diff --git a/fs/open.c b/fs/open.c
index a7c982d95bcbdf8cb44afa2d25c1a12646d2034e..7a3de5979dad83684bc5ef17a90629f214f5866b 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -126,6 +126,36 @@ int sys_chdir(const char * filename) {
     return (0);
 }
 
+static int check_char_dev(struct m_inode * inode, int dev, int flag) {
+    struct tty_struct *tty;
+    int min;
+
+    if (MAJOR(dev) == 4 || MAJOR(dev) == 5) {
+        if (MAJOR(dev) == 5)
+            min = current->tty;
+        else
+            min = MINOR(dev);
+        if (min < 0)
+            return -1;
+        tty = tty_table + min;
+
+        if (!(flag & O_NOCTTY) &&
+                current->leader &&
+                current->tty<0 &&
+                tty->session==0) {
+            current->tty = min;
+            tty->session= current->session;
+            tty->pgrp = current->pgrp;
+        }
+        if (flag & O_NONBLOCK) {
+            tty->termios.c_cc[VMIN] =0;
+            tty->termios.c_cc[VTIME] =0;
+            tty->termios.c_lflag &= ~ICANON;
+        }
+    }
+    return 0;
+}
+
 int sys_open(const char * filename,int flag,int mode) {
     struct m_inode * inode;
     struct file * f;
@@ -154,6 +184,15 @@ int sys_open(const char * filename,int flag,int mode) {
         return i;
     }
 
+    if (S_ISCHR(inode->i_mode)) {
+        if (check_char_dev(inode,inode->i_zone[0],flag)) {
+            iput(inode);
+            current->filp[fd]=NULL;
+            f->f_count=0;
+            return -EAGAIN;
+        }
+    }
+
     f->f_mode = inode->i_mode;
     f->f_flags = flag;
     f->f_count = 1;
diff --git a/include/linux/sys.h b/include/linux/sys.h
index 66d970ad002c100a20b5507c956438533be14990..4f5addf6dc5bda77657df765cab842247f7b2f42 100644
--- a/include/linux/sys.h
+++ b/include/linux/sys.h
@@ -35,7 +35,7 @@ extern int sys_access();
 extern int sys_nice();
 extern int sys_ftime();
 extern int sys_sync();
-//extern int sys_kill();
+extern int sys_kill();
 extern int sys_rename();
 extern int sys_mkdir();
 extern int sys_rmdir();
@@ -64,7 +64,7 @@ extern int sys_chroot();
 extern int sys_dup2();
 extern int sys_getppid();
 //extern int sys_getpgrp();
-//extern int sys_setsid();
+extern int sys_setsid();
 extern int sys_sigaction();
 //extern int sys_sgetmask();
 //extern int sys_ssetmask();
@@ -162,7 +162,7 @@ fn_ptr sys_call_table[] = {
     sys_dup2,
     sys_getppid,
     0, //    sys_getpgrp,
-    0, //    sys_setsid,
+    sys_setsid,
     sys_sigaction,
     0, //    sys_sgetmask,
     0, //    sys_ssetmask,
diff --git a/include/unistd.h b/include/unistd.h
index f94fe4c8f48d300824d1779d5f2ed0c5f27a9f5f..3cfeafa704788e46c199831eae117dfeb8132356 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -156,6 +156,7 @@ extern int errno;
 int chdir(const char* pathname);
 int close(int fildes);
 int dup(int fildes);
+volatile void _exit(int status);
 int execve(const char * filename, char ** argv, char ** envp);
 int fcntl(int fildes, int cmd, ...);
 int fork();
@@ -168,10 +169,11 @@ int read(int fildes, const char * buf, off_t count);
 int lseek(int fildes, off_t offset, int origin);
 
 int rmdir(const char* pathname);
-
+pid_t setsid(void);
 time_t time(time_t * tloc);
 mode_t umask(mode_t mask);
 int uname(struct utsname * name);
 int utime(const char * filename, struct utimbuf * times);
+pid_t wait(int * wait_stat);
 
 #endif
diff --git a/kernel/chr_drv/tty_ioctl.c b/kernel/chr_drv/tty_ioctl.c
index 7e0c8b03319510f5d9f25f979e1446840c6c865e..75c4c9839db29f8b3b07baf8d46ad8a5fb43e153 100644
--- a/kernel/chr_drv/tty_ioctl.c
+++ b/kernel/chr_drv/tty_ioctl.c
@@ -9,6 +9,7 @@
 #include <asm/segment.h>
 #include <asm/system.h>
 
+extern int session_of_pgrp(int pgrp);
 extern int tty_signal(int sig, struct tty_struct *tty);
 
 static void flush(struct tty_queue * queue) {
@@ -89,6 +90,7 @@ static int set_termio(struct tty_struct * tty, struct termio * termio,
 
 int tty_ioctl(int dev, int cmd, int arg) {
     struct tty_struct * tty;
+    int     pgrp;
 
     if (MAJOR(dev) == 5) {
         dev=current->tty;
@@ -152,6 +154,22 @@ int tty_ioctl(int dev, int cmd, int arg) {
                 flush(&tty->write_q);
             } else
                 return -EINVAL;
+        case TIOCGPGRP:
+            verify_area((void *) arg,4);
+            put_fs_long(tty->pgrp,(unsigned long *) arg);
+            return 0;
+        case TIOCSPGRP:
+            if ((current->tty < 0) ||
+                    (current->tty != dev) ||
+                    (tty->session != current->session))
+                return -ENOTTY;
+            pgrp=get_fs_long((unsigned long *) arg);
+            if (pgrp < 0)
+                return -EINVAL;
+            if (session_of_pgrp(pgrp) != current->session)
+                return -EPERM;
+            tty->pgrp = pgrp;
+            return 0;
         case TIOCOUTQ:
             verify_area((void *) arg,4);
             put_fs_long(CHARS(tty->write_q),(unsigned long *) arg);
diff --git a/kernel/exit.c b/kernel/exit.c
index 8b36d3e387dabc2f1143d8435720fb601daf9182..713fc310e712efaf92d23491ea626d651411880a 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -58,6 +58,16 @@ static inline int send_sig(long sig,struct task_struct * p,int priv) {
     return 0;
 }
 
+int session_of_pgrp(int pgrp) {
+    struct task_struct **p;
+    for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
+        if ((*p)->pgrp == pgrp)
+            return((*p)->session);
+    }
+
+    return -1;
+}
+
 int kill_pg(int pgrp, int sig, int priv) {
     struct task_struct **p;
     int err,retval = -ESRCH;
@@ -77,6 +87,38 @@ int kill_pg(int pgrp, int sig, int priv) {
     return(found ? 0 : retval);
 }
 
+int kill_proc(int pid, int sig, int priv) {
+    struct task_struct **p;
+
+    if (sig<1 || sig>32)
+        return -EINVAL;
+    for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
+        if ((*p)->pid == pid)
+            return(sig ? send_sig(sig,*p,priv) : 0);
+    }
+
+    return(-ESRCH);
+}
+
+int sys_kill(int pid,int sig) {
+    struct task_struct **p = NR_TASKS + task;
+    int err, retval = 0;
+
+    if (!pid)
+        return(kill_pg(current->pid,sig,0));
+    if (pid == -1) {
+        while (--p > &FIRST_TASK) {
+            if (err = send_sig(sig,*p,0))
+                retval = err;
+        }
+        return retval;
+    }
+
+    if (pid < 0)
+        return(kill_pg(-pid,sig,0));
+    return(kill_proc(pid,sig,0));
+}
+
 int is_orphaned_pgrp(int pgrp) {
     struct task_struct **p;
 
diff --git a/kernel/main.c b/kernel/main.c
index 162f97d7c52d8374335ceccc25600aac37ef8017..32f7e92fac9c3ff91be09a673e0f538bfee926ba 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -175,14 +175,49 @@ static void run_sh() {
 }
 
 void init() {
+    int pid,i;
+
     setup((void *) &drive_info);
     (void)open("/dev/tty0", O_RDWR, 0);
     (void) dup(0);
     (void) dup(0);
 
-    run_sh();
+    //run_sh();
     //easy_shell();
 
     printf("Free mem: %d bytes\n\r",memory_end-main_memory_start);
+    if (!(pid=fork())) {
+        close(0);
+        if (open("/etc/rc",O_RDONLY,0))
+            _exit(1);
+        execve("/bin/sh",argv_rc,envp_rc);
+        _exit(2);
+    }
+
+    if (pid>0) {
+        while (pid != wait(&i))
+            ;
+    }
+
+    while (1) {
+        if ((pid=fork())<0) {
+            printf("Fork failed in init\r\n");
+            continue;
+        }
+        if (!pid) {
+            close(0);close(1);close(2);
+            setsid();
+            (void) open("/dev/tty0",O_RDWR,0);
+            (void) dup(0);
+            (void) dup(0);
+            _exit(execve("/bin/sh",argv,envp));
+        }
+        while (1)
+            if (pid == wait(&i))
+                break;
+        printf("\n\rchild %d died with code %04x\n\r",pid,i);
+        sync();
+    }
+    _exit(0);
 }
 
diff --git a/kernel/sched.c b/kernel/sched.c
index b5a5820adb326ac7fa79566eb057a33a7365c399..c681ad1628a69cfe26d41038d5741e9ddb5d6b2e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -280,8 +280,12 @@ int sys_getegid() {
 }
 
 int sys_alarm(long seconds) {
-    printk("unimplement sys call alarm\n");
-    return 0;
+    int old = current->alarm;
+
+    if (old)
+        old = (old - jiffies) / HZ;
+    current->alarm = (seconds>0)?(jiffies+HZ*seconds):0;
+    return (old);
 }
 
 int sys_nice(long increment) {
diff --git a/kernel/sys.c b/kernel/sys.c
index 1fcb56267c42495216b794d5d9067d4e58314df1..585569cd804b3c548d33a446d08bf03075d338a0 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -32,6 +32,51 @@ int sys_prof() {
     return -ENOSYS;
 }
 
+int sys_setregid(int rgid, int egid) {
+    if (rgid>0) {
+        if ((current->gid == rgid) ||
+                suser())
+            current->gid = rgid;
+    }
+    else {
+        return(-EPERM);
+    }
+
+    if (egid>0) {
+        if ((current->gid == egid) ||
+                (current->egid == egid) ||
+                suser()) {
+            current->egid = egid;
+            current->sgid = egid;
+        }
+        else {
+            return(-EPERM);
+        }
+    }
+
+    return 0;
+}
+
+int sys_setgid(int gid) {
+    if (suser())
+        current->gid = current->egid = current->sgid = gid;
+    else if ((gid == current->gid) || (gid == current->sgid))
+        current->egid = gid;
+    else
+        return -EPERM;
+    return 0;
+}
+
+int sys_setsid() {
+    if (current->leader && !suser())
+        return -EPERM;
+    current->leader = 1;
+    current->session = current->pgrp = current->pid;
+    current->tty = -1;
+
+    return current->pgrp;
+}
+
 int sys_rename() {
     return -ENOSYS;
 }
@@ -103,7 +148,12 @@ int sys_uname(struct utsname * name) {
 }
 
 int sys_setuid(int uid) {
-    printk("unimplement sys call setuid\n");
+    if (suser())
+        current->uid = current->euid = current->suid = uid;
+    else if ((uid == current->uid) || (uid == current->suid))
+        current->euid = uid;
+    else
+        return -EPERM;
     return 0;
 }
 
diff --git a/lib/Makefile b/lib/Makefile
index 9618874db4ffc4be2e4282715d0de8e3ddee2c06..f76b1e73ac3313b881f84091ccaf2dcfbcd8319d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -2,7 +2,7 @@ AR  := ar
 LD  := ld
 GCC := gcc
 CCFLAG := -m32 -I../include -nostdinc -ffreestanding -fno-pic -Wall -fomit-frame-pointer -fno-stack-protector -c
-OBJS   := ctype.o write.o string.o open.o dup.o execve.o close.o
+OBJS   := ctype.o write.o string.o open.o dup.o execve.o close.o _exit.o wait.o setsid.o
 
 lib.a : $(OBJS)
 		$(AR) rcs $@ $^
@@ -29,6 +29,15 @@ execve.o : execve.c
 close.o : close.c
 		$(GCC) $(CCFLAG) -o $@ $<
 
+_exit.o : _exit.c
+		$(GCC) $(CCFLAG) -o $@ $<
+
+wait.o : wait.c
+	$(GCC) $(CCFLAG) -o $@ $<
+
+setsid.o : setsid.c
+	$(GCC) $(CCFLAG) -o $@ $<
+
 clean : 
 		-rm *.o
 		-rm lib.a
diff --git a/lib/_exit.c b/lib/_exit.c
new file mode 100644
index 0000000000000000000000000000000000000000..c0c9d69956962fa7bed801762f868584ae146064
--- /dev/null
+++ b/lib/_exit.c
@@ -0,0 +1,13 @@
+/*
+ *  linux/lib/_exit.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
+#define __LIBRARY__
+#include <unistd.h>
+
+volatile void _exit(int exit_code)
+{
+	__asm__("int $0x80"::"a" (__NR_exit),"b" (exit_code));
+}
diff --git a/lib/setsid.c b/lib/setsid.c
new file mode 100644
index 0000000000000000000000000000000000000000..68516c7e579d05c942b158d48e79c327d2b31c55
--- /dev/null
+++ b/lib/setsid.c
@@ -0,0 +1,10 @@
+/*
+ *  linux/lib/setsid.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
+#define __LIBRARY__
+#include <unistd.h>
+
+_syscall0(pid_t,setsid)