/****************************************************************/
/*  mdso: midipix dso scavenger                                 */
/*  Copyright (C) 2015  Z. Gilboa                               */
/*  Released under GPLv2 and GPLv3; see COPYING.MDSO.           */
/****************************************************************/
 
#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
 
#include <mdso/mdso.h>
#include "mdso_driver_impl.h"
 
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);
	}
 
	return status;
}
 
static FILE * mdso_stdin_to_tmp(void)
{
	FILE *	ftmp;
	char	buf[4096];
	ssize_t	nread;
	int	ret;
 
	if (!(ftmp = tmpfile()))
		return 0;
 
	nread = read(0,buf,sizeof(buf)-1);
 
	while (nread) {
		if (nread > 0) {
			buf[nread] = '\0';
			ret = fputs(buf,ftmp);
		} else
			ret = (errno == EINTR) ? 0 : -1;
 
		if (ret < 0) {
			fclose(ftmp);
			return 0;
		}
 
		nread = read(0,buf,sizeof(buf)-1);
	}
 
	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,
	struct mdso_unit_ctx **		pctx)
{
	struct mdso_unit_ctx_impl *	ctx;
	FILE *				ftmp;
	int				fd;
 
	if (!dctx || !(ctx = calloc(sizeof(*ctx),1)))
		return -1;
 
	if (strcmp(path,"-"))
		fd = -1;
	else if (!(ftmp = mdso_stdin_to_tmp()))
		return mdso_free_unit_ctx_impl(ctx,-1);
	else if ((fd = dup(fileno(ftmp))) < 0)
		return mdso_free_unit_ctx_impl(ctx,-1);
	else
		fclose(ftmp);
 
	if (mdso_map_input(fd,path,PROT_READ,&ctx->map))
		return mdso_free_unit_ctx_impl(ctx,-1);
 
	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));
 
	ctx->path	= path;
 
	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;
}
 
void mdso_free_unit_ctx(struct mdso_unit_ctx * ctx)
{
	struct mdso_unit_ctx_impl *	ictx;
	uintptr_t			addr;
 
	if (ctx) {
		addr = (uintptr_t)ctx - offsetof(struct mdso_unit_ctx_impl,uctx);
		ictx = (struct mdso_unit_ctx_impl *)addr;
		mdso_free_unit_ctx_impl(ictx,0);
	}
}