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

/*  slibtool: a skinny libtool implementation, written in C        */

/*  Copyright (C) 2016  Z. Gilboa                                  */

/*  Released under the Standard MIT License; see COPYING.SLIBTOOL. */

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

#include <stdint.h>

#include <unistd.h>

#include <stdlib.h>

#include <string.h>

#include <slibtool/slibtool.h>

#define SLBT_ARGV_SPARE_PTRS	16

struct slbt_exec_ctx_impl {

	int			argc;

	char *			args;

	char *			shadow;

	size_t			size;

	struct slbt_exec_ctx	ctx;

	char *			vbuffer[];

};

static size_t slbt_parse_comma_separated_flags(

	const char *	str,

	int *		argc)

{

	const char * ch;

	for (ch=str; *ch; ch++)

		if (*ch == ',')

			(*argc)++;

	return ch - str;

}

static char * slbt_source_file(char ** argv)

{

	char **	parg;

	char *	ch;

	for (parg=argv; *parg; parg++)

		if ((ch = strrchr(*parg,'.')))

			if ((!(strcmp(++ch,"s")))

					|| (!(strcmp(ch,"S")))

					|| (!(strcmp(ch,"asm")))

					|| (!(strcmp(ch,"c")))

					|| (!(strcmp(ch,"cc")))

					|| (!(strcmp(ch,"cxx"))))

				return *parg;

	return 0;

}

static struct slbt_exec_ctx_impl * slbt_exec_ctx_alloc(

	const struct slbt_driver_ctx *	dctx)

{

	struct slbt_exec_ctx_impl *	ictx;

	size_t				size;

	size_t				vsize;

	int				argc;

	char *				args;

	char *				shadow;

	char *				csrc;

	char **				parg;

	argc = 0;

	csrc = 0;

	/* clerical [worst-case] buffer size (guard, .libs, version) */

	size  = strlen(".lo") + sizeof('\0');

	size +=  8 * (strlen(".libs/") + sizeof('\0'));

	size += 36 * (strlen(".0000") + sizeof('\0'));

	/* buffer size (cargv, -Wc) */

	for (parg=dctx->cctx->cargv; *parg; parg++, argc++)

		if (!(strncmp("-Wc,",*parg,4)))

			size += sizeof('\0') + slbt_parse_comma_separated_flags(

					&(*parg)[4],&argc);

		else

			size += sizeof('\0') + strlen(*parg);

	/* buffer size (ldirname, lbasename, lobjname, aobjname, ltobjname) */

	if (dctx->cctx->output)

		size += 4*strlen(dctx->cctx->output);

	else if ((csrc = slbt_source_file(dctx->cctx->cargv)))

		size += 4*strlen(csrc);

	/* buffer size (.libs/%.o, pessimistic) */

	size += argc * strlen(".libs/");

	/* buffer size (linking) */

	if (dctx->cctx->mode == SLBT_MODE_LINK)

		size += strlen(dctx->cctx->settings.arprefix) + sizeof('\0')

			+ strlen(dctx->cctx->settings.arsuffix) + sizeof('\0')

			+ strlen(dctx->cctx->settings.dsoprefix) + sizeof('\0')

			+ strlen(dctx->cctx->settings.dsoprefix) + sizeof('\0')

			+ strlen(dctx->cctx->settings.exeprefix) + sizeof('\0')

			+ strlen(dctx->cctx->settings.exeprefix) + sizeof('\0')

			+ strlen(dctx->cctx->settings.impprefix) + sizeof('\0')

			+ strlen(dctx->cctx->settings.impprefix) + sizeof('\0');

	/* alloc */

	if (!(args = malloc(size)))

		return 0;

	if (!(shadow = malloc(size))) {

		free(args);

		return 0;

	}

	vsize = sizeof(*ictx) + (2*(argc+1)+SLBT_ARGV_SPARE_PTRS)*sizeof(char *);

	if (!(ictx = calloc(1,vsize))) {

		free(args);

		free(shadow);

		return 0;

	}

	ictx->args = args;

	ictx->argc = argc;

	ictx->size   = size;

	ictx->shadow = shadow;

	ictx->ctx.csrc = csrc;

	return ictx;

}

int  slbt_get_exec_ctx(

	const struct slbt_driver_ctx *	dctx,

	struct slbt_exec_ctx **		ectx)

{

	struct slbt_exec_ctx_impl *	ictx;

	char **				parg;

	char *				ch;

	char *				mark;

	char *				slash;

	const char *			ref;

	int				i;

	/* alloc */

	if (!(ictx = slbt_exec_ctx_alloc(dctx)))

		return -1;

	/* init with guard for later .lo check */

	ch                = ictx->args + strlen(".lo");

	ictx->ctx.argv    = ictx->vbuffer;

	ictx->ctx.altv    = &ictx->vbuffer[ictx->argc + 1];

	/* <compiler> */

	ictx->ctx.compiler = dctx->cctx->cargv[0];

	ictx->ctx.cargv    = ictx->ctx.argv;

	/* ldirname, lbasename */

	ref = (dctx->cctx->output)

		? dctx->cctx->output

		: ictx->ctx.csrc;

	if (ref && !ictx->ctx.csrc && (mark = strrchr(ref,'/'))) {

		ictx->ctx.ldirname = ch;

		strcpy(ch,ref);

		ch += mark - ref;

		ch += sprintf(ch,"%s","/.libs/");

		ch++;

		ictx->ctx.lbasename = ch;

		ch += sprintf(ch,"%s",++mark);

		ch++;

	} else if (ref) {

		ictx->ctx.ldirname = ch;

		ch += sprintf(ch,"%s",".libs/");

		ch++;

		ictx->ctx.lbasename = ch;

		mark = strrchr(ref,'/');

		ch += sprintf(ch,"%s",mark ? ++mark : ref);

		ch++;

	}

	/* lbasename suffix */

	if (ref && (dctx->cctx->mode == SLBT_MODE_COMPILE)) {

		if ((ch[-4] == '.') && (ch[-3] == 'l') && (ch[-2] == 'o')) {

			ch[-3] = 'o';

			ch[-2] = '\0';

			ch--;

		} else if (ictx->ctx.csrc) {

			if ((mark = strrchr(ictx->ctx.lbasename,'.'))) {

				ch    = mark;

				*++ch = 'o';

				*++ch = '\0';

				ch++;

			}

		}

	}

	/* cargv, -Wc */

	for (i=0, parg=dctx->cctx->cargv; *parg; parg++, ch++) {

		if (!(strncmp("-Wc,",*parg,4))) {

			strcpy(ch,&(*parg)[4]);

			ictx->ctx.argv[i++] = ch;

			for (; *ch; ch++)

				if (*ch == ',') {

					*ch++ = '\0';

					ictx->ctx.argv[i++] = ch;

				}

		} else {

			ictx->ctx.argv[i++] = ch;

			ch += sprintf(ch,"%s",*parg);

			ch += strlen(".libs/");

		}

	}

	/* placeholders for -DPIC, -fPIC, -c, -o, <output> */

	ictx->ctx.dpic = &ictx->ctx.argv[i++];

	ictx->ctx.fpic = &ictx->ctx.argv[i++];

	ictx->ctx.cass = &ictx->ctx.argv[i++];

	ictx->ctx.noundef = &ictx->ctx.argv[i++];

	ictx->ctx.lout[0] = &ictx->ctx.argv[i++];

	ictx->ctx.lout[1] = &ictx->ctx.argv[i++];

	ictx->ctx.sentinel= &ictx->ctx.argv[i++];

	slbt_reset_placeholders(&ictx->ctx);

	/* output file name */

	if (ref && ((dctx->cctx->mode == SLBT_MODE_COMPILE))) {

		*ictx->ctx.lout[0] = "-o";

		*ictx->ctx.lout[1] = ch;

		ictx->ctx.lobjname = ch;

		ch += sprintf(ch,"%s%s",

			ictx->ctx.ldirname,

			ictx->ctx.lbasename)

			+ sizeof('\0');

		ictx->ctx.aobjname = ch;

		ch += sprintf(ch,"%s",ictx->ctx.ldirname);

		ch -= strlen(".libs/");

		ch += sprintf(ch,"%s",

			ictx->ctx.lbasename)

			+ sizeof('\0');

		ictx->ctx.ltobjname = ch;

		strcpy(ch,ictx->ctx.aobjname);

		if ((mark = strrchr(ch,'.')))

			ch = mark + sprintf(mark,"%s",".lo")

				+ sizeof('\0');

	}

	/* linking: arfilename, lafilename, dsofilename */

	if (dctx->cctx->mode == SLBT_MODE_LINK && dctx->cctx->libname) {

		/* arfilename */

		ictx->ctx.arfilename = ch;

		ch += sprintf(ch,"%s%s%s%s",

				ictx->ctx.ldirname,

				dctx->cctx->settings.arprefix,

				dctx->cctx->libname,

				dctx->cctx->settings.arsuffix)

			+ sizeof('\0');

		/* lafilename */

		ictx->ctx.lafilename = ch;

		ch += sprintf(ch,"%s%s%s.la",

				ictx->ctx.ldirname,

				dctx->cctx->settings.dsoprefix,

				dctx->cctx->libname)

			+ sizeof('\0');

		/* dsofilename */

		ictx->ctx.dsofilename = ch;

		ch += sprintf(ch,"%s%s%s%s",

				ictx->ctx.ldirname,

				dctx->cctx->settings.dsoprefix,

				dctx->cctx->libname,

				dctx->cctx->settings.dsosuffix)

			+ sizeof('\0');

	}

	/* linking: exefilename */

	if (dctx->cctx->mode == SLBT_MODE_LINK && !dctx->cctx->libname) {

		ictx->ctx.exefilename = ch;

		if ((slash = strrchr(dctx->cctx->output,'/'))) {

			strcpy(ch,dctx->cctx->output);

			mark = ch + (slash - dctx->cctx->output);

			sprintf(++mark,".libs/%s",++slash);

			ch += strlen(ch) + sizeof('\0');

		} else

			ch += sprintf(ch,".libs/%s",dctx->cctx->output)

				+ sizeof('\0');

	}

	/* argument strings shadow copy */

	memcpy(ictx->shadow,ictx->args,ictx->size);

	*ectx = &ictx->ctx;

	return 0;

}

static int slbt_free_exec_ctx_impl(

	struct slbt_exec_ctx_impl *	ictx,

	int				status)

{

	free(ictx->args);

	free(ictx->shadow);

	free (ictx);

	return status;

}

void slbt_free_exec_ctx(struct slbt_exec_ctx * ctx)

{

	struct slbt_exec_ctx_impl *	ictx;

	uintptr_t			addr;

	if (ctx) {

		addr = (uintptr_t)ctx - offsetof(struct slbt_exec_ctx_impl,ctx);

		ictx = (struct slbt_exec_ctx_impl *)addr;

		slbt_free_exec_ctx_impl(ictx,0);

	}

}

void slbt_reset_arguments(struct slbt_exec_ctx * ectx)

{

	struct slbt_exec_ctx_impl *	ictx;

	uintptr_t			addr;

	addr = (uintptr_t)ectx - offsetof(struct slbt_exec_ctx_impl,ctx);

	ictx = (struct slbt_exec_ctx_impl *)addr;

	memcpy(ictx->args,ictx->shadow,ictx->size);

}

void slbt_reset_placeholders(struct slbt_exec_ctx * ectx)

{

	*ectx->dpic = "-USLIBTOOL_PLACEHOLDER_DPIC";

	*ectx->fpic = "-USLIBTOOL_PLACEHOLDER_FPIC";

	*ectx->cass = "-USLIBTOOL_PLACEHOLDER_COMPILE_ASSEMBLE";

	*ectx->noundef = "-USLIBTOOL_PLACEHOLDER_NO_UNDEFINED";

	*ectx->lout[0] = "-USLIBTOOL_PLACEHOLDER_OUTPUT_SWITCH";

	*ectx->lout[1] = "-USLIBTOOL_PLACEHOLDER_OUTPUT_FILE";

	*ectx->sentinel= 0;

}