1 // SPDX-License-Identifier: GPL-2.0 1 // SPDX-License-Identifier: GPL-2.0
2 /* 2 /*
3 * linux/kernel/acct.c 3 * linux/kernel/acct.c
4 * 4 *
5 * BSD Process Accounting for Linux 5 * BSD Process Accounting for Linux
6 * 6 *
7 * Author: Marco van Wieringen <mvw@planets.e 7 * Author: Marco van Wieringen <mvw@planets.elm.net>
8 * 8 *
9 * Some code based on ideas and code from: 9 * Some code based on ideas and code from:
10 * Thomas K. Dyas <tdyas@eden.rutgers.edu> 10 * Thomas K. Dyas <tdyas@eden.rutgers.edu>
11 * 11 *
12 * This file implements BSD-style process acc 12 * This file implements BSD-style process accounting. Whenever any
13 * process exits, an accounting record of typ 13 * process exits, an accounting record of type "struct acct" is
14 * written to the file specified with the acc 14 * written to the file specified with the acct() system call. It is
15 * up to user-level programs to do useful thi 15 * up to user-level programs to do useful things with the accounting
16 * log. The kernel just provides the raw acco 16 * log. The kernel just provides the raw accounting information.
17 * 17 *
18 * (C) Copyright 1995 - 1997 Marco van Wiering 18 * (C) Copyright 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V.
19 * 19 *
20 * Plugged two leaks. 1) It didn't return acc 20 * Plugged two leaks. 1) It didn't return acct_file into the free_filps if
21 * the file happened to be read-only. 2) If t 21 * the file happened to be read-only. 2) If the accounting was suspended
22 * due to the lack of space it happily allowe 22 * due to the lack of space it happily allowed to reopen it and completely
23 * lost the old acct_file. 3/10/98, Al Viro. 23 * lost the old acct_file. 3/10/98, Al Viro.
24 * 24 *
25 * Now we silently close acct_file on attempt 25 * Now we silently close acct_file on attempt to reopen. Cleaned sys_acct().
26 * XTerms and EMACS are manifestations of pur 26 * XTerms and EMACS are manifestations of pure evil. 21/10/98, AV.
27 * 27 *
28 * Fixed a nasty interaction with sys_umount( 28 * Fixed a nasty interaction with sys_umount(). If the accounting
29 * was suspeneded we failed to stop it on umo 29 * was suspeneded we failed to stop it on umount(). Messy.
30 * Another one: remount to readonly didn't st 30 * Another one: remount to readonly didn't stop accounting.
31 * Question: what should we do if we have 31 * Question: what should we do if we have CAP_SYS_ADMIN but not
32 * CAP_SYS_PACCT? Current code does the follo 32 * CAP_SYS_PACCT? Current code does the following: umount returns -EBUSY
33 * unless we are messing with the root. In th 33 * unless we are messing with the root. In that case we are getting a
34 * real mess with do_remount_sb(). 9/11/98, A 34 * real mess with do_remount_sb(). 9/11/98, AV.
35 * 35 *
36 * Fixed a bunch of races (and pair of leaks) 36 * Fixed a bunch of races (and pair of leaks). Probably not the best way,
37 * but this one obviously doesn't introduce d 37 * but this one obviously doesn't introduce deadlocks. Later. BTW, found
38 * one race (and leak) in BSD implementation. 38 * one race (and leak) in BSD implementation.
39 * OK, that's better. ANOTHER race and leak i 39 * OK, that's better. ANOTHER race and leak in BSD variant. There always
40 * is one more bug... 10/11/98, AV. 40 * is one more bug... 10/11/98, AV.
41 * 41 *
42 * Oh, fsck... Oopsable SMP race in do_pr 42 * Oh, fsck... Oopsable SMP race in do_process_acct() - we must hold
43 * ->mmap_lock to walk the vma list of current 43 * ->mmap_lock to walk the vma list of current->mm. Nasty, since it leaks
44 * a struct file opened for write. Fixed. 2/6/ 44 * a struct file opened for write. Fixed. 2/6/2000, AV.
45 */ 45 */
46 46
47 #include <linux/mm.h> 47 #include <linux/mm.h>
48 #include <linux/slab.h> 48 #include <linux/slab.h>
49 #include <linux/acct.h> 49 #include <linux/acct.h>
50 #include <linux/capability.h> 50 #include <linux/capability.h>
51 #include <linux/file.h> 51 #include <linux/file.h>
52 #include <linux/tty.h> 52 #include <linux/tty.h>
53 #include <linux/security.h> 53 #include <linux/security.h>
54 #include <linux/vfs.h> 54 #include <linux/vfs.h>
55 #include <linux/jiffies.h> 55 #include <linux/jiffies.h>
56 #include <linux/times.h> 56 #include <linux/times.h>
57 #include <linux/syscalls.h> 57 #include <linux/syscalls.h>
58 #include <linux/mount.h> 58 #include <linux/mount.h>
59 #include <linux/uaccess.h> 59 #include <linux/uaccess.h>
60 #include <linux/sched/cputime.h> 60 #include <linux/sched/cputime.h>
61 61
62 #include <asm/div64.h> 62 #include <asm/div64.h>
63 #include <linux/pid_namespace.h> 63 #include <linux/pid_namespace.h>
64 #include <linux/fs_pin.h> 64 #include <linux/fs_pin.h>
65 65
66 /* 66 /*
67 * These constants control the amount of frees 67 * These constants control the amount of freespace that suspend and
68 * resume the process accounting system, and t 68 * resume the process accounting system, and the time delay between
69 * each check. 69 * each check.
70 * Turned into sysctl-controllable parameters. 70 * Turned into sysctl-controllable parameters. AV, 12/11/98
71 */ 71 */
72 72
73 static int acct_parm[3] = {4, 2, 30}; 73 static int acct_parm[3] = {4, 2, 30};
74 #define RESUME (acct_parm[0]) /* >fo 74 #define RESUME (acct_parm[0]) /* >foo% free space - resume */
75 #define SUSPEND (acct_parm[1]) /* <fo 75 #define SUSPEND (acct_parm[1]) /* <foo% free space - suspend */
76 #define ACCT_TIMEOUT (acct_parm[2]) /* foo 76 #define ACCT_TIMEOUT (acct_parm[2]) /* foo second timeout between checks */
77 77
78 #ifdef CONFIG_SYSCTL 78 #ifdef CONFIG_SYSCTL
79 static struct ctl_table kern_acct_table[] = { 79 static struct ctl_table kern_acct_table[] = {
80 { 80 {
81 .procname = "acct", 81 .procname = "acct",
82 .data = &acct_parm, 82 .data = &acct_parm,
83 .maxlen = 3*sizeof(int 83 .maxlen = 3*sizeof(int),
84 .mode = 0644, 84 .mode = 0644,
85 .proc_handler = proc_dointve 85 .proc_handler = proc_dointvec,
86 }, 86 },
>> 87 { }
87 }; 88 };
88 89
89 static __init int kernel_acct_sysctls_init(voi 90 static __init int kernel_acct_sysctls_init(void)
90 { 91 {
91 register_sysctl_init("kernel", kern_ac 92 register_sysctl_init("kernel", kern_acct_table);
92 return 0; 93 return 0;
93 } 94 }
94 late_initcall(kernel_acct_sysctls_init); 95 late_initcall(kernel_acct_sysctls_init);
95 #endif /* CONFIG_SYSCTL */ 96 #endif /* CONFIG_SYSCTL */
96 97
97 /* 98 /*
98 * External references and all of the globals. 99 * External references and all of the globals.
99 */ 100 */
100 101
101 struct bsd_acct_struct { 102 struct bsd_acct_struct {
102 struct fs_pin pin; 103 struct fs_pin pin;
103 atomic_long_t count; 104 atomic_long_t count;
104 struct rcu_head rcu; 105 struct rcu_head rcu;
105 struct mutex lock; 106 struct mutex lock;
106 int active; 107 int active;
107 unsigned long needcheck; 108 unsigned long needcheck;
108 struct file *file; 109 struct file *file;
109 struct pid_namespace *ns; 110 struct pid_namespace *ns;
110 struct work_struct work; 111 struct work_struct work;
111 struct completion done; 112 struct completion done;
112 }; 113 };
113 114
114 static void do_acct_process(struct bsd_acct_st 115 static void do_acct_process(struct bsd_acct_struct *acct);
115 116
116 /* 117 /*
117 * Check the amount of free space and suspend/ 118 * Check the amount of free space and suspend/resume accordingly.
118 */ 119 */
119 static int check_free_space(struct bsd_acct_st 120 static int check_free_space(struct bsd_acct_struct *acct)
120 { 121 {
121 struct kstatfs sbuf; 122 struct kstatfs sbuf;
122 123
123 if (time_is_after_jiffies(acct->needch 124 if (time_is_after_jiffies(acct->needcheck))
124 goto out; 125 goto out;
125 126
126 /* May block */ 127 /* May block */
127 if (vfs_statfs(&acct->file->f_path, &s 128 if (vfs_statfs(&acct->file->f_path, &sbuf))
128 goto out; 129 goto out;
129 130
130 if (acct->active) { 131 if (acct->active) {
131 u64 suspend = sbuf.f_blocks * 132 u64 suspend = sbuf.f_blocks * SUSPEND;
132 do_div(suspend, 100); 133 do_div(suspend, 100);
133 if (sbuf.f_bavail <= suspend) 134 if (sbuf.f_bavail <= suspend) {
134 acct->active = 0; 135 acct->active = 0;
135 pr_info("Process accou 136 pr_info("Process accounting paused\n");
136 } 137 }
137 } else { 138 } else {
138 u64 resume = sbuf.f_blocks * R 139 u64 resume = sbuf.f_blocks * RESUME;
139 do_div(resume, 100); 140 do_div(resume, 100);
140 if (sbuf.f_bavail >= resume) { 141 if (sbuf.f_bavail >= resume) {
141 acct->active = 1; 142 acct->active = 1;
142 pr_info("Process accou 143 pr_info("Process accounting resumed\n");
143 } 144 }
144 } 145 }
145 146
146 acct->needcheck = jiffies + ACCT_TIMEO 147 acct->needcheck = jiffies + ACCT_TIMEOUT*HZ;
147 out: 148 out:
148 return acct->active; 149 return acct->active;
149 } 150 }
150 151
151 static void acct_put(struct bsd_acct_struct *p 152 static void acct_put(struct bsd_acct_struct *p)
152 { 153 {
153 if (atomic_long_dec_and_test(&p->count 154 if (atomic_long_dec_and_test(&p->count))
154 kfree_rcu(p, rcu); 155 kfree_rcu(p, rcu);
155 } 156 }
156 157
157 static inline struct bsd_acct_struct *to_acct( 158 static inline struct bsd_acct_struct *to_acct(struct fs_pin *p)
158 { 159 {
159 return p ? container_of(p, struct bsd_ 160 return p ? container_of(p, struct bsd_acct_struct, pin) : NULL;
160 } 161 }
161 162
162 static struct bsd_acct_struct *acct_get(struct 163 static struct bsd_acct_struct *acct_get(struct pid_namespace *ns)
163 { 164 {
164 struct bsd_acct_struct *res; 165 struct bsd_acct_struct *res;
165 again: 166 again:
166 smp_rmb(); 167 smp_rmb();
167 rcu_read_lock(); 168 rcu_read_lock();
168 res = to_acct(READ_ONCE(ns->bacct)); 169 res = to_acct(READ_ONCE(ns->bacct));
169 if (!res) { 170 if (!res) {
170 rcu_read_unlock(); 171 rcu_read_unlock();
171 return NULL; 172 return NULL;
172 } 173 }
173 if (!atomic_long_inc_not_zero(&res->co 174 if (!atomic_long_inc_not_zero(&res->count)) {
174 rcu_read_unlock(); 175 rcu_read_unlock();
175 cpu_relax(); 176 cpu_relax();
176 goto again; 177 goto again;
177 } 178 }
178 rcu_read_unlock(); 179 rcu_read_unlock();
179 mutex_lock(&res->lock); 180 mutex_lock(&res->lock);
180 if (res != to_acct(READ_ONCE(ns->bacct 181 if (res != to_acct(READ_ONCE(ns->bacct))) {
181 mutex_unlock(&res->lock); 182 mutex_unlock(&res->lock);
182 acct_put(res); 183 acct_put(res);
183 goto again; 184 goto again;
184 } 185 }
185 return res; 186 return res;
186 } 187 }
187 188
188 static void acct_pin_kill(struct fs_pin *pin) 189 static void acct_pin_kill(struct fs_pin *pin)
189 { 190 {
190 struct bsd_acct_struct *acct = to_acct 191 struct bsd_acct_struct *acct = to_acct(pin);
191 mutex_lock(&acct->lock); 192 mutex_lock(&acct->lock);
192 do_acct_process(acct); 193 do_acct_process(acct);
193 schedule_work(&acct->work); 194 schedule_work(&acct->work);
194 wait_for_completion(&acct->done); 195 wait_for_completion(&acct->done);
195 cmpxchg(&acct->ns->bacct, pin, NULL); 196 cmpxchg(&acct->ns->bacct, pin, NULL);
196 mutex_unlock(&acct->lock); 197 mutex_unlock(&acct->lock);
197 pin_remove(pin); 198 pin_remove(pin);
198 acct_put(acct); 199 acct_put(acct);
199 } 200 }
200 201
201 static void close_work(struct work_struct *wor 202 static void close_work(struct work_struct *work)
202 { 203 {
203 struct bsd_acct_struct *acct = contain 204 struct bsd_acct_struct *acct = container_of(work, struct bsd_acct_struct, work);
204 struct file *file = acct->file; 205 struct file *file = acct->file;
205 if (file->f_op->flush) 206 if (file->f_op->flush)
206 file->f_op->flush(file, NULL); 207 file->f_op->flush(file, NULL);
207 __fput_sync(file); 208 __fput_sync(file);
208 complete(&acct->done); 209 complete(&acct->done);
209 } 210 }
210 211
211 static int acct_on(struct filename *pathname) 212 static int acct_on(struct filename *pathname)
212 { 213 {
213 struct file *file; 214 struct file *file;
214 struct vfsmount *mnt, *internal; 215 struct vfsmount *mnt, *internal;
215 struct pid_namespace *ns = task_active 216 struct pid_namespace *ns = task_active_pid_ns(current);
216 struct bsd_acct_struct *acct; 217 struct bsd_acct_struct *acct;
217 struct fs_pin *old; 218 struct fs_pin *old;
218 int err; 219 int err;
219 220
220 acct = kzalloc(sizeof(struct bsd_acct_ 221 acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
221 if (!acct) 222 if (!acct)
222 return -ENOMEM; 223 return -ENOMEM;
223 224
224 /* Difference from BSD - they don't do 225 /* Difference from BSD - they don't do O_APPEND */
225 file = file_open_name(pathname, O_WRON 226 file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
226 if (IS_ERR(file)) { 227 if (IS_ERR(file)) {
227 kfree(acct); 228 kfree(acct);
228 return PTR_ERR(file); 229 return PTR_ERR(file);
229 } 230 }
230 231
231 if (!S_ISREG(file_inode(file)->i_mode) 232 if (!S_ISREG(file_inode(file)->i_mode)) {
232 kfree(acct); 233 kfree(acct);
233 filp_close(file, NULL); 234 filp_close(file, NULL);
234 return -EACCES; 235 return -EACCES;
235 } 236 }
236 237
237 if (!(file->f_mode & FMODE_CAN_WRITE)) 238 if (!(file->f_mode & FMODE_CAN_WRITE)) {
238 kfree(acct); 239 kfree(acct);
239 filp_close(file, NULL); 240 filp_close(file, NULL);
240 return -EIO; 241 return -EIO;
241 } 242 }
242 internal = mnt_clone_internal(&file->f 243 internal = mnt_clone_internal(&file->f_path);
243 if (IS_ERR(internal)) { 244 if (IS_ERR(internal)) {
244 kfree(acct); 245 kfree(acct);
245 filp_close(file, NULL); 246 filp_close(file, NULL);
246 return PTR_ERR(internal); 247 return PTR_ERR(internal);
247 } 248 }
248 err = mnt_get_write_access(internal); 249 err = mnt_get_write_access(internal);
249 if (err) { 250 if (err) {
250 mntput(internal); 251 mntput(internal);
251 kfree(acct); 252 kfree(acct);
252 filp_close(file, NULL); 253 filp_close(file, NULL);
253 return err; 254 return err;
254 } 255 }
255 mnt = file->f_path.mnt; 256 mnt = file->f_path.mnt;
256 file->f_path.mnt = internal; 257 file->f_path.mnt = internal;
257 258
258 atomic_long_set(&acct->count, 1); 259 atomic_long_set(&acct->count, 1);
259 init_fs_pin(&acct->pin, acct_pin_kill) 260 init_fs_pin(&acct->pin, acct_pin_kill);
260 acct->file = file; 261 acct->file = file;
261 acct->needcheck = jiffies; 262 acct->needcheck = jiffies;
262 acct->ns = ns; 263 acct->ns = ns;
263 mutex_init(&acct->lock); 264 mutex_init(&acct->lock);
264 INIT_WORK(&acct->work, close_work); 265 INIT_WORK(&acct->work, close_work);
265 init_completion(&acct->done); 266 init_completion(&acct->done);
266 mutex_lock_nested(&acct->lock, 1); 267 mutex_lock_nested(&acct->lock, 1); /* nobody has seen it yet */
267 pin_insert(&acct->pin, mnt); 268 pin_insert(&acct->pin, mnt);
268 269
269 rcu_read_lock(); 270 rcu_read_lock();
270 old = xchg(&ns->bacct, &acct->pin); 271 old = xchg(&ns->bacct, &acct->pin);
271 mutex_unlock(&acct->lock); 272 mutex_unlock(&acct->lock);
272 pin_kill(old); 273 pin_kill(old);
273 mnt_put_write_access(mnt); 274 mnt_put_write_access(mnt);
274 mntput(mnt); 275 mntput(mnt);
275 return 0; 276 return 0;
276 } 277 }
277 278
278 static DEFINE_MUTEX(acct_on_mutex); 279 static DEFINE_MUTEX(acct_on_mutex);
279 280
280 /** 281 /**
281 * sys_acct - enable/disable process accountin 282 * sys_acct - enable/disable process accounting
282 * @name: file name for accounting records or 283 * @name: file name for accounting records or NULL to shutdown accounting
283 * 284 *
284 * sys_acct() is the only system call needed t 285 * sys_acct() is the only system call needed to implement process
285 * accounting. It takes the name of the file w 286 * accounting. It takes the name of the file where accounting records
286 * should be written. If the filename is NULL, 287 * should be written. If the filename is NULL, accounting will be
287 * shutdown. 288 * shutdown.
288 * 289 *
289 * Returns: 0 for success or negative errno va 290 * Returns: 0 for success or negative errno values for failure.
290 */ 291 */
291 SYSCALL_DEFINE1(acct, const char __user *, nam 292 SYSCALL_DEFINE1(acct, const char __user *, name)
292 { 293 {
293 int error = 0; 294 int error = 0;
294 295
295 if (!capable(CAP_SYS_PACCT)) 296 if (!capable(CAP_SYS_PACCT))
296 return -EPERM; 297 return -EPERM;
297 298
298 if (name) { 299 if (name) {
299 struct filename *tmp = getname 300 struct filename *tmp = getname(name);
300 301
301 if (IS_ERR(tmp)) 302 if (IS_ERR(tmp))
302 return PTR_ERR(tmp); 303 return PTR_ERR(tmp);
303 mutex_lock(&acct_on_mutex); 304 mutex_lock(&acct_on_mutex);
304 error = acct_on(tmp); 305 error = acct_on(tmp);
305 mutex_unlock(&acct_on_mutex); 306 mutex_unlock(&acct_on_mutex);
306 putname(tmp); 307 putname(tmp);
307 } else { 308 } else {
308 rcu_read_lock(); 309 rcu_read_lock();
309 pin_kill(task_active_pid_ns(cu 310 pin_kill(task_active_pid_ns(current)->bacct);
310 } 311 }
311 312
312 return error; 313 return error;
313 } 314 }
314 315
315 void acct_exit_ns(struct pid_namespace *ns) 316 void acct_exit_ns(struct pid_namespace *ns)
316 { 317 {
317 rcu_read_lock(); 318 rcu_read_lock();
318 pin_kill(ns->bacct); 319 pin_kill(ns->bacct);
319 } 320 }
320 321
321 /* 322 /*
322 * encode an u64 into a comp_t 323 * encode an u64 into a comp_t
323 * 324 *
324 * This routine has been adopted from the enc 325 * This routine has been adopted from the encode_comp_t() function in
325 * the kern_acct.c file of the FreeBSD operat 326 * the kern_acct.c file of the FreeBSD operating system. The encoding
326 * is a 13-bit fraction with a 3-bit (base 8) 327 * is a 13-bit fraction with a 3-bit (base 8) exponent.
327 */ 328 */
328 329
329 #define MANTSIZE 13 330 #define MANTSIZE 13 /* 13 bit mantissa. */
330 #define EXPSIZE 3 331 #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
331 #define MAXFRACT ((1 << MANTSIZE) - 1) 332 #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
332 333
333 static comp_t encode_comp_t(u64 value) 334 static comp_t encode_comp_t(u64 value)
334 { 335 {
335 int exp, rnd; 336 int exp, rnd;
336 337
337 exp = rnd = 0; 338 exp = rnd = 0;
338 while (value > MAXFRACT) { 339 while (value > MAXFRACT) {
339 rnd = value & (1 << (EXPSIZE - 340 rnd = value & (1 << (EXPSIZE - 1)); /* Round up? */
340 value >>= EXPSIZE; /* Bas 341 value >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
341 exp++; 342 exp++;
342 } 343 }
343 344
344 /* 345 /*
345 * If we need to round up, do it (and 346 * If we need to round up, do it (and handle overflow correctly).
346 */ 347 */
347 if (rnd && (++value > MAXFRACT)) { 348 if (rnd && (++value > MAXFRACT)) {
348 value >>= EXPSIZE; 349 value >>= EXPSIZE;
349 exp++; 350 exp++;
350 } 351 }
351 352
352 if (exp > (((comp_t) ~0U) >> MANTSIZE) 353 if (exp > (((comp_t) ~0U) >> MANTSIZE))
353 return (comp_t) ~0U; 354 return (comp_t) ~0U;
354 /* 355 /*
355 * Clean it up and polish it off. 356 * Clean it up and polish it off.
356 */ 357 */
357 exp <<= MANTSIZE; /* Shi 358 exp <<= MANTSIZE; /* Shift the exponent into place */
358 exp += value; /* and 359 exp += value; /* and add on the mantissa. */
359 return exp; 360 return exp;
360 } 361 }
361 362
362 #if ACCT_VERSION == 1 || ACCT_VERSION == 2 363 #if ACCT_VERSION == 1 || ACCT_VERSION == 2
363 /* 364 /*
364 * encode an u64 into a comp2_t (24 bits) 365 * encode an u64 into a comp2_t (24 bits)
365 * 366 *
366 * Format: 5 bit base 2 exponent, 20 bits mant 367 * Format: 5 bit base 2 exponent, 20 bits mantissa.
367 * The leading bit of the mantissa is not stor 368 * The leading bit of the mantissa is not stored, but implied for
368 * non-zero exponents. 369 * non-zero exponents.
369 * Largest encodable value is 50 bits. 370 * Largest encodable value is 50 bits.
370 */ 371 */
371 372
372 #define MANTSIZE2 20 373 #define MANTSIZE2 20 /* 20 bit mantissa. */
373 #define EXPSIZE2 5 374 #define EXPSIZE2 5 /* 5 bit base 2 exponent. */
374 #define MAXFRACT2 ((1ul << MANTSIZE2) - 375 #define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */
375 #define MAXEXP2 ((1 << EXPSIZE2) - 1) 376 #define MAXEXP2 ((1 << EXPSIZE2) - 1) /* Maximum exponent. */
376 377
377 static comp2_t encode_comp2_t(u64 value) 378 static comp2_t encode_comp2_t(u64 value)
378 { 379 {
379 int exp, rnd; 380 int exp, rnd;
380 381
381 exp = (value > (MAXFRACT2>>1)); 382 exp = (value > (MAXFRACT2>>1));
382 rnd = 0; 383 rnd = 0;
383 while (value > MAXFRACT2) { 384 while (value > MAXFRACT2) {
384 rnd = value & 1; 385 rnd = value & 1;
385 value >>= 1; 386 value >>= 1;
386 exp++; 387 exp++;
387 } 388 }
388 389
389 /* 390 /*
390 * If we need to round up, do it (and 391 * If we need to round up, do it (and handle overflow correctly).
391 */ 392 */
392 if (rnd && (++value > MAXFRACT2)) { 393 if (rnd && (++value > MAXFRACT2)) {
393 value >>= 1; 394 value >>= 1;
394 exp++; 395 exp++;
395 } 396 }
396 397
397 if (exp > MAXEXP2) { 398 if (exp > MAXEXP2) {
398 /* Overflow. Return largest re 399 /* Overflow. Return largest representable number instead. */
399 return (1ul << (MANTSIZE2+EXPS 400 return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1;
400 } else { 401 } else {
401 return (value & (MAXFRACT2>>1) 402 return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1));
402 } 403 }
403 } 404 }
404 #elif ACCT_VERSION == 3 405 #elif ACCT_VERSION == 3
405 /* 406 /*
406 * encode an u64 into a 32 bit IEEE float 407 * encode an u64 into a 32 bit IEEE float
407 */ 408 */
408 static u32 encode_float(u64 value) 409 static u32 encode_float(u64 value)
409 { 410 {
410 unsigned exp = 190; 411 unsigned exp = 190;
411 unsigned u; 412 unsigned u;
412 413
413 if (value == 0) 414 if (value == 0)
414 return 0; 415 return 0;
415 while ((s64)value > 0) { 416 while ((s64)value > 0) {
416 value <<= 1; 417 value <<= 1;
417 exp--; 418 exp--;
418 } 419 }
419 u = (u32)(value >> 40) & 0x7fffffu; 420 u = (u32)(value >> 40) & 0x7fffffu;
420 return u | (exp << 23); 421 return u | (exp << 23);
421 } 422 }
422 #endif 423 #endif
423 424
424 /* 425 /*
425 * Write an accounting entry for an exiting p 426 * Write an accounting entry for an exiting process
426 * 427 *
427 * The acct_process() call is the workhorse o 428 * The acct_process() call is the workhorse of the process
428 * accounting system. The struct acct is buil 429 * accounting system. The struct acct is built here and then written
429 * into the accounting file. This function sh 430 * into the accounting file. This function should only be called from
430 * do_exit() or when switching to a different 431 * do_exit() or when switching to a different output file.
431 */ 432 */
432 433
433 static void fill_ac(acct_t *ac) 434 static void fill_ac(acct_t *ac)
434 { 435 {
435 struct pacct_struct *pacct = ¤t- 436 struct pacct_struct *pacct = ¤t->signal->pacct;
436 u64 elapsed, run_time; 437 u64 elapsed, run_time;
437 time64_t btime; 438 time64_t btime;
438 struct tty_struct *tty; 439 struct tty_struct *tty;
439 440
440 /* 441 /*
441 * Fill the accounting struct with the 442 * Fill the accounting struct with the needed info as recorded
442 * by the different kernel functions. 443 * by the different kernel functions.
443 */ 444 */
444 memset(ac, 0, sizeof(acct_t)); 445 memset(ac, 0, sizeof(acct_t));
445 446
446 ac->ac_version = ACCT_VERSION | ACCT_B 447 ac->ac_version = ACCT_VERSION | ACCT_BYTEORDER;
447 strscpy(ac->ac_comm, current->comm, si 448 strscpy(ac->ac_comm, current->comm, sizeof(ac->ac_comm));
448 449
449 /* calculate run_time in nsec*/ 450 /* calculate run_time in nsec*/
450 run_time = ktime_get_ns(); 451 run_time = ktime_get_ns();
451 run_time -= current->group_leader->sta 452 run_time -= current->group_leader->start_time;
452 /* convert nsec -> AHZ */ 453 /* convert nsec -> AHZ */
453 elapsed = nsec_to_AHZ(run_time); 454 elapsed = nsec_to_AHZ(run_time);
454 #if ACCT_VERSION == 3 455 #if ACCT_VERSION == 3
455 ac->ac_etime = encode_float(elapsed); 456 ac->ac_etime = encode_float(elapsed);
456 #else 457 #else
457 ac->ac_etime = encode_comp_t(elapsed < 458 ac->ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
458 (unsigned long 459 (unsigned long) elapsed : (unsigned long) -1l);
459 #endif 460 #endif
460 #if ACCT_VERSION == 1 || ACCT_VERSION == 2 461 #if ACCT_VERSION == 1 || ACCT_VERSION == 2
461 { 462 {
462 /* new enlarged etime field */ 463 /* new enlarged etime field */
463 comp2_t etime = encode_comp2_t 464 comp2_t etime = encode_comp2_t(elapsed);
464 465
465 ac->ac_etime_hi = etime >> 16; 466 ac->ac_etime_hi = etime >> 16;
466 ac->ac_etime_lo = (u16) etime; 467 ac->ac_etime_lo = (u16) etime;
467 } 468 }
468 #endif 469 #endif
469 do_div(elapsed, AHZ); 470 do_div(elapsed, AHZ);
470 btime = ktime_get_real_seconds() - ela 471 btime = ktime_get_real_seconds() - elapsed;
471 ac->ac_btime = clamp_t(time64_t, btime 472 ac->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX);
472 #if ACCT_VERSION == 2 473 #if ACCT_VERSION == 2
473 ac->ac_ahz = AHZ; 474 ac->ac_ahz = AHZ;
474 #endif 475 #endif
475 476
476 spin_lock_irq(¤t->sighand->siglo 477 spin_lock_irq(¤t->sighand->siglock);
477 tty = current->signal->tty; /* Saf 478 tty = current->signal->tty; /* Safe as we hold the siglock */
478 ac->ac_tty = tty ? old_encode_dev(tty_ 479 ac->ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
479 ac->ac_utime = encode_comp_t(nsec_to_A 480 ac->ac_utime = encode_comp_t(nsec_to_AHZ(pacct->ac_utime));
480 ac->ac_stime = encode_comp_t(nsec_to_A 481 ac->ac_stime = encode_comp_t(nsec_to_AHZ(pacct->ac_stime));
481 ac->ac_flag = pacct->ac_flag; 482 ac->ac_flag = pacct->ac_flag;
482 ac->ac_mem = encode_comp_t(pacct->ac_m 483 ac->ac_mem = encode_comp_t(pacct->ac_mem);
483 ac->ac_minflt = encode_comp_t(pacct->a 484 ac->ac_minflt = encode_comp_t(pacct->ac_minflt);
484 ac->ac_majflt = encode_comp_t(pacct->a 485 ac->ac_majflt = encode_comp_t(pacct->ac_majflt);
485 ac->ac_exitcode = pacct->ac_exitcode; 486 ac->ac_exitcode = pacct->ac_exitcode;
486 spin_unlock_irq(¤t->sighand->sig 487 spin_unlock_irq(¤t->sighand->siglock);
487 } 488 }
488 /* 489 /*
489 * do_acct_process does all actual work. Call 490 * do_acct_process does all actual work. Caller holds the reference to file.
490 */ 491 */
491 static void do_acct_process(struct bsd_acct_st 492 static void do_acct_process(struct bsd_acct_struct *acct)
492 { 493 {
493 acct_t ac; 494 acct_t ac;
494 unsigned long flim; 495 unsigned long flim;
495 const struct cred *orig_cred; 496 const struct cred *orig_cred;
496 struct file *file = acct->file; 497 struct file *file = acct->file;
497 498
498 /* 499 /*
499 * Accounting records are not subject 500 * Accounting records are not subject to resource limits.
500 */ 501 */
501 flim = rlimit(RLIMIT_FSIZE); 502 flim = rlimit(RLIMIT_FSIZE);
502 current->signal->rlim[RLIMIT_FSIZE].rl 503 current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
503 /* Perform file operations on behalf o 504 /* Perform file operations on behalf of whoever enabled accounting */
504 orig_cred = override_creds(file->f_cre 505 orig_cred = override_creds(file->f_cred);
505 506
506 /* 507 /*
507 * First check to see if there is enou 508 * First check to see if there is enough free_space to continue
508 * the process accounting system. 509 * the process accounting system.
509 */ 510 */
510 if (!check_free_space(acct)) 511 if (!check_free_space(acct))
511 goto out; 512 goto out;
512 513
513 fill_ac(&ac); 514 fill_ac(&ac);
514 /* we really need to bite the bullet a 515 /* we really need to bite the bullet and change layout */
515 ac.ac_uid = from_kuid_munged(file->f_c 516 ac.ac_uid = from_kuid_munged(file->f_cred->user_ns, orig_cred->uid);
516 ac.ac_gid = from_kgid_munged(file->f_c 517 ac.ac_gid = from_kgid_munged(file->f_cred->user_ns, orig_cred->gid);
517 #if ACCT_VERSION == 1 || ACCT_VERSION == 2 518 #if ACCT_VERSION == 1 || ACCT_VERSION == 2
518 /* backward-compatible 16 bit fields * 519 /* backward-compatible 16 bit fields */
519 ac.ac_uid16 = ac.ac_uid; 520 ac.ac_uid16 = ac.ac_uid;
520 ac.ac_gid16 = ac.ac_gid; 521 ac.ac_gid16 = ac.ac_gid;
521 #elif ACCT_VERSION == 3 522 #elif ACCT_VERSION == 3
522 { 523 {
523 struct pid_namespace *ns = acc 524 struct pid_namespace *ns = acct->ns;
524 525
525 ac.ac_pid = task_tgid_nr_ns(cu 526 ac.ac_pid = task_tgid_nr_ns(current, ns);
526 rcu_read_lock(); 527 rcu_read_lock();
527 ac.ac_ppid = task_tgid_nr_ns(r 528 ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent),
528 n 529 ns);
529 rcu_read_unlock(); 530 rcu_read_unlock();
530 } 531 }
531 #endif 532 #endif
532 /* 533 /*
533 * Get freeze protection. If the fs is 534 * Get freeze protection. If the fs is frozen, just skip the write
534 * as we could deadlock the system oth 535 * as we could deadlock the system otherwise.
535 */ 536 */
536 if (file_start_write_trylock(file)) { 537 if (file_start_write_trylock(file)) {
537 /* it's been opened O_APPEND, 538 /* it's been opened O_APPEND, so position is irrelevant */
538 loff_t pos = 0; 539 loff_t pos = 0;
539 __kernel_write(file, &ac, size 540 __kernel_write(file, &ac, sizeof(acct_t), &pos);
540 file_end_write(file); 541 file_end_write(file);
541 } 542 }
542 out: 543 out:
543 current->signal->rlim[RLIMIT_FSIZE].rl 544 current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
544 revert_creds(orig_cred); 545 revert_creds(orig_cred);
545 } 546 }
546 547
547 /** 548 /**
548 * acct_collect - collect accounting informati 549 * acct_collect - collect accounting information into pacct_struct
549 * @exitcode: task exit code 550 * @exitcode: task exit code
550 * @group_dead: not 0, if this thread is the l 551 * @group_dead: not 0, if this thread is the last one in the process.
551 */ 552 */
552 void acct_collect(long exitcode, int group_dea 553 void acct_collect(long exitcode, int group_dead)
553 { 554 {
554 struct pacct_struct *pacct = ¤t- 555 struct pacct_struct *pacct = ¤t->signal->pacct;
555 u64 utime, stime; 556 u64 utime, stime;
556 unsigned long vsize = 0; 557 unsigned long vsize = 0;
557 558
558 if (group_dead && current->mm) { 559 if (group_dead && current->mm) {
559 struct mm_struct *mm = current 560 struct mm_struct *mm = current->mm;
560 VMA_ITERATOR(vmi, mm, 0); 561 VMA_ITERATOR(vmi, mm, 0);
561 struct vm_area_struct *vma; 562 struct vm_area_struct *vma;
562 563
563 mmap_read_lock(mm); 564 mmap_read_lock(mm);
564 for_each_vma(vmi, vma) 565 for_each_vma(vmi, vma)
565 vsize += vma->vm_end - 566 vsize += vma->vm_end - vma->vm_start;
566 mmap_read_unlock(mm); 567 mmap_read_unlock(mm);
567 } 568 }
568 569
569 spin_lock_irq(¤t->sighand->siglo 570 spin_lock_irq(¤t->sighand->siglock);
570 if (group_dead) 571 if (group_dead)
571 pacct->ac_mem = vsize / 1024; 572 pacct->ac_mem = vsize / 1024;
572 if (thread_group_leader(current)) { 573 if (thread_group_leader(current)) {
573 pacct->ac_exitcode = exitcode; 574 pacct->ac_exitcode = exitcode;
574 if (current->flags & PF_FORKNO 575 if (current->flags & PF_FORKNOEXEC)
575 pacct->ac_flag |= AFOR 576 pacct->ac_flag |= AFORK;
576 } 577 }
577 if (current->flags & PF_SUPERPRIV) 578 if (current->flags & PF_SUPERPRIV)
578 pacct->ac_flag |= ASU; 579 pacct->ac_flag |= ASU;
579 if (current->flags & PF_DUMPCORE) 580 if (current->flags & PF_DUMPCORE)
580 pacct->ac_flag |= ACORE; 581 pacct->ac_flag |= ACORE;
581 if (current->flags & PF_SIGNALED) 582 if (current->flags & PF_SIGNALED)
582 pacct->ac_flag |= AXSIG; 583 pacct->ac_flag |= AXSIG;
583 584
584 task_cputime(current, &utime, &stime); 585 task_cputime(current, &utime, &stime);
585 pacct->ac_utime += utime; 586 pacct->ac_utime += utime;
586 pacct->ac_stime += stime; 587 pacct->ac_stime += stime;
587 pacct->ac_minflt += current->min_flt; 588 pacct->ac_minflt += current->min_flt;
588 pacct->ac_majflt += current->maj_flt; 589 pacct->ac_majflt += current->maj_flt;
589 spin_unlock_irq(¤t->sighand->sig 590 spin_unlock_irq(¤t->sighand->siglock);
590 } 591 }
591 592
592 static void slow_acct_process(struct pid_names 593 static void slow_acct_process(struct pid_namespace *ns)
593 { 594 {
594 for ( ; ns; ns = ns->parent) { 595 for ( ; ns; ns = ns->parent) {
595 struct bsd_acct_struct *acct = 596 struct bsd_acct_struct *acct = acct_get(ns);
596 if (acct) { 597 if (acct) {
597 do_acct_process(acct); 598 do_acct_process(acct);
598 mutex_unlock(&acct->lo 599 mutex_unlock(&acct->lock);
599 acct_put(acct); 600 acct_put(acct);
600 } 601 }
601 } 602 }
602 } 603 }
603 604
604 /** 605 /**
605 * acct_process - handles process accounting f 606 * acct_process - handles process accounting for an exiting task
606 */ 607 */
607 void acct_process(void) 608 void acct_process(void)
608 { 609 {
609 struct pid_namespace *ns; 610 struct pid_namespace *ns;
610 611
611 /* 612 /*
612 * This loop is safe lockless, since c 613 * This loop is safe lockless, since current is still
613 * alive and holds its namespace, whic 614 * alive and holds its namespace, which in turn holds
614 * its parent. 615 * its parent.
615 */ 616 */
616 for (ns = task_active_pid_ns(current); 617 for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent) {
617 if (ns->bacct) 618 if (ns->bacct)
618 break; 619 break;
619 } 620 }
620 if (unlikely(ns)) 621 if (unlikely(ns))
621 slow_acct_process(ns); 622 slow_acct_process(ns);
622 } 623 }
623 624
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