Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 1 | #include <linux/sched.h> |
| 2 | #include <linux/errno.h> |
| 3 | #include <linux/dcache.h> |
| 4 | #include <linux/path.h> |
| 5 | #include <linux/fdtable.h> |
| 6 | #include <linux/namei.h> |
| 7 | #include <linux/pid.h> |
| 8 | #include <linux/security.h> |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 9 | #include <linux/file.h> |
| 10 | #include <linux/seq_file.h> |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 11 | |
| 12 | #include <linux/proc_fs.h> |
| 13 | |
| 14 | #include "internal.h" |
| 15 | #include "fd.h" |
| 16 | |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 17 | static int seq_show(struct seq_file *m, void *v) |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 18 | { |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 19 | struct files_struct *files = NULL; |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 20 | int f_flags = 0, ret = -ENOENT; |
| 21 | struct file *file = NULL; |
| 22 | struct task_struct *task; |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 23 | |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 24 | task = get_proc_task(m->private); |
| 25 | if (!task) |
| 26 | return -ENOENT; |
| 27 | |
| 28 | files = get_files_struct(task); |
| 29 | put_task_struct(task); |
| 30 | |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 31 | if (files) { |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 32 | int fd = proc_fd(m->private); |
| 33 | |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 34 | spin_lock(&files->file_lock); |
| 35 | file = fcheck_files(files, fd); |
| 36 | if (file) { |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 37 | struct fdtable *fdt = files_fdtable(files); |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 38 | |
Al Viro | c6f3d81 | 2012-08-26 11:01:04 -0400 | [diff] [blame] | 39 | f_flags = file->f_flags; |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 40 | if (close_on_exec(fd, fdt)) |
| 41 | f_flags |= O_CLOEXEC; |
| 42 | |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 43 | get_file(file); |
| 44 | ret = 0; |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 45 | } |
| 46 | spin_unlock(&files->file_lock); |
| 47 | put_files_struct(files); |
| 48 | } |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 49 | |
| 50 | if (!ret) { |
| 51 | seq_printf(m, "pos:\t%lli\nflags:\t0%o\n", |
| 52 | (long long)file->f_pos, f_flags); |
Cyrill Gorcunov | 55985dd | 2012-12-17 16:04:55 -0800 | [diff] [blame] | 53 | if (file->f_op->show_fdinfo) |
| 54 | ret = file->f_op->show_fdinfo(m, file); |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 55 | fput(file); |
| 56 | } |
| 57 | |
| 58 | return ret; |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 59 | } |
| 60 | |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 61 | static int seq_fdinfo_open(struct inode *inode, struct file *file) |
| 62 | { |
| 63 | return single_open(file, seq_show, inode); |
| 64 | } |
| 65 | |
| 66 | static const struct file_operations proc_fdinfo_file_operations = { |
| 67 | .open = seq_fdinfo_open, |
| 68 | .read = seq_read, |
| 69 | .llseek = seq_lseek, |
| 70 | .release = single_release, |
| 71 | }; |
| 72 | |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 73 | static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags) |
| 74 | { |
| 75 | struct files_struct *files; |
| 76 | struct task_struct *task; |
| 77 | const struct cred *cred; |
| 78 | struct inode *inode; |
| 79 | int fd; |
| 80 | |
| 81 | if (flags & LOOKUP_RCU) |
| 82 | return -ECHILD; |
| 83 | |
| 84 | inode = dentry->d_inode; |
| 85 | task = get_proc_task(inode); |
| 86 | fd = proc_fd(inode); |
| 87 | |
| 88 | if (task) { |
| 89 | files = get_files_struct(task); |
| 90 | if (files) { |
| 91 | struct file *file; |
| 92 | |
| 93 | rcu_read_lock(); |
| 94 | file = fcheck_files(files, fd); |
| 95 | if (file) { |
| 96 | unsigned f_mode = file->f_mode; |
| 97 | |
| 98 | rcu_read_unlock(); |
| 99 | put_files_struct(files); |
| 100 | |
| 101 | if (task_dumpable(task)) { |
| 102 | rcu_read_lock(); |
| 103 | cred = __task_cred(task); |
| 104 | inode->i_uid = cred->euid; |
| 105 | inode->i_gid = cred->egid; |
| 106 | rcu_read_unlock(); |
| 107 | } else { |
| 108 | inode->i_uid = GLOBAL_ROOT_UID; |
| 109 | inode->i_gid = GLOBAL_ROOT_GID; |
| 110 | } |
| 111 | |
| 112 | if (S_ISLNK(inode->i_mode)) { |
| 113 | unsigned i_mode = S_IFLNK; |
| 114 | if (f_mode & FMODE_READ) |
| 115 | i_mode |= S_IRUSR | S_IXUSR; |
| 116 | if (f_mode & FMODE_WRITE) |
| 117 | i_mode |= S_IWUSR | S_IXUSR; |
| 118 | inode->i_mode = i_mode; |
| 119 | } |
| 120 | |
| 121 | security_task_to_inode(task, inode); |
| 122 | put_task_struct(task); |
| 123 | return 1; |
| 124 | } |
| 125 | rcu_read_unlock(); |
| 126 | put_files_struct(files); |
| 127 | } |
| 128 | put_task_struct(task); |
| 129 | } |
| 130 | |
| 131 | d_drop(dentry); |
| 132 | return 0; |
| 133 | } |
| 134 | |
| 135 | static const struct dentry_operations tid_fd_dentry_operations = { |
| 136 | .d_revalidate = tid_fd_revalidate, |
| 137 | .d_delete = pid_delete_dentry, |
| 138 | }; |
| 139 | |
| 140 | static int proc_fd_link(struct dentry *dentry, struct path *path) |
| 141 | { |
Cyrill Gorcunov | ddd3e07 | 2012-08-26 18:28:20 +0400 | [diff] [blame] | 142 | struct files_struct *files = NULL; |
| 143 | struct task_struct *task; |
| 144 | int ret = -ENOENT; |
| 145 | |
| 146 | task = get_proc_task(dentry->d_inode); |
| 147 | if (task) { |
| 148 | files = get_files_struct(task); |
| 149 | put_task_struct(task); |
| 150 | } |
| 151 | |
| 152 | if (files) { |
| 153 | int fd = proc_fd(dentry->d_inode); |
| 154 | struct file *fd_file; |
| 155 | |
| 156 | spin_lock(&files->file_lock); |
| 157 | fd_file = fcheck_files(files, fd); |
| 158 | if (fd_file) { |
| 159 | *path = fd_file->f_path; |
| 160 | path_get(&fd_file->f_path); |
| 161 | ret = 0; |
| 162 | } |
| 163 | spin_unlock(&files->file_lock); |
| 164 | put_files_struct(files); |
| 165 | } |
| 166 | |
| 167 | return ret; |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 168 | } |
| 169 | |
| 170 | static struct dentry * |
| 171 | proc_fd_instantiate(struct inode *dir, struct dentry *dentry, |
| 172 | struct task_struct *task, const void *ptr) |
| 173 | { |
| 174 | struct dentry *error = ERR_PTR(-ENOENT); |
| 175 | unsigned fd = (unsigned long)ptr; |
| 176 | struct proc_inode *ei; |
| 177 | struct inode *inode; |
| 178 | |
| 179 | inode = proc_pid_make_inode(dir->i_sb, task); |
| 180 | if (!inode) |
| 181 | goto out; |
| 182 | |
| 183 | ei = PROC_I(inode); |
| 184 | ei->fd = fd; |
| 185 | |
| 186 | inode->i_mode = S_IFLNK; |
| 187 | inode->i_op = &proc_pid_link_inode_operations; |
| 188 | inode->i_size = 64; |
| 189 | |
| 190 | ei->op.proc_get_link = proc_fd_link; |
| 191 | |
| 192 | d_set_d_op(dentry, &tid_fd_dentry_operations); |
| 193 | d_add(dentry, inode); |
| 194 | |
| 195 | /* Close the race of the process dying before we return the dentry */ |
| 196 | if (tid_fd_revalidate(dentry, 0)) |
| 197 | error = NULL; |
| 198 | out: |
| 199 | return error; |
| 200 | } |
| 201 | |
| 202 | static struct dentry *proc_lookupfd_common(struct inode *dir, |
| 203 | struct dentry *dentry, |
| 204 | instantiate_t instantiate) |
| 205 | { |
| 206 | struct task_struct *task = get_proc_task(dir); |
| 207 | struct dentry *result = ERR_PTR(-ENOENT); |
| 208 | unsigned fd = name_to_int(dentry); |
| 209 | |
| 210 | if (!task) |
| 211 | goto out_no_task; |
| 212 | if (fd == ~0U) |
| 213 | goto out; |
| 214 | |
| 215 | result = instantiate(dir, dentry, task, (void *)(unsigned long)fd); |
| 216 | out: |
| 217 | put_task_struct(task); |
| 218 | out_no_task: |
| 219 | return result; |
| 220 | } |
| 221 | |
| 222 | static int proc_readfd_common(struct file * filp, void * dirent, |
| 223 | filldir_t filldir, instantiate_t instantiate) |
| 224 | { |
| 225 | struct dentry *dentry = filp->f_path.dentry; |
| 226 | struct inode *inode = dentry->d_inode; |
| 227 | struct task_struct *p = get_proc_task(inode); |
| 228 | struct files_struct *files; |
| 229 | unsigned int fd, ino; |
| 230 | int retval; |
| 231 | |
| 232 | retval = -ENOENT; |
| 233 | if (!p) |
| 234 | goto out_no_task; |
| 235 | retval = 0; |
| 236 | |
| 237 | fd = filp->f_pos; |
| 238 | switch (fd) { |
| 239 | case 0: |
| 240 | if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0) |
| 241 | goto out; |
| 242 | filp->f_pos++; |
| 243 | case 1: |
| 244 | ino = parent_ino(dentry); |
| 245 | if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0) |
| 246 | goto out; |
| 247 | filp->f_pos++; |
| 248 | default: |
| 249 | files = get_files_struct(p); |
| 250 | if (!files) |
| 251 | goto out; |
| 252 | rcu_read_lock(); |
| 253 | for (fd = filp->f_pos - 2; |
| 254 | fd < files_fdtable(files)->max_fds; |
| 255 | fd++, filp->f_pos++) { |
| 256 | char name[PROC_NUMBUF]; |
| 257 | int len; |
| 258 | int rv; |
| 259 | |
| 260 | if (!fcheck_files(files, fd)) |
| 261 | continue; |
| 262 | rcu_read_unlock(); |
| 263 | |
| 264 | len = snprintf(name, sizeof(name), "%d", fd); |
| 265 | rv = proc_fill_cache(filp, dirent, filldir, |
| 266 | name, len, instantiate, p, |
| 267 | (void *)(unsigned long)fd); |
| 268 | if (rv < 0) |
| 269 | goto out_fd_loop; |
| 270 | rcu_read_lock(); |
| 271 | } |
| 272 | rcu_read_unlock(); |
| 273 | out_fd_loop: |
| 274 | put_files_struct(files); |
| 275 | } |
| 276 | out: |
| 277 | put_task_struct(p); |
| 278 | out_no_task: |
| 279 | return retval; |
| 280 | } |
| 281 | |
Cyrill Gorcunov | faf60af | 2012-08-23 14:43:24 +0400 | [diff] [blame] | 282 | static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir) |
| 283 | { |
| 284 | return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate); |
| 285 | } |
| 286 | |
| 287 | const struct file_operations proc_fd_operations = { |
| 288 | .read = generic_read_dir, |
| 289 | .readdir = proc_readfd, |
| 290 | .llseek = default_llseek, |
| 291 | }; |
| 292 | |
| 293 | static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry, |
| 294 | unsigned int flags) |
| 295 | { |
| 296 | return proc_lookupfd_common(dir, dentry, proc_fd_instantiate); |
| 297 | } |
| 298 | |
| 299 | /* |
| 300 | * /proc/pid/fd needs a special permission handler so that a process can still |
| 301 | * access /proc/self/fd after it has executed a setuid(). |
| 302 | */ |
| 303 | int proc_fd_permission(struct inode *inode, int mask) |
| 304 | { |
| 305 | int rv = generic_permission(inode, mask); |
| 306 | if (rv == 0) |
| 307 | return 0; |
| 308 | if (task_pid(current) == proc_pid(inode)) |
| 309 | rv = 0; |
| 310 | return rv; |
| 311 | } |
| 312 | |
| 313 | const struct inode_operations proc_fd_inode_operations = { |
| 314 | .lookup = proc_lookupfd, |
| 315 | .permission = proc_fd_permission, |
| 316 | .setattr = proc_setattr, |
| 317 | }; |
| 318 | |
| 319 | static struct dentry * |
| 320 | proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry, |
| 321 | struct task_struct *task, const void *ptr) |
| 322 | { |
| 323 | struct dentry *error = ERR_PTR(-ENOENT); |
| 324 | unsigned fd = (unsigned long)ptr; |
| 325 | struct proc_inode *ei; |
| 326 | struct inode *inode; |
| 327 | |
| 328 | inode = proc_pid_make_inode(dir->i_sb, task); |
| 329 | if (!inode) |
| 330 | goto out; |
| 331 | |
| 332 | ei = PROC_I(inode); |
| 333 | ei->fd = fd; |
| 334 | |
| 335 | inode->i_mode = S_IFREG | S_IRUSR; |
| 336 | inode->i_fop = &proc_fdinfo_file_operations; |
| 337 | |
| 338 | d_set_d_op(dentry, &tid_fd_dentry_operations); |
| 339 | d_add(dentry, inode); |
| 340 | |
| 341 | /* Close the race of the process dying before we return the dentry */ |
| 342 | if (tid_fd_revalidate(dentry, 0)) |
| 343 | error = NULL; |
| 344 | out: |
| 345 | return error; |
| 346 | } |
| 347 | |
| 348 | static struct dentry * |
| 349 | proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags) |
| 350 | { |
| 351 | return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate); |
| 352 | } |
| 353 | |
| 354 | static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir) |
| 355 | { |
| 356 | return proc_readfd_common(filp, dirent, filldir, |
| 357 | proc_fdinfo_instantiate); |
| 358 | } |
| 359 | |
| 360 | const struct inode_operations proc_fdinfo_inode_operations = { |
| 361 | .lookup = proc_lookupfdinfo, |
| 362 | .setattr = proc_setattr, |
| 363 | }; |
| 364 | |
| 365 | const struct file_operations proc_fdinfo_operations = { |
| 366 | .read = generic_read_dir, |
| 367 | .readdir = proc_readfdinfo, |
| 368 | .llseek = default_llseek, |
| 369 | }; |