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/**
* slibc — Yet another C library
* Copyright © 2015 Mattias Andrée (maandree@member.fsf.org)
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include <slibc-human.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>
/**
* Convert file permission from machine representation to human representation.
*
* @param buffer Sufficiently large buffer for the output, or `NULL`.
* 18 characters is always sufficient, regardless of `mode`.
* @param perm Machine representation of the permissions, will be masked with 07777.
* @param mode Representation style, 0 for default.
* @return Human representation of the file permissions, `NULL` on error.
* On success, the caller is responsible for deallocating the
* returned pointer, if and only if `buffer` is `NULL`.
*
* @throws EINVAL If `mode` is invalid.
* @throws ENOMEM The process cannot allocate more memory.
*
* @since Always.
*/
char* humanmode(char* restrict buffer, mode_t perm, enum humanmode_mode mode)
{
mode_t perm_ = perm | (mode != HUMANMODE_MASK ? 07777 : 0);
int name = mode & HUMANMODE_MASK;
char* w;
if (mode & ~(mode_t)3)
return errno = EINVAL, NULL;
if (!mode)
mode = HUMANMODE_STAT;
if (buffer == NULL)
buffer = malloc((mode == HUMANMODE_STAT ? 10 : 18) * sizeof(char));
if (buffer == NULL)
return NULL;
w = buffer;
if (name) *w++ = 'u', *w++ = '=';
if (perm_ & S_IRUSR) *w++ = (perm & S_IRUSR) ? 'r' : '-';
if (perm_ & S_IWUSR) *w++ = (perm & S_IWUSR) ? 'w' : '-';
if (perm & S_ISUID) *w++ = (perm & S_IXUSR) ? 's' : 'S';
else if (perm_ & S_IXUSR) *w++ = (perm & S_IXUSR) ? 'x' : '-';
if (name) *w++ = ',', *w++ = 'g', *w++ = '=';
if (perm_ & S_IRGRP) *w++ = (perm & S_IRGRP) ? 'r' : '-';
if (perm_ & S_IWGRP) *w++ = (perm & S_IWGRP) ? 'w' : '-';
if (perm & S_ISGID) *w++ = (perm & S_IXGRP) ? 's' : 'S';
else if (perm_ & S_IXGRP) *w++ = (perm & S_IXGRP) ? 'x' : '-';
if (name) *w++ = ',', *w++ = 'o', *w++ = '=';
if (perm_ & S_IROTH) *w++ = (perm & S_IROTH) ? 'r' : '-';
if (perm_ & S_IWOTH) *w++ = (perm & S_IWOTH) ? 'w' : '-';
if (perm & S_ISVTX) *w++ = (perm & S_IXOTH) ? 't' : 'T';
else if (perm_ & S_IXOTH) *w++ = (perm & S_IXOTH) ? 'x' : '-';
return *w = 0, buffer;
}
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