arch/x86/kernel/sys_i386_32.c

   1 /*
   2  * This file contains various random system calls that
   3  * have a non-standard calling sequence on the Linux/i386
   4  * platform.
   5  */
   6
   7 #include <linux/errno.h>
   8 #include <linux/sched.h>
   9 #include <linux/mm.h>
  10 #include <linux/fs.h>
  11 #include <linux/smp.h>
  12 #include <linux/sem.h>
  13 #include <linux/msg.h>
  14 #include <linux/shm.h>
  15 #include <linux/stat.h>
  16 #include <linux/syscalls.h>
  17 #include <linux/mman.h>
  18 #include <linux/file.h>
  19 #include <linux/utsname.h>
  20 #include <linux/ipc.h>
  21
  22 #include <linux/uaccess.h>
  23 #include <linux/unistd.h>
  24
  25 #include <asm/syscalls.h>
  26
  27 /*
  28  * Perform the select(nd, in, out, ex, tv) and mmap() system
  29  * calls. Linux/i386 didn't use to be able to handle more than
  30  * 4 system call parameters, so these system calls used a memory
  31  * block for parameter passing..
  32  */
  33
  34 struct mmap_arg_struct {
  35         unsigned long addr;
  36         unsigned long len;
  37         unsigned long prot;
  38         unsigned long flags;
  39         unsigned long fd;
  40         unsigned long offset;
  41 };
  42
  43 asmlinkage int old_mmap(struct mmap_arg_struct __user *arg)
  44 {
  45         struct mmap_arg_struct a;
  46         int err = -EFAULT;
  47
  48         if (copy_from_user(&a, arg, sizeof(a)))
  49                 goto out;
  50
  51         err = -EINVAL;
  52         if (a.offset & ~PAGE_MASK)
  53                 goto out;
  54
  55         err = sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags,
  56                         a.fd, a.offset >> PAGE_SHIFT);
  57 out:
  58         return err;
  59 }
  60
  61
  62 struct sel_arg_struct {
  63         unsigned long n;
  64         fd_set __user *inp, *outp, *exp;
  65         struct timeval __user *tvp;
  66 };
  67
  68 asmlinkage int old_select(struct sel_arg_struct __user *arg)
  69 {
  70         struct sel_arg_struct a;
  71
  72         if (copy_from_user(&a, arg, sizeof(a)))
  73                 return -EFAULT;
  74         /* sys_select() does the appropriate kernel locking */
  75         return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
  76 }
  77
  78 /*
  79  * sys_ipc() is the de-multiplexer for the SysV IPC calls..
  80  *
  81  * This is really horribly ugly.
  82  */
  83 asmlinkage int sys_ipc(uint call, int first, int second,
  84                         int third, void __user *ptr, long fifth)
  85 {
  86         int version, ret;
  87
  88         version = call >> 16; /* hack for backward compatibility */
  89         call &= 0xffff;
  90
  91         switch (call) {
  92         case SEMOP:
  93                 return sys_semtimedop(first, (struct sembuf __user *)ptr, second, NULL);
  94         case SEMTIMEDOP:
  95                 return sys_semtimedop(first, (struct sembuf __user *)ptr, second,
  96                                         (const struct timespec __user *)fifth);
  97
  98         case SEMGET:
  99                 return sys_semget(first, second, third);
 100         case SEMCTL: {
 101                 union semun fourth;
 102                 if (!ptr)
 103                         return -EINVAL;
 104                 if (get_user(fourth.__pad, (void __user * __user *) ptr))
 105                         return -EFAULT;
 106                 return sys_semctl(first, second, third, fourth);
 107         }
 108
 109         case MSGSND:
 110                 return sys_msgsnd(first, (struct msgbuf __user *) ptr,
 111                                    second, third);
 112         case MSGRCV:
 113                 switch (version) {
 114                 case 0: {
 115                         struct ipc_kludge tmp;
 116                         if (!ptr)
 117                                 return -EINVAL;
 118
 119                         if (copy_from_user(&tmp,
 120                                            (struct ipc_kludge __user *) ptr,
 121                                            sizeof(tmp)))
 122                                 return -EFAULT;
 123                         return sys_msgrcv(first, tmp.msgp, second,
 124                                            tmp.msgtyp, third);
 125                 }
 126                 default:
 127                         return sys_msgrcv(first,
 128                                            (struct msgbuf __user *) ptr,
 129                                            second, fifth, third);
 130                 }
 131         case MSGGET:
 132                 return sys_msgget((key_t) first, second);
 133         case MSGCTL:
 134                 return sys_msgctl(first, second, (struct msqid_ds __user *) ptr);
 135
 136         case SHMAT:
 137                 switch (version) {
 138                 default: {
 139                         ulong raddr;
 140                         ret = do_shmat(first, (char __user *) ptr, second, &raddr);
 141                         if (ret)
 142                                 return ret;
 143                         return put_user(raddr, (ulong __user *) third);
 144                 }
 145                 case 1: /* iBCS2 emulator entry point */
 146                         if (!segment_eq(get_fs(), get_ds()))
 147                                 return -EINVAL;
 148                         /* The "(ulong *) third" is valid _only_ because of the kernel segment thing */
 149                         return do_shmat(first, (char __user *) ptr, second, (ulong *) third);
 150                 }
 151         case SHMDT:
 152                 return sys_shmdt((char __user *)ptr);
 153         case SHMGET:
 154                 return sys_shmget(first, second, third);
 155         case SHMCTL:
 156                 return sys_shmctl(first, second,
 157                                    (struct shmid_ds __user *) ptr);
 158         default:
 159                 return -ENOSYS;
 160         }
 161 }
 162
 163 /*
 164  * Old cruft
 165  */
 166 asmlinkage int sys_uname(struct old_utsname __user *name)
 167 {
 168         int err;
 169         if (!name)
 170                 return -EFAULT;
 171         down_read(&uts_sem);
 172         err = copy_to_user(name, utsname(), sizeof(*name));
 173         up_read(&uts_sem);
 174         return err? -EFAULT:0;
 175 }
 176
 177 asmlinkage int sys_olduname(struct oldold_utsname __user *name)
 178 {
 179         int error;
 180
 181         if (!name)
 182                 return -EFAULT;
 183         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
 184                 return -EFAULT;
 185
 186         down_read(&uts_sem);
 187
 188         error = __copy_to_user(&name->sysname, &utsname()->sysname,
 189                                __OLD_UTS_LEN);
 190         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
 191         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
 192                                 __OLD_UTS_LEN);
 193         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
 194         error |= __copy_to_user(&name->release, &utsname()->release,
 195                                 __OLD_UTS_LEN);
 196         error |= __put_user(0, name->release + __OLD_UTS_LEN);
 197         error |= __copy_to_user(&name->version, &utsname()->version,
 198                                 __OLD_UTS_LEN);
 199         error |= __put_user(0, name->version + __OLD_UTS_LEN);
 200         error |= __copy_to_user(&name->machine, &utsname()->machine,
 201                                 __OLD_UTS_LEN);
 202         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
 203
 204         up_read(&uts_sem);
 205
 206         error = error ? -EFAULT : 0;
 207
 208         return error;
 209 }
 210
 211
 212 /*
 213  * Do a system call from kernel instead of calling sys_execve so we
 214  * end up with proper pt_regs.
 215  */
 216 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 217 {
 218         long __res;
 219         asm volatile ("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"
 220         : "=a" (__res)
 221         : "0" (__NR_execve), "ri" (filename), "c" (argv), "d" (envp) : "memory");
 222         return __res;
 223 }