/*
   * (C) Copyright 2011 Free Electrons
   * David Wagner <david.wagner@free-electrons.com>
   *
   * Inspired from envcrc.c:
   * (C) Copyright 2001
   * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
   *

   * SPDX-License-Identifier:	GPL-2.0+

   */
  
  #include <errno.h>
  #include <fcntl.h>
  #include <stdio.h>

  #include <stdlib.h>

  #include <stdint.h>
  #include <string.h>
  #include <unistd.h>

  #include <libgen.h>

  #include <sys/types.h>
  #include <sys/stat.h>

  #include <sys/mman.h>

  #include "compiler.h"

  #include <u-boot/crc.h>

  #include <version.h>

  
  #define CRC_SIZE sizeof(uint32_t)
  
  static void usage(const char *exec_name)
  {

  	fprintf(stderr, "%s [-h] [-r] [-b] [-p <byte>] -s <environment partition size> -o <output> <input file>
  "

  	       "
  "

  	       "This tool takes a key=value input file (same as would a `printenv' show) and generates the corresponding environment image, ready to be flashed.
  "

  	       "
  "
  	       "\tThe input file is in format:
  "
  	       "\t\tkey1=value1
  "
  	       "\t\tkey2=value2
  "
  	       "\t\t...
  "

  	       "\tEmpty lines are skipped, and lines with a # in the first
  "
  	       "\tcolumn are treated as comments (also skipped).
  "

  	       "\t-r : the environment has multiple copies in flash
  "
  	       "\t-b : the target is big endian (default is little endian)
  "

  	       "\t-p <byte> : fill the image with <byte> bytes instead of 0xff bytes
  "

  	       "\t-V : print version information and exit
  "

  	       "
  "
  	       "If the input file is \"-\", data is read from standard input
  ",
  	       exec_name);
  }

  long int xstrtol(const char *s)
  {
  	long int tmp;
  
  	errno = 0;
  	tmp = strtol(s, NULL, 0);
  	if (!errno)
  		return tmp;
  
  	if (errno == ERANGE)
  		fprintf(stderr, "Bad integer format: %s
  ",  s);
  	else
  		fprintf(stderr, "Error while parsing %s: %s
  ", s,
  				strerror(errno));
  
  	exit(EXIT_FAILURE);
  }

  int main(int argc, char **argv)
  {
  	uint32_t crc, targetendian_crc;
  	const char *txt_filename = NULL, *bin_filename = NULL;
  	int txt_fd, bin_fd;
  	unsigned char *dataptr, *envptr;
  	unsigned char *filebuf = NULL;
  	unsigned int filesize = 0, envsize = 0, datasize = 0;
  	int bigendian = 0;
  	int redundant = 0;
  	unsigned char padbyte = 0xff;
  
  	int option;
  	int ret = EXIT_SUCCESS;
  
  	struct stat txt_file_stat;
  
  	int fp, ep;

  	const char *prg;
  
  	prg = basename(argv[0]);

  	/* Turn off getopt()'s internal error message */
  	opterr = 0;

  	/* Parse the cmdline */

  	while ((option = getopt(argc, argv, ":s:o:rbp:hV")) != -1) {

  		switch (option) {
  		case 's':

  			datasize = xstrtol(optarg);

  			break;
  		case 'o':
  			bin_filename = strdup(optarg);
  			if (!bin_filename) {

  				fprintf(stderr, "Can't strdup() the output filename
  ");

  				return EXIT_FAILURE;
  			}
  			break;
  		case 'r':
  			redundant = 1;
  			break;
  		case 'b':
  			bigendian = 1;
  			break;
  		case 'p':

  			padbyte = xstrtol(optarg);

  			break;
  		case 'h':

  			usage(prg);

  			return EXIT_SUCCESS;

  		case 'V':
  			printf("%s version %s
  ", prg, PLAIN_VERSION);
  			return EXIT_SUCCESS;

  		case ':':
  			fprintf(stderr, "Missing argument for option -%c
  ",

  				optopt);

  			usage(prg);

  			return EXIT_FAILURE;

  		default:

  			fprintf(stderr, "Wrong option -%c
  ", optopt);

  			usage(prg);

  			return EXIT_FAILURE;
  		}
  	}
  
  	/* Check datasize and allocate the data */
  	if (datasize == 0) {

  		fprintf(stderr, "Please specify the size of the environment partition.
  ");

  		usage(prg);

  		return EXIT_FAILURE;
  	}
  
  	dataptr = malloc(datasize * sizeof(*dataptr));
  	if (!dataptr) {

  		fprintf(stderr, "Can't alloc %d bytes for dataptr.
  ",
  				datasize);

  		return EXIT_FAILURE;
  	}
  
  	/*
  	 * envptr points to the beginning of the actual environment (after the

  	 * crc and possible `redundant' byte

  	 */
  	envsize = datasize - (CRC_SIZE + redundant);
  	envptr = dataptr + CRC_SIZE + redundant;
  
  	/* Pad the environment with the padding byte */
  	memset(envptr, padbyte, envsize);
  
  	/* Open the input file ... */

  	if (optind >= argc || strcmp(argv[optind], "-") == 0) {

  		int readbytes = 0;

  		int readlen = sizeof(*envptr) * 4096;

  		txt_fd = STDIN_FILENO;
  
  		do {
  			filebuf = realloc(filebuf, readlen);

  			if (!filebuf) {
  				fprintf(stderr, "Can't realloc memory for the input file buffer
  ");
  				return EXIT_FAILURE;
  			}

  			readbytes = read(txt_fd, filebuf + filesize, readlen);

  			if (errno) {
  				fprintf(stderr, "Error while reading stdin: %s
  ",
  						strerror(errno));
  				return EXIT_FAILURE;
  			}

  			filesize += readbytes;
  		} while (readbytes == readlen);
  
  	} else {

  		txt_filename = argv[optind];

  		txt_fd = open(txt_filename, O_RDONLY);
  		if (txt_fd == -1) {
  			fprintf(stderr, "Can't open \"%s\": %s
  ",
  					txt_filename, strerror(errno));
  			return EXIT_FAILURE;
  		}
  		/* ... and check it */
  		ret = fstat(txt_fd, &txt_file_stat);
  		if (ret == -1) {

  			fprintf(stderr, "Can't stat() on \"%s\": %s
  ",
  					txt_filename, strerror(errno));

  			return EXIT_FAILURE;
  		}
  
  		filesize = txt_file_stat.st_size;

  
  		filebuf = mmap(NULL, sizeof(*envptr) * filesize, PROT_READ,
  			       MAP_PRIVATE, txt_fd, 0);
  		if (filebuf == MAP_FAILED) {

  			fprintf(stderr, "mmap (%zu bytes) failed: %s
  ",

  					sizeof(*envptr) * filesize,
  					strerror(errno));
  			fprintf(stderr, "Falling back to read()
  ");
  
  			filebuf = malloc(sizeof(*envptr) * filesize);
  			ret = read(txt_fd, filebuf, sizeof(*envptr) * filesize);
  			if (ret != sizeof(*envptr) * filesize) {

  				fprintf(stderr, "Can't read the whole input file (%zu bytes): %s
  ",

  					sizeof(*envptr) * filesize,
  					strerror(errno));
  
  				return EXIT_FAILURE;
  			}

  		}
  		ret = close(txt_fd);
  	}

  	/* Parse a byte at time until reaching the file OR until the environment fills
  	 * up. Check ep against envsize - 1 to allow for extra trailing '\0'. */
  	for (fp = 0, ep = 0 ; fp < filesize && ep < envsize - 1; fp++) {

  		if (filebuf[fp] == '
  ') {

  			if (fp == 0 || filebuf[fp-1] == '
  ') {

  				/*

  				 * Skip empty lines.

  				 */
  				continue;
  			} else if (filebuf[fp-1] == '\\') {
  				/*
  				 * Embedded newline in a variable.
  				 *

  				 * The backslash was added to the envptr; rewind
  				 * and replace it with a newline

  				 */
  				ep--;
  				envptr[ep++] = '
  ';
  			} else {
  				/* End of a variable */
  				envptr[ep++] = '\0';
  			}

  		} else if ((fp == 0 || filebuf[fp-1] == '
  ') && filebuf[fp] == '#') {
  			/* Comment, skip the line. */
  			while (++fp < filesize && filebuf[fp] != '
  ')
  			continue;

  		} else {
  			envptr[ep++] = filebuf[fp];
  		}
  	}

  	/* If there are more bytes in the file still, it means the env filled up
  	 * before parsing the whole file.  Eat comments & whitespace here to see if
  	 * there was anything meaning full left in the file, and if so, throw a error
  	 * and exit. */
  	for( ; fp < filesize; fp++ )
  	{
  		if (filebuf[fp] == '
  ') {
  			if (fp == 0 || filebuf[fp-1] == '
  ') {
  				/* Ignore blank lines */
  				continue;
  			}
  		} else if ((fp == 0 || filebuf[fp-1] == '
  ') && filebuf[fp] == '#') {
  			while (++fp < filesize && filebuf[fp] != '
  ')
  			continue;
  		} else {
  			fprintf(stderr, "The environment file is too large for the target environment storage
  ");
  			return EXIT_FAILURE;
  		}
  	}

  	/*
  	 * Make sure there is a final '\0'
  	 * And do it again on the next byte to mark the end of the environment.
  	 */
  	if (envptr[ep-1] != '\0') {
  		envptr[ep++] = '\0';
  		/*
  		 * The text file doesn't have an ending newline.  We need to
  		 * check the env size again to make sure we have room for two \0
  		 */
  		if (ep >= envsize) {

  			fprintf(stderr, "The environment file is too large for the target environment storage
  ");

  			return EXIT_FAILURE;
  		}
  		envptr[ep] = '\0';
  	} else {
  		envptr[ep] = '\0';
  	}
  
  	/* Computes the CRC and put it at the beginning of the data */
  	crc = crc32(0, envptr, envsize);
  	targetendian_crc = bigendian ? cpu_to_be32(crc) : cpu_to_le32(crc);

  	memcpy(dataptr, &targetendian_crc, sizeof(targetendian_crc));
  	if (redundant)
  		dataptr[sizeof(targetendian_crc)] = 1;

  	if (!bin_filename || strcmp(bin_filename, "-") == 0) {
  		bin_fd = STDOUT_FILENO;
  	} else {

  		bin_fd = creat(bin_filename, S_IRUSR | S_IWUSR | S_IRGRP |
  					     S_IWGRP);

  		if (bin_fd == -1) {
  			fprintf(stderr, "Can't open output file \"%s\": %s
  ",
  					bin_filename, strerror(errno));
  			return EXIT_FAILURE;
  		}

  	}
  
  	if (write(bin_fd, dataptr, sizeof(*dataptr) * datasize) !=
  			sizeof(*dataptr) * datasize) {
  		fprintf(stderr, "write() failed: %s
  ", strerror(errno));
  		return EXIT_FAILURE;
  	}
  
  	ret = close(bin_fd);
  
  	return ret;
  }