feat(command): commands are executed

src/command.c

@@ -0,0 +1,17 @@
+#include "command.h"
+
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "parse.h"
+
+unsigned char invoke(struct Args args) {
+  pid_t child = fork();
+  if (child == 0 && args.argc > 0) {
+    execvp(args.argv[0], args.argv);
+    return 1;
+  }
+  waitpid(child, NULL, 0);
+
+  return 0;
+}

src/command.h

@@ -0,0 +1,8 @@
+#ifndef COMMAND_H
+#define COMMAND_H
+
+#include "parse.h"
+
+unsigned char invoke(struct Args args);
+
+#endif /* COMMAND_H */

src/main.c

@@ -1,16 +1,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "command.h"
+#include "parse.h"
 #include "reader.h"
 
 int main() {
-  /*
-  size_t buffer_size;
-  size_t initial_buffer_size = 64;
-  char *input_buffer;
-  char *initial_buffer_position;
-  unsigned int how_many_characters_to_read;
-  */
   char *input_line;
 
   while (1) {
@@ -20,32 +15,9 @@ int main() {
       return 0;
     }
 
-    printf("command: '%s'\n", input_line);
-
+    struct Args args = parse(input_line);
     free(input_line);
-    /*
-    buffer_size = initial_buffer_size;
-    how_many_characters_to_read = buffer_size + 1;
-    input_buffer = malloc(how_many_characters_to_read);
-    initial_buffer_position = input_buffer;
 
-    printf("shell> ");
-    while (fgets(input_buffer, how_many_characters_to_read, stdin) != NULL &&
-           input_buffer[strlen(input_buffer) - 1] != '\n') {
-      size_t new_buffer_size = buffer_size * 2;
-      if (buffer_size != initial_buffer_size) {
-        how_many_characters_to_read = buffer_size + 1;
-      }
-      input_buffer = realloc(initial_buffer_position, new_buffer_size + 1);
-      initial_buffer_position = input_buffer;
-      input_buffer += buffer_size;
-      buffer_size = new_buffer_size;
-    }
-    input_buffer = initial_buffer_position;
-
-    printf("%s", input_buffer);
-
-    free(input_buffer);
-    */
+    invoke(args);
   }
 }

src/parse.c

@@ -0,0 +1,53 @@
+#include "parse.h"
+
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define ARGV_INIT_SIZE 4
+
+void add_arg(struct Args *args, char *arg_ptr, unsigned int arg_length) {
+  if (args->argv_size == 0) {
+    args->argv_size = ARGV_INIT_SIZE;
+    args->argv = malloc(args->argv_size * sizeof(char *));
+  }
+
+  if (args->argc == args->argv_size) {
+    args->argv_size *= 2;
+    args->argv = realloc(args->argv, sizeof(char *) * args->argv_size);
+  }
+
+  char *arg = malloc(arg_length + 1);
+  strncpy(arg, arg_ptr, arg_length);
+
+  args->argv[args->argc] = arg;
+  args->argc++;
+}
+
+void parse_worker(struct Args *args, char *arg_position,
+                  unsigned int arg_length, char *line) {
+  if (line[0] == '\n') {
+    if (arg_length != 0) {
+      add_arg(args, arg_position, arg_length);
+    }
+    return;
+  } else if (isspace(line[0])) {
+    add_arg(args, arg_position, arg_length);
+    while (line[0] != '\n' && isspace(line[0])) {
+      line++;
+    }
+    parse_worker(args, line, 0, line);
+  } else {
+    parse_worker(args, arg_position, arg_length + 1, line + 1);
+  }
+}
+
+struct Args parse(char *line) {
+  struct Args args;
+  args.argc = 0;
+  args.argv_size = 0;
+
+  parse_worker(&args, line, 0, line);
+
+  return args;
+}

src/parse.h

@@ -0,0 +1,16 @@
+#ifndef PARSE_H
+#define PARSE_H
+
+#include <sys/types.h>
+
+struct Args {
+  unsigned int argc;
+  size_t argv_size;
+  char **argv;
+};
+
+void add_arg(struct Args *args, char *arg_ptr, unsigned int arg_length);
+void parse_worker(struct Args *args, char *arg_position, unsigned int arg_length, char *line);
+struct Args parse(char *line);
+
+#endif /* PARSE_H */

src/reader.c

@@ -28,6 +28,7 @@ char *read_a_line(FILE *file_to_read) {
   if (!feof(file_to_read)) {
     return input_buffer;
   } else {
+    free(input_buffer);
     return NULL;
   }
 }