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sortix--sortix/libc/grp/fgetgrent_r.c
Jonas 'Sortie' Termansen 2b72262b4f Relicense Sortix to the ISC license.
I hereby relicense all my work on Sortix under the ISC license as below.

All Sortix contributions by other people are already under this license,
are not substantial enough to be copyrightable, or have been removed.

All imported code from other projects is compatible with this license.

All GPL licensed code from other projects had previously been removed.

Copyright 2011-2016 Jonas 'Sortie' Termansen and contributors.

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.
2016-03-05 22:21:50 +01:00

218 lines
4.8 KiB
C

/*
* Copyright (c) 2013 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.
*
* grp/fgetgrent_r.c
* Reads a group entry from a FILE.
*/
#include <sys/types.h>
#include <errno.h>
#include <grp.h>
#include <inttypes.h>
#include <stdalign.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static char* next_field(char** current)
{
char* result = *current;
if ( result )
{
char* next = result;
while ( *next && *next != ':' )
next++;
if ( !*next )
next = NULL;
else
*next++ = '\0';
*current = next;
}
return result;
}
static bool next_field_uintmax(char** current, uintmax_t* result)
{
char* id_str = next_field(current);
if ( !id_str )
return false;
char* id_endptr;
uintmax_t id_umax = strtoumax(id_str, &id_endptr, 10);
if ( *id_endptr )
return false;
*result = id_umax;
return true;
}
static gid_t next_field_gid(char** current, gid_t* result)
{
uintmax_t id_umax;
if ( !next_field_uintmax(current, &id_umax) )
return false;
gid_t gid = (gid_t) id_umax;
if ( (uintmax_t) gid != (uintmax_t) id_umax )
return false;
*result = gid;
return true;
}
static size_t count_num_members(const char* member_string)
{
size_t result = 0;
while ( *member_string )
{
result++;
while ( *member_string && *member_string != ',' )
member_string++;
if ( *member_string == ',' )
member_string++;
}
return result;
}
static char* next_member(char** current)
{
char* result = *current;
if ( result )
{
char* next = result;
while ( *next && *next != ',' )
next++;
if ( !*next )
next = NULL;
else
*next++ = '\0';
*current = next;
}
return result;
}
int fgetgrent_r(FILE* restrict fp,
struct group* restrict result,
char* restrict buf,
size_t buf_len,
struct group** restrict result_pointer)
{
if ( !result_pointer )
return errno = EINVAL;
if ( !fp || !result || !buf )
return *result_pointer = NULL, errno = EINVAL;
int original_errno = errno;
flockfile(fp);
off_t original_offset = ftello(fp);
if ( original_offset < 0 )
{
funlockfile(fp);
return *result_pointer = NULL, errno;
}
size_t buf_used = 0;
int ic;
while ( (ic = fgetc(fp)) != EOF )
{
if ( ic == '\n' )
break;
if ( buf_used == buf_len )
{
fseeko(fp, original_offset, SEEK_SET);
funlockfile(fp);
return *result_pointer = NULL, errno = ERANGE;
}
buf[buf_used++] = (char) ic;
}
if ( ferror(fp) )
{
int original_error = errno;
fseeko(fp, original_offset, SEEK_SET);
funlockfile(fp);
return *result_pointer = NULL, original_error;
}
if ( !buf_used && feof(fp) )
{
funlockfile(fp);
return *result_pointer = NULL, errno = original_errno, 0;
}
if ( buf_used == buf_len )
{
fseeko(fp, original_offset, SEEK_SET);
funlockfile(fp);
return *result_pointer = NULL, errno = ERANGE;
}
buf[buf_used++] = '\0';
if ( false )
{
parse_failure:
fseeko(fp, original_offset, SEEK_SET);
funlockfile(fp);
return errno = EINVAL;
}
if ( false )
{
range_failure:
fseeko(fp, original_offset, SEEK_SET);
funlockfile(fp);
return *result_pointer = NULL, errno = ERANGE;
}
char* parse_str = buf;
if ( !(result->gr_name = next_field(&parse_str)) )
goto parse_failure;
if ( !(result->gr_passwd = next_field(&parse_str)) )
goto parse_failure;
if ( !next_field_gid(&parse_str, &result->gr_gid) )
goto parse_failure;
char* member_string;
if ( !(member_string = next_field(&parse_str)) )
goto parse_failure;
if ( parse_str )
goto parse_failure;
while ( buf_used % alignof(char*) != 0 )
{
if ( buf_used == buf_len )
goto range_failure;
buf_used++;
}
size_t num_members = count_num_members(member_string);
size_t member_list_bytes = (num_members + 1) * sizeof(char*);
size_t available_bytes = buf_len - buf_used;
if ( available_bytes < member_list_bytes )
goto range_failure;
result->gr_mem = (char**) (buf + buf_used);
char* member_parse_str = member_string;
for ( size_t i = 0; i < num_members + 1; i++ )
result->gr_mem[i] = next_member(&member_parse_str);
funlockfile(fp);
return *result_pointer = result, 0;
}