/****************************************************************/

/*  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);

	}

}