Shell-II releaseshell-II

Implementation of launching external programs via fork().
Running cd as a change to the current process directory (chdir).
Ability to change to user's home directory (cd without arguments).

4 files changed, 109 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index 671c740..0fc988b 100644
--- a/Makefile
+++ b/Makefile
@@ -3,12 +3,12 @@ OBJMODULES = $(SRCMODULES:.c=.o)
 CC = gcc
 CFLAGS = -Wall -g -c
 
-all: shell1
+all: shell-II
 
 %.o: %.с %.h
 	$(CC) $(CFLAGS) $< -o $@
 
-shell1: $(OBJMODULES)
+shell-II: $(OBJMODULES)
 	$(CC) $(LIBS) $^ -o $@
 
 -include deps.mk
diff --git a/queue.c b/queue.c
index 861f1e5..eed3cf8 100644
--- a/queue.c
+++ b/queue.c
@@ -33,6 +33,7 @@ void queue_clear(struct queue *q)
     q->last = NULL;
 }
 
+#if 0
 void queue_processing(const struct queue *q, void (*callback)(char*))
 {
     struct word_item *tmp;
@@ -42,3 +43,22 @@ void queue_processing(const struct queue *q, void (*callback)(char*))
         tmp = tmp->next;
     }
 }
+#endif
+
+int queue_get_word_count(const struct queue *q)
+{
+    struct word_item *tmp;
+    int counter;
+    for(counter = 0, tmp = q->first; tmp; tmp = tmp->next, ++counter)
+    {}
+    return counter;
+}
+
+void queue_copy_words_to_args(const struct queue *q, char **cmdline)
+{
+    struct word_item *tmp;
+    int mas_idx;
+    for(tmp = q->first, mas_idx = 0; tmp; tmp = tmp->next, ++mas_idx)
+        cmdline[mas_idx] = tmp->word;
+    cmdline[mas_idx] = NULL;
+}
diff --git a/queue.h b/queue.h
index db8ac54..fedcd0b 100644
--- a/queue.h
+++ b/queue.h
@@ -14,6 +14,10 @@ struct queue {
 void queue_init(struct queue *q);
 void queue_push(struct queue *q, char *word);
 void queue_clear(struct queue *q);
+#if 0
 void queue_processing(const struct queue *q, void (*callback)(char*));
+#endif
+int queue_get_word_count(const struct queue *q);
+void queue_copy_words_to_args(const struct queue *q, char **cmdline);
 
 #endif
diff --git a/shell.c b/shell.c
index f635c12..a1b5b29 100644
--- a/shell.c
+++ b/shell.c
@@ -2,6 +2,9 @@
 #include "dynamic_array.h"
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/wait.h>
 
 enum modes { word_separation, whole_word };
 enum {
@@ -57,7 +60,8 @@ static int is_double_quotes_pair(struct param_type params)
 
 static int check_separation(int ch, struct param_type params)
 {
-    return (ch == whitespace || ch == tab) && params.is_word && !params.escape_sequences;
+    return (ch == whitespace || ch == tab) && params.is_word &&
+            !params.escape_sequences;
 }
 
 static int ignore_spaces(int ch, struct param_type params)
@@ -87,6 +91,7 @@ static void add_word(struct queue *word_chain,
     params->is_word = 0;
 }
 
+#if 0
 static void print_word(char *word)
 {
     putchar('[');
@@ -101,6 +106,77 @@ static void print_line(const struct queue *word_chain)
 {
     queue_processing(word_chain, print_word);
 }
+#endif
+
+static char** create_cmdline(const struct queue *word_chain,
+                                   int word_counter)
+{
+    char **cmdline = malloc((word_counter + 1) * sizeof(char*));
+    queue_copy_words_to_args(word_chain, cmdline);
+    return cmdline;
+}
+
+static int check_cd(const char *arg)
+{
+    return !strcmp(arg, "cd");
+}
+
+static void change_directory(char **cmdline)
+{
+    int result;
+    char *first_arg = cmdline[1];
+    char *path = NULL;
+    /* change to user home directory */
+    if(first_arg == NULL) {
+        path = getenv("HOME");
+        if(!path) {
+            perror("I don't know where's your home...");
+            return;
+        }
+    } else {
+        if(cmdline[2]) {
+            perror("cd: too many arguments");
+            return;
+        }
+        path = first_arg;
+    }
+    result = chdir(path);
+    if(result == -1)
+        perror(path);
+}
+
+static void clean_up_memory(struct queue *word_chain, char **cmdline)
+{
+    queue_clear(word_chain);
+    free(cmdline);
+}
+
+static void run_external_program(struct queue *word_chain)
+{
+    int pid, result;
+    char **cmdline = create_cmdline(word_chain,
+                                    queue_get_word_count(word_chain));
+    if(check_cd(cmdline[0])) {
+        change_directory(cmdline);
+        clean_up_memory(word_chain, cmdline);
+    }
+    else {
+        pid = fork();
+        if(pid == -1) {
+            perror("fork error");
+            exit(1);
+        }
+        /* child process  */
+        if(pid == 0) {
+            execvp(cmdline[0], cmdline);
+            perror(cmdline[0]);
+            exit(1);
+        }
+        /* parent process */
+        wait(&result);
+        clean_up_memory(word_chain, cmdline);
+    }
+}
 
 static void new_line_processing(struct param_type *params,
                                 enum modes *current_mode,
@@ -119,14 +195,18 @@ static void new_line_processing(struct param_type *params,
             dynarr_push_back(tmp_word, '\0');
         add_word(word_chain, tmp_word, params);
     }
+    run_external_program(word_chain);
+#if 0
     print_line(word_chain);
+#endif
     prepare_new_line(params, current_mode, word_chain, tmp_word);
     show_invitation();
 }
 
 static int is_empty_word(int ch, struct param_type params)
 {
-    return (ch == whitespace || ch == tab) && !params.is_word && params.empty_word_flag;
+    return (ch == whitespace || ch == tab) && !params.is_word &&
+            params.empty_word_flag;
 }
 
 static void word_separation_processing(int ch, struct param_type *params,
@@ -198,6 +278,7 @@ static void whole_word_processing(int ch, struct param_type *params,
     if(escape_double_quotes_or_backslash(ch, *params)) {
         dynarr_push_back(tmp_word, ch);
         params->escape_sequences = 0;
+        params->is_word = 1;
         return;
     }
     if(start_escape_sequence(ch, *params)) {
@@ -235,7 +316,6 @@ int main()
                                   &tmp_word);
     }
     putchar(new_line);
-    queue_clear(&word_chain);
     dynarr_clear(&tmp_word);
     return 0;
 }