4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
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12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.gnu.org/licenses/gpl-2.0.html
23 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Use is subject to license terms.
26 * Copyright (c) 2012, 2017, Intel Corporation.
29 * This file is part of Lustre, http://www.lustre.org/
30 * Lustre is a trademark of Sun Microsystems, Inc.
32 * libcfs/libcfs/linux/linux-curproc.c
34 * Lustre curproc API implementation for Linux kernel
36 * Author: Nikita Danilov <nikita@clusterfs.com>
39 #include <linux/sched.h>
40 #ifdef HAVE_SCHED_HEADERS
41 #include <linux/sched/signal.h>
42 #include <linux/sched/mm.h>
44 #include <linux/pagemap.h>
45 #include <linux/compat.h>
46 #include <linux/thread_info.h>
48 #define DEBUG_SUBSYSTEM S_LNET
50 #include <libcfs/libcfs.h>
53 * Implementation of cfs_curproc API (see portals/include/libcfs/curproc.h)
57 /* Currently all the CFS_CAP_* defines match CAP_* ones. */
58 #define cfs_cap_pack(cap) (cap)
59 #define cfs_cap_unpack(cap) (cap)
61 static void cfs_kernel_cap_pack(kernel_cap_t kcap, cfs_cap_t *cap)
63 #if defined (_LINUX_CAPABILITY_VERSION) && _LINUX_CAPABILITY_VERSION == 0x19980330
64 *cap = cfs_cap_pack(kcap);
65 #elif defined (_LINUX_CAPABILITY_VERSION) && _LINUX_CAPABILITY_VERSION == 0x20071026
66 *cap = cfs_cap_pack(kcap[0]);
67 #elif defined(_KERNEL_CAPABILITY_VERSION) && _KERNEL_CAPABILITY_VERSION == 0x20080522
68 /* XXX lost high byte */
69 *cap = cfs_cap_pack(kcap.cap[0]);
71 #error "need correct _KERNEL_CAPABILITY_VERSION "
75 static void cfs_kernel_cap_unpack(kernel_cap_t *kcap, cfs_cap_t cap)
77 #if defined (_LINUX_CAPABILITY_VERSION) && _LINUX_CAPABILITY_VERSION == 0x19980330
78 *kcap = cfs_cap_unpack(cap);
79 #elif defined (_LINUX_CAPABILITY_VERSION) && _LINUX_CAPABILITY_VERSION == 0x20071026
80 (*kcap)[0] = cfs_cap_unpack(cap);
81 #elif defined(_KERNEL_CAPABILITY_VERSION) && _KERNEL_CAPABILITY_VERSION == 0x20080522
82 kcap->cap[0] = cfs_cap_unpack(cap);
84 #error "need correct _KERNEL_CAPABILITY_VERSION "
88 cfs_cap_t cfs_curproc_cap_pack(void)
91 cfs_kernel_cap_pack(current_cap(), &cap);
95 void cfs_curproc_cap_unpack(cfs_cap_t cap)
98 if ((cred = prepare_creds())) {
99 cfs_kernel_cap_unpack(&cred->cap_effective, cap);
104 int cfs_capable(cfs_cap_t cap)
106 return capable(cfs_cap_unpack(cap));
109 static int cfs_access_process_vm(struct task_struct *tsk,
110 struct mm_struct *mm,
112 void *buf, int len, int write)
114 /* Just copied from kernel for the kernels which doesn't
115 * have access_process_vm() exported */
116 struct vm_area_struct *vma;
120 /* Avoid deadlocks on mmap_lock if called from sys_mmap_pgoff(),
121 * which is already holding mmap_lock for writes. If some other
122 * thread gets the write lock in the meantime, this thread will
123 * block, but at least it won't deadlock on itself. LU-1735 */
124 if (!mmap_read_trylock(mm))
127 /* ignore errors, just check how much was successfully transferred */
129 int bytes, rc, offset;
132 #if defined(HAVE_GET_USER_PAGES_GUP_FLAGS)
133 rc = get_user_pages(addr, 1, write ? FOLL_WRITE : 0, &page, &vma);
134 #elif defined(HAVE_GET_USER_PAGES_6ARG)
135 rc = get_user_pages(addr, 1, write, 1, &page, &vma);
137 rc = get_user_pages(tsk, mm, addr, 1, write, 1, &page, &vma);
143 offset = addr & (PAGE_SIZE-1);
144 if (bytes > PAGE_SIZE-offset)
145 bytes = PAGE_SIZE-offset;
149 copy_to_user_page(vma, page, addr,
150 maddr + offset, buf, bytes);
151 set_page_dirty_lock(page);
153 copy_from_user_page(vma, page, addr,
154 buf, maddr + offset, bytes);
162 mmap_read_unlock(mm);
164 return buf - old_buf;
167 /* Read the environment variable of current process specified by @key. */
168 int cfs_get_environ(const char *key, char *value, int *val_len)
170 struct mm_struct *mm;
172 int buf_len = PAGE_SIZE;
173 int key_len = strlen(key);
179 buffer = kmalloc(buf_len, GFP_USER);
183 mm = get_task_mm(current);
189 addr = mm->env_start;
190 while (addr < mm->env_end) {
191 int this_len, retval, scan_len;
192 char *env_start, *env_end;
194 memset(buffer, 0, buf_len);
196 this_len = min_t(int, mm->env_end - addr, buf_len);
197 retval = cfs_access_process_vm(current, mm, addr, buffer,
200 GOTO(out, rc = retval);
201 else if (retval != this_len)
206 /* Parse the buffer to find out the specified key/value pair.
207 * The "key=value" entries are separated by '\0'. */
214 env_end = memscan(env_start, '\0', scan_len);
215 LASSERT(env_end >= env_start &&
216 env_end <= env_start + scan_len);
218 /* The last entry of this buffer cross the buffer
219 * boundary, reread it in next cycle. */
220 if (unlikely(env_end - env_start == scan_len)) {
221 /* Just skip the entry larger than page size,
222 * it can't be jobID env variable. */
223 if (unlikely(scan_len == this_len))
228 } else if (unlikely(skip)) {
234 entry_len = env_end - env_start;
235 CDEBUG(D_INFO, "key: %s, entry: %s\n", key, entry);
237 /* Key length + length of '=' */
238 if (entry_len > key_len + 1 &&
239 entry[key_len] == '=' &&
240 !memcmp(entry, key, key_len)) {
241 entry += key_len + 1;
242 entry_len -= key_len + 1;
244 /* The 'value' buffer passed in is too small.
245 * Copy what fits, but return -EOVERFLOW. */
246 if (entry_len >= *val_len) {
247 memcpy(value, entry, *val_len);
248 value[*val_len - 1] = 0;
249 GOTO(out, rc = -EOVERFLOW);
252 memcpy(value, entry, entry_len);
253 *val_len = entry_len;
257 scan_len -= (env_end - env_start + 1);
258 env_start = env_end + 1;
261 GOTO(out, rc = -ENOENT);
265 kfree((void *)buffer);
268 EXPORT_SYMBOL(cfs_get_environ);
270 EXPORT_SYMBOL(cfs_curproc_cap_pack);
271 EXPORT_SYMBOL(cfs_capable);
275 * c-indentation-style: "K&R"