116 lines
2.5 KiB
C
116 lines
2.5 KiB
C
/*
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* Copyright 2011 Marian Ohligs, Chair for Operating Systems,
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* RWTH Aachen University
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <ctype.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#undef errno
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extern int errno;
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void showlogo() {
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printf("\n\n");
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printf("================================================================================\n");
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printf(" m(etalsvm)shell\n\n");
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printf("================================================================================\n");
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}
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void help() {
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printf("possible commands: \n");
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printf("exit > exit shell \n");
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}
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#define MAXARGS 16
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#define ST_WHITE 0
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#define ST_ARG 1
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char** splitargs(char* args) {
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static char* ret[MAXARGS+1];
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int i = 0;
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int state = ST_WHITE;
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while (*args != '\0') {
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if (state == ST_WHITE) {
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if (!isspace(*args)) {
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ret[i++] = args;
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if (i == MAXARGS)
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break;
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state = ST_ARG;
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}
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}
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else {
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if (isspace(*args)) {
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*args = '\0';
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state = ST_WHITE;
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}
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}
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args++;
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}
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ret[i] = NULL;
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return ret;
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}
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int main(int argc, char** argv)
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{
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char commandline[1024];
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char* command;
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int size = 0, status = 0;
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pid_t pid;
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system("clear");
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showlogo();
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while(1) {
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char** newargv;
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char* newenv[] = {"USER=root", "PATH=/bin:/sbin:/usr/bin", "PWD=/", "TEMP=/tmp", NULL};
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printf("mshell> ");
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gets(commandline);
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newargv = splitargs(commandline);
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command = newargv[0];
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if(command == NULL) {
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continue;
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}
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if(!strcmp(command, "exit")) {
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return 0;
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}
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if(!strcmp(command, "help")) {
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help();
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} else {
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char path[128];
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sprintf(path, "/bin/%s", command);
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pid = fork();
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if (pid == 0) { //child
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status = execve(path, newargv, newenv);
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if (status)
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printf("mshell: %s: command not found\n", path);
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return errno;
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} else {
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wait(&status);
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}
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}
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}
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return errno;
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}
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