text: /*
   * Copyright (c) 2015, 2016 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.
   *
   * release.c
   * Utility functions to handle release information.
   */
  
  #include <err.h>
  #include <errno.h>
  #include <stdbool.h>
  #include <stddef.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "release.h"
  
  void release_free(struct release* release)
  {
  	free(release->pretty_name);
  }
  
  static char* os_release_eval(const char* string)
  {
  	char* result;
  	size_t result_size;
  	FILE* fp = open_memstream(&result, &result_size);
  	if ( !fp )
  		return NULL;
  	bool escaped = false;
  	bool singly_quote = false;
  	bool doubly_quote = false;
  	while ( *string )
  	{
  		char c = *string++;
  		if ( !escaped && !singly_quote && c == '\\' )
  			escaped = true;
  		else if ( !escaped && !doubly_quote && c == '\'' )
  			singly_quote = !singly_quote;
  		else if ( !escaped && !singly_quote && c == '"' )
  			doubly_quote = !doubly_quote;
  		else
  		{
  			fputc((unsigned char) c, fp);
  			escaped = false;
  		}
  	}
  	if ( fclose(fp) == EOF )
  	{
  		free(result);
  		return NULL;
  	}
  	return result;
  }
  
  static void parse_version(const char* string,
                            unsigned long* major_ptr,
                            unsigned long* minor_ptr)
  
  {
  	*major_ptr = strtoul(string, (char**) &string, 10);
  	if ( *string == '.' )
  		string++;
  	*minor_ptr = strtoul(string, (char**) &string, 10);
  }
  
  static void parse_release(const char* string,
                            unsigned long* major_ptr,
                            unsigned long* minor_ptr,
                            bool* dev_ptr)
  
  {
  	*major_ptr = strtoul(string, (char**) &string, 10);
  	if ( *string == '.' )
  		string++;
  	*minor_ptr = strtoul(string, (char**) &string, 10);
  	*dev_ptr = *string != '\0';
  }
  
  bool os_release_load(struct release* release,
                       const char* path,
                       const char* errpath)
  {
  	memset(release, 0, sizeof(*release));
  	FILE* fp = fopen(path, "r");
  	if ( !fp )
  	{
  		if ( errno != ENOENT )
  			warn("%s", errpath);
  		return false;
  	}
  	bool failure = false;
  	bool success = false;
  	bool found_id = false;
  	bool found_pretty_name = false;
  	bool found_sortix_abi = false;
  	bool found_version_id = false;
  	char* line = NULL;
  	size_t line_size = 0;
  	ssize_t line_length;
  	while ( 0 < (errno = 0, line_length = getline(&line, &line_size, fp)) )
  	{
  		if ( line[line_length-1] == '\n' )
  			line[--line_length] = '\0';
  		if ( !strncmp(line, "ID=", strlen("ID=")) )
  		{
  			const char* param = line + strlen("ID=");
  			found_id = true;
  			char* value = os_release_eval(param);
  			if ( value )
  			{
  				if ( strcmp(value, "sortix") != 0 )
  				{
  					warn("%s: ID does not specify a 'sortix' system", errpath);
  					failure = true;
  				}
  				free(value);
  			}
  			else
  			{
  				warn("malloc");
  				failure = true;
  			}
  		}
  		else if ( !strncmp(line, "PRETTY_NAME=", strlen("PRETTY_NAME=")) )
  		{
  			const char* param = line + strlen("PRETTY_NAME=");
  			found_pretty_name = true;
  			if ( !(release->pretty_name = os_release_eval(param)) )
  			{
  				warn("malloc");
  				failure = true;
  			}
  		}
  		else if ( !strncmp(line, "SORTIX_ABI=", strlen("SORTIX_ABI=")) )
  		{
  			const char* param = line + strlen("SORTIX_ABI=");
  			found_sortix_abi = true;
  			char* value = os_release_eval(param);
  			if ( value )
  			{
  				parse_version(value, &release->abi_major, &release->abi_minor);
  				free(value);
  			}
  			else
  			{
  				warn("malloc");
  				failure = true;
  			}
  		}
  		else if ( !strncmp(line, "VERSION_ID=", strlen("VERSION_ID=")) )
  		{
  			const char* param = line + strlen("VERSION_ID=");
  			found_version_id = true;
  			char* value = os_release_eval(param);
  			if ( value )
  			{
  				parse_release(value, &release->version_major,
  				              &release->version_minor, &release->version_dev);
  				free(value);
  			}
  			else
  			{
  				warn("malloc");
  				failure = true;
  			}
  		}
  	}
  	if ( errno )
  		warn("%s", errpath);
  	else if ( failure )
  		;
  	else if ( !found_id )
  		warnx("%s: No ID", errpath);
  	else if ( !found_pretty_name )
  		warnx("%s: No PRETTY_NAME", errpath);
  	else if ( !found_sortix_abi )
  		warnx("%s: No SORTIX_ABI", errpath);
  	else if ( !found_version_id )
  		warnx("%s: No VERSION_ID", errpath);
  	else
  		success = true;
  	free(line);
  	fclose(fp);
  	if ( failure || !success )
  	{
  		release_free(release);
  		return false;
  	}
  	return true;
  }
  