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

/*  tpax: a topological pax implementation            */

/*  Copyright (C) 2020  Z. Gilboa                     */

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

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

#include <stdint.h>

#include <string.h>

#include <unistd.h>

#include <fcntl.h>

#include <errno.h>

#define ARGV_DRIVER

#include <tpax/tpax.h>

#include "tpax_version.h"

#include "tpax_driver_impl.h"

#include "argv/argv.h"

#define TPAX_DRIVER_EXEC_MODE_MASK \

	(TPAX_DRIVER_EXEC_MODE_LIST \

	| TPAX_DRIVER_EXEC_MODE_READ \

	| TPAX_DRIVER_EXEC_MODE_WRITE \

	| TPAX_DRIVER_EXEC_MODE_COPY)

/* package info */

static const struct tpax_source_version tpax_src_version = {

	TPAX_TAG_VER_MAJOR,

	TPAX_TAG_VER_MINOR,

	TPAX_TAG_VER_PATCH,

	TPAX_GIT_VERSION

};

/* default fd context */

static const struct tpax_fd_ctx tpax_default_fdctx = {

	.fdin  = STDIN_FILENO,

	.fdout = STDOUT_FILENO,

	.fderr = STDERR_FILENO,

	.fdcwd = AT_FDCWD,

	.fddst = AT_FDCWD,

	.fdlog = (-1),

};

struct tpax_driver_ctx_alloc {

	struct argv_meta *		meta;

	struct tpax_driver_ctx_impl	ctx;

	uint64_t			guard;

	const char *			units[];

};

static uint32_t tpax_argv_flags(uint32_t flags)

{

	uint32_t ret = ARGV_CLONE_VECTOR;

	if (flags & TPAX_DRIVER_VERBOSITY_NONE)

		ret |= ARGV_VERBOSITY_NONE;

	if (flags & TPAX_DRIVER_VERBOSITY_ERRORS)

		ret |= ARGV_VERBOSITY_ERRORS;

	if (flags & TPAX_DRIVER_VERBOSITY_STATUS)

		ret |= ARGV_VERBOSITY_STATUS;

	return ret;

}

static int tpax_driver_usage(

	int				fdout,

	const char *			program,

	const char *			arg,

	const struct argv_option **	optv,

	struct argv_meta *		meta)

{

	char header[512];

	snprintf(header,sizeof(header),

		"%s — topological pax implementation\n\n"

		"Synopsis:\n"

		"       %s\n"

		"       %s -r\n"

		"       %s -w\n"

		"       %s -r -w\n\n"

		"Options:\n",

		program,program,program,program,program);

	argv_usage(fdout,header,optv,arg);

	argv_free(meta);

	return TPAX_USAGE;

}

static int tpax_driver_usage_exec_mode(

	int				fdout,

	const char *			program,

	const char *			arg,

	const struct argv_option **	optv,

	struct argv_meta *		meta)

{

	tpax_driver_usage(

		fdout,program,

		arg,optv,meta);

	tpax_dprintf(

		fdout,

		"\nWhen using explicit (long) mode options, "

		"only one of --list, --read, --write, --copy "

		"may be used.\n");

	return TPAX_USAGE;

}

static int tpax_driver_usage_copy_mode(

	int				fdout,

	const char *			program,

	const char *			arg,

	const struct argv_option **	optv,

	struct argv_meta *		meta,

	struct argv_entry *		operand)

{

	const char * errdesc;

	if (!operand) {

		tpax_driver_usage(

			fdout,program,

			arg,optv,meta);

		tpax_dprintf(

			fdout,

			"\nThe copy mode requires a destination "

			"directory argument.\n\n");

		return TPAX_USAGE;

	}

	switch (errno) {

		case ENOENT:

			tpax_dprintf(

				fdout,

				"%s: error: "

				"the destination directory '%s' "

				"does not exist.\n\n",

				program,operand->arg);

			break;

		case ENOTDIR:

			tpax_dprintf(

				fdout,

				"%s: error: "

				"'%s' is not a directory.\n\n",

				program,operand->arg);

			break;

		default:

			if (!(errdesc = strerror(errno)))

				errdesc = "<no error description>";

			tpax_dprintf(

				fdout,

				"%s: error: while opening the "

				"destination directory '%s': %s.\n\n",

				program,operand->arg,errdesc);

			break;

	}

	argv_free(meta);

	return TPAX_USAGE;

}

static int tpax_driver_error_not_implemented(

	int				fdout,

	const char *			program,

	const char *			feature,

	struct argv_meta *		meta)

{

	tpax_dprintf(

		fdout,"%s: error: %s is not yet implemented!\n\n",

		program,feature);

	argv_free(meta);

	return TPAX_FATAL;

}

static struct tpax_driver_ctx_impl * tpax_driver_ctx_alloc(

	struct argv_meta *		meta,

	const struct tpax_fd_ctx *	fdctx,

	const struct tpax_common_ctx *	cctx,

	size_t				nunits)

{

	struct tpax_driver_ctx_alloc *	ictx;

	size_t				size;

	struct argv_entry *		entry;

	const char **			units;

	int				elements;

	size =  sizeof(struct tpax_driver_ctx_alloc);

	size += (nunits+1)*sizeof(const char *);

	if (!(ictx = calloc(1,size)))

		return 0;

	memcpy(&ictx->ctx.fdctx,fdctx,sizeof(*fdctx));

	memcpy(&ictx->ctx.cctx,cctx,sizeof(*cctx));

	elements = sizeof(ictx->ctx.erribuf) / sizeof(*ictx->ctx.erribuf);

	ictx->ctx.errinfp  = &ictx->ctx.erriptr[0];

	ictx->ctx.erricap  = &ictx->ctx.erriptr[--elements];

	ictx->meta = meta;

	for (entry=meta->entries,units=ictx->units; entry->fopt || entry->arg; entry++)

		if (!entry->fopt)

			*units++ = entry->arg;

	ictx->ctx.ctx.units = ictx->units;

	ictx->ctx.ctx.errv  = ictx->ctx.errinfp;

	return &ictx->ctx;

}

static int tpax_get_driver_ctx_fail(struct argv_meta * meta)

{

	argv_free(meta);

	return -1;

}

int tpax_get_driver_ctx(

	char **				argv,

	char **				envp,

	uint32_t			flags,

	const struct tpax_fd_ctx *	fdctx,

	struct tpax_driver_ctx ** 	pctx)

{

	struct tpax_driver_ctx_impl *	ctx;

	struct tpax_common_ctx		cctx;

	const struct argv_option *	optv[TPAX_OPTV_ELEMENTS];

	struct argv_meta *		meta;

	struct argv_entry *		entry;

	struct argv_entry *		operand;

	size_t				nunits;

	const char *			program;

	int				fddst;

	(void)envp;

	if (!fdctx)

		fdctx = &tpax_default_fdctx;

	argv_optv_init(tpax_default_options,optv);

	if (!(meta = argv_get(

			argv,optv,

			tpax_argv_flags(flags),

			fdctx->fderr)))

		return -1;

	nunits	= 0;

	operand = 0;

	program = argv_program_name(argv[0]);

	memset(&cctx,0,sizeof(cctx));

	cctx.drvflags = flags;

	fddst         = fdctx->fddst;

	/* get options, count units */

	for (entry=meta->entries; entry->fopt || entry->arg; entry++) {

		if (entry->fopt) {

			switch (entry->tag) {

				case TAG_HELP:

					if (flags & TPAX_DRIVER_VERBOSITY_USAGE)

						return tpax_driver_usage(

							fdctx->fdout,

							program,entry->arg,

							optv,meta);

					break;

				case TAG_VERSION:

					cctx.drvflags |= TPAX_DRIVER_VERSION;

					break;

				case TAG_LIST:

					cctx.drvflags |= TPAX_DRIVER_EXEC_MODE_LIST;

					break;

				case TAG_READ:

					cctx.drvflags |= TPAX_DRIVER_EXEC_MODE_READ;

					break;

				case TAG_WRITE:

					cctx.drvflags |= TPAX_DRIVER_EXEC_MODE_WRITE;

					break;

				case TAG_COPY:

					cctx.drvflags |= TPAX_DRIVER_EXEC_MODE_COPY;

					break;

			}

		} else {

			operand = entry;

			nunits++;

		}

	}

	/* incompatible arguments? */

	switch (cctx.drvflags & TPAX_DRIVER_EXEC_MODE_MASK) {

		case 0:

			if (!(cctx.drvflags & TPAX_DRIVER_VERSION))

				cctx.drvflags |= TPAX_DRIVER_EXEC_MODE_LIST;

			break;

		case TPAX_DRIVER_EXEC_MODE_READ|TPAX_DRIVER_EXEC_MODE_WRITE:

			cctx.drvflags &= ~(uint64_t)(TPAX_DRIVER_EXEC_MODE_READ);

			cctx.drvflags &= ~(uint64_t)(TPAX_DRIVER_EXEC_MODE_WRITE);

			cctx.drvflags |= TPAX_DRIVER_EXEC_MODE_COPY;

			break;

		case TPAX_DRIVER_EXEC_MODE_LIST:

		case TPAX_DRIVER_EXEC_MODE_READ:

		case TPAX_DRIVER_EXEC_MODE_WRITE:

		case TPAX_DRIVER_EXEC_MODE_COPY:

			break;

		default:

			return tpax_driver_usage_exec_mode(

				fdctx->fderr,

				program,entry->arg,

				optv,meta);

	}

	/* copy mode: destination directory */

	if (cctx.drvflags & TPAX_DRIVER_EXEC_MODE_COPY) {

		if (!operand)

			return tpax_driver_usage_copy_mode(

				fdctx->fderr,

				program,entry->arg,

				optv,meta,operand);

		fddst = openat(

			fdctx->fdcwd,

			operand->arg,

			O_RDONLY|O_DIRECTORY|O_CLOEXEC,0);

		if (fddst < 0)

			return tpax_driver_usage_copy_mode(

				fdctx->fderr,

				program,entry->arg,

				optv,meta,operand);

	}

	/* not implemented mode(s) */

	switch (cctx.drvflags & TPAX_DRIVER_EXEC_MODE_MASK) {

		case TPAX_DRIVER_EXEC_MODE_LIST:

			return tpax_driver_error_not_implemented(

				fdctx->fderr,program,"list mode",meta);

		case TPAX_DRIVER_EXEC_MODE_READ:

			return tpax_driver_error_not_implemented(

				fdctx->fderr,program,"read mode",meta);

		case TPAX_DRIVER_EXEC_MODE_WRITE:

			return tpax_driver_error_not_implemented(

				fdctx->fderr,program,"write mode",meta);

		case TPAX_DRIVER_EXEC_MODE_COPY:

			close(fddst);

			return tpax_driver_error_not_implemented(

				fdctx->fderr,program,"copy mode",meta);

		default:

			break;

	}

	if (!(ctx = tpax_driver_ctx_alloc(meta,fdctx,&cctx,nunits))) {

		if (cctx.drvflags & TPAX_DRIVER_EXEC_MODE_COPY)

			close(fddst);

		return tpax_get_driver_ctx_fail(meta);

	}

	ctx->ctx.program	= program;

	ctx->ctx.cctx		= &ctx->cctx;

	*pctx = &ctx->ctx;

	return TPAX_OK;

}

static void tpax_free_driver_ctx_impl(struct tpax_driver_ctx_alloc * ictx)

{

	argv_free(ictx->meta);

	free(ictx);

}

void tpax_free_driver_ctx(struct tpax_driver_ctx * ctx)

{

	struct tpax_driver_ctx_alloc *	ictx;

	uintptr_t			addr;

	if (ctx) {

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

		addr = addr - offsetof(struct tpax_driver_ctx_alloc,ctx);

		ictx = (struct tpax_driver_ctx_alloc *)addr;

		tpax_free_driver_ctx_impl(ictx);

	}

}

const struct tpax_source_version * tpax_source_version(void)

{

	return &tpax_src_version;

}

int tpax_get_driver_fdctx(

	const struct tpax_driver_ctx *	dctx,

	struct tpax_fd_ctx *		fdctx)

{

	struct tpax_driver_ctx_impl *	ictx;

	ictx = tpax_get_driver_ictx(dctx);

	fdctx->fdin  = ictx->fdctx.fdin;

	fdctx->fdout = ictx->fdctx.fdout;

	fdctx->fderr = ictx->fdctx.fderr;

	fdctx->fdlog = ictx->fdctx.fdlog;

	fdctx->fdcwd = ictx->fdctx.fdcwd;

	fdctx->fddst = ictx->fdctx.fddst;

	return 0;

}

int tpax_set_driver_fdctx(

	struct tpax_driver_ctx *	dctx,

	const struct tpax_fd_ctx *	fdctx)

{

	struct tpax_driver_ctx_impl *	ictx;

	ictx = tpax_get_driver_ictx(dctx);

	ictx->fdctx.fdin  = fdctx->fdin;

	ictx->fdctx.fdout = fdctx->fdout;

	ictx->fdctx.fderr = fdctx->fderr;

	ictx->fdctx.fdlog = fdctx->fdlog;

	ictx->fdctx.fdcwd = fdctx->fdcwd;

	ictx->fdctx.fddst = fdctx->fddst;

	return 0;

}