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

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

/*  Copyright (C) 2016--2018  Z. Gilboa                            */

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

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

#include <fcntl.h>

#include <stdio.h>

#include <stdint.h>

#include <stdbool.h>

#include <unistd.h>

#include <sys/mman.h>

#include <sys/stat.h>

#include "slibtool_lconf_impl.h"

#include "slibtool_driver_impl.h"

#include "slibtool_errinfo_impl.h"

#include "slibtool_symlink_impl.h"

#include "slibtool_readlink_impl.h"

enum slbt_lconf_opt {

	SLBT_LCONF_OPT_UNKNOWN,

	SLBT_LCONF_OPT_NO,

	SLBT_LCONF_OPT_YES,

};

static void slbt_lconf_close(int fdcwd, int fdlconfdir)

{

	if (fdlconfdir != fdcwd)

		close(fdlconfdir);

}

static int slbt_lconf_open(

	struct slbt_driver_ctx *	dctx,

	const char *			lconf)

{

	int		fdcwd;

	int		fdlconf;

	int		fdlconfdir;

	int		fdparent;

	struct stat	stcwd;

	struct stat	stparent;

	ino_t		stinode;

	fdcwd      = slbt_driver_fdcwd(dctx);

	fdlconfdir = fdcwd;

	if (lconf && strchr(lconf,'/'))

		return ((fdlconf = openat(fdcwd,lconf,O_RDONLY,0)) < 0)

			? SLBT_CUSTOM_ERROR(dctx,SLBT_ERR_LCONF_OPEN)

			: fdlconf;

	if (fstatat(fdlconfdir,".",&stcwd,0) < 0)

		return SLBT_SYSTEM_ERROR(dctx,0);

	lconf   = lconf ? lconf : "libtool";

	fdlconf = openat(fdlconfdir,lconf,O_RDONLY,0);

	stinode = stcwd.st_ino;

	while (fdlconf < 0) {

		fdparent = openat(fdlconfdir,"../",O_DIRECTORY,0);

		slbt_lconf_close(fdcwd,fdlconfdir);

		if (fdparent < 0)

			return SLBT_SYSTEM_ERROR(dctx,0);

		if (fstat(fdparent,&stparent) < 0) {

			close(fdparent);

			return SLBT_SYSTEM_ERROR(dctx,0);

		}

		if (stparent.st_dev != stcwd.st_dev) {

			close(fdparent);

			return SLBT_CUSTOM_ERROR(

				dctx,SLBT_ERR_LCONF_OPEN);

		}

		if (stparent.st_ino == stinode) {

			close(fdparent);

			return SLBT_CUSTOM_ERROR(

				dctx,SLBT_ERR_LCONF_OPEN);

		}

		fdlconfdir = fdparent;

		fdlconf    = openat(fdlconfdir,lconf,O_RDONLY,0);

		stinode    = stparent.st_ino;

	}

	slbt_lconf_close(fdcwd,fdlconfdir);

	return fdlconf;

}

int slbt_get_lconf_flags(

	struct slbt_driver_ctx *	dctx,

	const char *			lconf,

	uint64_t *			flags)

{

	int				fdlconf;

	struct stat			st;

	void *				addr;

	const char *			mark;

	const char *			cap;

	uint64_t			optshared;

	uint64_t			optstatic;

	int				optlenmax;

	int				optsharedlen;

	int				optstaticlen;

	const char *			optsharedstr;

	const char *			optstaticstr;

	/* open relative libtool script */

	if ((fdlconf = slbt_lconf_open(dctx,lconf)) < 0)

		return SLBT_NESTED_ERROR(dctx);

	/* map relative libtool script */

	if (fstat(fdlconf,&st) < 0)

		return SLBT_SYSTEM_ERROR(dctx,0);

	addr = mmap(

		0,st.st_size,

		PROT_READ,MAP_SHARED,

		fdlconf,0);

	close(fdlconf);

	if (addr == MAP_FAILED)

		return SLBT_CUSTOM_ERROR(

			dctx,SLBT_ERR_LCONF_MAP);

	mark = addr;

	cap  = &mark[st.st_size];

	/* hard-coded options in the generated libtool precede the code */

	if (st.st_size >= (optlenmax = strlen("build_libtool_libs=yes\n")))

		cap -= optlenmax;

	/* scan */

	optshared = 0;

	optstatic = 0;

	optsharedstr = "build_libtool_libs=";

	optstaticstr = "build_old_libs=";

	optsharedlen = strlen(optsharedstr);

	optstaticlen = strlen(optstaticstr);

	for (; mark && mark

		if (!strncmp(mark,optsharedstr,optsharedlen)) {

			mark += optsharedlen;

			if ((mark[0]=='n')

					&& (mark[1]=='o')

					&& (mark[2]=='\n'))

				optshared = SLBT_DRIVER_DISABLE_SHARED;

			if ((mark[0]=='y')

					&& (mark[1]=='e')

					&& (mark[2]=='s')

					&& (mark[3]=='\n'))

				optshared = SLBT_DRIVER_SHARED;

		} if (!strncmp(mark,optstaticstr,optstaticlen)) {

			mark += optstaticlen;

			if ((mark[0]=='n')

					&& (mark[1]=='o')

					&& (mark[2]=='\n'))

				optstatic = SLBT_DRIVER_DISABLE_STATIC;

			if ((mark[0]=='y')

					&& (mark[1]=='e')

					&& (mark[2]=='s')

					&& (mark[3]=='\n'))

				optstatic = SLBT_DRIVER_STATIC;

		}

		if (optshared && optstatic)

			mark = 0;

		else {

			for (; (mark

				mark++;

			mark++;

		}

	}

	munmap(addr,st.st_size);

	if (!optshared || !optstatic)

		return SLBT_CUSTOM_ERROR(

			dctx,SLBT_ERR_LCONF_PARSE);

	*flags = optshared | optstatic;

	return 0;

}