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

/*  mdso: midipix dso scavenger                                 */

/*  Copyright (C) 2015--2021  SysDeer Technologies, LLC         */

/*  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"

#include "mdso_errinfo_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 int mdso_stdin_to_tmp(const struct mdso_driver_ctx * dctx)

{

	struct mdso_driver_ctx_impl *	ictx;

	uintptr_t			addr;

	int				fdtmp;

	ssize_t ret;

	ssize_t cnt;

	char *	ch;

	char	buf[4096];

	char	tmpname[] = "/tmp/mdso_stdin_to_tmp_XXXXXX";

	addr = (uintptr_t)dctx - offsetof(struct mdso_driver_ctx_impl,ctx);

	ictx = (struct mdso_driver_ctx_impl *)addr;

	if (ictx->fdtmpin >= 0)

		return dup(ictx->fdtmpin);

	if ((fdtmp = mkstemp(tmpname)) < 0)

		return -1;

	if ((ictx->fdtmpin = dup(fdtmp)) < 0) {

		close(fdtmp);

		unlink(tmpname);

		return -1;

	}

	strcpy(ictx->tmpname,tmpname);

	for (;;) {

		ret = read(0,buf,sizeof(buf)-1);

		while ((ret < 0) && (errno == EINTR))

			ret = read(0,buf,sizeof(buf)-1);

		if (ret < 0) {

			close(fdtmp);

			return -1;

		} else if (ret == 0) {

			return fdtmp;

		} else {

			ch  = buf;

			cnt = ret;

			ret = 0;

			for (; cnt; ) {

				ret = write(fdtmp,ch,cnt);

				while ((ret < 0) && (errno == EINTR))

					ret = write(fdtmp,ch,cnt);

				if (ret < 0) {

					close(fdtmp);

					return -1;

				}

				ch  += ret;

				cnt -= ret;

			}

		}

	}

}

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)*sizeof(const char *);

	if (!(ctx->expsyms = calloc(1,size)))

		return -1;

	if (!(ctx->expsyms->buffer = calloc(1,ctx->map.size)))

		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;

	int				fd;

	if (!dctx)

		return MDSO_CUSTOM_ERROR(dctx,0);

	else if (!(ctx = calloc(1,sizeof(*ctx))))

		return MDSO_BUFFER_ERROR(dctx);

	mdso_driver_set_ectx(

		dctx,0,path);

	if (strcmp(path,"-"))

		fd = -1;

	else if ((fd = mdso_stdin_to_tmp(dctx)) < 0)

		return mdso_free_unit_ctx_impl(

			ctx,MDSO_FILE_ERROR(dctx));

	if (mdso_map_input(dctx,fd,path,PROT_READ,&ctx->map))

		return mdso_free_unit_ctx_impl(

			ctx,MDSO_NESTED_ERROR(dctx));

	if (fd >= 0)

		close(fd);

	if (mdso_create_symbol_vector(ctx))

		return mdso_free_unit_ctx_impl(

			ctx,MDSO_BUFFER_ERROR(dctx));

	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);

	}

}