arch/x86/kernel/sys_x86_64.c

   1 #include <linux/errno.h>
   2 #include <linux/sched.h>
   3 #include <linux/syscalls.h>
   4 #include <linux/mm.h>
   5 #include <linux/fs.h>
   6 #include <linux/smp.h>
   7 #include <linux/sem.h>
   8 #include <linux/msg.h>
   9 #include <linux/shm.h>
  10 #include <linux/stat.h>
  11 #include <linux/mman.h>
  12 #include <linux/file.h>
  13 #include <linux/utsname.h>
  14 #include <linux/personality.h>
  15
  16 #include <asm/uaccess.h>
  17 #include <asm/ia32.h>
  18
  19 /*
  20  * sys_pipe() is the normal C calling standard for creating
  21  * a pipe. It's not the way Unix traditionally does this, though.
  22  */
  23 asmlinkage long sys_pipe(int __user *fildes)
  24 {
  25         int fd[2];
  26         int error;
  27
  28         error = do_pipe(fd);
  29         if (!error) {
  30                 if (copy_to_user(fildes, fd, 2*sizeof(int)))
  31                         error = -EFAULT;
  32         }
  33         return error;
  34 }
  35
  36 asmlinkage long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags,
  37         unsigned long fd, unsigned long off)
  38 {
  39         long error;
  40         struct file * file;
  41
  42         error = -EINVAL;
  43         if (off & ~PAGE_MASK)
  44                 goto out;
  45
  46         error = -EBADF;
  47         file = NULL;
  48         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
  49         if (!(flags & MAP_ANONYMOUS)) {
  50                 file = fget(fd);
  51                 if (!file)
  52                         goto out;
  53         }
  54         down_write(&current->mm->mmap_sem);
  55         error = do_mmap_pgoff(file, addr, len, prot, flags, off >> PAGE_SHIFT);
  56         up_write(&current->mm->mmap_sem);
  57
  58         if (file)
  59                 fput(file);
  60 out:
  61         return error;
  62 }
  63
  64 static void find_start_end(unsigned long flags, unsigned long *begin,
  65                            unsigned long *end)
  66 {
  67         if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) {
  68                 /* This is usually used needed to map code in small
  69                    model, so it needs to be in the first 31bit. Limit
  70                    it to that.  This means we need to move the
  71                    unmapped base down for this case. This can give
  72                    conflicts with the heap, but we assume that glibc
  73                    malloc knows how to fall back to mmap. Give it 1GB
  74                    of playground for now. -AK */
  75                 *begin = 0x40000000;
  76                 *end = 0x80000000;
  77         } else {
  78                 *begin = TASK_UNMAPPED_BASE;
  79                 *end = TASK_SIZE;
  80         }
  81 }
  82
  83 unsigned long
  84 arch_get_unmapped_area(struct file *filp, unsigned long addr,
  85                 unsigned long len, unsigned long pgoff, unsigned long flags)
  86 {
  87         struct mm_struct *mm = current->mm;
  88         struct vm_area_struct *vma;
  89         unsigned long start_addr;
  90         unsigned long begin, end;
  91
  92         if (flags & MAP_FIXED)
  93                 return addr;
  94
  95         find_start_end(flags, &begin, &end);
  96
  97         if (len > end)
  98                 return -ENOMEM;
  99
 100         if (addr) {
 101                 addr = PAGE_ALIGN(addr);
 102                 vma = find_vma(mm, addr);
 103                 if (end - len >= addr &&
 104                     (!vma || addr + len <= vma->vm_start))
 105                         return addr;
 106         }
 107         if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
 108             && len <= mm->cached_hole_size) {
 109                 mm->cached_hole_size = 0;
 110                 mm->free_area_cache = begin;
 111         }
 112         addr = mm->free_area_cache;
 113         if (addr < begin)
 114                 addr = begin;
 115         start_addr = addr;
 116
 117 full_search:
 118         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 119                 /* At this point:  (!vma || addr < vma->vm_end). */
 120                 if (end - len < addr) {
 121                         /*
 122                          * Start a new search - just in case we missed
 123                          * some holes.
 124                          */
 125                         if (start_addr != begin) {
 126                                 start_addr = addr = begin;
 127                                 mm->cached_hole_size = 0;
 128                                 goto full_search;
 129                         }
 130                         return -ENOMEM;
 131                 }
 132                 if (!vma || addr + len <= vma->vm_start) {
 133                         /*
 134                          * Remember the place where we stopped the search:
 135                          */
 136                         mm->free_area_cache = addr + len;
 137                         return addr;
 138                 }
 139                 if (addr + mm->cached_hole_size < vma->vm_start)
 140                         mm->cached_hole_size = vma->vm_start - addr;
 141
 142                 addr = vma->vm_end;
 143         }
 144 }
 145
 146 asmlinkage long sys_uname(struct new_utsname __user * name)
 147 {
 148         int err;
 149         down_read(&uts_sem);
 150         err = copy_to_user(name, utsname(), sizeof (*name));
 151         up_read(&uts_sem);
 152         if (personality(current->personality) == PER_LINUX32)
 153                 err |= copy_to_user(&name->machine, "i686", 5);
 154         return err ? -EFAULT : 0;
 155 }