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

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

/*  Copyright (C) 2016--2024  SysDeer Technologies, LLC            */

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

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

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <fcntl.h>

#include <errno.h>

#include <sys/stat.h>

#include <slibtool/slibtool.h>

#include "slibtool_driver_impl.h"

#include "slibtool_errinfo_impl.h"

#include "slibtool_linkcmd_impl.h"

#include "slibtool_mapfile_impl.h"

#include "slibtool_metafile_impl.h"

#include "slibtool_snprintf_impl.h"

#include "slibtool_symlink_impl.h"

#include "slibtool_spawn_impl.h"

static int slbt_linkcmd_exit(

	struct slbt_deps_meta *	depsmeta,

	int			ret)

{

	if (depsmeta->altv)

		free(depsmeta->altv);

	if (depsmeta->args)

		free(depsmeta->args);

	return ret;

}

static void slbt_emit_fdwrap_dl_path_fixup(

	char *	cwd,

	char *	dpfixup,

	size_t	dpfixup_size,

	char *	wrapper)

{

	char *	p;

	char *	q;

	char *	wrapper_dname;

	/* obtain cwd-relative directory name of wrapper */

	for (p=cwd,q=wrapper; *p && *q && (*p==*q); p++,q++)

		(void)0;

	wrapper_dname = (*q == '/') ? (q + 1) : q;

	dpfixup[0] = 0; strncat(dpfixup,"${0%/*}",dpfixup_size - 1);

	/* append parent directory fixup for each level of depth in wrapper_dname */

	for (p=wrapper_dname,q=0; *p; ) {

		if ((p[0] == '.') && (p[1] == '/')) {

			p++; p++;

		} else if ((q = strchr(p, '/'))) {

			strncat(dpfixup,"/..",dpfixup_size-1); p = (q + 1);

		} else {

			break;

		}

	}

	strncat(dpfixup,"/",dpfixup_size-1);

}

int slbt_exec_link_create_executable(

	const struct slbt_driver_ctx *	dctx,

	struct slbt_exec_ctx *		ectx,

	const char *			exefilename)

{

	int	fdcwd;

	int	fdwrap;

	char ** parg;

	char ** xarg;

	char *	base;

	char *	ccwrap;

	char	cwd    [PATH_MAX];

	char	dpfixup[PATH_MAX];

	char	output [PATH_MAX];

	char	wrapper[PATH_MAX];

	char	wraplnk[PATH_MAX];

	bool	fabspath;

	bool	fpic;

	const struct slbt_source_version * verinfo;

	struct slbt_deps_meta depsmeta = {0,0,0,0};

	struct stat st;

	/* initial state */

	slbt_reset_arguments(ectx);

	/* placeholders */

	slbt_reset_placeholders(ectx);

	/* fdcwd */

	fdcwd = slbt_driver_fdcwd(dctx);

	/* fpic */

	fpic = !(dctx->cctx->drvflags & SLBT_DRIVER_ALL_STATIC);

	/* input argument adjustment */

	for (parg=ectx->cargv; *parg; parg++)

		slbt_adjust_object_argument(*parg,fpic,true,fdcwd);

	/* linker argument adjustment */

	for (parg=ectx->cargv, xarg=ectx->xargv; *parg; parg++, xarg++)

		if (slbt_adjust_linker_argument(

				dctx,

				*parg,xarg,true,

				dctx->cctx->settings.dsosuffix,

				dctx->cctx->settings.arsuffix,

				&depsmeta) < 0)

			return SLBT_NESTED_ERROR(dctx);

	/* --no-undefined */

	if (dctx->cctx->drvflags & SLBT_DRIVER_NO_UNDEFINED)

		*ectx->noundef = "-Wl,--no-undefined";

	/* executable wrapper: create */

	if (slbt_snprintf(wrapper,sizeof(wrapper),

				"%s.wrapper.tmp",

				dctx->cctx->output) < 0)

		return SLBT_BUFFER_ERROR(dctx);

	if ((fdwrap = openat(fdcwd,wrapper,O_RDWR|O_CREAT|O_TRUNC,0644)) < 0)

		return SLBT_SYSTEM_ERROR(dctx,wrapper);

	slbt_exec_set_fdwrapper(ectx,fdwrap);

	/* executable wrapper: header */

	verinfo = slbt_source_version();

	/* cwd, DL_PATH fixup */

	if (slbt_realpath(fdcwd,".",O_DIRECTORY,cwd,sizeof(cwd)))

		return SLBT_SYSTEM_ERROR(dctx,0);

	slbt_emit_fdwrap_dl_path_fixup(

		cwd,dpfixup,sizeof(dpfixup),

		wrapper);

	if (slbt_dprintf(fdwrap,

			"#!/bin/sh\n"

			"# libtool compatible executable wrapper\n"

			"# Generated by %s (slibtool %d.%d.%d)\n"

			"# [commit reference: %s]\n\n"

			"if [ -z \"$%s\" ]; then\n"

			"\tDL_PATH=\n"

			"\tCOLON=\n"

			"\tLCOLON=\n"

			"else\n"

			"\tDL_PATH=\n"

			"\tCOLON=\n"

			"\tLCOLON=':'\n"

			"fi\n\n"

			"DL_PATH_FIXUP=\"%s\";\n\n",

			dctx->program,

			verinfo->major,verinfo->minor,verinfo->revision,

			verinfo->commit,

			dctx->cctx->settings.ldpathenv,

			dpfixup) < 0)

		return SLBT_SYSTEM_ERROR(dctx,0);

	/* output */

	if (slbt_snprintf(output,sizeof(output),

			"%s",exefilename) < 0)

		return SLBT_BUFFER_ERROR(dctx);

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

	*ectx->lout[1] = output;

	/* static? */

	if (dctx->cctx->drvflags & SLBT_DRIVER_ALL_STATIC)

		*ectx->dpic = "-static";

	/* .libs/libfoo.so --> -L.libs -lfoo */

	if (slbt_exec_link_adjust_argument_vector(

			dctx,ectx,&depsmeta,cwd,false))

		return SLBT_NESTED_ERROR(dctx);

	/* using alternate argument vector */

	ccwrap        = (char *)dctx->cctx->ccwrap;

	ectx->argv    = depsmeta.altv;

	ectx->program = ccwrap ? ccwrap : depsmeta.altv[0];

	/* executable wrapper symlink */

	if (slbt_snprintf(wraplnk,sizeof(wraplnk),

			"%s.exe.wrapper",

			exefilename) < 0)

		return slbt_linkcmd_exit(

			&depsmeta,

			SLBT_BUFFER_ERROR(dctx));

	/* executable wrapper: base name */

	base = strrchr(wraplnk,'/');

	base++;

	/* executable wrapper: footer */

	fabspath = (exefilename[0] == '/');

	if (slbt_dprintf(fdwrap,

			"DL_PATH=\"${DL_PATH}${LCOLON}${%s}\"\n\n"

			"export %s=\"$DL_PATH\"\n\n"

			"if [ $(basename \"$0\") = \"%s\" ]; then\n"

			"\tprogram=\"$1\"; shift\n"

			"\texec \"$program\" \"$@\"\n"

			"fi\n\n"

			"exec %s/%s \"$@\"\n",

			dctx->cctx->settings.ldpathenv,

			dctx->cctx->settings.ldpathenv,

			base,

			fabspath ? "" : cwd,

			fabspath ? &exefilename[1] : exefilename) < 0)

		return slbt_linkcmd_exit(

			&depsmeta,

			SLBT_SYSTEM_ERROR(dctx,0));

	/* sigh */

	if (slbt_exec_link_finalize_argument_vector(dctx,ectx))

		return SLBT_NESTED_ERROR(dctx);

	/* step output */

	if (!(dctx->cctx->drvflags & SLBT_DRIVER_SILENT))

		if (slbt_output_link(dctx,ectx))

			return slbt_linkcmd_exit(

				&depsmeta,

				SLBT_NESTED_ERROR(dctx));

	/* spawn */

	if ((slbt_spawn(ectx,true) < 0) && (ectx->pid < 0)) {

		return slbt_linkcmd_exit(

			&depsmeta,

			SLBT_SPAWN_ERROR(dctx));

	} else if (ectx->exitcode) {

		return slbt_linkcmd_exit(

			&depsmeta,

			SLBT_CUSTOM_ERROR(

				dctx,

				SLBT_ERR_LINK_ERROR));

	}

	/* executable wrapper: finalize */

	slbt_exec_close_fdwrapper(ectx);

	if (slbt_create_symlink(

			dctx,ectx,

			dctx->cctx->output,wraplnk,

			SLBT_SYMLINK_WRAPPER))

		return slbt_linkcmd_exit(

			&depsmeta,

			SLBT_NESTED_ERROR(dctx));

	if (fstatat(fdcwd,wrapper,&st,0))

		return slbt_linkcmd_exit(

			&depsmeta,

			SLBT_SYSTEM_ERROR(dctx,wrapper));

	if (renameat(fdcwd,wrapper,fdcwd,dctx->cctx->output))

		return slbt_linkcmd_exit(

			&depsmeta,

			SLBT_SYSTEM_ERROR(dctx,dctx->cctx->output));

	if (fchmodat(fdcwd,dctx->cctx->output,0755,0))

		return slbt_linkcmd_exit(

			&depsmeta,

			SLBT_SYSTEM_ERROR(dctx,dctx->cctx->output));

	return slbt_linkcmd_exit(&depsmeta,0);

}