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/* [ - evaluate expression
* Copyright (C) 2022 Ferass EL HAFIDI
*
* 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 <https://www.gnu.org/licenses/>.
*/
#define _POSIX_C_SOURCE 200809L
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <libgen.h>
#include <sys/stat.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
int getopt(int argc, char *const argv[], const char *optstring);
void printUsage();
/* For readability reasons, define true, false */
int true = 0;
int false = 1;
int main(int argc, char *argv[]) {
int argument;
char param[256];
struct stat file_status;
for (int i = 0; i < 256; i++) param[i] = 0;
if (!strcmp(basename(argv[0]), "[")) {
if (strcmp(argv[argc - 1], "]")) {
/* FIXME: Is printing an error message POSIX-compliant? */
fprintf(stderr, "[: No matching ]\n");
return 1;
}
argc--;
argv[argc] = 0;
}
if (argc < 2) return false;
if (!strcmp(argv[1], "!")) {
true = 1;
false = 0;
argc--;
argv++;
}
if (argc == 3) {
param[(uint8_t)argv[1][1]] = argv[1][1];
/* Files */
stat(argv[2], &file_status);
if (!errno) {
if (param['b'] && S_ISBLK(file_status.st_mode) != 0) return true;
else if (param['c'] && S_ISCHR(file_status.st_mode) != 0) return true;
else if (param['d'] && S_ISDIR(file_status.st_mode) != 0) return true;
/* Just return true, if -e is used. If it was false, stat() would
* have failed. If it failed, there's a check about which value
* to return. Return false if -e is used, otherwise, return errno
*/
else if (param['e']) return true;
else if (param['f'] && S_ISREG(file_status.st_mode) != 0) return true;
else if (param['g'] && file_status.st_mode & S_ISGID) return true;
else if ((param['h'] || param['L'])
&& S_ISLNK(file_status.st_mode) != 0) return true;
else if (param['p'] && S_ISFIFO(file_status.st_mode) != 0) return true;
/* TODO: Better check for -r/-w. */
else if (param['r'] && (file_status.st_mode & S_IRUSR
|| file_status.st_mode & S_IROTH)) return true;
else if (param['S'] && S_ISSOCK(file_status.st_mode) != 0) return true;
else if (param['s'] && file_status.st_size > 0) return true;
else if (param['u'] && S_ISDIR(file_status.st_mode)
&& file_status.st_mode & S_ISUID) return true;
else if (param['w'] && (file_status.st_mode & S_IWUSR
|| file_status.st_mode & S_IWOTH)) return true;
else if (param['x'] && (file_status.st_mode & S_IXUSR
|| file_status.st_mode & S_IXOTH)) return true;
}
else if (errno && param['e']) return false;
if (param['t']) {
if (isatty(strtol(argv[2], NULL, 10))) return true;
else return false;
}
/* Strings */
if (param['n'] && strlen(argv[2])) return true;
else if (param['z'] && !strlen(argv[2])) return true;
}
else if (argc == 4) {
if (!strcmp(argv[2], "=") && !strcmp(argv[1], argv[3])) return true;
else if (!strcmp(argv[2], "!=") && strcmp(argv[1], argv[3])) return true;
else if (!strcmp(argv[2], "-eq") && !strcmp(argv[1], argv[3])) return true;
else if (!strcmp(argv[2], "-ne") && strcmp(argv[1], argv[3])) return true;
else if (!strcmp(argv[2], "-gt") &&
strtol(argv[1], NULL, 10) > strtol(argv[3], NULL, 10)) return true;
else if (!strcmp(argv[2], "-ge") &&
strtol(argv[1], NULL, 10)>= strtol(argv[3], NULL, 10)) return true;
else if (!strcmp(argv[2], "-lt") &&
strtol(argv[1], NULL, 10) < strtol(argv[3], NULL, 10)) return true;
else if (!strcmp(argv[2], "-le") &&
strtol(argv[1], NULL, 10)<= strtol(argv[3], NULL, 10)) return true;
}
/* TODO: Better error handling. */
return false;
}
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