Startpunkten

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2026-03-05 13:31:50 +01:00
commit 86a20ae0e1
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Lab2/lab2.c Normal file
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/*
* Laboration 2 i C och UNIX
*
* Komplett shell
* =========================================
*
* Christian Ohlsson, di7chro@cse.kau.se
* Stefan Sonesson, di7stes@cse.kau.se
*
* Karlstads Universitet, 991209
*
*
*===========================================
*/
#include "lab2.h"
extern treePtr tree;
/*Array med alla inmatningar som gjorts*/
char *symTable[SYMTBLSIZE];
/*Global räknare för symTable*/
int place=0;
/*Kopierar alla WORD & NULL till symTable*/
int insert(char *str){
if(str) symTable[place]=(char*)strdup(str);
else symTable[place]=str;
return place++;
}
/*Rensar symTable*/
void delTable() {
int i=0;
for(i=0 ; i<SYMTBLSIZE ; i++) symTable[i] = NULL;
place=0;
}
/*Exekverar varje kommando som en egen process*/
void cmd(treePtr tPtr) {
int pid, status;
switch(pid=fork()){
case -1: printf("Could not fork. (cmd)\n"); break;
case 0: if((execvp(symTable[tPtr->index], &symTable[tPtr->index])) == -1) {
fprintf(stderr, "Could not execute that.\n");
exit(1); /* Child */
}
exit(1); break;
default: if((waitpid(pid, &status,0)) == -1) { /* Parent */
fprintf(stderr, "Could not wait. (cmd)\n");
return;
/*exit(1);*/
}
break;
}
}
/*Hanterar pipes och ställer om fildescriptorer*/
void pipa(treePtr tPtr) {
int status, pfd[2];
if((pipe(pfd)) == -1) {
fprintf(stderr, "Pipe failed. (pipa) \n");
return;
}
switch(fork()) {
case -1: fprintf(stderr, "Fork failed. (pipa)\n");break;
case 0 : if((dup2(pfd[1], 1)) == -1) { /* Child 1 */
fprintf(stderr, "Could not dup.(pipa)\n");
exit(1);
}
if((close(pfd[0])) == -1) {
fprintf(stderr, "Could not close filedescriptor.(pipa)\n");
exit(1);
}
doTree(tPtr->left);
exit(1); break;
default: /* Parent 1 */
switch(fork()) {
case -1: fprintf(stderr, "Fork failed(pipa)\n");break;
case 0 : if((dup2(pfd[0], 0)) == -1) { /* Child 2 */
fprintf(stderr, "Could not dup(pipa).\n");
exit(1);
}
if((close(pfd[1])) == -1) {
fprintf(stderr, "Could not close filedescriptor.(pipa)\n");
exit(1);
}
doTree(tPtr->right);
exit(1); break;
default: if((close(pfd[0])) == -1) { /* Parent 2 */
fprintf(stderr, "Could not close filedescriptor 0.(pipa)\n");
exit(1);
}
if((close(pfd[1])) == -1) {
fprintf(stderr, "Could not close filedescriptor 1.(pipa)\n");
exit(1);
}
if((wait(&status)) == -1) {
fprintf(stderr, "Could not wait.(pipa)\n");
exit(1);
}
if((wait(&status)) == -1) {
fprintf(stderr, "Could not wait.(pipa)\n");
exit(1);
}
break;
}
break;
}
}
/*Hanterar semikolon, Kör vänster-delen om
semikolonet, och när det är klart körs högerdelen*/
void semi(treePtr tPtr) {
int status;
switch(fork()) {
case -1: fprintf(stderr, "Fork failed. (semi)\n");break;
case 0 : doTree(tPtr->left); /* Child */
exit(1);
break;
default: if((wait(&status)) == -1) { /* Parent */
fprintf(stderr, "Could not wait.(semi)\n");
exit(-1);
}
if(tPtr->right)
doTree(tPtr->right);
break;
}
}
/*Ställer om utmatningsfil från STDOUT till utfil
Om filen finns, trunkeras den*/
void great(treePtr tPtr) {
int fd, status;
if((fd=open(symTable[tPtr->right->index],O_CREAT|O_TRUNC|O_WRONLY, PERMS))==-1) {
fprintf(stderr, "Could not open file. (great)\n");
exit(1);
}
switch(fork()) {
case -1: fprintf(stderr, "Fork failed\n"); break;
case 0 : if((dup2(fd, 1)) == -1) { /* Child */
fprintf(stderr, "Could not dup. (great)\n");
exit(1);
}
doTree(tPtr->left);
exit(1); break;
default: if((wait(&status)) == -1) { /* Parent */
fprintf(stderr, "Could not wait. (great)\n");
exit(1);
}
break;
}
if((close(fd)) == -1) {
fprintf(stderr, "Could not close file. (great)\n");
exit(1);
}
}
/*Ställer om indirigering från STDIN till fil*/
void less(treePtr tPtr) {
int fd, status;
if((fd=open(symTable[tPtr->right->index], O_RDONLY, PERMS))==-1){
fprintf(stderr, "Could not open file (less)\n");
return;
}
switch(fork()) {
case -1: fprintf(stderr, "Fork failed\n"); break;
case 0 : if((dup2(fd, 0)) == -1) { /* Child */
fprintf(stderr, "Could not dup.(less)\n");
exit(1);
}
doTree(tPtr->left);
exit(1); break;
default: if((wait(&status)) == -1) { /* Parent */
fprintf(stderr, "Could not wait.(less)\n");
exit(1);
}
break;
}
if((close(fd)) == -1) {
fprintf(stderr, "Could not close file.(less)\n");
exit(1);
}
}
/*Kör processer utan att de behöver invänta den andre*/
void and(treePtr tPtr) {
int status;
switch(fork()) {
case -1: fprintf(stderr, "Fork failed. (and)\n");break;
case 0: if(tPtr->left) doTree(tPtr->left); /* Child */
exit(0);
break;
default: if(tPtr->right) doTree(tPtr->right); /* Parent */
break;
}
}
/*Ställer om utmatningsfil från STDOUT till utfil
Om filen finns, appendas den*/
void dblarr(treePtr tPtr) {
int fd, status;
if((fd=open(symTable[tPtr->right->index],O_CREAT|O_APPEND|O_WRONLY, PERMS))==-1) {
fprintf(stderr, "Could not open file. (dblarr)\n");
exit(1);
}
switch(fork()) {
case -1: fprintf(stderr, "Fork failed\n"); break;
case 0: if((dup2(fd, 1)) == -1) {
fprintf(stderr, "Could not dup. (dblarr)\n");
exit(1);
}
doTree(tPtr->left);
exit(1); break;
default: if((wait(&status)) == -1) {
fprintf(stderr, "Could not wait. (dblarr)\n");
exit(1);
}
break;
}
if((close(fd)) == -1) {
fprintf(stderr, "Could not close file. (dblarr)\n");
exit(1);
}
}
/*Anropar rätt funktion beroende på metatecken*/
void doTree(treePtr tPtr) {
if(tPtr->nodeType == 0) cmd(tPtr);
if(tPtr->nodeType == PIPE) pipa(tPtr);
if(tPtr->nodeType == SEMI) semi(tPtr);
if(tPtr->nodeType == GREAT) great(tPtr);
if(tPtr->nodeType == LESS) less(tPtr);
if(tPtr->nodeType == AND) and(tPtr);
if(tPtr->nodeType == DBLARR) dblarr(tPtr);
delTable();
}
/*Anropar Lex och Yacc med yyparse och sedan exeveras trädet*/
int main() {
signal(SIGTERM, SIG_IGN);
signal(SIGKILL, SIG_IGN);
signal(SIGCHLD,SIG_IGN);
signal(SIGINT,SIG_IGN);
system("clear");
write(1, "Welcome to WARPshell 1.0\n",26);
while(1) {
fflush(stdout);
write(1,"C:\\> ",5);
yyparse();
if(tree) doTree(tree);
}
return 1;
}