From 43f283847eaa4d83a790698befad1427fe5af667 Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: Sat, 19 Dec 2015 08:28:11 -0500
Subject: driver: mdso_create_symbol_vector(): initial implementation.

---
 include/mdso/mdso.h             |  1 +
 src/driver/mdso_unit_ctx.c      | 87 +++++++++++++++++++++++++++++++++++++++++
 src/internal/mdso_driver_impl.h |  6 +++
 3 files changed, 94 insertions(+)

diff --git a/include/mdso/mdso.h b/include/mdso/mdso.h
index 14a5817..de0bd89 100644
--- a/include/mdso/mdso.h
+++ b/include/mdso/mdso.h
@@ -63,6 +63,7 @@ struct mdso_unit_ctx {
 	const char * const *		path;
 	const struct mdso_input *	map;
 	const struct mdso_common_ctx *	cctx;
+	const char * const *		syms;
 	void *				any;
 	int				status;
 	int				nerrors;
diff --git a/src/driver/mdso_unit_ctx.c b/src/driver/mdso_unit_ctx.c
index d955f7f..d46820b 100644
--- a/src/driver/mdso_unit_ctx.c
+++ b/src/driver/mdso_unit_ctx.c
@@ -18,6 +18,12 @@
 static int mdso_free_unit_ctx_impl(struct mdso_unit_ctx_impl * ctx, int status)
 {
 	if (ctx) {
+		if (ctx->expsyms && ctx->expsyms->buffer)
+			free(ctx->expsyms->buffer);
+
+		if (ctx->expsyms)
+			free(ctx->expsyms);
+
 		mdso_unmap_input(&ctx->map);
 		free(ctx);
 	}
@@ -55,6 +61,83 @@ static FILE * mdso_stdin_to_tmp(void)
 	return ftmp;
 }
 
+static int mdso_create_symbol_vector(struct mdso_unit_ctx_impl * ctx)
+{
+	int		nsyms;
+	size_t		nbytes;
+	size_t		size;
+	char *		dst;
+	const char *	ch;
+	const char **	sym;
+
+	const char	exphdr[] = "EXPORTS\n";
+	const char	imphdr[] = "IMPORTS\n";
+
+	ch	= ctx->map.addr;
+	nbytes	= ctx->map.size;
+
+	for (nsyms=0; nbytes; ch++,nbytes--)
+		nsyms += (*ch == '\n');
+
+	size = offsetof(struct mdso_unit_ctx_impl,expsyms);
+	size += (nsyms+1)*sizeof(const char *);
+
+	if (!(ctx->expsyms = calloc(size,1)))
+		return -1;
+
+	if (!(ctx->expsyms->buffer = calloc(ctx->map.size,1)))
+		return -1;
+
+	ch	= ctx->map.addr;
+	nbytes	= ctx->map.size;
+	sym	= ctx->expsyms->syms;
+	dst	= ctx->expsyms->buffer;
+	size	= strlen(exphdr);
+
+	/* support .def input files */
+	if ((nbytes >= size) && !(strncmp(ch,exphdr,size))) {
+		ch	+= size;
+		nbytes	-= size;
+	}
+
+	/* advance to first symbol */
+	for (; nbytes && ((*ch==' ')
+			|| (*ch=='\t')
+			|| (*ch=='\r')
+			|| (*ch=='\n')); nbytes--)
+		ch++;
+
+	/* support .def input files */
+	size = strlen(imphdr);
+
+	while (nbytes && ((nbytes < size) || (strncmp(ch,imphdr,size)))) {
+		/* vector */
+		*sym++ = dst;
+
+		/* symbol */
+		for (; nbytes && ((*ch!=' ')
+				&& (*ch!='\t')
+				&& (*ch!='\r')
+				&& (*ch!='\n')); nbytes--)
+			*dst++ = *ch++;
+
+		dst++;
+
+		/* discard rest of input line */
+		for (; nbytes && (*ch!='\n'); nbytes--)
+			ch++;
+
+		/* advance to next symbol */
+		for (; nbytes && ((*ch==' ')
+				|| (*ch=='\t')
+				|| (*ch=='\r')
+				|| (*ch=='\n')); nbytes--)
+			ch++;
+	}
+
+	return 0;
+}
+
 int mdso_get_unit_ctx(
 	const struct mdso_driver_ctx *	dctx,
 	const char *			path,
@@ -82,6 +165,9 @@ int mdso_get_unit_ctx(
 	if (fd > 0)
 		close(fd);
 
+	if (mdso_create_symbol_vector(ctx))
+		return mdso_free_unit_ctx_impl(ctx,-1);
+
 	memcpy(&ctx->cctx,dctx->cctx,
 		sizeof(ctx->cctx));
 
@@ -90,6 +176,7 @@ int mdso_get_unit_ctx(
 	ctx->uctx.path	= &ctx->path;
 	ctx->uctx.map	= &ctx->map;
 	ctx->uctx.cctx	= &ctx->cctx;
+	ctx->uctx.syms	= ctx->expsyms->syms;
 
 	*pctx = &ctx->uctx;
 	return 0;
diff --git a/src/internal/mdso_driver_impl.h b/src/internal/mdso_driver_impl.h
index 2c4554f..aa09197 100644
--- a/src/internal/mdso_driver_impl.h
+++ b/src/internal/mdso_driver_impl.h
@@ -12,6 +12,11 @@ enum app_tags {
 	TAG_VERSION,
 };
 
+struct mdso_expsyms {
+	char *		buffer;
+	const char *	syms[];
+};
+
 struct mdso_driver_ctx_impl {
 	struct mdso_common_ctx	cctx;
 	struct mdso_driver_ctx	ctx;
@@ -20,6 +25,7 @@ struct mdso_driver_ctx_impl {
 struct mdso_unit_ctx_impl {
 	const char *		path;
 	struct mdso_input	map;
+	struct mdso_expsyms *	expsyms;
 	struct mdso_common_ctx	cctx;
 	struct mdso_unit_ctx	uctx;
 };
-- 
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