core/main.c

@@ -28,6 +28,7 @@
 #include "time.h"
 #include "types.h"
 #include "vga.h"
+#include "zero.h"
 
 #define CHECK_FLAG(flags, bit) ((flags) & (1 << (bit)))
 

core/syscall.c

@@ -5,6 +5,7 @@
 #include "stdarg.h"
 #include "thread.h"
 #include "types.h"
+#include "uaccess.h"
 #include "uaddrspace.h"
 
 int syscallExecute(int syscallId, const struct cpu_state *userCtx)
@@ -55,6 +56,24 @@ int syscallExecute(int syscallId, const struct cpu_state *userCtx)
             threadChangeCurrentContext(NULL);
             break;
         }
+        case SYSCALL_ID_MMAP: {
+            struct uAddrSpace *as;
+            uaddr_t uaddr;
+            size_t size;
+            uint32_t rights;
+            uint32_t flags;
+            uaddr_t userPath;
+
+            char path[256];
+
+            as  = processGetAddrSpace(getCurrentThread()->process);
+            ret = syscallGet5args(userCtx, (unsigned int *)&uaddr, (unsigned int *)&size, (unsigned int *)&rights,
+                                  (unsigned int *)&flags, (unsigned int *)&userPath);
+            strzcpyFromUser((vaddr_t *)path, (uaddr_t *)userPath, sizeof(path));
+            printf("Trying mmap for device %s\n", path);
+            (void)as;
+            break;
+        }
         default:
             printf("Unknon syscall id %d\n", syscallId);
             ret = -ENOENT;

core/syscall.h

@@ -9,6 +9,7 @@
 #define SYSCALL_ID_READ 4
 #define SYSCALL_ID_TEST 5
 #define SYSCALL_ID_BRK  6
+#define SYSCALL_ID_MMAP 7
 
 #ifdef __KERNEL__
 int syscallExecute(int syscallId, const struct cpu_state *user_ctx);

core/uaccess.c

@@ -1,10 +1,12 @@
+#include "uaccess.h"
 #include "assert.h"
 #include "errno.h"
+#include "minmax.h"
 #include "mmuContext.h"
 #include "paging.h"
 #include "process.h"
 #include "thread.h"
-#include "uaccess.h"
+#include "types.h"
 
 static int bindtoUserContext()
 {
@@ -52,3 +54,37 @@ int memcpyFromUser(vaddr_t to, uaddr_t from, size_t size)
 
     return memcpyUserMemNoCheck(to, from, size);
 }
+
+static int strzcpyFromUserNoCheck(char *to, char *from, size_t size)
+{
+    int ret;
+
+    ret = bindtoUserContext();
+    if (ret != 0)
+        return ret;
+
+    for (unsigned int i = 0; i < size; i++) {
+        to[i] = from[i];
+        if (from[i] == '\0')
+            break;
+    }
+
+    if (size > 0)
+        to[size - 1] = '\0';
+
+    ret = unbindUserContext();
+    if (ret != 0)
+        return ret;
+
+    return size;
+}
+
+int strzcpyFromUser(vaddr_t *to, uaddr_t *from, size_t size)
+{
+    if ((uint)from < PAGING_BASE_USER_ADDRESS)
+        return -EPERM;
+    if ((uint)from > PAGING_TOP_USER_ADDRESS - size)
+        return -EPERM;
+
+    return strzcpyFromUserNoCheck((char *)to, (char *)from, size);
+}

core/uaccess.h

@@ -3,3 +3,4 @@
 #include "stdarg.h"
 
 int memcpyFromUser(vaddr_t to, uaddr_t from, size_t size);
+int strzcpyFromUser(vaddr_t *to, uaddr_t *from, size_t size);

disk.sfdisk

@@ -2,7 +2,6 @@ label: dos
 label-id: 0x9ec19bcc
 device: disk.img
 unit: sectors
-sector-size: 512
 
 disk.img1 : start=        2048, size=       32768, type=6, bootable
 disk.img2 : start=       34816, size=       30720, type=83

drivers/zero.h

@@ -0,0 +1,9 @@
+#pragma once
+
+
+#include "types.h"
+#include <stddef.h>
+#include <stdint.h>
+int zeroSetup();
+
+int zeroMmap(uaddr_t *uaddr, size_t size, uint32_t rights, uint32_t flags);

userspace/kernel/syscall.h

@@ -9,6 +9,7 @@
 #define SYSCALL_ID_READ 4
 #define SYSCALL_ID_TEST 5
 #define SYSCALL_ID_BRK  6
+#define SYSCALL_ID_MMAP 7
 
 #ifdef __KERNEL__
 int syscallExecute(int syscallId, const struct cpu_state *user_ctx);

userspace/libc.c

@@ -725,3 +725,7 @@ void *realloc(void *ptr, size_t size)
     return new_ptr;
 }
 
+void *mmap(void *addr, size_t len, int prot, int flags, char *path){
+
+    return (void *)syscall5(SYSCALL_ID_MMAP, (unsigned int)addr, len, prot, flags, (unsigned int)path);
+}

userspace/libc.h

@@ -36,6 +36,7 @@ int putc(const int c);
 int vsnprintf(char *str, size_t size, const char *format, va_list ap) __attribute__ ((__format__ (printf, 3, 0)));
 int vprintf(const char *format, va_list ap) __attribute__ ((__format__ (printf, 1, 0)));
 int printf(const char *format, ...) __attribute__ ((__format__ (printf, 1, 2)));
+void *mmap(void *addr, size_t len, int prot, int flags, char *path);
 
 int asprintf(char **strp, const char *fmt, ...) __attribute__ ((__format__ (printf, 2, 3)));
 int vasprintf(char **strp, const char *fmt, va_list ap) __attribute__ ((__format__ (printf, 2, 0)));

userspace/main_user.c

@@ -55,6 +55,15 @@ int func_alloc()
         return 0;
 }
 
+int func_mmap()
+{
+
+        char *path ="/dev/zero";
+        mmap(0, 4096, 0, 0, path);
+
+        return 0;
+}
+
 int main(int argc, char *argv[])
 {
         (void)argc;
@@ -85,6 +94,10 @@ int main(int argc, char *argv[])
                         func_tiny();
                         continue;
                 }
+                if (strcmp(buf, "mmap") == 0) {
+                        func_mmap();
+                        continue;
+                }
         }
         return 0;
 }