blob: c3c76fe78346485c9d55c8df9e46bb6fd1ca0c2b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/attr.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * changes by Thomas Schoebel-Theuer
6 */
7
8#include <linux/module.h>
9#include <linux/time.h>
10#include <linux/mm.h>
11#include <linux/string.h>
12#include <linux/smp_lock.h>
13#include <linux/dnotify.h>
14#include <linux/fcntl.h>
15#include <linux/quotaops.h>
16#include <linux/security.h>
17#include <linux/time.h>
18
19/* Taken over from the old code... */
20
21/* POSIX UID/GID verification for setting inode attributes. */
22int inode_change_ok(struct inode *inode, struct iattr *attr)
23{
24 int retval = -EPERM;
25 unsigned int ia_valid = attr->ia_valid;
26
27 /* If force is set do it anyway. */
28 if (ia_valid & ATTR_FORCE)
29 goto fine;
30
31 /* Make sure a caller can chown. */
32 if ((ia_valid & ATTR_UID) &&
33 (current->fsuid != inode->i_uid ||
34 attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
35 goto error;
36
37 /* Make sure caller can chgrp. */
38 if ((ia_valid & ATTR_GID) &&
39 (current->fsuid != inode->i_uid ||
40 (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
41 !capable(CAP_CHOWN))
42 goto error;
43
44 /* Make sure a caller can chmod. */
45 if (ia_valid & ATTR_MODE) {
46 if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
47 goto error;
48 /* Also check the setgid bit! */
49 if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
50 inode->i_gid) && !capable(CAP_FSETID))
51 attr->ia_mode &= ~S_ISGID;
52 }
53
54 /* Check for setting the inode time. */
55 if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {
56 if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
57 goto error;
58 }
59fine:
60 retval = 0;
61error:
62 return retval;
63}
64
65EXPORT_SYMBOL(inode_change_ok);
66
67int inode_setattr(struct inode * inode, struct iattr * attr)
68{
69 unsigned int ia_valid = attr->ia_valid;
70 int error = 0;
71
72 if (ia_valid & ATTR_SIZE) {
73 if (attr->ia_size != i_size_read(inode)) {
74 error = vmtruncate(inode, attr->ia_size);
75 if (error || (ia_valid == ATTR_SIZE))
76 goto out;
77 } else {
78 /*
79 * We skipped the truncate but must still update
80 * timestamps
81 */
82 ia_valid |= ATTR_MTIME|ATTR_CTIME;
83 }
84 }
85
86 if (ia_valid & ATTR_UID)
87 inode->i_uid = attr->ia_uid;
88 if (ia_valid & ATTR_GID)
89 inode->i_gid = attr->ia_gid;
90 if (ia_valid & ATTR_ATIME)
91 inode->i_atime = timespec_trunc(attr->ia_atime,
92 inode->i_sb->s_time_gran);
93 if (ia_valid & ATTR_MTIME)
94 inode->i_mtime = timespec_trunc(attr->ia_mtime,
95 inode->i_sb->s_time_gran);
96 if (ia_valid & ATTR_CTIME)
97 inode->i_ctime = timespec_trunc(attr->ia_ctime,
98 inode->i_sb->s_time_gran);
99 if (ia_valid & ATTR_MODE) {
100 umode_t mode = attr->ia_mode;
101
102 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
103 mode &= ~S_ISGID;
104 inode->i_mode = mode;
105 }
106 mark_inode_dirty(inode);
107out:
108 return error;
109}
110
111EXPORT_SYMBOL(inode_setattr);
112
113int setattr_mask(unsigned int ia_valid)
114{
115 unsigned long dn_mask = 0;
116
117 if (ia_valid & ATTR_UID)
118 dn_mask |= DN_ATTRIB;
119 if (ia_valid & ATTR_GID)
120 dn_mask |= DN_ATTRIB;
121 if (ia_valid & ATTR_SIZE)
122 dn_mask |= DN_MODIFY;
123 /* both times implies a utime(s) call */
124 if ((ia_valid & (ATTR_ATIME|ATTR_MTIME)) == (ATTR_ATIME|ATTR_MTIME))
125 dn_mask |= DN_ATTRIB;
126 else if (ia_valid & ATTR_ATIME)
127 dn_mask |= DN_ACCESS;
128 else if (ia_valid & ATTR_MTIME)
129 dn_mask |= DN_MODIFY;
130 if (ia_valid & ATTR_MODE)
131 dn_mask |= DN_ATTRIB;
132 return dn_mask;
133}
134
135int notify_change(struct dentry * dentry, struct iattr * attr)
136{
137 struct inode *inode = dentry->d_inode;
138 mode_t mode;
139 int error;
140 struct timespec now;
141 unsigned int ia_valid = attr->ia_valid;
142
143 if (!inode)
144 BUG();
145
146 mode = inode->i_mode;
147 now = current_fs_time(inode->i_sb);
148
149 attr->ia_ctime = now;
150 if (!(ia_valid & ATTR_ATIME_SET))
151 attr->ia_atime = now;
152 if (!(ia_valid & ATTR_MTIME_SET))
153 attr->ia_mtime = now;
154 if (ia_valid & ATTR_KILL_SUID) {
155 attr->ia_valid &= ~ATTR_KILL_SUID;
156 if (mode & S_ISUID) {
157 if (!(ia_valid & ATTR_MODE)) {
158 ia_valid = attr->ia_valid |= ATTR_MODE;
159 attr->ia_mode = inode->i_mode;
160 }
161 attr->ia_mode &= ~S_ISUID;
162 }
163 }
164 if (ia_valid & ATTR_KILL_SGID) {
165 attr->ia_valid &= ~ ATTR_KILL_SGID;
166 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
167 if (!(ia_valid & ATTR_MODE)) {
168 ia_valid = attr->ia_valid |= ATTR_MODE;
169 attr->ia_mode = inode->i_mode;
170 }
171 attr->ia_mode &= ~S_ISGID;
172 }
173 }
174 if (!attr->ia_valid)
175 return 0;
176
177 if (ia_valid & ATTR_SIZE)
178 down_write(&dentry->d_inode->i_alloc_sem);
179
180 if (inode->i_op && inode->i_op->setattr) {
181 error = security_inode_setattr(dentry, attr);
182 if (!error)
183 error = inode->i_op->setattr(dentry, attr);
184 } else {
185 error = inode_change_ok(inode, attr);
186 if (!error)
187 error = security_inode_setattr(dentry, attr);
188 if (!error) {
189 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
190 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
191 error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
192 if (!error)
193 error = inode_setattr(inode, attr);
194 }
195 }
196
197 if (ia_valid & ATTR_SIZE)
198 up_write(&dentry->d_inode->i_alloc_sem);
199
200 if (!error) {
201 unsigned long dn_mask = setattr_mask(ia_valid);
202 if (dn_mask)
203 dnotify_parent(dentry, dn_mask);
204 }
205 return error;
206}
207
208EXPORT_SYMBOL(notify_change);