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 asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
  26                           unsigned long prot, unsigned long flags,
  27                           unsigned long fd, unsigned long pgoff)
  28 {
  29         int error = -EBADF;
  30         struct file *file = NULL;
  31         struct mm_struct *mm = current->mm;
  32
  33         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
  34         if (!(flags & MAP_ANONYMOUS)) {
  35                 file = fget(fd);
  36                 if (!file)
  37                         goto out;
  38         }
  39
  40         down_write(&mm->mmap_sem);
  41         error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
  42         up_write(&mm->mmap_sem);
  43
  44         if (file)
  45                 fput(file);
  46 out:
  47         return error;
  48 }
  49
  50 /*
  51  * Perform the select(nd, in, out, ex, tv) and mmap() system
  52  * calls. Linux/i386 didn't use to be able to handle more than
  53  * 4 system call parameters, so these system calls used a memory
  54  * block for parameter passing..
  55  */
  56
  57 struct mmap_arg_struct {
  58         unsigned long addr;
  59         unsigned long len;
  60         unsigned long prot;
  61         unsigned long flags;
  62         unsigned long fd;
  63         unsigned long offset;
  64 };
  65
  66 asmlinkage int old_mmap(struct mmap_arg_struct __user *arg)
  67 {
  68         struct mmap_arg_struct a;
  69         int err = -EFAULT;
  70
  71         if (copy_from_user(&a, arg, sizeof(a)))
  72                 goto out;
  73
  74         err = -EINVAL;
  75         if (a.offset & ~PAGE_MASK)
  76                 goto out;
  77
  78         err = sys_mmap2(a.addr, a.len, a.prot, a.flags,
  79                         a.fd, a.offset >> PAGE_SHIFT);
  80 out:
  81         return err;
  82 }
  83
  84
  85 struct sel_arg_struct {
  86         unsigned long n;
  87         fd_set __user *inp, *outp, *exp;
  88         struct timeval __user *tvp;
  89 };
  90
  91 asmlinkage int old_select(struct sel_arg_struct __user *arg)
  92 {
  93         struct sel_arg_struct a;
  94
  95         if (copy_from_user(&a, arg, sizeof(a)))
  96                 return -EFAULT;
  97         /* sys_select() does the appropriate kernel locking */
  98         return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
  99 }
 100
 101 /*
 102  * sys_ipc() is the de-multiplexer for the SysV IPC calls..
 103  *
 104  * This is really horribly ugly.
 105  */
 106 asmlinkage int sys_ipc(uint call, int first, int second,
 107                         int third, void __user *ptr, long fifth)
 108 {
 109         int version, ret;
 110
 111         version = call >> 16; /* hack for backward compatibility */
 112         call &= 0xffff;
 113
 114         switch (call) {
 115         case SEMOP:
 116                 return sys_semtimedop(first, (struct sembuf __user *)ptr, second, NULL);
 117         case SEMTIMEDOP:
 118                 return sys_semtimedop(first, (struct sembuf __user *)ptr, second,
 119                                         (const struct timespec __user *)fifth);
 120
 121         case SEMGET:
 122                 return sys_semget(first, second, third);
 123         case SEMCTL: {
 124                 union semun fourth;
 125                 if (!ptr)
 126                         return -EINVAL;
 127                 if (get_user(fourth.__pad, (void __user * __user *) ptr))
 128                         return -EFAULT;
 129                 return sys_semctl(first, second, third, fourth);
 130         }
 131
 132         case MSGSND:
 133                 return sys_msgsnd(first, (struct msgbuf __user *) ptr,
 134                                    second, third);
 135         case MSGRCV:
 136                 switch (version) {
 137                 case 0: {
 138                         struct ipc_kludge tmp;
 139                         if (!ptr)
 140                                 return -EINVAL;
 141
 142                         if (copy_from_user(&tmp,
 143                                            (struct ipc_kludge __user *) ptr,
 144                                            sizeof(tmp)))
 145                                 return -EFAULT;
 146                         return sys_msgrcv(first, tmp.msgp, second,
 147                                            tmp.msgtyp, third);
 148                 }
 149                 default:
 150                         return sys_msgrcv(first,
 151                                            (struct msgbuf __user *) ptr,
 152                                            second, fifth, third);
 153                 }
 154         case MSGGET:
 155                 return sys_msgget((key_t) first, second);
 156         case MSGCTL:
 157                 return sys_msgctl(first, second, (struct msqid_ds __user *) ptr);
 158
 159         case SHMAT:
 160                 switch (version) {
 161                 default: {
 162                         ulong raddr;
 163                         ret = do_shmat(first, (char __user *) ptr, second, &raddr);
 164                         if (ret)
 165                                 return ret;
 166                         return put_user(raddr, (ulong __user *) third);
 167                 }
 168                 case 1: /* iBCS2 emulator entry point */
 169                         if (!segment_eq(get_fs(), get_ds()))
 170                                 return -EINVAL;
 171                         /* The "(ulong *) third" is valid _only_ because of the kernel segment thing */
 172                         return do_shmat(first, (char __user *) ptr, second, (ulong *) third);
 173                 }
 174         case SHMDT:
 175                 return sys_shmdt((char __user *)ptr);
 176         case SHMGET:
 177                 return sys_shmget(first, second, third);
 178         case SHMCTL:
 179                 return sys_shmctl(first, second,
 180                                    (struct shmid_ds __user *) ptr);
 181         default:
 182                 return -ENOSYS;
 183         }
 184 }
 185
 186 /*
 187  * Old cruft
 188  */
 189 asmlinkage int sys_uname(struct old_utsname __user *name)
 190 {
 191         int err;
 192         if (!name)
 193                 return -EFAULT;
 194         down_read(&uts_sem);
 195         err = copy_to_user(name, utsname(), sizeof(*name));
 196         up_read(&uts_sem);
 197         return err? -EFAULT:0;
 198 }
 199
 200 asmlinkage int sys_olduname(struct oldold_utsname __user *name)
 201 {
 202         int error;
 203
 204         if (!name)
 205                 return -EFAULT;
 206         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
 207                 return -EFAULT;
 208
 209         down_read(&uts_sem);
 210
 211         error = __copy_to_user(&name->sysname, &utsname()->sysname,
 212                                __OLD_UTS_LEN);
 213         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
 214         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
 215                                 __OLD_UTS_LEN);
 216         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
 217         error |= __copy_to_user(&name->release, &utsname()->release,
 218                                 __OLD_UTS_LEN);
 219         error |= __put_user(0, name->release + __OLD_UTS_LEN);
 220         error |= __copy_to_user(&name->version, &utsname()->version,
 221                                 __OLD_UTS_LEN);
 222         error |= __put_user(0, name->version + __OLD_UTS_LEN);
 223         error |= __copy_to_user(&name->machine, &utsname()->machine,
 224                                 __OLD_UTS_LEN);
 225         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
 226
 227         up_read(&uts_sem);
 228
 229         error = error ? -EFAULT : 0;
 230
 231         return error;
 232 }
 233
 234
 235 /*
 236  * Do a system call from kernel instead of calling sys_execve so we
 237  * end up with proper pt_regs.
 238  */
 239 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 240 {
 241         long __res;
 242         asm volatile ("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"
 243         : "=a" (__res)
 244         : "0" (__NR_execve), "ri" (filename), "c" (argv), "d" (envp) : "memory");
 245         return __res;
 246 }