text: /*
   * Copyright (c) 2015 Jonas 'Sortie' Termansen.
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   *
   * mktemp.c
   * Create temporary files and directories.
   */
  
  #include <errno.h>
  #include <error.h>
  #include <limits.h>
  #include <locale.h>
  #include <stdarg.h>
  #include <stdbool.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  __attribute__((format(printf, 1, 2)))
  char* print_string(const char* format, ...)
  {
  	va_list ap;
  	va_start(ap, format);
  	char* ret;
  	if ( vasprintf(&ret, format, ap) < 0 )
  		ret = NULL;
  	va_end(ap);
  	return ret;
  }
  
  char* join_paths(const char* a, const char* b)
  {
  	size_t a_len = strlen(a);
  	bool has_slash = (a_len && a[a_len-1] == '/') || b[0] == '/';
  	return has_slash ? print_string("%s%s", a, b) : print_string("%s/%s", a, b);
  }
  
  static void compact_arguments(int* argc, char*** argv)
  {
  	for ( int i = 0; i < *argc; i++ )
  	{
  		while ( i < *argc && !(*argv)[i] )
  		{
  			for ( int n = i; n < *argc; n++ )
  				(*argv)[n] = (*argv)[n+1];
  			(*argc)--;
  		}
  	}
  }
  
  static void help(FILE* fp, const char* argv0)
  {
  	fprintf(fp, "Usage: %s [OPTION]... [TEMPLATE]\n", argv0);
  	fprintf(fp, "Create a temporary file or directory, safely, and print its name.\n");
  	fprintf(fp, "TEMPLATE must contain at least 6 consecutive 'X's in last component.\n");
  	fprintf(fp, "If TEMPLATE is not specified, use tmp.XXXXXX, and --tmpdir is implied.\n");
  	fprintf(fp, "Files are created u+rw, and directories u+rwx, minus umask restrictions.\n");
  	fprintf(fp, "\n");
  	fprintf(fp, "  -d, --directory     create a directory, not a file\n");
  	fprintf(fp, "  -p, --tmpdir[=DIR]  interpret TEMPLATE relative to DIR.\n");
  	fprintf(fp, "  -t                  interpret TEMPLATE as a single file name component,\n");
  	fprintf(fp, "                        relative to a directory.\n");
  	fprintf(fp, "      --suffix=SUFF   append SUFF to TEMPLATE.  SUFF must not contain slash.\n");
  	fprintf(fp, "                        This option is implied if TEMPLATE does not end in X.\n");
  	fprintf(fp, "  -q, --quiet         suppress diagnostics about file/dir-creation failure\n");
  	fprintf(fp, "      --help          display this help and exit\n");
  	fprintf(fp, "      --version       output version information and exit\n");
  }
  
  static void version(FILE* fp, const char* argv0)
  {
  	fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
  }
  
  int main(int argc, char* argv[])
  {
  	setlocale(LC_ALL, "");
  
  	bool directory = false;
  	bool quiet = false;
  	bool rooted = false;
  	const char* suffix = NULL;
  	const char* tmpdir = getenv("TMPDIR");
  	if ( !tmpdir )
  		tmpdir = "/tmp";
  
  	const char* argv0 = argv[0];
  	for ( int i = 1; i < argc; i++ )
  	{
  		const char* arg = argv[i];
  		if ( arg[0] != '-' || !arg[1] )
  			continue;
  		argv[i] = NULL;
  		if ( !strcmp(arg, "--") )
  			break;
  		if ( arg[1] != '-' )
  		{
  			char c;
  			while ( (c = *++arg) ) switch ( c )
  			{
  			case 'd': directory = true; break;
  			case 'p':
  				if ( !*(tmpdir = arg + 1) )
  				{
  					if ( i + 1 == argc )
  					{
  						error(0, 0, "option requires an argument -- 'p'");
  						fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]);
  						exit(125);
  					}
  					tmpdir = argv[i+1];
  					argv[++i] = NULL;
  				}
  				rooted = true;
  				arg = "p";
  				break;
  			case 't': rooted = true; break;
  			case 'q': quiet = true; break;
  			default:
  				fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
  				help(stderr, argv0);
  				exit(1);
  			}
  		}
  		else if ( !strcmp(arg, "--directory") )
  			directory = true;
  		else if ( !strncmp(arg, "--suffix=", strlen("--suffix=")) )
  			suffix = arg + strlen("--suffix=");
  		else if ( !strcmp(arg, "--suffix") )
  		{
  			if ( i + 1 == argc )
  			{
  				error(0, 0, "option '--suffix' requires an argument");
  				fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]);
  				exit(125);
  			}
  			suffix = argv[i+1];
  			argv[++i] = NULL;
  		}
  		else if ( !strncmp(arg, "--tmpdir=", strlen("--tmpdir=")) )
  		{
  			tmpdir = arg + strlen("--tmpdir=");
  			rooted = true;
  		}
  		else if ( !strcmp(arg, "--tmpdir") )
  		{
  			if ( i + 1 == argc )
  			{
  				error(0, 0, "option '--tmpdir' requires an argument");
  				fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]);
  				exit(125);
  			}
  			tmpdir = argv[i+1];
  			argv[++i] = NULL;
  			rooted = true;
  		}
  		else if ( !strcmp(arg, "--help") )
  			help(stdout, argv0), exit(0);
  		else if ( !strcmp(arg, "--version") )
  			version(stdout, argv0), exit(0);
  		else
  		{
  			fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
  			help(stderr, argv0);
  			exit(1);
  		}
  	}
  
  	compact_arguments(&argc, &argv);
  
  	if ( quiet && !freopen("/dev/null", "w", stderr) )
  		close(2);
  
  	if ( 3 <= argc )
  	{
  		error(0, 0, "too many templates");
  		fprintf(stderr, "Try `%s --help' for more information\n", argv0);
  		exit(1);
  	}
  
  	// TODO: Add support for an arbitrary amount of X's in mkstemps and use it.
  	//       Then increase the default below to 10 X's and in --help as well.
  	const char* input_templ;
  	if ( 2 <= argc )
  	{
  		input_templ = argv[1];
  	}
  	else
  	{
  		input_templ = "tmp.XXXXXX";
  		rooted = true;
  	}
  
  	char* templ;
  	if ( rooted )
  	{
  		templ = join_paths(tmpdir, input_templ);
  		if ( !templ )
  			error(1, errno, "malloc");
  	}
  	else
  	{
  		templ = strdup(input_templ);
  		if ( !templ )
  			error(1, errno, "malloc");
  	}
  
  	size_t suffix_length;
  	if ( suffix )
  	{
  		suffix_length = strlen(suffix);
  		if ( INT_MAX < suffix_length )
  			error(1, 0, "suffix is too long");
  		char* new_templ;
  		if ( asprintf(&new_templ, "%s%s", templ, suffix) < 0 )
  			error(1, errno, "malloc");
  		free(templ);
  		templ = new_templ;
  	}
  	else
  	{
  		size_t templ_length = strlen(templ);
  		suffix_length = 0;
  		while ( templ_length - suffix_length &&
  		        templ[templ_length - suffix_length - 1] != 'X' &&
  		        templ[templ_length - suffix_length - 1] != '/' )
  			suffix_length++;
  	}
  
  	size_t templ_length = strlen(templ);
  	size_t xcount = 0;
  	while ( templ_length - (suffix_length + xcount) &&
  	        templ[templ_length - (suffix_length + xcount) - 1] == 'X' )
  		xcount++;
  
  	if ( xcount < 6 )
  		error(1, 0, "too few X's in template `%s'", templ);
  
  	char* path = strdup(templ);
  	if ( !path )
  		error(1, errno, "strdup");
  	if ( directory )
  	{
  		if ( !mkdtemps(path, suffix_length) )
  			error(1, errno, "%s", templ);
  	}
  	else
  	{
  		if ( INT_MAX < suffix_length )
  			error(1, 0, "suffix is too long");
  		int fd = mkstemps(path, (int) suffix_length);
  		if ( fd < 0 )
  			error(1, errno, "%s", templ);
  		close(fd);
  	}
  	puts(path);
  	free(path);
  
  	free(templ);
  
  	if ( ferror(stdout) || fflush(stdout) == EOF )
  		return 1;
  	return 0;
  }
  