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 <asm/uaccess.h>
  23 #include <asm/unistd.h>
  24
  25 /*
  26  * sys_pipe() is the normal C calling standard for creating
  27  * a pipe. It's not the way Unix traditionally does this, though.
  28  */
  29 asmlinkage int sys_pipe(unsigned long __user * fildes)
  30 {
  31         int fd[2];
  32         int error;
  33
  34         error = do_pipe(fd);
  35         if (!error) {
  36                 if (copy_to_user(fildes, fd, 2*sizeof(int)))
  37                         error = -EFAULT;
  38         }
  39         return error;
  40 }
  41
  42 asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
  43                           unsigned long prot, unsigned long flags,
  44                           unsigned long fd, unsigned long pgoff)
  45 {
  46         int error = -EBADF;
  47         struct file *file = NULL;
  48         struct mm_struct *mm = current->mm;
  49
  50         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
  51         if (!(flags & MAP_ANONYMOUS)) {
  52                 file = fget(fd);
  53                 if (!file)
  54                         goto out;
  55         }
  56
  57         down_write(&mm->mmap_sem);
  58         error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
  59         up_write(&mm->mmap_sem);
  60
  61         if (file)
  62                 fput(file);
  63 out:
  64         return error;
  65 }
  66
  67 /*
  68  * Perform the select(nd, in, out, ex, tv) and mmap() system
  69  * calls. Linux/i386 didn't use to be able to handle more than
  70  * 4 system call parameters, so these system calls used a memory
  71  * block for parameter passing..
  72  */
  73
  74 struct mmap_arg_struct {
  75         unsigned long addr;
  76         unsigned long len;
  77         unsigned long prot;
  78         unsigned long flags;
  79         unsigned long fd;
  80         unsigned long offset;
  81 };
  82
  83 asmlinkage int old_mmap(struct mmap_arg_struct __user *arg)
  84 {
  85         struct mmap_arg_struct a;
  86         int err = -EFAULT;
  87
  88         if (copy_from_user(&a, arg, sizeof(a)))
  89                 goto out;
  90
  91         err = -EINVAL;
  92         if (a.offset & ~PAGE_MASK)
  93                 goto out;
  94
  95         err = sys_mmap2(a.addr, a.len, a.prot, a.flags,
  96                         a.fd, a.offset >> PAGE_SHIFT);
  97 out:
  98         return err;
  99 }
 100
 101
 102 struct sel_arg_struct {
 103         unsigned long n;
 104         fd_set __user *inp, *outp, *exp;
 105         struct timeval __user *tvp;
 106 };
 107
 108 asmlinkage int old_select(struct sel_arg_struct __user *arg)
 109 {
 110         struct sel_arg_struct a;
 111
 112         if (copy_from_user(&a, arg, sizeof(a)))
 113                 return -EFAULT;
 114         /* sys_select() does the appropriate kernel locking */
 115         return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
 116 }
 117
 118 /*
 119  * sys_ipc() is the de-multiplexer for the SysV IPC calls..
 120  *
 121  * This is really horribly ugly.
 122  */
 123 asmlinkage int sys_ipc (uint call, int first, int second,
 124                         int third, void __user *ptr, long fifth)
 125 {
 126         int version, ret;
 127
 128         version = call >> 16; /* hack for backward compatibility */
 129         call &= 0xffff;
 130
 131         switch (call) {
 132         case SEMOP:
 133                 return sys_semtimedop (first, (struct sembuf __user *)ptr, second, NULL);
 134         case SEMTIMEDOP:
 135                 return sys_semtimedop(first, (struct sembuf __user *)ptr, second,
 136                                         (const struct timespec __user *)fifth);
 137
 138         case SEMGET:
 139                 return sys_semget (first, second, third);
 140         case SEMCTL: {
 141                 union semun fourth;
 142                 if (!ptr)
 143                         return -EINVAL;
 144                 if (get_user(fourth.__pad, (void __user * __user *) ptr))
 145                         return -EFAULT;
 146                 return sys_semctl (first, second, third, fourth);
 147         }
 148
 149         case MSGSND:
 150                 return sys_msgsnd (first, (struct msgbuf __user *) ptr,
 151                                    second, third);
 152         case MSGRCV:
 153                 switch (version) {
 154                 case 0: {
 155                         struct ipc_kludge tmp;
 156                         if (!ptr)
 157                                 return -EINVAL;
 158
 159                         if (copy_from_user(&tmp,
 160                                            (struct ipc_kludge __user *) ptr,
 161                                            sizeof (tmp)))
 162                                 return -EFAULT;
 163                         return sys_msgrcv (first, tmp.msgp, second,
 164                                            tmp.msgtyp, third);
 165                 }
 166                 default:
 167                         return sys_msgrcv (first,
 168                                            (struct msgbuf __user *) ptr,
 169                                            second, fifth, third);
 170                 }
 171         case MSGGET:
 172                 return sys_msgget ((key_t) first, second);
 173         case MSGCTL:
 174                 return sys_msgctl (first, second, (struct msqid_ds __user *) ptr);
 175
 176         case SHMAT:
 177                 switch (version) {
 178                 default: {
 179                         ulong raddr;
 180                         ret = do_shmat (first, (char __user *) ptr, second, &raddr);
 181                         if (ret)
 182                                 return ret;
 183                         return put_user (raddr, (ulong __user *) third);
 184                 }
 185                 case 1: /* iBCS2 emulator entry point */
 186                         if (!segment_eq(get_fs(), get_ds()))
 187                                 return -EINVAL;
 188                         /* The "(ulong *) third" is valid _only_ because of the kernel segment thing */
 189                         return do_shmat (first, (char __user *) ptr, second, (ulong *) third);
 190                 }
 191         case SHMDT:
 192                 return sys_shmdt ((char __user *)ptr);
 193         case SHMGET:
 194                 return sys_shmget (first, second, third);
 195         case SHMCTL:
 196                 return sys_shmctl (first, second,
 197                                    (struct shmid_ds __user *) ptr);
 198         default:
 199                 return -ENOSYS;
 200         }
 201 }
 202
 203 /*
 204  * Old cruft
 205  */
 206 asmlinkage int sys_uname(struct old_utsname __user * name)
 207 {
 208         int err;
 209         if (!name)
 210                 return -EFAULT;
 211         down_read(&uts_sem);
 212         err = copy_to_user(name, utsname(), sizeof (*name));
 213         up_read(&uts_sem);
 214         return err?-EFAULT:0;
 215 }
 216
 217 asmlinkage int sys_olduname(struct oldold_utsname __user * name)
 218 {
 219         int error;
 220
 221         if (!name)
 222                 return -EFAULT;
 223         if (!access_ok(VERIFY_WRITE,name,sizeof(struct oldold_utsname)))
 224                 return -EFAULT;
 225
 226         down_read(&uts_sem);
 227
 228         error = __copy_to_user(&name->sysname, &utsname()->sysname,
 229                                __OLD_UTS_LEN);
 230         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
 231         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
 232                                 __OLD_UTS_LEN);
 233         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
 234         error |= __copy_to_user(&name->release, &utsname()->release,
 235                                 __OLD_UTS_LEN);
 236         error |= __put_user(0, name->release + __OLD_UTS_LEN);
 237         error |= __copy_to_user(&name->version, &utsname()->version,
 238                                 __OLD_UTS_LEN);
 239         error |= __put_user(0, name->version + __OLD_UTS_LEN);
 240         error |= __copy_to_user(&name->machine, &utsname()->machine,
 241                                 __OLD_UTS_LEN);
 242         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
 243
 244         up_read(&uts_sem);
 245
 246         error = error ? -EFAULT : 0;
 247
 248         return error;
 249 }
 250
 251
 252 /*
 253  * Do a system call from kernel instead of calling sys_execve so we
 254  * end up with proper pt_regs.
 255  */
 256 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 257 {
 258         long __res;
 259         asm volatile ("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"
 260         : "=a" (__res)
 261         : "0" (__NR_execve),"ri" (filename),"c" (argv), "d" (envp) : "memory");
 262         return __res;
 263 }