[RFC] gsmd multi-line response support, 2nd try

[pHilipp Zabel]

On 7/31/07, Harald Welte <laforge at openmoko.org> wrote:
> On Tue, Jul 31, 2007 at 11:11:58AM +0200, pHilipp Zabel wrote:
> > On 7/31/07, Harald Welte <laforge at openmoko.org> wrote:
> > > On Mon, Jun 18, 2007 at 04:16:41PM +0200, Philipp Zabel wrote:
> > > > Hi!
> > > >
> > > > This second try works much better in that every extended response causes
> > > > a flush of the previous mlbuf and starts collecting new response lines.
> > > > Also, final_cb is now really only reached for final responses and the
> > > > code for case 'A' won't overwrite the command buffer with the response
> > > > anymore. I throw in '\n' as a separator for multi-line responses, and
> > > > the callback is called for each response this way.
> > >
> > > I've now committed this patch, just changing one minor detail: the
> > > static size of 1024 for mlbuf has been replaced with a constat that's
> > > defined in the header file to 65535.
> > >
> > > I'd actually prefer to have that buffer static in bss, rather than
> > > putting it on the stack every time we enter the parser.
> >
> > Like this?
>
> thinking more about it, we should not have any global variables in order
> to have the architecture to support multiple modems or the like.  Thus,
> the buffer should actually be part of struct gsmd (or rather: Something
> that is allocated and where a pointer member from struct gsmd points to)

I agree. This patch just moves mlbuf into struct gsmd, as a pointer to
talloc'ated memory. Where should the corresponding talloc_free() be put?

Index: gsm/include/gsmd/gsmd.h
===================================================================
--- gsm.orig/include/gsmd/gsmd.h	2007-07-31 14:07:47.000000000 +0200
+++ gsm/include/gsmd/gsmd.h	2007-07-31 14:09:02.000000000 +0200
@@ -74,6 +74,8 @@
 	struct gsmd_device_state dev_state;

 	struct llist_head operators;		/* cached list of operator names */
+	unsigned int mlbuf_len;
+	unsigned char *mlbuf;		/* ml_parse buffer */
 };

 struct gsmd_user {
Index: gsm/src/gsmd/atcmd.c
===================================================================
--- gsm.orig/src/gsmd/atcmd.c	2007-07-31 14:06:49.000000000 +0200
+++ gsm/src/gsmd/atcmd.c	2007-07-31 14:12:33.000000000 +0200
@@ -175,9 +175,7 @@
 {
 	struct gsmd *g = ctx;
 	struct gsmd_atcmd *cmd = NULL;
-	static char mlbuf[MLPARSE_BUF_SIZE];
 	int rc = 0, final = 0;
-	int mlbuf_len;

 	DEBUGP("buf=`%s'(%d)\n", buf, len);

@@ -273,15 +271,15 @@

 			/* it might be a multiline response, so if there's a previous
 			   response, send out mlbuf and start afresh with an empty buffer */
-			if (mlbuf[0] != 0) {
+			if (g->mlbuf[0] != 0) {
 				if (!cmd->cb) {
 					gsmd_log(GSMD_NOTICE, "command without cb!!!\n");
 				} else {
 					DEBUGP("Calling cmd->cb()\n");
-					cmd->resp = mlbuf;
+					cmd->resp = g->mlbuf;
 					rc = cmd->cb(cmd, cmd->ctx, cmd->resp);
 					DEBUGP("Clearing mlbuf\n");
-					mlbuf[0] = 0;
+					g->mlbuf[0] = 0;
 				}
 			}

@@ -334,16 +332,16 @@
 	/* we reach here, if we are at an information response that needs to be
 	 * passed on */

-	if (mlbuf[0] == 0) {
+	if (g->mlbuf[0] == 0) {
 		DEBUGP("Filling mlbuf\n");
-		strncat(mlbuf, buf, sizeof(mlbuf)-1);
+		strncat(g->mlbuf, buf, MLPARSE_BUF_SIZE-1);
 	} else {
 		DEBUGP("Appending buf to mlbuf\n");
-		mlbuf_len = strlen(mlbuf);
-		if (mlbuf_len+1 < sizeof(mlbuf)) {
-			mlbuf[mlbuf_len] = '\n';
-			mlbuf[mlbuf_len+1] = '\0';
-			strncat(mlbuf, buf, sizeof(mlbuf)-mlbuf_len-2);
+		g->mlbuf_len = strlen(g->mlbuf);
+		if (mlbuf_len+1 < sizeof(g->mlbuf)) {
+			g->mlbuf[g->mlbuf_len] = '\n';
+			g->mlbuf[g->mlbuf_len+1] = '\0';
+			strncat(g->mlbuf, buf, MLPARSE_BUF_SIZE-g->mlbuf_len-2);
 		} else {
 			DEBUGP("response too big for mlbuf!!!\n");
 			return -EFBIG;
@@ -365,13 +363,13 @@
 	} else {
 		DEBUGP("Calling final cmd->cb()\n");
 		/* send final result code if there is no information response in mlbuf */
-		if (mlbuf[0] == 0)
+		if (g->mlbuf[0] == 0)
 			cmd->resp = buf;
 		else
-			cmd->resp = mlbuf;
+			cmd->resp = g->mlbuf;
 		rc = cmd->cb(cmd, cmd->ctx, cmd->resp);
 		DEBUGP("Clearing mlbuf\n");
-		mlbuf[0] = 0;
+		g->mlbuf[0] = 0;
 	}

 	/* remove from list of currently executing cmds */
Index: gsm/src/gsmd/gsmd.c
===================================================================
--- gsm.orig/src/gsmd/gsmd.c	2007-07-31 14:06:47.000000000 +0200
+++ gsm/src/gsmd/gsmd.c	2007-07-31 14:06:50.000000000 +0200
@@ -300,6 +300,10 @@
 {
 	INIT_LLIST_HEAD(&g->users);

+	g->mlbuf = talloc_array(gsmd_tallocs, unsigned char, MLPARSE_BUF_SIZE);
+	if (!g->mlbuf)
+		return -ENOMEM;
+
 	return 0;
 }
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