/*
    getopt.c - Enhanced implementation of BSD getopt(1)
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/*
 * Version 1.0-b4: Tue Sep 23 1997. First public release.
 * Version 1.0: Wed Nov 19 1997.
 *   Bumped up the version number to 1.0
 *   Fixed minor typo (CSH instead of TCSH)
 * Version 1.0.1: Tue Jun 3 1998
 *   Fixed sizeof instead of strlen bug
 *   Bumped up the version number to 1.0.1
 * Version 1.0.2: Thu Jun 11 1998 (not present)
 *   Fixed gcc-2.8.1 warnings
 *   Fixed --version/-V option (not present)
 * Version 1.0.5: Tue Jun 22 1999
 *   Make -u option work (not present)
 * Version 1.0.6: Tue Jun 27 2000
 *   No important changes
 * Version 1.1.0: Tue Jun 30 2000
 *   Added NLS support (partly written by Arkadiusz Mi<B6>kiewicz
 *     <misiek@pld.org.pl>)
 * Version 1.1.4: Mon Nov 7 2005
 *   Fixed a few type's in the manpage
 */

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <getopt.h>

/* NON_OPT is the code that is returned when a non-option is found in '+'
   mode */
#define NON_OPT 1
/* LONG_OPT is the code that is returned when a long option is found. */
#define LONG_OPT 2

/* The shells recognized. */
typedef enum { BASH, TCSH } shell_t;

/* Some global variables that tells us how to parse. */
shell_t shell        = BASH; /* The shell we generate output for. */
int     quiet_errors = 0;    /* 0 is not quiet. */
int     quiet_output = 0;    /* 0 is not quiet. */
int     quote        = 1;    /* 1 is do quote. */
int     alternative  = 0;    /* 0 is getopt_long, 1 is getopt_long_only */

/* Function prototypes */
void *      our_malloc(size_t size);
void *      our_realloc(void *ptr, size_t size);
const char *normalize(const char *arg);
int  generate_output(char *argv[], int argc, const char *optstr, const struct option *longopts);
int  main(int argc, char *argv[]);
void parse_error(const char *message);
void add_long_options(char *options);
void add_longopt(const char *name, int has_arg);
void print_help(void);
void set_shell(const char *new_shell);
void set_initial_shell(void);

void *our_malloc(size_t size)
{
  void *ret = malloc(size);
  if (!ret) {
    fprintf(stderr, ("%s: Out of memory!\n"), "getopt");
    exit(3);
  }
  return (ret);
}

void *our_realloc(void *ptr, size_t size)
{
  void *ret = realloc(ptr, size);
  if (!ret && size) {
    fprintf(stderr, ("%s: Out of memory!\n"), "getopt");
    exit(3);
  }
  return (ret);
}

/*
 * This function 'normalizes' a single argument: it puts single quotes around
 * it and escapes other special characters. If quote is false, it just
 * returns its argument.
 * Bash only needs special treatment for single quotes; tcsh also recognizes
 * exclamation marks within single quotes, and nukes whitespace.
 * This function returns a pointer to a buffer that is overwritten by
 * each call.
 */
const char *normalize(const char *arg)
{
  static char *BUFFER = NULL;
  const char * argptr = arg;
  char *       bufptr;

  if (BUFFER != NULL)
    free(BUFFER);

  if (!quote) { /* Just copy arg */
    BUFFER = our_malloc(strlen(arg) + 1);

    strcpy(BUFFER, arg);
    return BUFFER;
  }

  /* Each character in arg may take up to four characters in the result:
     For a quote we need a closing quote, a backslash, a quote and an
     opening quote! We need also the global opening and closing quote,
     and one extra character for '\0'. */
  BUFFER = our_malloc(strlen(arg) * 4 + 3);

  bufptr    = BUFFER;
  *bufptr++ = '\'';

  while (*argptr) {
    if (*argptr == '\'') {
      /* Quote: replace it with: '\'' */
      *bufptr++ = '\'';
      *bufptr++ = '\\';
      *bufptr++ = '\'';
      *bufptr++ = '\'';
    }
    else if (shell == TCSH && *argptr == '!') {
      /* Exclamation mark: replace it with: \! */
      *bufptr++ = '\'';
      *bufptr++ = '\\';
      *bufptr++ = '!';
      *bufptr++ = '\'';
    }
    else if (shell == TCSH && *argptr == '\n') {
      /* Newline: replace it with: \n */
      *bufptr++ = '\\';
      *bufptr++ = 'n';
    }
    else if (shell == TCSH && isspace(*argptr)) {
      /* Non-newline whitespace: replace it with \<ws> */
      *bufptr++ = '\'';
      *bufptr++ = '\\';
      *bufptr++ = *argptr;
      *bufptr++ = '\'';
    }
    else
      /* Just copy */
      *bufptr++ = *argptr;
    argptr++;
  }
  *bufptr++ = '\'';
  *bufptr++ = '\0';
  return BUFFER;
}

/*
 * Generate the output. argv[0] is the program name (used for reporting errors).
 * argv[1..] contains the options to be parsed. argc must be the number of
 * elements in argv (ie. 1 if there are no options, only the program name),
 * optstr must contain the short options, and longopts the long options.
 * Other settings are found in global variables.
 */
int generate_output(char *argv[], int argc, const char *optstr, const struct option *longopts)
{
  int         exit_code = 0; /* We assume everything will be OK */
  int         opt;
  int         longindex;
  const char *charptr;

  if (quiet_errors) /* No error reporting from getopt(3) */
    opterr = 0;
  optind = 0; /* Reset getopt(3) */

  while ((opt = (alternative ? getopt_long_only(argc, argv, optstr, longopts, &longindex)
                             : getopt_long(argc, argv, optstr, longopts, &longindex))) != EOF)
    if (opt == '?' || opt == ':')
      exit_code = 1;
    else if (!quiet_output) {
      if (opt == LONG_OPT) {
        printf(" --%s", longopts[longindex].name);
        if (longopts[longindex].has_arg)
          printf(" %s", normalize(optarg ? optarg : ""));
      }
      else if (opt == NON_OPT)
        printf(" %s", normalize(optarg ? optarg : ""));
      else {
        printf(" -%c", opt);
        charptr = strchr(optstr, opt);
        if (charptr != NULL && *++charptr == ':')
          printf(" %s", normalize(optarg ? optarg : ""));
      }
    }

  if (!quiet_output) {
    printf(" --");
    while (optind < argc)
      printf(" %s", normalize(argv[optind++]));
    printf("\n");
  }
  return exit_code;
}

/*
 * Report an error when parsing getopt's own arguments.
 * If message is NULL, we already sent a message, we just exit with a helpful
 * hint.
 */
void parse_error(const char *message)
{
  if (message)
    fprintf(stderr, "getopt: %s\n", message);
  fputs("Try `getopt --help' for more information.\n", stderr);
  exit(2);
}

static struct option *long_options        = NULL;
static int            long_options_length = 0; /* Length of array */
static int            long_options_nr     = 0; /* Nr of used elements in array */
#define LONG_OPTIONS_INCR 10
#define init_longopt() add_longopt(NULL, 0)

/* Register a long option. The contents of name is copied. */
void add_longopt(const char *name, int has_arg)
{
  char *tmp;
  if (!name) { /* init */
    free(long_options);
    long_options        = NULL;
    long_options_length = 0;
    long_options_nr     = 0;
  }

  if (long_options_nr == long_options_length) {
    long_options_length += LONG_OPTIONS_INCR;
    long_options = our_realloc(long_options, sizeof(struct option) * long_options_length);
  }

  long_options[long_options_nr].name    = NULL;
  long_options[long_options_nr].has_arg = 0;
  long_options[long_options_nr].flag    = NULL;
  long_options[long_options_nr].val     = 0;

  if (long_options_nr) { /* Not for init! */
    long_options[long_options_nr - 1].has_arg = has_arg;
    long_options[long_options_nr - 1].flag    = NULL;
    long_options[long_options_nr - 1].val     = LONG_OPT;
    tmp                                       = our_malloc(strlen(name) + 1);
    strcpy(tmp, name);
    long_options[long_options_nr - 1].name = tmp;
  }
  long_options_nr++;
}

/*
 * Register several long options. options is a string of long options,
 * separated by commas or whitespace.
 * This nukes options!
 */
void add_long_options(char *options)
{
  int   arg_opt;
  char *tokptr = strtok(options, ", \t\n");
  while (tokptr) {
    arg_opt = no_argument;
    if (strlen(tokptr) > 0) {
      if (tokptr[strlen(tokptr) - 1] == ':') {
        if (tokptr[strlen(tokptr) - 2] == ':') {
          tokptr[strlen(tokptr) - 2] = '\0';
          arg_opt                    = optional_argument;
        }
        else {
          tokptr[strlen(tokptr) - 1] = '\0';
          arg_opt                    = required_argument;
        }
        if (strlen(tokptr) == 0)
          parse_error("empty long option after "
                      "-l or --long argument");
      }
      add_longopt(tokptr, arg_opt);
    }
    tokptr = strtok(NULL, ", \t\n");
  }
}

void set_shell(const char *new_shell)
{
  if (!strcmp(new_shell, "bash"))
    shell = BASH;
  else if (!strcmp(new_shell, "tcsh"))
    shell = TCSH;
  else if (!strcmp(new_shell, "sh"))
    shell = BASH;
  else if (!strcmp(new_shell, "csh"))
    shell = TCSH;
  else
    parse_error("unknown shell after -s or --shell argument");
}

void print_help(void)
{
  fputs("Usage: getopt optstring parameters\n", stderr);
  fputs("       getopt [options] [--] optstring parameters\n", stderr);
  fputs("       getopt [options] -o|--options optstring [options] [--]\n", stderr);
  fputs("              parameters\n", stderr);
  fputs("  -a, --alternative            Allow long options starting with single -\n", stderr);
  fputs("  -h, --help                   This small usage guide\n", stderr);
  fputs("  -l, --longoptions=longopts   Long options to be recognized\n", stderr);
  fputs("  -n, --name=progname          The name under which errors are reported\n", stderr);
  fputs("  -o, --options=optstring      Short options to be recognized\n", stderr);
  fputs("  -q, --quiet                  Disable error reporting by getopt(3)\n", stderr);
  fputs("  -Q, --quiet-output           No normal output\n", stderr);
  fputs("  -s, --shell=shell            Set shell quoting conventions\n", stderr);
  fputs("  -T, --test                   Test for getopt(1) version\n", stderr);
  fputs("  -u, --unqote                 Do not quote the output\n", stderr);
  fputs("  -V, --version                Output version information\n", stderr);
  exit(2);
}

/* Exit codes:
 *   0) No errors, successful operation.
 *   1) getopt(3) returned an error.
 *   2) A problem with parameter parsing for getopt(1).
 *   3) Internal error, out of memory
 *   4) Returned for -T
 */

static struct option longopts[] = {
    {"options", required_argument, NULL, 'o'}, {"longoptions", required_argument, NULL, 'l'},
    {"quiet", no_argument, NULL, 'q'},         {"quiet-output", no_argument, NULL, 'Q'},
    {"shell", required_argument, NULL, 's'},   {"test", no_argument, NULL, 'T'},
    {"unquoted", no_argument, NULL, 'u'},      {"help", no_argument, NULL, 'h'},
    {"alternative", no_argument, NULL, 'a'},   {"name", required_argument, NULL, 'n'},
    {"version", no_argument, NULL, 'V'},       {NULL, 0, NULL, 0}};

/* Stop scanning as soon as a non-option argument is found! */
static const char *shortopts = "+ao:l:n:qQs:TuhV";

int main(int argc, char *argv[])
{
  char *optstr = NULL;
  char *name   = NULL;
  int   opt;
  int   compatible = 0;

  init_longopt();

  if (getenv("GETOPT_COMPATIBLE"))
    compatible = 1;

  if (argc == 1) {
    if (compatible) {
      /* For some reason, the original getopt gave no error
         when there were no arguments. */
      printf(" --\n");
      exit(0);
    }
    else
      parse_error("missing optstring argument");
  }

  if (argv[1][0] != '-' || compatible) {
    quote  = 0;
    optstr = our_malloc(strlen(argv[1]) + 1);
    strcpy(optstr, argv[1] + strspn(argv[1], "-+"));
    argv[1] = argv[0];
    exit(generate_output(argv + 1, argc - 1, optstr, long_options));
  }

  while ((opt = getopt_long(argc, argv, shortopts, longopts, NULL)) != EOF)
    switch (opt) {
    case 'a': alternative = 1; break;
    case 'h': print_help(); exit(0);
    case 'o':
      if (optstr)
        free(optstr);
      optstr = our_malloc(strlen(optarg ? optarg : "") + 1);
      strcpy(optstr, optarg ? optarg : "");
      break;
    case 'l': add_long_options(optarg ? optarg : ""); break;
    case 'n':
      if (name)
        free(name);
      name = our_malloc(strlen(optarg ? optarg : "") + 1);
      strcpy(name, optarg ? optarg : "");
      break;
    case 'q': quiet_errors = 1; break;
    case 'Q': quiet_output = 1; break;
    case 's': set_shell(optarg ? optarg : ""); break;
    case 'T': exit(4);
    case 'u': quote = 0; break;
    case 'V': printf("getopt (enhanced) 1.1.4\n"); exit(0);
    case '?':
    case ':': parse_error(NULL);
    default: parse_error("internal error, contact the author.");
    }

  if (!optstr) {
    if (optind >= argc)
      parse_error("missing optstring argument");
    else {
      optstr = our_malloc(strlen(argv[optind]) + 1);
      strcpy(optstr, argv[optind]);
      optind++;
    }
  }
  if (name)
    argv[optind - 1] = name;
  else
    argv[optind - 1] = argv[0];
  exit(generate_output(argv + optind - 1, argc - optind + 1, optstr, long_options));
}
