+ struct mm_struct *mm;
+ char *buffer;
+ int buf_len = PAGE_CACHE_SIZE;
+ int key_len = strlen(key);
+ unsigned long addr;
+ int rc;
+ bool skip = false;
+ ENTRY;
+
+ buffer = kmalloc(buf_len, GFP_USER);
+ if (!buffer)
+ RETURN(-ENOMEM);
+
+ mm = get_task_mm(current);
+ if (!mm) {
+ kfree(buffer);
+ RETURN(-EINVAL);
+ }
+
+ 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, mm, addr, buffer,
+ this_len, 0);
+ if (retval < 0)
+ GOTO(out, rc = retval);
+ else 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)) {
+ /* Just skip the entry larger than page size,
+ * it can't be jobID env variable. */
+ if (unlikely(scan_len == this_len))
+ skip = true;
+ else
+ addr -= scan_len;
+ break;
+ } else if (unlikely(skip)) {
+ skip = false;
+ goto skip;
+ }
+
+ 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);
+ }
+skip:
+ scan_len -= (env_end - env_start + 1);
+ env_start = env_end + 1;
+ }
+ }
+ GOTO(out, rc = -ENOENT);
+
+out:
+ mmput(mm);
+ kfree((void *)buffer);
+ return rc;