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

/*  tpax: a topological pax implementation                    */

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

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

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

#define _DEFAULT_SOURCE 1

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <fcntl.h>

#include <errno.h>

#include <sys/mman.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)

#define TPAX_DRIVER_WRITE_FORMAT_MASK \

	(TPAX_DRIVER_WRITE_FORMAT_PAX  \

	| TPAX_DRIVER_WRITE_FORMAT_CPIO \

	| TPAX_DRIVER_WRITE_FORMAT_USTAR \

	| TPAX_DRIVER_WRITE_FORMAT_RUSTAR)

/* 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 [-d] [-f archive]\n"

		"       %s -r [-d] [-f archive]\n"

		"       %s -w [−x format] [-b blocksize] [-d] [-f archive]\n"

		"       %s -r -w [-d]\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,

		"\n%s: usage error: When using explicit (long) mode options, "

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

		"may be used.\n",program);

	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,

	struct argv_entry *		archive)

{

	const char * errdesc;

	if (archive || !operand) {

		tpax_driver_usage(

			fdout,program,

			arg,optv,meta);

		if (archive) {

			tpax_dprintf(

				fdout,

				"\n%s: usage error: the __copy__ mode does not permit specifying "

				"an archive path.\n\n",program);

		} else {

			tpax_dprintf(

				fdout,

				"\n%s: usage error: the __copy__ mode requires a destination "

				"directory argument.\n\n",program);

		}

		return TPAX_USAGE;

	}

	switch (errno) {

		case ENOENT:

			tpax_dprintf(

				fdout,

				"%s: file-system error: "

				"the destination directory '%s' "

				"does not exist.\n\n",

				program,operand->arg);

			break;

		case ENOTDIR:

			tpax_dprintf(

				fdout,

				"%s: file-system 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: general 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_usage_write_format(

	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,

		"\n%s: usage error: Archive format may only be specified "

		"in write mode.\n",program);

	return TPAX_USAGE;

}

static int tpax_driver_usage_block_size(

	int				fdout,

	const char *			program,

	const char *			arg,

	struct argv_meta *		meta)

{

	tpax_dprintf(

		fdout,

		"%s: usage error: the requested block size `%s' is not a positive decimal integer.\n",

		program,arg);

	argv_free(meta);

	return TPAX_USAGE;

}

static int tpax_driver_usage_block_size_range(

	int				fdout,

	const char *			program,

	const char *			arg,

	struct argv_meta *		meta)

{

	tpax_dprintf(

		fdout,

		"%s: usage error: `%s' is outside the specified range of 512 to 32256.\n",

		program,arg);

	argv_free(meta);

	return TPAX_USAGE;

}

static int tpax_driver_usage_block_constraints(

	int				fdout,

	const char *			program,

	const char *			arg,

	struct argv_meta *		meta)

{

	tpax_dprintf(

		fdout,

		"%s: usage error: the specified block size `%s' is not a multiple of 512 bytes.\n",

		program,arg);

	argv_free(meta);

	return TPAX_USAGE;

}

static int tpax_driver_error_archive_path(

	int				fdout,

	const char *			program,

	const char *			arg,

	struct argv_meta *		meta,

	bool                            fwrite)

{

	int             lerrno;

	const char *    errstr;

	lerrno = errno;

	errno  = 0;

	errstr = strerror(lerrno);

	errstr = errno ? "" : errstr;

	errno  = lerrno;

	if (fwrite) {

		tpax_dprintf(

			fdout,

			"%s: file-system error: archive file <%s> could not be created "

			"or opened for writing (%s).\n",

			program,arg,errstr);

	} else {

		tpax_dprintf(

			fdout,

			"%s: file-system error: archive file <%s> could not be opened "

			"for reading (%s).\n",

			program,arg,errstr);

	}

	argv_free(meta);

	return TPAX_FATAL;

}

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 void tpax_set_archive_block_size(struct tpax_common_ctx * cctx)

{

	if (cctx->blksize)

		(void)0;

	else if (cctx->drvflags & TPAX_DRIVER_WRITE_FORMAT_PAX)

		cctx->blksize = TPAX_PAX_BLOCK_SIZE;

	else if (cctx->drvflags & TPAX_DRIVER_WRITE_FORMAT_CPIO)

		cctx->blksize = TPAX_CPIO_BLOCK_SIZE;

	else if (cctx->drvflags & TPAX_DRIVER_WRITE_FORMAT_USTAR)

		cctx->blksize = TPAX_USTAR_BLOCK_SIZE;

	else if (cctx->drvflags & TPAX_DRIVER_WRITE_FORMAT_RUSTAR)

		cctx->blksize = TPAX_USTAR_BLOCK_SIZE;

}

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];

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

	ictx->ctx.prefixv  = &ictx->ctx.prefptr[0];

	ictx->ctx.prefixp  = &ictx->ctx.prefptr[0];

	ictx->ctx.prefcap  = &ictx->ctx.prefptr[--elements];

	ictx->meta = meta;

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

		if (!entry->fopt)

			*units++ = entry->arg;

	if (cctx->drvflags & TPAX_DRIVER_EXEC_MODE_WRITE_COPY) {

		ictx->ctx.bufsize = TPAX_FILEIO_BUFLEN;

		ictx->ctx.bufaddr = mmap(

			0,ictx->ctx.bufsize,

			PROT_READ|PROT_WRITE,

			MAP_PRIVATE|MAP_ANONYMOUS,

			-1,0);

		if (ictx->ctx.bufaddr == MAP_FAILED) {

			free(ictx);

			return 0;

		}

		ictx->ctx.dirbuff = mmap(

			0,TPAX_DIRENT_BUFLEN,

			PROT_READ|PROT_WRITE,

			MAP_PRIVATE|MAP_ANONYMOUS,

			-1,0);

		if (ictx->ctx.dirbuff == MAP_FAILED) {

			munmap(ictx->ctx.bufaddr,ictx->ctx.bufsize);

			free(ictx);

			return 0;

		}

	}

	tpax_set_archive_block_size(&ictx->ctx.cctx);

	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_lib_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 *		archive;

	struct argv_entry *		operand;

	struct tpax_fd_ctx              lfdctx;

	size_t				nunits;

	const char *			program;

	int				fddst;

	const char *			ch;

	(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;

	archive = 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;

				case TAG_FILE:

					archive = entry;

					break;

				case TAG_FORMAT:

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

					if (!strcmp(entry->arg,"pax"))

						cctx.drvflags |= TPAX_DRIVER_WRITE_FORMAT_PAX;

					else if (!strcmp(entry->arg,"cpio"))

						cctx.drvflags |= TPAX_DRIVER_WRITE_FORMAT_CPIO;

					else if (!strcmp(entry->arg,"ustar"))

						cctx.drvflags |= TPAX_DRIVER_WRITE_FORMAT_USTAR;

					else if (!strcmp(entry->arg,"rustar"))

						cctx.drvflags |= TPAX_DRIVER_WRITE_FORMAT_RUSTAR;

					break;

				case TAG_BLKSIZE:

					ch = (entry->arg[0] == '+')

						? &entry->arg[1]

						: entry->arg;

					for (; *ch; ch++)

						if ((*ch < '0') || (*ch > '9'))

							return tpax_driver_usage_block_size(

								fdctx->fderr,

								program,entry->arg,

								meta);

					cctx.blksize = atoi(entry->arg);

					if ((cctx.blksize < 512) || (cctx.blksize > 32256))

						return tpax_driver_usage_block_size_range(

							fdctx->fderr,

							program,entry->arg,

							meta);

					if (cctx.blksize % 512)

						return tpax_driver_usage_block_constraints(

							fdctx->fderr,

							program,entry->arg,

							meta);

					break;

				case TAG_RECURSE:

					cctx.drvflags |= TPAX_DRIVER_DIR_MEMBER_RECURSE;

					break;

				case TAG_NORECURSE:

					cctx.drvflags &= ~(uintptr_t)TPAX_DRIVER_DIR_MEMBER_RECURSE;

					break;

				case TAG_PRESERVE_ATIME:

					cctx.drvflags |= TPAX_DRIVER_PRESERVE_ATIME;

					break;

				case TAG_PAX_SYMLINK_ARGS:

					cctx.drvflags |= TPAX_DRIVER_PAX_SYMLINK_ARGS;

					break;

				case TAG_PAX_SYMLINK_ITEMS:

					cctx.drvflags |= TPAX_DRIVER_PAX_SYMLINK_ARGS;

					cctx.drvflags |= TPAX_DRIVER_PAX_SYMLINK_ITEMS;

					break;

				case TAG_STRICT_PATH:

					cctx.drvflags |= TPAX_DRIVER_STRICT_PATH_INPUT;

					break;

				case TAG_PURE_PATH:

					cctx.drvflags |= TPAX_DRIVER_PURE_PATH_OUTPUT;

					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 (archive || !operand)

			return tpax_driver_usage_copy_mode(

				fdctx->fderr,

				program,entry->arg,

				optv,meta,operand,archive);

		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,archive);

	}

	/* archive path */

	if (archive && (cctx.drvflags & TPAX_DRIVER_EXEC_MODE_WRITE)) {

		memcpy(&lfdctx,fdctx,sizeof(*fdctx));

		lfdctx.fdout = openat(

			fdctx->fdcwd,

			archive->arg,

			O_WRONLY|O_CREAT|O_TRUNC,

			0644);

		if (lfdctx.fdout < 0)

			return tpax_driver_error_archive_path(

				fdctx->fderr,

				program,archive->arg,

				meta,true);

		fdctx = &lfdctx;

	} else if (archive) {

		memcpy(&lfdctx,fdctx,sizeof(*fdctx));

		lfdctx.fdin = openat(

			fdctx->fdcwd,

			archive->arg,

			O_RDONLY,0);

		if (lfdctx.fdin < 0)

			return tpax_driver_error_archive_path(

				fdctx->fderr,

				program,archive->arg,

				meta,false);

		fdctx = &lfdctx;

	}

	/* 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_COPY:

			close(fddst);

			return tpax_driver_error_not_implemented(

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

		default:

			break;

	}

	/* archive format vs. execution mode*/

	switch (cctx.drvflags & TPAX_DRIVER_EXEC_MODE_MASK) {

		case TPAX_DRIVER_EXEC_MODE_WRITE:

			if (!(cctx.drvflags & TPAX_DRIVER_WRITE_FORMAT_MASK))

				cctx.drvflags |= TPAX_DRIVER_WRITE_FORMAT_USTAR;

			break;

		default:

			if (cctx.drvflags & TPAX_DRIVER_WRITE_FORMAT_MASK)

				return tpax_driver_usage_write_format(

					fdctx->fderr,program,

					entry->arg,optv,meta);

	}

	/* not implemented archive format(s) */

	switch (cctx.drvflags & TPAX_DRIVER_WRITE_FORMAT_MASK) {

		case TPAX_DRIVER_WRITE_FORMAT_PAX:

			return tpax_driver_error_not_implemented(

				fdctx->fderr,program,"the pax format",meta);

		case TPAX_DRIVER_WRITE_FORMAT_CPIO:

			return tpax_driver_error_not_implemented(

				fdctx->fderr,program,"the cpio format",meta);

		default:

			break;

	}

	/* driver ctx */

	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);

	}

	if (archive) {

		ctx->file     = archive->arg;

		ctx->ctx.file = &ctx->file;

	}

	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)

{

	void *  next;

	size_t  size;

	char ** ppref;

	for (; ictx->ctx.dirents; ) {

		next = ictx->ctx.dirents->next;

		size = ictx->ctx.dirents->size;

		munmap(ictx->ctx.dirents,size);

		ictx->ctx.dirents = (struct tpax_dirent_buffer *)next;

	}

	if (ictx->ctx.bufaddr)