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 asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
  28                           unsigned long prot, unsigned long flags,
  29                           unsigned long fd, unsigned long pgoff)
  30 {
  31         int error = -EBADF;
  32         struct file *file = NULL;
  33         struct mm_struct *mm = current->mm;
  34
  35         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
  36         if (!(flags & MAP_ANONYMOUS)) {
  37                 file = fget(fd);
  38                 if (!file)
  39                         goto out;
  40         }
  41
  42         down_write(&mm->mmap_sem);
  43         error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
  44         up_write(&mm->mmap_sem);
  45
  46         if (file)
  47                 fput(file);
  48 out:
  49         return error;
  50 }
  51
  52 /*
  53  * Perform the select(nd, in, out, ex, tv) and mmap() system
  54  * calls. Linux/i386 didn't use to be able to handle more than
  55  * 4 system call parameters, so these system calls used a memory
  56  * block for parameter passing..
  57  */
  58
  59 struct mmap_arg_struct {
  60         unsigned long addr;
  61         unsigned long len;
  62         unsigned long prot;
  63         unsigned long flags;
  64         unsigned long fd;
  65         unsigned long offset;
  66 };
  67
  68 asmlinkage int old_mmap(struct mmap_arg_struct __user *arg)
  69 {
  70         struct mmap_arg_struct a;
  71         int err = -EFAULT;
  72
  73         if (copy_from_user(&a, arg, sizeof(a)))
  74                 goto out;
  75
  76         err = -EINVAL;
  77         if (a.offset & ~PAGE_MASK)
  78                 goto out;
  79
  80         err = sys_mmap2(a.addr, a.len, a.prot, a.flags,
  81                         a.fd, a.offset >> PAGE_SHIFT);
  82 out:
  83         return err;
  84 }
  85
  86
  87 struct sel_arg_struct {
  88         unsigned long n;
  89         fd_set __user *inp, *outp, *exp;
  90         struct timeval __user *tvp;
  91 };
  92
  93 asmlinkage int old_select(struct sel_arg_struct __user *arg)
  94 {
  95         struct sel_arg_struct a;
  96
  97         if (copy_from_user(&a, arg, sizeof(a)))
  98                 return -EFAULT;
  99         /* sys_select() does the appropriate kernel locking */
 100         return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
 101 }
 102
 103 /*
 104  * sys_ipc() is the de-multiplexer for the SysV IPC calls..
 105  *
 106  * This is really horribly ugly.
 107  */
 108 asmlinkage int sys_ipc(uint call, int first, int second,
 109                         int third, void __user *ptr, long fifth)
 110 {
 111         int version, ret;
 112
 113         version = call >> 16; /* hack for backward compatibility */
 114         call &= 0xffff;
 115
 116         switch (call) {
 117         case SEMOP:
 118                 return sys_semtimedop(first, (struct sembuf __user *)ptr, second, NULL);
 119         case SEMTIMEDOP:
 120                 return sys_semtimedop(first, (struct sembuf __user *)ptr, second,
 121                                         (const struct timespec __user *)fifth);
 122
 123         case SEMGET:
 124                 return sys_semget(first, second, third);
 125         case SEMCTL: {
 126                 union semun fourth;
 127                 if (!ptr)
 128                         return -EINVAL;
 129                 if (get_user(fourth.__pad, (void __user * __user *) ptr))
 130                         return -EFAULT;
 131                 return sys_semctl(first, second, third, fourth);
 132         }
 133
 134         case MSGSND:
 135                 return sys_msgsnd(first, (struct msgbuf __user *) ptr,
 136                                    second, third);
 137         case MSGRCV:
 138                 switch (version) {
 139                 case 0: {
 140                         struct ipc_kludge tmp;
 141                         if (!ptr)
 142                                 return -EINVAL;
 143
 144                         if (copy_from_user(&tmp,
 145                                            (struct ipc_kludge __user *) ptr,
 146                                            sizeof(tmp)))
 147                                 return -EFAULT;
 148                         return sys_msgrcv(first, tmp.msgp, second,
 149                                            tmp.msgtyp, third);
 150                 }
 151                 default:
 152                         return sys_msgrcv(first,
 153                                            (struct msgbuf __user *) ptr,
 154                                            second, fifth, third);
 155                 }
 156         case MSGGET:
 157                 return sys_msgget((key_t) first, second);
 158         case MSGCTL:
 159                 return sys_msgctl(first, second, (struct msqid_ds __user *) ptr);
 160
 161         case SHMAT:
 162                 switch (version) {
 163                 default: {
 164                         ulong raddr;
 165                         ret = do_shmat(first, (char __user *) ptr, second, &raddr);
 166                         if (ret)
 167                                 return ret;
 168                         return put_user(raddr, (ulong __user *) third);
 169                 }
 170                 case 1: /* iBCS2 emulator entry point */
 171                         if (!segment_eq(get_fs(), get_ds()))
 172                                 return -EINVAL;
 173                         /* The "(ulong *) third" is valid _only_ because of the kernel segment thing */
 174                         return do_shmat(first, (char __user *) ptr, second, (ulong *) third);
 175                 }
 176         case SHMDT:
 177                 return sys_shmdt((char __user *)ptr);
 178         case SHMGET:
 179                 return sys_shmget(first, second, third);
 180         case SHMCTL:
 181                 return sys_shmctl(first, second,
 182                                    (struct shmid_ds __user *) ptr);
 183         default:
 184                 return -ENOSYS;
 185         }
 186 }
 187
 188 /*
 189  * Old cruft
 190  */
 191 asmlinkage int sys_uname(struct old_utsname __user *name)
 192 {
 193         int err;
 194         if (!name)
 195                 return -EFAULT;
 196         down_read(&uts_sem);
 197         err = copy_to_user(name, utsname(), sizeof(*name));
 198         up_read(&uts_sem);
 199         return err? -EFAULT:0;
 200 }
 201
 202 asmlinkage int sys_olduname(struct oldold_utsname __user *name)
 203 {
 204         int error;
 205
 206         if (!name)
 207                 return -EFAULT;
 208         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
 209                 return -EFAULT;
 210
 211         down_read(&uts_sem);
 212
 213         error = __copy_to_user(&name->sysname, &utsname()->sysname,
 214                                __OLD_UTS_LEN);
 215         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
 216         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
 217                                 __OLD_UTS_LEN);
 218         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
 219         error |= __copy_to_user(&name->release, &utsname()->release,
 220                                 __OLD_UTS_LEN);
 221         error |= __put_user(0, name->release + __OLD_UTS_LEN);
 222         error |= __copy_to_user(&name->version, &utsname()->version,
 223                                 __OLD_UTS_LEN);
 224         error |= __put_user(0, name->version + __OLD_UTS_LEN);
 225         error |= __copy_to_user(&name->machine, &utsname()->machine,
 226                                 __OLD_UTS_LEN);
 227         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
 228
 229         up_read(&uts_sem);
 230
 231         error = error ? -EFAULT : 0;
 232
 233         return error;
 234 }
 235
 236
 237 /*
 238  * Do a system call from kernel instead of calling sys_execve so we
 239  * end up with proper pt_regs.
 240  */
 241 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 242 {
 243         long __res;
 244         asm volatile ("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"
 245         : "=a" (__res)
 246         : "0" (__NR_execve), "ri" (filename), "c" (argv), "d" (envp) : "memory");
 247         return __res;
 248 }