arch/i386/kernel/sys_i386.c

   1 /*
   2  * linux/arch/i386/kernel/sys_i386.c
   3  *
   4  * This file contains various random system calls that
   5  * have a non-standard calling sequence on the Linux/i386
   6  * platform.
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/sched.h>
  11 #include <linux/mm.h>
  12 #include <linux/fs.h>
  13 #include <linux/smp.h>
  14 #include <linux/sem.h>
  15 #include <linux/msg.h>
  16 #include <linux/shm.h>
  17 #include <linux/stat.h>
  18 #include <linux/syscalls.h>
  19 #include <linux/mman.h>
  20 #include <linux/file.h>
  21 #include <linux/utsname.h>
  22
  23 #include <asm/uaccess.h>
  24 #include <asm/unistd.h>
  25 #include <asm/ipc.h>
  26
  27 /*
  28  * sys_pipe() is the normal C calling standard for creating
  29  * a pipe. It's not the way Unix traditionally does this, though.
  30  */
  31 asmlinkage int sys_pipe(unsigned long __user * fildes)
  32 {
  33         int fd[2];
  34         int error;
  35
  36         error = do_pipe(fd);
  37         if (!error) {
  38                 if (copy_to_user(fildes, fd, 2*sizeof(int)))
  39                         error = -EFAULT;
  40         }
  41         return error;
  42 }
  43
  44 asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
  45                           unsigned long prot, unsigned long flags,
  46                           unsigned long fd, unsigned long pgoff)
  47 {
  48         int error = -EBADF;
  49         struct file *file = NULL;
  50         struct mm_struct *mm = current->mm;
  51
  52         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
  53         if (!(flags & MAP_ANONYMOUS)) {
  54                 file = fget(fd);
  55                 if (!file)
  56                         goto out;
  57         }
  58
  59         down_write(&mm->mmap_sem);
  60         error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
  61         up_write(&mm->mmap_sem);
  62
  63         if (file)
  64                 fput(file);
  65 out:
  66         return error;
  67 }
  68
  69 /*
  70  * Perform the select(nd, in, out, ex, tv) and mmap() system
  71  * calls. Linux/i386 didn't use to be able to handle more than
  72  * 4 system call parameters, so these system calls used a memory
  73  * block for parameter passing..
  74  */
  75
  76 struct mmap_arg_struct {
  77         unsigned long addr;
  78         unsigned long len;
  79         unsigned long prot;
  80         unsigned long flags;
  81         unsigned long fd;
  82         unsigned long offset;
  83 };
  84
  85 asmlinkage int old_mmap(struct mmap_arg_struct __user *arg)
  86 {
  87         struct mmap_arg_struct a;
  88         int err = -EFAULT;
  89
  90         if (copy_from_user(&a, arg, sizeof(a)))
  91                 goto out;
  92
  93         err = -EINVAL;
  94         if (a.offset & ~PAGE_MASK)
  95                 goto out;
  96
  97         err = sys_mmap2(a.addr, a.len, a.prot, a.flags,
  98                         a.fd, a.offset >> PAGE_SHIFT);
  99 out:
 100         return err;
 101 }
 102
 103
 104 struct sel_arg_struct {
 105         unsigned long n;
 106         fd_set __user *inp, *outp, *exp;
 107         struct timeval __user *tvp;
 108 };
 109
 110 asmlinkage int old_select(struct sel_arg_struct __user *arg)
 111 {
 112         struct sel_arg_struct a;
 113
 114         if (copy_from_user(&a, arg, sizeof(a)))
 115                 return -EFAULT;
 116         /* sys_select() does the appropriate kernel locking */
 117         return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
 118 }
 119
 120 /*
 121  * sys_ipc() is the de-multiplexer for the SysV IPC calls..
 122  *
 123  * This is really horribly ugly.
 124  */
 125 asmlinkage int sys_ipc (uint call, int first, int second,
 126                         int third, void __user *ptr, long fifth)
 127 {
 128         int version, ret;
 129
 130         version = call >> 16; /* hack for backward compatibility */
 131         call &= 0xffff;
 132
 133         switch (call) {
 134         case SEMOP:
 135                 return sys_semtimedop (first, (struct sembuf __user *)ptr, second, NULL);
 136         case SEMTIMEDOP:
 137                 return sys_semtimedop(first, (struct sembuf __user *)ptr, second,
 138                                         (const struct timespec __user *)fifth);
 139
 140         case SEMGET:
 141                 return sys_semget (first, second, third);
 142         case SEMCTL: {
 143                 union semun fourth;
 144                 if (!ptr)
 145                         return -EINVAL;
 146                 if (get_user(fourth.__pad, (void __user * __user *) ptr))
 147                         return -EFAULT;
 148                 return sys_semctl (first, second, third, fourth);
 149         }
 150
 151         case MSGSND:
 152                 return sys_msgsnd (first, (struct msgbuf __user *) ptr,
 153                                    second, third);
 154         case MSGRCV:
 155                 switch (version) {
 156                 case 0: {
 157                         struct ipc_kludge tmp;
 158                         if (!ptr)
 159                                 return -EINVAL;
 160
 161                         if (copy_from_user(&tmp,
 162                                            (struct ipc_kludge __user *) ptr,
 163                                            sizeof (tmp)))
 164                                 return -EFAULT;
 165                         return sys_msgrcv (first, tmp.msgp, second,
 166                                            tmp.msgtyp, third);
 167                 }
 168                 default:
 169                         return sys_msgrcv (first,
 170                                            (struct msgbuf __user *) ptr,
 171                                            second, fifth, third);
 172                 }
 173         case MSGGET:
 174                 return sys_msgget ((key_t) first, second);
 175         case MSGCTL:
 176                 return sys_msgctl (first, second, (struct msqid_ds __user *) ptr);
 177
 178         case SHMAT:
 179                 switch (version) {
 180                 default: {
 181                         ulong raddr;
 182                         ret = do_shmat (first, (char __user *) ptr, second, &raddr);
 183                         if (ret)
 184                                 return ret;
 185                         return put_user (raddr, (ulong __user *) third);
 186                 }
 187                 case 1: /* iBCS2 emulator entry point */
 188                         if (!segment_eq(get_fs(), get_ds()))
 189                                 return -EINVAL;
 190                         /* The "(ulong *) third" is valid _only_ because of the kernel segment thing */
 191                         return do_shmat (first, (char __user *) ptr, second, (ulong *) third);
 192                 }
 193         case SHMDT:
 194                 return sys_shmdt ((char __user *)ptr);
 195         case SHMGET:
 196                 return sys_shmget (first, second, third);
 197         case SHMCTL:
 198                 return sys_shmctl (first, second,
 199                                    (struct shmid_ds __user *) ptr);
 200         default:
 201                 return -ENOSYS;
 202         }
 203 }
 204
 205 /*
 206  * Old cruft
 207  */
 208 asmlinkage int sys_uname(struct old_utsname __user * name)
 209 {
 210         int err;
 211         if (!name)
 212                 return -EFAULT;
 213         down_read(&uts_sem);
 214         err = copy_to_user(name, utsname(), sizeof (*name));
 215         up_read(&uts_sem);
 216         return err?-EFAULT:0;
 217 }
 218
 219 asmlinkage int sys_olduname(struct oldold_utsname __user * name)
 220 {
 221         int error;
 222
 223         if (!name)
 224                 return -EFAULT;
 225         if (!access_ok(VERIFY_WRITE,name,sizeof(struct oldold_utsname)))
 226                 return -EFAULT;
 227
 228         down_read(&uts_sem);
 229
 230         error = __copy_to_user(&name->sysname, &utsname()->sysname,
 231                                __OLD_UTS_LEN);
 232         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
 233         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
 234                                 __OLD_UTS_LEN);
 235         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
 236         error |= __copy_to_user(&name->release, &utsname()->release,
 237                                 __OLD_UTS_LEN);
 238         error |= __put_user(0, name->release + __OLD_UTS_LEN);
 239         error |= __copy_to_user(&name->version, &utsname()->version,
 240                                 __OLD_UTS_LEN);
 241         error |= __put_user(0, name->version + __OLD_UTS_LEN);
 242         error |= __copy_to_user(&name->machine, &utsname()->machine,
 243                                 __OLD_UTS_LEN);
 244         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
 245
 246         up_read(&uts_sem);
 247
 248         error = error ? -EFAULT : 0;
 249
 250         return error;
 251 }
 252
 253
 254 /*
 255  * Do a system call from kernel instead of calling sys_execve so we
 256  * end up with proper pt_regs.
 257  */
 258 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 259 {
 260         long __res;
 261         asm volatile ("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"
 262         : "=a" (__res)
 263         : "0" (__NR_execve),"ri" (filename),"c" (argv), "d" (envp) : "memory");
 264         return __res;
 265 }