provided code

src/lib/user/console.c

@@ -0,0 +1,94 @@
+#include <stdio.h>
+#include <string.h>
+#include <syscall.h>
+#include <syscall-nr.h>
+
+/* The standard vprintf() function,
+   which is like printf() but uses a va_list. */
+int
+vprintf (const char *format, va_list args) 
+{
+  return vhprintf (STDOUT_FILENO, format, args);
+}
+
+/* Like printf(), but writes output to the given HANDLE. */
+int
+hprintf (int handle, const char *format, ...) 
+{
+  va_list args;
+  int retval;
+
+  va_start (args, format);
+  retval = vhprintf (handle, format, args);
+  va_end (args);
+
+  return retval;
+}
+
+/* Writes string S to the console, followed by a new-line
+   character. */
+int
+puts (const char *s) 
+{
+  write (STDOUT_FILENO, s, strlen (s));
+  putchar ('\n');
+
+  return 0;
+}
+
+/* Writes C to the console. */
+int
+putchar (int c) 
+{
+  char c2 = c;
+  write (STDOUT_FILENO, &c2, 1);
+  return c;
+}
+
+/* Auxiliary data for vhprintf_helper(). */
+struct vhprintf_aux 
+  {
+    char buf[64];       /* Character buffer. */
+    char *p;            /* Current position in buffer. */
+    int char_cnt;       /* Total characters written so far. */
+    int handle;         /* Output file handle. */
+  };
+
+static void add_char (char, void *);
+static void flush (struct vhprintf_aux *);
+
+/* Formats the printf() format specification FORMAT with
+   arguments given in ARGS and writes the output to the given
+   HANDLE. */
+int
+vhprintf (int handle, const char *format, va_list args) 
+{
+  struct vhprintf_aux aux;
+  aux.p = aux.buf;
+  aux.char_cnt = 0;
+  aux.handle = handle;
+  __vprintf (format, args, add_char, &aux);
+  flush (&aux);
+  return aux.char_cnt;
+}
+
+/* Adds C to the buffer in AUX, flushing it if the buffer fills
+   up. */
+static void
+add_char (char c, void *aux_) 
+{
+  struct vhprintf_aux *aux = aux_;
+  *aux->p++ = c;
+  if (aux->p >= aux->buf + sizeof aux->buf)
+    flush (aux);
+  aux->char_cnt++;
+}
+
+/* Flushes the buffer in AUX. */
+static void
+flush (struct vhprintf_aux *aux)
+{
+  if (aux->p > aux->buf)
+    write (aux->handle, aux->buf, aux->p - aux->buf);
+  aux->p = aux->buf;
+}

src/lib/user/debug.c

@@ -0,0 +1,25 @@
+#include <debug.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <syscall.h>
+
+/* Aborts the user program, printing the source file name, line
+   number, and function name, plus a user-specific message. */
+void
+debug_panic (const char *file, int line, const char *function,
+             const char *message, ...)
+{
+  va_list args;
+
+  printf ("User process ABORT at %s:%d in %s(): ", file, line, function);
+
+  va_start (args, message);
+  vprintf (message, args);
+  printf ("\n");
+  va_end (args);
+
+  debug_backtrace ();
+  
+  exit (1);
+}

src/lib/user/entry.c

@@ -0,0 +1,10 @@
+#include <syscall.h>
+
+int main (int, char *[]);
+void _start (int argc, char *argv[]);
+
+void
+_start (int argc, char *argv[]) 
+{
+  exit (main (argc, argv));
+}

src/lib/user/stdio.h

@@ -0,0 +1,7 @@
+#ifndef __LIB_USER_STDIO_H
+#define __LIB_USER_STDIO_H
+
+int hprintf (int, const char *, ...) PRINTF_FORMAT (2, 3);
+int vhprintf (int, const char *, va_list) PRINTF_FORMAT (2, 0);
+
+#endif /* lib/user/stdio.h */

src/lib/user/syscall.c

@@ -0,0 +1,184 @@
+#include <syscall.h>
+#include "../syscall-nr.h"
+
+/* Invokes syscall NUMBER, passing no arguments, and returns the
+   return value as an `int'. */
+#define syscall0(NUMBER)                                        \
+        ({                                                      \
+          int retval;                                           \
+          asm volatile                                          \
+            ("pushl %[number]; int $0x30; addl $4, %%esp"       \
+               : "=a" (retval)                                  \
+               : [number] "i" (NUMBER)                          \
+               : "memory");                                     \
+          retval;                                               \
+        })
+
+/* Invokes syscall NUMBER, passing argument ARG0, and returns the
+   return value as an `int'. */
+#define syscall1(NUMBER, ARG0)                                           \
+        ({                                                               \
+          int retval;                                                    \
+          asm volatile                                                   \
+            ("pushl %[arg0]; pushl %[number]; int $0x30; addl $8, %%esp" \
+               : "=a" (retval)                                           \
+               : [number] "i" (NUMBER),                                  \
+                 [arg0] "g" (ARG0)                                       \
+               : "memory");                                              \
+          retval;                                                        \
+        })
+
+/* Invokes syscall NUMBER, passing arguments ARG0 and ARG1, and
+   returns the return value as an `int'. */
+#define syscall2(NUMBER, ARG0, ARG1)                            \
+        ({                                                      \
+          int retval;                                           \
+          asm volatile                                          \
+            ("pushl %[arg1]; pushl %[arg0]; "                   \
+             "pushl %[number]; int $0x30; addl $12, %%esp"      \
+               : "=a" (retval)                                  \
+               : [number] "i" (NUMBER),                         \
+                 [arg0] "g" (ARG0),                             \
+                 [arg1] "g" (ARG1)                              \
+               : "memory");                                     \
+          retval;                                               \
+        })
+
+/* Invokes syscall NUMBER, passing arguments ARG0, ARG1, and
+   ARG2, and returns the return value as an `int'. */
+#define syscall3(NUMBER, ARG0, ARG1, ARG2)                      \
+        ({                                                      \
+          int retval;                                           \
+          asm volatile                                          \
+            ("pushl %[arg2]; pushl %[arg1]; pushl %[arg0]; "    \
+             "pushl %[number]; int $0x30; addl $16, %%esp"      \
+               : "=a" (retval)                                  \
+               : [number] "i" (NUMBER),                         \
+                 [arg0] "g" (ARG0),                             \
+                 [arg1] "g" (ARG1),                             \
+                 [arg2] "g" (ARG2)                              \
+               : "memory");                                     \
+          retval;                                               \
+        })
+
+void
+halt (void) 
+{
+  syscall0 (SYS_HALT);
+  NOT_REACHED ();
+}
+
+void
+exit (int status)
+{
+  syscall1 (SYS_EXIT, status);
+  NOT_REACHED ();
+}
+
+pid_t
+exec (const char *file)
+{
+  return (pid_t) syscall1 (SYS_EXEC, file);
+}
+
+int
+wait (pid_t pid)
+{
+  return syscall1 (SYS_WAIT, pid);
+}
+
+bool
+create (const char *file, unsigned initial_size)
+{
+  return syscall2 (SYS_CREATE, file, initial_size);
+}
+
+bool
+remove (const char *file)
+{
+  return syscall1 (SYS_REMOVE, file);
+}
+
+int
+open (const char *file)
+{
+  return syscall1 (SYS_OPEN, file);
+}
+
+int
+filesize (int fd) 
+{
+  return syscall1 (SYS_FILESIZE, fd);
+}
+
+int
+read (int fd, void *buffer, unsigned size)
+{
+  return syscall3 (SYS_READ, fd, buffer, size);
+}
+
+int
+write (int fd, const void *buffer, unsigned size)
+{
+  return syscall3 (SYS_WRITE, fd, buffer, size);
+}
+
+void
+seek (int fd, unsigned position) 
+{
+  syscall2 (SYS_SEEK, fd, position);
+}
+
+unsigned
+tell (int fd) 
+{
+  return syscall1 (SYS_TELL, fd);
+}
+
+void
+close (int fd)
+{
+  syscall1 (SYS_CLOSE, fd);
+}
+
+mapid_t
+mmap (int fd, void *addr)
+{
+  return syscall2 (SYS_MMAP, fd, addr);
+}
+
+void
+munmap (mapid_t mapid)
+{
+  syscall1 (SYS_MUNMAP, mapid);
+}
+
+bool
+chdir (const char *dir)
+{
+  return syscall1 (SYS_CHDIR, dir);
+}
+
+bool
+mkdir (const char *dir)
+{
+  return syscall1 (SYS_MKDIR, dir);
+}
+
+bool
+readdir (int fd, char name[READDIR_MAX_LEN + 1]) 
+{
+  return syscall2 (SYS_READDIR, fd, name);
+}
+
+bool
+isdir (int fd) 
+{
+  return syscall1 (SYS_ISDIR, fd);
+}
+
+int
+inumber (int fd) 
+{
+  return syscall1 (SYS_INUMBER, fd);
+}

src/lib/user/syscall.h

@@ -0,0 +1,48 @@
+#ifndef __LIB_USER_SYSCALL_H
+#define __LIB_USER_SYSCALL_H
+
+#include <stdbool.h>
+#include <debug.h>
+
+/* Process identifier. */
+typedef int pid_t;
+#define PID_ERROR ((pid_t) -1)
+
+/* Map region identifier. */
+typedef int mapid_t;
+#define MAP_FAILED ((mapid_t) -1)
+
+/* Maximum characters in a filename written by readdir(). */
+#define READDIR_MAX_LEN 14
+
+/* Typical return values from main() and arguments to exit(). */
+#define EXIT_SUCCESS 0          /* Successful execution. */
+#define EXIT_FAILURE 1          /* Unsuccessful execution. */
+
+/* Tasks 2 and later. */
+void halt (void) NO_RETURN;
+void exit (int status) NO_RETURN;
+pid_t exec (const char *file);
+int wait (pid_t);
+bool create (const char *file, unsigned initial_size);
+bool remove (const char *file);
+int open (const char *file);
+int filesize (int fd);
+int read (int fd, void *buffer, unsigned length);
+int write (int fd, const void *buffer, unsigned length);
+void seek (int fd, unsigned position);
+unsigned tell (int fd);
+void close (int fd);
+
+/* Task 3 and optionally task 4. */
+mapid_t mmap (int fd, void *addr);
+void munmap (mapid_t);
+
+/* Task 4 only. */
+bool chdir (const char *dir);
+bool mkdir (const char *dir);
+bool readdir (int fd, char name[READDIR_MAX_LEN + 1]);
+bool isdir (int fd);
+int inumber (int fd);
+
+#endif /* lib/user/syscall.h */

src/lib/user/user.lds

@@ -0,0 +1,57 @@
+OUTPUT_FORMAT("elf32-i386")
+OUTPUT_ARCH(i386)
+ENTRY(_start)
+
+SECTIONS
+{
+  /* Read-only sections, merged into text segment, at fixed start offset. */
+  __executable_start = 0x08048000;
+  . = 0x08048000;
+  .text : { *(.text) }
+  .rodata : { *(.rodata) }
+
+  /* Adjust the address for the data segment.  We want to adjust up to
+     the same address within the page on the next page up.  */
+  . = ALIGN (0x1000) - ((0x1000 - .) & (0x1000 - 1)); 
+  . = DATA_SEGMENT_ALIGN (0x1000, 0x1000);
+
+  .data : { *(.data) }
+  .bss : { *(.bss) }
+
+  /* Stabs debugging sections.  */
+  .stab          0 : { *(.stab) }
+  .stabstr       0 : { *(.stabstr) }
+  .stab.excl     0 : { *(.stab.excl) }
+  .stab.exclstr  0 : { *(.stab.exclstr) }
+  .stab.index    0 : { *(.stab.index) }
+  .stab.indexstr 0 : { *(.stab.indexstr) }
+  .comment       0 : { *(.comment) }
+
+  /* DWARF debug sections.
+  Symbols in the DWARF debugging sections are relative to the beginning
+  of the section so we begin them at 0.  */
+  /* DWARF 1 */
+  .debug          0 : { *(.debug) }
+  .line           0 : { *(.line) }
+  /* GNU DWARF 1 extensions */
+  .debug_srcinfo  0 : { *(.debug_srcinfo) }
+  .debug_sfnames  0 : { *(.debug_sfnames) }
+  /* DWARF 1.1 and DWARF 2 */
+  .debug_aranges  0 : { *(.debug_aranges) }
+  .debug_pubnames 0 : { *(.debug_pubnames) }
+  /* DWARF 2 */
+  .debug_info     0 : { *(.debug_info .gnu.linkonce.wi.*) }
+  .debug_abbrev   0 : { *(.debug_abbrev) }
+  .debug_line     0 : { *(.debug_line) }
+  .debug_frame    0 : { *(.debug_frame) }
+  .debug_str      0 : { *(.debug_str) }
+  .debug_loc      0 : { *(.debug_loc) }
+  .debug_macinfo  0 : { *(.debug_macinfo) }
+  /* SGI/MIPS DWARF 2 extensions */
+  .debug_weaknames 0 : { *(.debug_weaknames) }
+  .debug_funcnames 0 : { *(.debug_funcnames) }
+  .debug_typenames 0 : { *(.debug_typenames) }
+  .debug_varnames  0 : { *(.debug_varnames) }
+  /DISCARD/ : { *(.note.GNU-stack) }
+  /DISCARD/ : { *(.eh_frame) }
+}