Added variable support

9 files changed, 148 insertions, 10 deletions

diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..785aa2b
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "external/libmap"]
+	path = external/libmap
+	url = git@hecate.lan:libmap.git
diff --git a/Makefile b/Makefile
index b89409d..fbe4e9d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,12 @@
 all: bin/hush
 	
-bin/hush: build/lexer.o build/command.o src/hush.c build
-	gcc -Iinclude build/lexer.o build/command.o src/hush.c -ggdb -o bin/hush
+LIBMAP_DIR := external/libmap
+LIBMAP_LIB := $(LIBMAP_DIR)/lib/libmap.a
+$(LIBMAP_LIB): $(LIBMAP_DIR)/Makefile
+	make -C $(LIBMAP_DIR) lib/libmap.a
 
+bin/hush: build/lexer.o build/command.o src/hush.c build build/variables.o $(LIBMAP_LIB)
+	gcc -Iinclude -I$(LIBMAP_DIR)/include build/lexer.o build/command.o build/variables.o src/hush.c $(LIBMAP_LIB) -ggdb -o bin/hush
 
 build/lexer.o: include/lexer.h src/lexer.c build
 	gcc -Iinclude -c src/lexer.c -ggdb -o build/lexer.o
@@ -10,6 +14,9 @@ build/lexer.o: include/lexer.h src/lexer.c build
 build/command.o: include/lexer.h include/command.h src/command.c
 	gcc -Iinclude -c src/command.c -ggdb -o build/command.o
 
+build/variables.o: include/variables.h
+	gcc -Iinclude -I$(LIBMAP_DIR)/include -c src/variables.c  -ggdb -o build/variables.o
+
 .PHONY: build clean
 build:
 	-mkdir build
@@ -18,5 +25,6 @@ build:
 clean:
 	-rm -r build
 	-rm -r bin
+	make -C $(LIBMAP_DIR) clean
 
 
diff --git a/compile_flags.txt b/compile_flags.txt
index 30679be..16adf22 100644
--- a/compile_flags.txt
+++ b/compile_flags.txt
@@ -1 +1,2 @@
 -Iinclude
+-Iexternal/libmap/include
diff --git a/external/libmap b/external/libmap
new file mode 160000
+Subproject f16156b328c87630e0c7da036353b9992b9dbf0
diff --git a/include/command.h b/include/command.h
index f44c103..2948aca 100644
--- a/include/command.h
+++ b/include/command.h
@@ -11,16 +11,16 @@
 #include "config.h"
 
 typedef struct command {
-  char *command;
-  char *infile;
-  char *outfile;
+  const char *command;
+  const char *infile;
+  const char *outfile;
   struct command *next;
   struct command *prev;
   pid_t pid;
 
   int pipe[2];
 
-  char *args[MAX_ARGUMENT_CNT + 2];
+  const char *args[MAX_ARGUMENT_CNT + 2];
 } command;
 
 
diff --git a/include/variables.h b/include/variables.h
new file mode 100644
index 0000000..7511690
--- /dev/null
+++ b/include/variables.h
@@ -0,0 +1,29 @@
+/*
+ *
+ */
+#ifndef H_HUSH_VARIABLES
+#define H_HUSH_VARIABLES
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "strmap.h"
+#include "hashfuncs.h"
+
+static inline bool is_variable(const char *token) {
+  return (token) ? token[0] == '$' : false;
+}
+
+bool init_variable_store(void);
+
+bool add_variable(const char *key, const char *val);
+
+const char *get_variable(const char *key);
+
+bool promote_variable_to_env(const char *key);
+
+void destroy_variable_store();
+
+
+#endif
diff --git a/src/command.c b/src/command.c
index 20b00b1..3d63121 100644
--- a/src/command.c
+++ b/src/command.c
@@ -119,7 +119,15 @@ pid_t execute_command(command *cmd) {
       close(cmd->pipe[1]);
     }
     
-    execvp(cmd->command, cmd->args);
+    /* 
+     * NOTE: discarding the const qualifier here is okay because either
+     * 1) exec fails, in which case the process is aborted immediately
+     * 2) exec succeeds, in which case the memory is released immediately
+     *
+     * In either case, the args won't be accessed again.
+     */
+    execvp(cmd->command, (char**)cmd->args);
+
     perror("Could not run command");
     exit(EXIT_FAILURE);
   }  else if (res < 0) {
diff --git a/src/hush.c b/src/hush.c
index 557ae1e..0d25244 100644
--- a/src/hush.c
+++ b/src/hush.c
@@ -14,6 +14,7 @@
 #include "config.h"
 #include "lexer.h"
 #include "command.h"
+#include "variables.h"
 
 FILE *open_input(int argc, char **argv) {
   FILE *input_file = (argc > 1) ? fopen(argv[1], "r") : stdin;
@@ -34,10 +35,38 @@ static size_t get_command_len(char *cmdstr) {
   return len;
 }
 
+void variable_substitution(command *cmds) {
+  for (command *cmd = cmds; cmd; cmd = cmd->next) {
+    fprintf(stderr, "Before substitution\n");
+    print_commands(stderr, cmd);
+    for (size_t i=0; i < MAX_ARGUMENT_CNT + 1; i++) {
+      if (is_variable(cmd->args[i])) { 
+        cmd->args[i] = get_variable(cmd->args[i]);
+      }
+    }
+
+    if (is_variable(cmd->outfile)) {
+      cmd->outfile = get_variable(cmd->outfile);
+    }
+
+    if (is_variable(cmd->infile)) {
+      cmd->infile = get_variable(cmd->infile);
+    }
+
+    fprintf(stderr, "After substitution\n");
+    print_commands(stderr, cmd);
+  }
+}
+
 int main(int argc, char **argv) {
   FILE *input_file = open_input(argc, argv);
   char buffer[MAX_LINE_LEN];
 
+  if (!init_variable_store()) {
+    fprintf(stderr, "ERROR: Failed to initialize variable store\n");
+    exit(EXIT_FAILURE);
+  }
+
   fprintf(stdout, "$ ");
   while (fgets(buffer, MAX_LINE_LEN, input_file)) {
     char *cmdstr = trim(buffer);
@@ -68,7 +97,9 @@ int main(int argc, char **argv) {
     // print_parsed_command(stdout, parsed_cmd);
 
     if (parsed_cmd->type == TKN_VARKEY) {
-      /* handle variable creation */
+      if (!add_variable(parsed_cmd->text, parsed_cmd->next->text)) {
+        fprintf(stderr, "ERROR: Failed to create variable\n");
+      }
       goto free_tokens;
     }
 
@@ -79,6 +110,7 @@ int main(int argc, char **argv) {
       goto free_tokens;
     }
 
+    variable_substitution(cmds);
 
     for (command *cmd = cmds; cmd; cmd = cmd->next) {
       pid_t result = execute_command(cmd);
@@ -91,9 +123,7 @@ int main(int argc, char **argv) {
 
     for (command *cmd = cmds; cmd; cmd = cmd->next) {
       if (cmd->pid > 0) {
-        fprintf(stderr, "Waiting for %d\n", cmd->pid);
         waitpid(cmd->pid, NULL, 0);
-        fprintf(stderr, "%d completed\n", cmd->pid);
       }
     }
 
@@ -107,4 +137,6 @@ int main(int argc, char **argv) {
   draw_prompt:
     fprintf(stdout, "$ ");
   }
+
+  destroy_variable_store();
 }
diff --git a/src/variables.c b/src/variables.c
new file mode 100644
index 0000000..c7cc4da
--- /dev/null
+++ b/src/variables.c
@@ -0,0 +1,57 @@
+/* 
+ *
+ */
+
+#include "variables.h"
+#include "strmap.h"
+
+static strmap *map;
+
+bool init_variable_store(void) {
+  map = strmap_create(hash_key);
+  return map;
+}
+
+bool add_variable(const char *key, const char *val) {
+  if (strmap_put(map, key, val) != STRMAP_OK) {
+    return false;
+  }
+
+  return true;
+}
+
+const char *get_variable(const char *key) {
+  fprintf(stderr, "Key is: %s\n", key);
+
+  key += (key[0] == '$');
+  const char *val;
+  strmap_status stat = strmap_get(map, key, &val);
+  switch (stat) {
+    case STRMAP_OK:
+      break;
+    case STRMAP_NOTFOUND:
+      val = getenv(key);
+      break;
+    default:
+      val = NULL;
+      break;
+  }
+
+  val = (val) ? val : "";
+  fprintf(stderr, "Value is: %s\n", val);
+
+  return val;
+}
+
+bool promote_variable_to_env(const char *key) {
+  const char *val = get_variable(key);
+  if (!val) {
+    val = "";
+  }
+
+  return !setenv(key, val, 1);
+}
+
+void destroy_variable_store() {
+  strmap_destroy(map);
+}