/*
* For some reason arguments passed to kernel are not correctly splitted
* in argv array - in our case all arguments are stored in one string argv[1],
* but we want to keep every argument in separate argv entry. This function
* tokenize all argv strings and store every single token into individual entry
* of new array.
*
* For our needs we also convert passed environment variables and put them
* into new argv array.
*
* Example:
*
* For arguments:
* argc=3;
* argv={"test.elf", "arg1 arg2=val arg3=foobar ", " init=/bin/sh "};
* envp={"memsize", "128MiB", "uart.speed", "115200"};
*
* instruction:
* setup_kenv(argc, argv, envp);
*
* will set global variable _kenv as follows:
* _kenv.argc=5;
* _kenv.argv={"test.elf", "arg1", "arg2=val", "arg3=foobar",
* "init=/bin/sh", "memsize=128MiB", "uart.speed=115200"};
*/
static void setup_kenv(int argc, char **argv, char **envp) {
unsigned ntokens = 0;
for (int i = 0; i < argc; ++i)
ntokens += count_tokens(argv[i]);
for (char **pair = envp; *pair; pair += 2)
ntokens++;
_kenv.argc = ntokens;
char **tokens = kernel_sbrk(ntokens * sizeof(char *));
_kenv.argv = tokens;
for (int i = 0; i < argc; ++i)
tokens = extract_tokens(argv[i], tokens);
for (char **pair = envp; *pair; pair += 2)
*tokens++ = make_pair(pair[0], pair[1]);
}
/* main */
int main() {
bool exit_flag = false;
int oldest_history = HISTORY_SIZE - 1,
status;
char *username,
input[MAX_INPUT_SIZE],
history[HISTORY_SIZE][MAX_INPUT_SIZE] = {'\0'},
*tokens[CMD_MAX];
signal(SIGINT, handle_sigint);
//shell loop
while(!exit_flag) {
//print the prompt and get the input
printf("%s> " , get_username());
fgets(input, MAX_INPUT_SIZE, stdin);
format_input(input);
//built-in exit function
if(!strcmp(input, "exit")) exit_flag = true;
//built-in history function
else if(!strcmp(input, "history")) {
int i;
for(i = oldest_history+1; i!=oldest_history; i = (i+1)%HISTORY_SIZE) {
if(history[i][0] != '\0') printf("%s\n", history[i]);
}
}
//non-built-in function
else if(strcmp(input, "")) {
int token_index,
num_tokens;
pid_t pid;
char *tokens[CMD_MAX];
//get the token list and size
num_tokens = make_tokenlist(input, tokens);
//fork a child process
pid = fork();
//parent: wait for child to finish
if(pid > 0) {
pid = wait(&status);
}
//child: execute command
if(pid == 0) {
//redirect output
token_index = contains_token(tokens, num_tokens, ">");
if(token_index >= 0 && token_index+1 < num_tokens) {
int fd_o = open(tokens[token_index+1], O_CREAT|O_TRUNC|O_WRONLY, 0644);
if(dup2(fd_o, STDOUT_FILENO)<0) {
perror("dup2 error");
exit(EXIT_FAILURE);
}
close(fd_o);
//remove ">" and the output file from the list of arguments
tokens[token_index ] = '\0';
tokens[token_index+1] = '\0';
}
//redirect input
token_index = contains_token(tokens, num_tokens, "<");
if(token_index >= 0 && token_index+1 < num_tokens) {
int fd_i = open(tokens[token_index+1], O_RDONLY);
dup2(fd_i, STDIN_FILENO);
close(fd_i);
//remove "<" and the input file from the list of arguments
tokens[token_index ] = '\0';
tokens[token_index+1] = '\0';
}
//handle pipe
int num_pipes = count_pipes(tokens, num_tokens);
if(num_pipes > 0) {
//get the indices of the pipes to extract the commands
int pipe_indices[CMD_MAX];
get_pipe_indices(tokens, num_tokens, pipe_indices);
//extract all the commands
char *commands[CMD_MAX][CMD_MAX];
for(int i=0; i<=num_pipes; i++) {
extract_tokens(tokens, commands[i], pipe_indices[i]+1, pipe_indices[i+1]);
}
//connect and run all the pipe commands
int fds[2],
in = STDIN_FILENO;
for(int i=0; i<num_pipes; i++) {
pipe(fds);
execute_piped_process(in, fds[1], commands[i]);
close(fds[1]);
in = fds[0];
}
//execute the last command
if(in != STDIN_FILENO) dup2(in, STDIN_FILENO);
execvp(commands[num_pipes][0], commands[num_pipes]);
}
//execute command
execvp(tokens[0], tokens);
printf("%s: invalid command\n", tokens[0]);
exit(EXIT_FAILURE);
}
}
//update history
if(strcmp(input, "") && status==0) {
strcpy( history[oldest_history], input );
oldest_history--;
if(oldest_history < 0) oldest_history = HISTORY_SIZE - 1;
}
}
}
int main (int argc, char *argv[]) {
char buffer[10000];
token tokens[500];
int t; //total number of tokens
int i; //general use counter
int res;
FILE *fp;
if (argc < 2) { //check if the number of arguments is correct
printf("Usage: %s <input_file> -o <output_file>\n", argv[0]);
return 1;
}
else if ((fp = fopen(argv[1], "r")) == NULL) { //try to open the input file
printf("%s\n", strerror(errno));
return 2;
}
else {
/*Phase 0: Put instuctions from the input file to the buffer serialized*/
res = serialize_input(buffer, fp);
/*If is on DEBUG_MODE print debuggin info*/
if (DEBUG_MODE) {
printf("Phase 0: Put instuctions from the input file to the buffer serialized:\n%s\n\n", buffer);
}
close(fp);
if (res == 0) {
puts("Empty input file.");
return 3;
}
}
/*Phase 1: Parse the code*/
validate_tokens(buffer);
/*If is on DEBUG_MODE print debuggin info*/
if (DEBUG_MODE) {
printf("Phase 1: Remove lines with invalid tokens:\n%s\n\n", buffer);
}
/*Phase 2: Extract the tokens*/
t = extract_tokens(buffer, tokens);
/*If is on DEBUG_MODE print debuggin info*/
if (DEBUG_MODE) {
puts("Phase 2: Extract the tokens:");
print_tokens(tokens, t);
putchar('\n');
}
/*Phase 3: Do syntax analysis on the tokens*/
t = analize_tokens(tokens, t);
/*If is on DEBUG_MODE print debuggin info*/
if (DEBUG_MODE) {
puts("Phase 3: Do syntax analysis on the tokens:");
print_tokens(tokens, t);
putchar('\n');
}
/*Phase 4: Do optimization on the tokens*/
t = optimize_tokens(tokens, t);
/*If is on DEBUG_MODE print debuggin info*/
if (DEBUG_MODE) {
puts("Phase 4: Do optimization on the tokens:");
print_tokens(tokens, t);
putchar('\n');
}
/*Phase 5: Do code generation based on the tokens*/
generate_code(buffer, tokens, t);
/*If is on DEBUG_MODE print debuggin info*/
if (DEBUG_MODE) {
printf("Phase 5: Do code generation based on the tokens:\n%s\n\n", buffer);
}
/*Print errors buffer*/
if (error_cnt != 0) {
puts(error_buffer);
}
else {
puts("No Errors");
}
/*Final Phase: Save the code in a file*/
if (argc == 4 && strcmp(argv[2], "-o") == 0) { //check if user provided output file name
save_code(buffer, argv[3]);
}
else {
save_code(buffer, "out.c");
}
return 0;
}
