Semi working - garbedge in args**

This commit is contained in:
Sagi Dayan 2014-03-25 15:20:44 +02:00
commit 5a7914e9d7
4 changed files with 250 additions and 0 deletions

41
Makefile Normal file
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# Sagi Dayan - Makefile
#
# compiler
CC=gcc
# compile arguments
CFLAGS+=-c -g -Wall
# linker flags
LDFLAGS+=
# libraries
LIBS+=
# our source files
SOURCES=main.c
# a macro to define the objects from sources
OBJECTS=$(SOURCES:.c=.o)
# executable name
EXECUTABLE=myTerminal
$(EXECUTABLE): $(OBJECTS)
@echo "Building target" $@ "..."
$(CC) $(LDFLAGS) $(OBJECTS) -o $@ $(LIBS)
@echo "Done!"
# a rule for generating object files given their c files
.c.o:
@echo "Compiling" $< "..."
$(CC) $(CFLAGS) $< -o $@
@echo "Done!"
clean:
@echo "Ceaning up *.o Files..."
rm -rf *s *o $(EXECUTABLE)
@echo "Done!"
.PHONY: all clean

209
main.c Normal file
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#include <unistd.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define LEN 512
#define PATH "/bin/"
#define ERROR -1
#define EXIT_1 256
int getHostName(char* host);
int getUserName(char* name);
int runExec(char** args);
void PrintTokens (char** tokens);
char** ReadTokens(FILE* stream) ;
void FreeTokens(char** tokens) ;
void checkIfQuit(char* word);
int main()
{
int exitCode = 0;
char* host_n = (char *)malloc(sizeof(char));
char* user_n = (char *)malloc(sizeof(char));
char** args;
if(getHostName(host_n) == ERROR)
goto quit;
if(getUserName(user_n) == ERROR)
goto quit;
while(1)
{
printf("%d %s@%s$ ",exitCode, user_n, host_n);
args = ReadTokens(stdin);
if(args != NULL)
{
exitCode = runExec(args);
FreeTokens(args); //in case of error while trying to create process - this method will free the memory already
if(exitCode == ERROR)
goto quit;
}
}
quit:
free(host_n);
free(user_n);
return 0;
}
int getHostName(char* host)
{
if(gethostname(host, 10) != 0)
{
fprintf(stderr, "%s\n", "Error: while getting host name");
return -1;
}
return 0;
}
int getUserName(char* name)
{
if(getlogin_r(name, 10) != 0)
{
fprintf(stderr, "%s\n", "Error: while getting User name");
return ERROR;
}
return 0;
}
/**
* This function will atempt to create a new Process.
* and will return the exit status code of the child
* @param args - an array of strings that contains all the arguments from the user
* @return int - exit status of child
*/
int runExec(char** args)
{
int status;
pid_t pid;
char* path = (char *)malloc(sizeof(char));
strcpy(path, PATH);
strcat(path, args[0]);
pid = fork();
if(pid < 0)
{
fprintf(stderr, "%s\n", "Error: Could not create a new process");
return ERROR;
}
else if(pid == 0) // child
{
if(execv(path, args) != 0)
{
fprintf(stderr, "%s%s%s\n", "myTerminal: ", args[0] ,": command not found");
exit(1); //child error - chield needs to be closed manually. exit code 225;
}
}
else //pid > 0 father
waitpid(pid,&status,0);
free(path);
if(status == EXIT_1) //in my computer exit(1) returns 256 - ex demands wanted 255
return status-1;
return status;
}
/**
* this func will read a full line and will store all the arguments in an array (of char*).
* if the line will have only 1 word - it will call afunction to check if the word is "quit".
*
* @param stream FILE* - in our case stdin
* @return if all went well , an Array of arguements from the input line.
*/
char** ReadTokens(FILE* stream)
{
char** returnArr;
char input[LEN]; // the var to hold the line
char temp[LEN]; // will be a copy of the input line - so we can figure how many words we have
int wordCnt = 0; // word counter
int i = 0; //index for second iteration
fgets(input, LEN, stream); // get the linei
strcpy(temp, input); // copy the line
//strkot first iteration to count words (corrups temp var)
char* tok;
tok = strtok(temp," \n");
while (tok != NULL)
{
wordCnt++;
tok = strtok(NULL, " \n");
}
if(wordCnt == 0) //if there are no "words" in input - return null
return NULL;
returnArr = (char**)malloc((wordCnt + 1)*sizeof(char*)); //allocates the memory for the array
if(returnArr == NULL) //check if the malloc func finished successfuly
{
fprintf(stderr,"%s\n", "ERROR: unable to allocate memory.");
exit(1);
}
//strtok second iteration - puts all words in an index of the array
tok = strtok(input," \n");
while (tok != NULL)
{
returnArr[i] = tok;
if(wordCnt == 1)
checkIfQuit(tok);
tok = strtok(NULL, " \n");
i++;
}
returnArr[wordCnt] = NULL; // the last index will be NULL - so we know where the end is.
return returnArr;
}
/**
* if there is only one word in the input nile the ReadTokens func will call this func.
* it will check if user want to exit our program
*
* @param word - the one word to check
*/
void checkIfQuit(char* word)
{
if(strcmp(word, "quit") == 0)
exit(0);
}
/**
* this func will print an array of char*, it will know when to finish if the
* last index is NULL!
* @param tokens - char* Array
*/
void PrintTokens (char** tokens)
{
int i;
for (i = 0; tokens[i] != NULL; i++)
{
printf("%s\n", tokens[i]);
}
}
/**
* this will make sure no memory leeks will occurd.
* runs through all indexes change them to null and then free them.
* after that it will fraa the array pinter itself.
* @param tokens - an array to free
*/
void FreeTokens(char** tokens)
{
int i = 0;
while(tokens[i] != NULL) // free all the indexes except the last one (NULL)
{
tokens[i] = NULL;
free(tokens[i]);
i++;
}
free(tokens[i]); // free the last index
tokens = NULL; // free the array
free(tokens);
}

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main.o Normal file

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BIN
myTerminal Executable file

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