libnftables: Simplify nft_run_cmd_from_buffer footprint

With libnftables documentation being upstream and one confirmed external
user (nftlb), time to break the API!

First of all, the command buffer passed to nft_run_cmd_from_buffer may
(and should) be const. One should consider it a bug if that function
ever changed it's content.

On the other hand, there is no point in passing the buffer's length as
separate argument: NULL bytes are not expected to occur in the input, so
it is safe to rely upon strlen(). Also, the actual parsers don't require
a buffer length passed to them, either. The only use-case for it is when
reallocating the buffer to append a final newline character, there
strlen() is perfectly sufficient.

Suggested-by: Harald Welte <laforge@gnumonks.org>
Cc: Laura Garcia Liebana <nevola@gmail.com>
Cc: Eric Leblond <eric@regit.org>
Cc: Arturo Borrero Gonzalez <arturo@netfilter.org>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

5 files changed, 10 insertions, 11 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index a4ad8cb3..92ac61a6 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -70,6 +70,7 @@ libparser_la_CFLAGS = ${AM_CFLAGS} \
 		      -Wno-redundant-decls
 
 libnftables_la_LIBADD = ${LIBMNL_LIBS} ${LIBNFTNL_LIBS} libparser.la
+libnftables_la_LDFLAGS = -version-info 1:0:0
 
 if BUILD_MINIGMP
 noinst_LTLIBRARIES += libminigmp.la
diff --git a/src/cli.c b/src/cli.c
index 241ea010..ca3869ab 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -110,7 +110,7 @@ static void cli_complete(char *line)
 	if (hist == NULL || strcmp(hist->line, line))
 		add_history(line);
 
-	nft_run_cmd_from_buffer(cli_nft, line, strlen(line) + 1);
+	nft_run_cmd_from_buffer(cli_nft, line);
 	xfree(line);
 }
 
diff --git a/src/libnftables.c b/src/libnftables.c
index dda986ca..9a97a3c5 100644
--- a/src/libnftables.c
+++ b/src/libnftables.c
@@ -396,7 +396,7 @@ static const struct input_descriptor indesc_cmdline = {
 	.name	= "<cmdline>",
 };
 
-static int nft_parse_bison_buffer(struct nft_ctx *nft, char *buf, size_t buflen,
+static int nft_parse_bison_buffer(struct nft_ctx *nft, const char *buf,
 				  struct list_head *msgs, struct list_head *cmds)
 {
 	struct cmd *cmd;
@@ -438,23 +438,21 @@ static int nft_parse_bison_filename(struct nft_ctx *nft, const char *filename,
 	return 0;
 }
 
-int nft_run_cmd_from_buffer(struct nft_ctx *nft, char *buf, size_t buflen)
+int nft_run_cmd_from_buffer(struct nft_ctx *nft, const char *buf)
 {
 	struct cmd *cmd, *next;
 	LIST_HEAD(msgs);
 	LIST_HEAD(cmds);
-	size_t nlbuflen;
 	char *nlbuf;
 	int rc = -EINVAL;
 
-	nlbuflen = max(buflen + 1, strlen(buf) + 2);
-	nlbuf = xzalloc(nlbuflen);
-	snprintf(nlbuf, nlbuflen, "%s\n", buf);
+	nlbuf = xzalloc(strlen(buf) + 2);
+	sprintf(nlbuf, "%s\n", buf);
 
 	if (nft->output.json)
-		rc = nft_parse_json_buffer(nft, nlbuf, nlbuflen, &msgs, &cmds);
+		rc = nft_parse_json_buffer(nft, nlbuf, &msgs, &cmds);
 	if (rc == -EINVAL)
-		rc = nft_parse_bison_buffer(nft, nlbuf, nlbuflen, &msgs, &cmds);
+		rc = nft_parse_bison_buffer(nft, nlbuf, &msgs, &cmds);
 	if (rc)
 		goto err;
 
diff --git a/src/main.c b/src/main.c
index f3615974..b2966a41 100644
--- a/src/main.c
+++ b/src/main.c
@@ -279,7 +279,7 @@ int main(int argc, char * const *argv)
 			if (i + 1 < argc)
 				strcat(buf, " ");
 		}
-		rc = !!nft_run_cmd_from_buffer(nft, buf, len);
+		rc = !!nft_run_cmd_from_buffer(nft, buf);
 	} else if (filename != NULL) {
 		rc = !!nft_run_cmd_from_filename(nft, filename);
 	} else if (interactive) {
diff --git a/src/parser_json.c b/src/parser_json.c
index 2fd0ef83..8f29aaf7 100644
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -3120,7 +3120,7 @@ static int __json_parse(struct json_ctx *ctx, json_t *root)
 }
 
 
-int nft_parse_json_buffer(struct nft_ctx *nft, char *buf, size_t buflen,
+int nft_parse_json_buffer(struct nft_ctx *nft, const char *buf,
 			  struct list_head *msgs, struct list_head *cmds)
 {
 	struct json_ctx ctx = {