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

/*  tpax: a topological pax implementation                    */

/*  Copyright (C) 2020--2024  SysDeer Technologies, LLC       */

/*  Released under GPLv2 and GPLv3; see COPYING.TPAX.         */

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

#include <stdint.h>

#include <stddef.h>

#include <stdlib.h>

#include <string.h>

#include <fcntl.h>

#include <sys/stat.h>

#include <tpax/tpax.h>

#include "tpax_driver_impl.h"

#include "tpax_errinfo_impl.h"

#include "tpax_readlink_impl.h"

static int tpax_free_unit_ctx_impl(struct tpax_unit_ctx_impl * ctx, int ret)

{

	if (ctx) {

		free(ctx);

	}

	return ret;

}

int tpax_lib_get_unit_ctx(

	const struct tpax_driver_ctx *	dctx,

	int				fdat,

	const char *			path,

	struct tpax_unit_ctx **		pctx)

{

	int				ret;

	struct tpax_unit_ctx_impl *	ctx;

	if (!dctx)

		return TPAX_CUSTOM_ERROR(

			dctx,TPAX_ERR_NULL_CONTEXT);

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

		return TPAX_BUFFER_ERROR(dctx);

	tpax_driver_set_ectx(

		dctx,0,path);

	if (dctx->cctx->drvflags & TPAX_DRIVER_EXEC_MODE_WRITE_COPY) {

		ret = fstatat(

			fdat,path,&ctx->st,

			AT_SYMLINK_NOFOLLOW);

		if (ret < 0) {

			free(ctx);

			return TPAX_SYSTEM_ERROR(dctx);

		}

	}

	if (S_ISLNK(ctx->st.st_mode)) {

		if (tpax_readlinkat(

				fdat,path,ctx->linkbuf,

				sizeof(ctx->linkbuf)) < 0) {

			free(ctx);

			return TPAX_SYSTEM_ERROR(dctx);

		}

	}

	ctx->path	= path;

	ctx->link	= ctx->linkbuf[0] ? ctx->linkbuf : 0;

	ctx->uctx.path	= &ctx->path;

	ctx->uctx.link	= &ctx->link;

	ctx->uctx.st	= &ctx->st;

	*pctx = &ctx->uctx;

	return 0;

}

void tpax_lib_free_unit_ctx(struct tpax_unit_ctx * ctx)

{

	struct tpax_unit_ctx_impl *	ictx;

	uintptr_t			addr;

	if (ctx) {

		addr = (uintptr_t)ctx - offsetof(struct tpax_unit_ctx_impl,uctx);

		ictx = (struct tpax_unit_ctx_impl *)addr;

		tpax_free_unit_ctx_impl(ictx,0);

	}

}