-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
+/*
* GPL HEADER START
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
+ *
+ * Copyright (c) 2012, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
return capable(cfs_cap_unpack(cap));
}
-/* Check if task is running in 32-bit API mode, for the purpose of
- * userspace binary interfaces. On 32-bit Linux this is (unfortunately)
- * always true, even if the application is using LARGEFILE64 and 64-bit
- * APIs, because Linux provides no way for the filesystem to know if it
- * is called via 32-bit or 64-bit APIs. Other clients may vary. On
- * 64-bit systems, this will only be true if the binary is calling a
- * 32-bit system call. */
-int cfs_curproc_is_32bit(void)
+static int cfs_access_process_vm(struct task_struct *tsk, unsigned long addr,
+ void *buf, int len, int write)
{
-#ifdef HAVE_IS_COMPAT_TASK
- return is_compat_task();
-#else
- return (BITS_PER_LONG == 32);
-#endif
+ /* Just copied from kernel for the kernels which doesn't
+ * have access_process_vm() exported */
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ struct page *page;
+ void *old_buf = buf;
+
+ mm = get_task_mm(tsk);
+ if (!mm)
+ return 0;
+
+ down_read(&mm->mmap_sem);
+ /* ignore errors, just check how much was sucessfully transfered */
+ while (len) {
+ int bytes, rc, offset;
+ void *maddr;
+
+ rc = get_user_pages(tsk, mm, addr, 1,
+ write, 1, &page, &vma);
+ if (rc <= 0)
+ break;
+
+ bytes = len;
+ offset = addr & (PAGE_SIZE-1);
+ if (bytes > PAGE_SIZE-offset)
+ bytes = PAGE_SIZE-offset;
+
+ maddr = kmap(page);
+ if (write) {
+ copy_to_user_page(vma, page, addr,
+ maddr + offset, buf, bytes);
+ set_page_dirty_lock(page);
+ } else {
+ copy_from_user_page(vma, page, addr,
+ buf, maddr + offset, bytes);
+ }
+ kunmap(page);
+ page_cache_release(page);
+ len -= bytes;
+ buf += bytes;
+ addr += bytes;
+ }
+ up_read(&mm->mmap_sem);
+ mmput(mm);
+
+ return buf - old_buf;
+}
+
+/* Read the environment variable of current process specified by @key. */
+int cfs_get_environ(const char *key, char *value, int *val_len)
+{
+ struct mm_struct *mm;
+ char *buffer;
+ int buf_len = PAGE_CACHE_SIZE;
+ int key_len = strlen(key);
+ unsigned long addr;
+ int rc;
+ ENTRY;
+
+ buffer = kmalloc(buf_len, GFP_USER);
+ if (!buffer)
+ RETURN(-ENOMEM);
+
+ mm = get_task_mm(current);
+ if (!mm) {
+ kfree(buffer);
+ RETURN(-EINVAL);
+ }
+
+ /* Avoid deadlocks on mmap_sem if called from sys_mmap_pgoff(),
+ * which is already holding mmap_sem for writes. If some other
+ * thread gets the write lock in the meantime, this thread will
+ * block, but at least it won't deadlock on itself. LU-1735 */
+ if (down_read_trylock(&mm->mmap_sem) == 0) {
+ kfree(buffer);
+ return -EDEADLK;
+ }
+ up_read(&mm->mmap_sem);
+
+ addr = mm->env_start;
+ while (addr < mm->env_end) {
+ int this_len, retval, scan_len;
+ char *env_start, *env_end;
+
+ memset(buffer, 0, buf_len);
+
+ this_len = min_t(int, mm->env_end - addr, buf_len);
+ retval = cfs_access_process_vm(current, addr, buffer,
+ this_len, 0);
+ if (retval != this_len)
+ break;
+
+ addr += retval;
+
+ /* Parse the buffer to find out the specified key/value pair.
+ * The "key=value" entries are separated by '\0'. */
+ env_start = buffer;
+ scan_len = this_len;
+ while (scan_len) {
+ char *entry;
+ int entry_len;
+
+ env_end = memscan(env_start, '\0', scan_len);
+ LASSERT(env_end >= env_start &&
+ env_end <= env_start + scan_len);
+
+ /* The last entry of this buffer cross the buffer
+ * boundary, reread it in next cycle. */
+ if (unlikely(env_end - env_start == scan_len)) {
+ /* This entry is too large to fit in buffer */
+ if (unlikely(scan_len == this_len)) {
+ CERROR("Too long env variable.\n");
+ GOTO(out, rc = -EINVAL);
+ }
+ addr -= scan_len;
+ break;
+ }
+
+ entry = env_start;
+ entry_len = env_end - env_start;
+
+ /* Key length + length of '=' */
+ if (entry_len > key_len + 1 &&
+ !memcmp(entry, key, key_len)) {
+ entry += key_len + 1;
+ entry_len -= key_len + 1;
+ /* The 'value' buffer passed in is too small.*/
+ if (entry_len >= *val_len)
+ GOTO(out, rc = -EOVERFLOW);
+
+ memcpy(value, entry, entry_len);
+ *val_len = entry_len;
+ GOTO(out, rc = 0);
+ }
+
+ scan_len -= (env_end - env_start + 1);
+ env_start = env_end + 1;
+ }
+ }
+ GOTO(out, rc = -ENOENT);
+
+out:
+ mmput(mm);
+ kfree((void *)buffer);
+ return rc;
}
+EXPORT_SYMBOL(cfs_get_environ);
EXPORT_SYMBOL(cfs_curproc_uid);
EXPORT_SYMBOL(cfs_curproc_pid);
EXPORT_SYMBOL(cfs_curproc_cap_pack);
EXPORT_SYMBOL(cfs_curproc_cap_unpack);
EXPORT_SYMBOL(cfs_capable);
-EXPORT_SYMBOL(cfs_curproc_is_32bit);
/*
* Local variables: