diff --git a/Documents/Program Logic b/Documents/Program Logic
new file mode 100644
index 0000000000000000000000000000000000000000..6439eeb908f025923d92d50381fa9e39b4e49185
--- /dev/null
+++ b/Documents/Program Logic
@@ -0,0 +1,30 @@
+
+Program Logic
+
+
+Pipe - |
+ Takes stdout of item on left and uses as stdin of item on right.
+
+
+Three cases:
+ Pipe on right side:
+ First command in line. Should be handled by original shell.
+
+ Pipe on left side:
+ Last command in line. Original shell should fork this.
+
+ Pipe on both sides:
+ Middle elements.
+ "Base Case" if no more middle items are present after this one.
+
+
+How to handle by recursion:
+ First read command line. Regardless, fork to run at least once process.
+ If multiple piped items, recursion starts:
+ Handle "rightmost" item by sending remaining line, minus item on right.
+ Base Case:
+ If no more values to remove, then done.
+ Next, copy standard out of each "child" into the standard in of each "parent".
+ End recursion. Should handle all values back to initial fork.
+ Copy output of fork to original terminal. Originally forked to ensure that original terminal should never close.
+
diff --git a/Main.c b/Main.c
index 3d0a214b533445d23b2db1da39d7576b886bdd12..b73490997bcc49f086a9b53f41efba71a790ff13 100644
--- a/Main.c
+++ b/Main.c
@@ -33,12 +33,16 @@
// Variables.
+typedef struct{
+ int argc;
+ char*** argv;
+} makeargv_struct;
// Method Declaration.
int makeargv(); // Creates argv using passed line.
void parse_line(); // Parses provided line into commands.
-char** parse_command(); // Parses provided command into subsections.
+makeargv_struct* parse_command(); // Parses provided command into subsections.
void execute_command(); // Executes provided command.
void make_arg_example();
@@ -67,100 +71,81 @@ int main(int argc, char* argv[]) {
*/
void parse_line(char* command_line) {
int index;
- int array_index;
- int string_index;
- int token_number;
- char*** commands;
- char*** line_tokens;
+ int index2;
+ makeargv_struct* line_argv; // Pointer to makeargv struct.
+ makeargv_struct* command_argv; // Pointer to makeargv struct.
printf("Beginning command line parse... ");
- line_tokens = calloc(1, sizeof(char***));
- token_number = makeargv(command_line, "|", line_tokens);
- if (token_number < 0) {
+ // Parse line into struct. Seperates by each found "|" in argument.
+ // Each seperated value should be an individual commmand.
+ line_argv = calloc(1, sizeof(makeargv_struct));
+ line_argv->argv = calloc(1, sizeof(char***));
+ line_argv->argc = makeargv(command_line, "|", line_argv->argv);
+
+ // Check for errors.
+ if (line_argv->argc < 0) {
err_sys("Unexpected error parsing command line.");
}
- printf("%d tokens found.\n", token_number);
- commands = calloc(token_number, sizeof(char***));
-
- // Check for multiple tokens within command line.
- if (token_number == 1) {
- // Only one command line token. Probably can be added into the
- // "multi-token" section below, but it's easier to separate so
- // that "simple" case logic can be worked out first.
-
- // Get arguments of individual command.
- *commands = parse_command(**line_tokens);
- printf("%s ", **commands);
- if (*(*commands + 1) != NULL) {
- printf("%s\n", *(*commands + 1));
- } else {
- printf("\n");
- }
+ printf("%d tokens found.\n", line_argv->argc);
+ command_argv = calloc(1, sizeof(makeargv_struct));
+ command_argv->argv = calloc(1, sizeof(char***));
- execute_command(*commands);
+ // For each argument above, parse again.
+ // This will separate the individual arguments of each given command.
+ index = 0;
+ while (index < line_argv->argc) {
- free(**commands);
- free(*(*commands + 1));
- free(*commands);
- } else if (token_number > 1) {
- // Multiple command line tokens detected.
- index = 0;
+ printf("%s\n", (**(line_argv->argv + index)));
+ command_argv->argc = makeargv((**(line_argv->argv)), " ", command_argv->argv);
- // Separate token values and hold within array of arrays of strings.
- while (*(*line_tokens + index) != NULL) {
- //printf("%s ", (*(*line_tokens + index)));
+ // Check for errors.
+ if (command_argv->argc < 0) {
+ err_sys("Unexpected error parsing command line.");
+ }
- *(commands + index) = parse_command(*(*line_tokens + index));
- printf("%s ", **(commands + index));
- printf("%s\n", *(*(commands + index) + 1));
- index++;
+ index2 = 0;
+ while (index2 < command_argv->argc) {
+ printf("%s ", (*(*command_argv->argv + index2)));
+ index2++;
}
printf("\n");
- // Free used memory.
- array_index = 0;
- while (array_index < token_number) {
- string_index = 0;
- while (string_index < 2) {
- free(*(*(commands + array_index) + string_index));
- //printf("%s\n", *(*(commands + array_index) + string_index));
- string_index++;
- }
- free(*(commands + array_index));
- // printf("%s\n", *(commands + array_index));
- array_index++;
- }
+ execute_command(*command_argv->argv);
+ index++;
}
+ // Free memory.
+ index = 0;
+ while (index < line_argv->argc) {
+ free(*(*(line_argv->argv + index)));
+ free(*(line_argv->argv + index));
+ index2 = 0;
+ // // Not needed?
+ // while (index2 < command_argv->argc) {
+ // //printf("%s ", (*(*command_argv->argv + index2)));
+ // free(*(*command_argv->argv + index2));
+ // index2++;
+ // }
+ free(*(*command_argv->argv + index2));
+ free(*(command_argv->argv + index));
+ index++;
+ }
+ if (line_argv->argc == 0) {
+ free(*line_argv->argv);
+ }
- free(commands);
- free(**line_tokens);
- free(*line_tokens);
- free(line_tokens);
- printf("\n");
- printf("\n");
+ free(command_argv->argv);
+ free(line_argv->argv);
+ free(command_argv);
+ free(line_argv);
}
/**
- * Parses an individual command by separating command from args.
- *
- * Returns a string array of parsed command items.
+ * Takes provided command and runs appropriately.
*/
-char** parse_command(char* command) {
- char** command_arguments;
- printf("Beginning command parse...\n");
-
- command_arguments = calloc(2, sizeof(char**));
- *command_arguments = copy_string(strtok(command, " "));
- *(command_arguments + 1) = copy_string(strtok(NULL, ""));
-
- return command_arguments;
-}
-
-
void execute_command(char** command) {
int status;
int fd[2];
@@ -181,11 +166,14 @@ void execute_command(char** command) {
// ls with one arg example.
//execlp("ls", "ls", "-l", (char*) NULL);
- if (*(command + 1) != NULL) {
- execlp(*command, *command, *(command + 1), (char*) NULL);
- } else {
- execlp(*command, *command, (char*) NULL);
- }
+ // execlp example.
+ // if (*(command + 1) != NULL) {
+ // execlp(*command, *command, *(command + 1), (char*) NULL);
+ // } else {
+ // execlp(*command, *command, (char*) NULL);
+ // }
+
+ execvp(*command, command);
err_sys("Child execution did not work.");
break;
@@ -196,7 +184,7 @@ void execute_command(char** command) {
close(fd[0]); // Parent does not need this.
printf("IMA PARENT.\n");
wait(&status); // Wait for child process to end.
- printf("\nOh, he ded. No longer a parent.\n");
+ printf("\nOh, he ded. No longer a parent.\n\n");
break;
}
}