From 78768d172afa01b1a186a7e0857dd10100405d65 Mon Sep 17 00:00:00 2001
From: Ali Mashtizadeh <mashti@uwaterloo.ca>
Date: Sun, 1 Oct 2023 19:36:02 -0400
Subject: [PATCH] Implementing strtok and adding strtok to the shell

---
 bin/shell/shell.c | 11 ++++-------
 include/string.h  |  2 ++
 lib/libc/string.c | 35 +++++++++++++++++++++++++++++++++++
 sys/kern/printf.c |  9 ++++++++-
 4 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/bin/shell/shell.c b/bin/shell/shell.c
index 7e2b3ef..5902607 100644
--- a/bin/shell/shell.c
+++ b/bin/shell/shell.c
@@ -95,16 +95,13 @@ DispatchCommand(char *buf)
     }
 
     // parse input
-    argv[0] = buf;
-    for (argc = 1; argc < SHELL_MAX_ARGS; argc++) {
-        nextArg = strchr(argv[argc - 1], ' ');
+    nextArg = strtok(buf, " \t\r\n");
+    for (argc = 0; argc < SHELL_MAX_ARGS; argc++) {
         if (nextArg == NULL)
-        {
             break;
-        }
 
-        *nextArg = '\0';
-        argv[argc] = nextArg + 1;
+        argv[argc] = nextArg;
+	nextArg = strtok(NULL, " \t\r\n");
     }
 
     // execute command
diff --git a/include/string.h b/include/string.h
index cfca4d3..ce6025f 100644
--- a/include/string.h
+++ b/include/string.h
@@ -18,5 +18,7 @@ char *strncpy(char *to, const char *from, size_t len);
 char *strcat(char *s, const char *append);
 char *strncat(char *s, const char *append, size_t count);
 
+char *strtok(char *str, const char *delim);
+
 #endif /* __STRING_H__ */
 
diff --git a/lib/libc/string.c b/lib/libc/string.c
index 1b9e50c..a0e9aaf 100644
--- a/lib/libc/string.c
+++ b/lib/libc/string.c
@@ -118,6 +118,41 @@ strlen(const char *str)
     return (s - str);
 }
 
+char *
+strtok(char *str, const char *delim)
+{
+    char *rval;
+    static char *last;
+
+    if (str == NULL)
+	str = last;
+
+    // Skip deliminaters in the front
+    while ((str[0] != '\0') && strchr(delim, str[0])) {
+	str++;
+    }
+
+    // We've reached the end of the string
+    if (str[0] == '\0')
+	return NULL;
+
+    // Return first non-delim until the next
+    rval = str;
+
+    // Skip deliminaters in the front
+    while ((str[0] != '\0') && !strchr(delim, str[0])) {
+	str++;
+    }
+
+    if (str[0] != '\0') {
+	str[0] = '\0';
+	str++;
+    }
+    last = str;
+
+    return rval;
+}
+
 void *
 memset(void *dst, int c, size_t length)
 {
diff --git a/sys/kern/printf.c b/sys/kern/printf.c
index 1356d09..6fab079 100644
--- a/sys/kern/printf.c
+++ b/sys/kern/printf.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006-2018 Ali Mashtizadeh
+ * Copyright (c) 2006-2023 Ali Mashtizadeh
  * All rights reserved.
  */
 
@@ -226,6 +226,13 @@ void Debug_Assert(const char *fmt, ...)
     va_start(ap, fmt);
     kvprintf(fmt, consoleputc, 0, ap);
     va_end(ap);
+
+    kprintf("PC %lx FP %lx\n", __builtin_return_address(0), __builtin_frame_address(0));
+    kprintf("PC %lx FP %lx\n", __builtin_return_address(1), __builtin_frame_address(1));
+    kprintf("PC %lx FP %lx\n", __builtin_return_address(2), __builtin_frame_address(2));
+    kprintf("PC %lx FP %lx\n", __builtin_return_address(3), __builtin_frame_address(3));
+    kprintf("PC %lx FP %lx\n", __builtin_return_address(4), __builtin_frame_address(4));
+    kprintf("PC %lx FP %lx\n", __builtin_return_address(5), __builtin_frame_address(5));
    
     Panic("");
 }