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authorAl Viro <viro@zeniv.linux.org.uk>2009-12-24 00:44:44 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2010-01-14 09:05:26 -0500
commit4ecf09fd3a7c8858198875171b684c73338fad83 (patch)
tree3e14954a67e438be9a1bad29a6817ab3ddeff81f /arch/um
parent7b264fc2bef4a3de8bc5ff1a6c5b9e890b069a04 (diff)
Unrot uml mconsole a bit
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/drivers/mconsole_kern.c49
1 files changed, 18 insertions, 31 deletions
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 51069245b79a..3b3c36601a7b 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -125,50 +125,36 @@ void mconsole_log(struct mc_request *req)
125void mconsole_proc(struct mc_request *req) 125void mconsole_proc(struct mc_request *req)
126{ 126{
127 struct nameidata nd; 127 struct nameidata nd;
128 struct file_system_type *proc; 128 struct vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt;
129 struct super_block *super;
130 struct file *file; 129 struct file *file;
131 int n, err; 130 int n, err;
132 char *ptr = req->request.data, *buf; 131 char *ptr = req->request.data, *buf;
132 mm_segment_t old_fs = get_fs();
133 133
134 ptr += strlen("proc"); 134 ptr += strlen("proc");
135 ptr = skip_spaces(ptr); 135 ptr = skip_spaces(ptr);
136 136
137 proc = get_fs_type("proc"); 137 err = vfs_path_lookup(mnt->mnt_root, mnt, ptr, LOOKUP_FOLLOW, &nd);
138 if (proc == NULL) { 138 if (err) {
139 mconsole_reply(req, "procfs not registered", 1, 0); 139 mconsole_reply(req, "Failed to look up file", 1, 0);
140 goto out; 140 goto out;
141 } 141 }
142 142
143 super = (*proc->get_sb)(proc, 0, NULL, NULL); 143 err = may_open(&nd.path, MAY_READ, FMODE_READ);
144 put_filesystem(proc); 144 if (result) {
145 if (super == NULL) { 145 mconsole_reply(req, "Failed to open file", 1, 0);
146 mconsole_reply(req, "Failed to get procfs superblock", 1, 0); 146 path_put(&nd.path);
147 goto out; 147 goto out;
148 } 148 }
149 up_write(&super->s_umount);
150
151 nd.path.dentry = super->s_root;
152 nd.path.mnt = NULL;
153 nd.flags = O_RDONLY + 1;
154 nd.last_type = LAST_ROOT;
155
156 /* START: it was experienced that the stability problems are closed
157 * if commenting out these two calls + the below read cycle. To
158 * make UML crash again, it was enough to readd either one.*/
159 err = link_path_walk(ptr, &nd);
160 if (err) {
161 mconsole_reply(req, "Failed to look up file", 1, 0);
162 goto out_kill;
163 }
164 149
165 file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY, 150 file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
166 current_cred()); 151 current_cred());
152 err = PTR_ERR(file);
167 if (IS_ERR(file)) { 153 if (IS_ERR(file)) {
168 mconsole_reply(req, "Failed to open file", 1, 0); 154 mconsole_reply(req, "Failed to open file", 1, 0);
169 goto out_kill; 155 path_put(&nd.path);
156 goto out;
170 } 157 }
171 /*END*/
172 158
173 buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 159 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
174 if (buf == NULL) { 160 if (buf == NULL) {
@@ -176,10 +162,13 @@ void mconsole_proc(struct mc_request *req)
176 goto out_fput; 162 goto out_fput;
177 } 163 }
178 164
179 if ((file->f_op != NULL) && (file->f_op->read != NULL)) { 165 if (file->f_op->read) {
180 do { 166 do {
181 n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1, 167 loff_t pos;
182 &file->f_pos); 168 set_fs(KERNEL_DS);
169 n = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
170 file_pos_write(file, pos);
171 set_fs(old_fs);
183 if (n >= 0) { 172 if (n >= 0) {
184 buf[n] = '\0'; 173 buf[n] = '\0';
185 mconsole_reply(req, buf, 0, (n > 0)); 174 mconsole_reply(req, buf, 0, (n > 0));
@@ -197,8 +186,6 @@ void mconsole_proc(struct mc_request *req)
197 kfree(buf); 186 kfree(buf);
198 out_fput: 187 out_fput:
199 fput(file); 188 fput(file);
200 out_kill:
201 deactivate_super(super);
202 out: ; 189 out: ;
203} 190}
204#endif 191#endif