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