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/fs_struct.h>
45 #include <linux/pagemap.h>
46 #include <linux/compat.h>
47 #include <linux/thread_info.h>
49 #define DEBUG_SUBSYSTEM S_LNET
51 #include <libcfs/libcfs.h>
54 * Implementation of cfs_curproc API (see portals/include/libcfs/curproc.h)
58 /* Currently all the CFS_CAP_* defines match CAP_* ones. */
59 #define cfs_cap_pack(cap) (cap)
60 #define cfs_cap_unpack(cap) (cap)
62 static void cfs_kernel_cap_pack(kernel_cap_t kcap, cfs_cap_t *cap)
64 #if defined (_LINUX_CAPABILITY_VERSION) && _LINUX_CAPABILITY_VERSION == 0x19980330
65 *cap = cfs_cap_pack(kcap);
66 #elif defined (_LINUX_CAPABILITY_VERSION) && _LINUX_CAPABILITY_VERSION == 0x20071026
67 *cap = cfs_cap_pack(kcap[0]);
68 #elif defined(_KERNEL_CAPABILITY_VERSION) && _KERNEL_CAPABILITY_VERSION == 0x20080522
69 /* XXX lost high byte */
70 *cap = cfs_cap_pack(kcap.cap[0]);
72 #error "need correct _KERNEL_CAPABILITY_VERSION "
76 static void cfs_kernel_cap_unpack(kernel_cap_t *kcap, cfs_cap_t cap)
78 #if defined (_LINUX_CAPABILITY_VERSION) && _LINUX_CAPABILITY_VERSION == 0x19980330
79 *kcap = cfs_cap_unpack(cap);
80 #elif defined (_LINUX_CAPABILITY_VERSION) && _LINUX_CAPABILITY_VERSION == 0x20071026
81 (*kcap)[0] = cfs_cap_unpack(cap);
82 #elif defined(_KERNEL_CAPABILITY_VERSION) && _KERNEL_CAPABILITY_VERSION == 0x20080522
83 kcap->cap[0] = cfs_cap_unpack(cap);
85 #error "need correct _KERNEL_CAPABILITY_VERSION "
89 cfs_cap_t cfs_curproc_cap_pack(void)
92 cfs_kernel_cap_pack(current_cap(), &cap);
96 void cfs_curproc_cap_unpack(cfs_cap_t cap)
99 if ((cred = prepare_creds())) {
100 cfs_kernel_cap_unpack(&cred->cap_effective, cap);
105 int cfs_capable(cfs_cap_t cap)
107 return capable(cfs_cap_unpack(cap));
110 static int cfs_access_process_vm(struct task_struct *tsk,
111 struct mm_struct *mm,
113 void *buf, int len, int write)
115 /* Just copied from kernel for the kernels which doesn't
116 * have access_process_vm() exported */
117 struct vm_area_struct *vma;
121 /* Avoid deadlocks on mmap_sem if called from sys_mmap_pgoff(),
122 * which is already holding mmap_sem for writes. If some other
123 * thread gets the write lock in the meantime, this thread will
124 * block, but at least it won't deadlock on itself. LU-1735 */
125 if (down_read_trylock(&mm->mmap_sem) == 0)
128 /* ignore errors, just check how much was successfully transferred */
130 int bytes, rc, offset;
133 #if defined(HAVE_GET_USER_PAGES_GUP_FLAGS)
134 rc = get_user_pages(addr, 1, write ? FOLL_WRITE : 0, &page, &vma);
135 #elif defined(HAVE_GET_USER_PAGES_6ARG)
136 rc = get_user_pages(addr, 1, write, 1, &page, &vma);
138 rc = get_user_pages(tsk, mm, addr, 1, write, 1, &page, &vma);
144 offset = addr & (PAGE_SIZE-1);
145 if (bytes > PAGE_SIZE-offset)
146 bytes = PAGE_SIZE-offset;
150 copy_to_user_page(vma, page, addr,
151 maddr + offset, buf, bytes);
152 set_page_dirty_lock(page);
154 copy_from_user_page(vma, page, addr,
155 buf, maddr + offset, bytes);
163 up_read(&mm->mmap_sem);
165 return buf - old_buf;
168 /* Read the environment variable of current process specified by @key. */
169 int cfs_get_environ(const char *key, char *value, int *val_len)
171 struct mm_struct *mm;
173 int buf_len = PAGE_SIZE;
174 int key_len = strlen(key);
180 buffer = kmalloc(buf_len, GFP_USER);
184 mm = get_task_mm(current);
190 addr = mm->env_start;
191 while (addr < mm->env_end) {
192 int this_len, retval, scan_len;
193 char *env_start, *env_end;
195 memset(buffer, 0, buf_len);
197 this_len = min_t(int, mm->env_end - addr, buf_len);
198 retval = cfs_access_process_vm(current, mm, addr, buffer,
201 GOTO(out, rc = retval);
202 else if (retval != this_len)
207 /* Parse the buffer to find out the specified key/value pair.
208 * The "key=value" entries are separated by '\0'. */
215 env_end = memscan(env_start, '\0', scan_len);
216 LASSERT(env_end >= env_start &&
217 env_end <= env_start + scan_len);
219 /* The last entry of this buffer cross the buffer
220 * boundary, reread it in next cycle. */
221 if (unlikely(env_end - env_start == scan_len)) {
222 /* Just skip the entry larger than page size,
223 * it can't be jobID env variable. */
224 if (unlikely(scan_len == this_len))
229 } else if (unlikely(skip)) {
235 entry_len = env_end - env_start;
237 /* Key length + length of '=' */
238 if (entry_len > key_len + 1 &&
239 !memcmp(entry, key, key_len)) {
240 entry += key_len + 1;
241 entry_len -= key_len + 1;
243 /* The 'value' buffer passed in is too small.
244 * Copy what fits, but return -EOVERFLOW. */
245 if (entry_len >= *val_len) {
246 memcpy(value, entry, *val_len);
247 value[*val_len - 1] = 0;
248 GOTO(out, rc = -EOVERFLOW);
251 memcpy(value, entry, entry_len);
252 *val_len = entry_len;
256 scan_len -= (env_end - env_start + 1);
257 env_start = env_end + 1;
260 GOTO(out, rc = -ENOENT);
264 kfree((void *)buffer);
267 EXPORT_SYMBOL(cfs_get_environ);
269 EXPORT_SYMBOL(cfs_curproc_cap_pack);
270 EXPORT_SYMBOL(cfs_capable);
274 * c-indentation-style: "K&R"