",
-				   (*expr)->value, mask);
+				   "Value %s exceeds valid range 0-%s",
+				   valstr, rangestr);
+			free(valstr);
+			free(rangestr);
 			mpz_clear(mask);
 			return -1;
 		}
diff --git a/src/gmputil.c b/src/gmputil.c
index cb46445..acbf369 100644
--- a/src/gmputil.c
+++ b/src/gmputil.c
@@ -14,7 +14,6 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <string.h>
-#include <gmp.h>
 
 #include <nftables.h>
 #include <datatype.h>
@@ -148,6 +147,59 @@ void mpz_switch_byteorder(mpz_t rop, unsigned int len)
 	mpz_import_data(rop, data, BYTEORDER_HOST_ENDIAN, len);
 }
 
+int mpz_printf(const char *f, const mpz_t value)
+{
+	/* minimalistic gmp_printf replacement to format a single mpz_t
+	 * using only mini-gmp functions */
+	int n = 0;
+	while (*f) {
+		if (*f != '%') {
+			if (fputc(*f, stdout) != *f)
+				return -1;
+
+			++n;
+		} else {
+			unsigned long prec = 0;
+			int base;
+			size_t len;
+			char *str;
+			bool ok;
+
+			if (*++f == '.')
+				prec = strtoul(++f, (char**)&f, 10);
+
+			if (*f++ != 'Z')
+				return -1;
+
+			if (*f == 'u')
+				base = 10;
+			else if (*f == 'x')
+				base = 16;
+			else
+				return -1;
+
+			len = mpz_sizeinbase(value, base);
+			while (prec-- > len) {
+				if (fputc('0', stdout) != '0')
+					return -1;
+
+				++n;
+			}
+
+			str = mpz_get_str(NULL, base, value);
+			ok = str && fwrite(str, 1, len, stdout) == len;
+			free(str);
+
+			if (!ok)
+				return -1;
+
+			n += len;
+		}
+		++f;
+	}
+	return n;
+}
+
 static void *gmp_xrealloc(void *ptr, size_t old_size, size_t new_size)
 {
 	return xrealloc(ptr, new_size);
diff --git a/src/parser_bison.y b/src/parser_bison.y
index 99dbd08..eb5cf90 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -237,7 +237,7 @@ static void location_update(struct location *loc, struct location *rhs, int n)
 %token OPERATION		"operation"
 
 %token IP			"ip"
-%token VERSION			"version"
+%token IPHDRVERSION		"version"
 %token HDRLENGTH		"hdrlength"
 %token TOS			"tos"
 %token LENGTH			"length"
@@ -1947,7 +1947,7 @@ ip_hdr_expr		:	IP	ip_hdr_field
 			}
 			;
 
-ip_hdr_field		:	VERSION		{ $$ = IPHDR_VERSION; }
+ip_hdr_field		:	IPHDRVERSION	{ $$ = IPHDR_VERSION; }
 			|	HDRLENGTH	{ $$ = IPHDR_HDRLENGTH; }
 			|	TOS		{ $$ = IPHDR_TOS; }
 			|	LENGTH		{ $$ = IPHDR_LENGTH; }
@@ -1994,7 +1994,7 @@ ip6_hdr_expr		:	IP6	ip6_hdr_field
 			}
 			;
 
-ip6_hdr_field		:	VERSION		{ $$ = IP6HDR_VERSION; }
+ip6_hdr_field		:	IPHDRVERSION	{ $$ = IP6HDR_VERSION; }
 			|	PRIORITY	{ $$ = IP6HDR_PRIORITY; }
 			|	FLOWLABEL	{ $$ = IP6HDR_FLOWLABEL; }
 			|	LENGTH		{ $$ = IP6HDR_LENGTH; }
diff --git a/src/scanner.l b/src/scanner.l
index ed87da6..92b6a10 100644
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -349,7 +349,7 @@ addrstring	({macaddr}|{ip4addr}|{ip6addr})
 "operation"		{ return OPERATION; }
 
 "ip"			{ return IP; }
-"version"		{ return VERSION; }
+"version"		{ return IPHDRVERSION; }
 "hdrlength"		{ return HDRLENGTH; }
 "tos"			{ return TOS; }
 "length"		{ return LENGTH; }
-- 
2.1.3