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Diffstat (limited to 'kernel/acct.c')
| -rw-r--r-- | kernel/acct.c | 561 |
1 files changed, 561 insertions, 0 deletions
diff --git a/kernel/acct.c b/kernel/acct.c new file mode 100644 index 00000000000..4168f631868 --- /dev/null +++ b/kernel/acct.c @@ -0,0 +1,561 @@ +/* + * linux/kernel/acct.c + * + * BSD Process Accounting for Linux + * + * Author: Marco van Wieringen <mvw@planets.elm.net> + * + * Some code based on ideas and code from: + * Thomas K. Dyas <tdyas@eden.rutgers.edu> + * + * This file implements BSD-style process accounting. Whenever any + * process exits, an accounting record of type "struct acct" is + * written to the file specified with the acct() system call. It is + * up to user-level programs to do useful things with the accounting + * log. The kernel just provides the raw accounting information. + * + * (C) Copyright 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V. + * + * Plugged two leaks. 1) It didn't return acct_file into the free_filps if + * the file happened to be read-only. 2) If the accounting was suspended + * due to the lack of space it happily allowed to reopen it and completely + * lost the old acct_file. 3/10/98, Al Viro. + * + * Now we silently close acct_file on attempt to reopen. Cleaned sys_acct(). + * XTerms and EMACS are manifestations of pure evil. 21/10/98, AV. + * + * Fixed a nasty interaction with with sys_umount(). If the accointing + * was suspeneded we failed to stop it on umount(). Messy. + * Another one: remount to readonly didn't stop accounting. + * Question: what should we do if we have CAP_SYS_ADMIN but not + * CAP_SYS_PACCT? Current code does the following: umount returns -EBUSY + * unless we are messing with the root. In that case we are getting a + * real mess with do_remount_sb(). 9/11/98, AV. + * + * Fixed a bunch of races (and pair of leaks). Probably not the best way, + * but this one obviously doesn't introduce deadlocks. Later. BTW, found + * one race (and leak) in BSD implementation. + * OK, that's better. ANOTHER race and leak in BSD variant. There always + * is one more bug... 10/11/98, AV. + * + * Oh, fsck... Oopsable SMP race in do_process_acct() - we must hold + * ->mmap_sem to walk the vma list of current->mm. Nasty, since it leaks + * a struct file opened for write. Fixed. 2/6/2000, AV. + */ + +#include <linux/config.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/acct.h> +#include <linux/file.h> +#include <linux/tty.h> +#include <linux/security.h> +#include <linux/vfs.h> +#include <linux/jiffies.h> +#include <linux/times.h> +#include <linux/syscalls.h> +#include <asm/uaccess.h> +#include <asm/div64.h> +#include <linux/blkdev.h> /* sector_div */ + +/* + * These constants control the amount of freespace that suspend and + * resume the process accounting system, and the time delay between + * each check. + * Turned into sysctl-controllable parameters. AV, 12/11/98 + */ + +int acct_parm[3] = {4, 2, 30}; +#define RESUME (acct_parm[0]) /* >foo% free space - resume */ +#define SUSPEND (acct_parm[1]) /* <foo% free space - suspend */ +#define ACCT_TIMEOUT (acct_parm[2]) /* foo second timeout between checks */ + +/* + * External references and all of the globals. + */ +static void do_acct_process(long, struct file *); + +/* + * This structure is used so that all the data protected by lock + * can be placed in the same cache line as the lock. This primes + * the cache line to have the data after getting the lock. + */ +struct acct_glbs { + spinlock_t lock; + volatile int active; + volatile int needcheck; + struct file *file; + struct timer_list timer; +}; + +static struct acct_glbs acct_globals __cacheline_aligned = {SPIN_LOCK_UNLOCKED}; + +/* + * Called whenever the timer says to check the free space. + */ +static void acct_timeout(unsigned long unused) +{ + acct_globals.needcheck = 1; +} + +/* + * Check the amount of free space and suspend/resume accordingly. + */ +static int check_free_space(struct file *file) +{ + struct kstatfs sbuf; + int res; + int act; + sector_t resume; + sector_t suspend; + + spin_lock(&acct_globals.lock); + res = acct_globals.active; + if (!file || !acct_globals.needcheck) + goto out; + spin_unlock(&acct_globals.lock); + + /* May block */ + if (vfs_statfs(file->f_dentry->d_inode->i_sb, &sbuf)) + return res; + suspend = sbuf.f_blocks * SUSPEND; + resume = sbuf.f_blocks * RESUME; + + sector_div(suspend, 100); + sector_div(resume, 100); + + if (sbuf.f_bavail <= suspend) + act = -1; + else if (sbuf.f_bavail >= resume) + act = 1; + else + act = 0; + + /* + * If some joker switched acct_globals.file under us we'ld better be + * silent and _not_ touch anything. + */ + spin_lock(&acct_globals.lock); + if (file != acct_globals.file) { + if (act) + res = act>0; + goto out; + } + + if (acct_globals.active) { + if (act < 0) { + acct_globals.active = 0; + printk(KERN_INFO "Process accounting paused\n"); + } + } else { + if (act > 0) { + acct_globals.active = 1; + printk(KERN_INFO "Process accounting resumed\n"); + } + } + + del_timer(&acct_globals.timer); + acct_globals.needcheck = 0; + acct_globals.timer.expires = jiffies + ACCT_TIMEOUT*HZ; + add_timer(&acct_globals.timer); + res = acct_globals.active; +out: + spin_unlock(&acct_globals.lock); + return res; +} + +/* + * Close the old accouting file (if currently open) and then replace + * it with file (if non-NULL). + * + * NOTE: acct_globals.lock MUST be held on entry and exit. + */ +static void acct_file_reopen(struct file *file) +{ + struct file *old_acct = NULL; + + if (acct_globals.file) { + old_acct = acct_globals.file; + del_timer(&acct_globals.timer); + acct_globals.active = 0; + acct_globals.needcheck = 0; + acct_globals.file = NULL; + } + if (file) { + acct_globals.file = file; + acct_globals.needcheck = 0; + acct_globals.active = 1; + /* It's been deleted if it was used before so this is safe */ + init_timer(&acct_globals.timer); + acct_globals.timer.function = acct_timeout; + acct_globals.timer.expires = jiffies + ACCT_TIMEOUT*HZ; + add_timer(&acct_globals.timer); + } + if (old_acct) { + spin_unlock(&acct_globals.lock); + do_acct_process(0, old_acct); + filp_close(old_acct, NULL); + spin_lock(&acct_globals.lock); + } +} + +/* + * sys_acct() is the only system call needed to implement process + * accounting. It takes the name of the file where accounting records + * should be written. If the filename is NULL, accounting will be + * shutdown. + */ +asmlinkage long sys_acct(const char __user *name) +{ + struct file *file = NULL; + char *tmp; + int error; + + if (!capable(CAP_SYS_PACCT)) + return -EPERM; + + if (name) { + tmp = getname(name); + if (IS_ERR(tmp)) { + return (PTR_ERR(tmp)); + } + /* Difference from BSD - they don't do O_APPEND */ + file = filp_open(tmp, O_WRONLY|O_APPEND, 0); + putname(tmp); + if (IS_ERR(file)) { + return (PTR_ERR(file)); + } + if (!S_ISREG(file->f_dentry->d_inode->i_mode)) { + filp_close(file, NULL); + return (-EACCES); + } + + if (!file->f_op->write) { + filp_close(file, NULL); + return (-EIO); + } + } + + error = security_acct(file); + if (error) { + if (file) + filp_close(file, NULL); + return error; + } + + spin_lock(&acct_globals.lock); + acct_file_reopen(file); + spin_unlock(&acct_globals.lock); + + return (0); +} + +/* + * If the accouting is turned on for a file in the filesystem pointed + * to by sb, turn accouting off. + */ +void acct_auto_close(struct super_block *sb) +{ + spin_lock(&acct_globals.lock); + if (acct_globals.file && + acct_globals.file->f_dentry->d_inode->i_sb == sb) { + acct_file_reopen((struct file *)NULL); + } + spin_unlock(&acct_globals.lock); +} + +/* + * encode an unsigned long into a comp_t + * + * This routine has been adopted from the encode_comp_t() function in + * the kern_acct.c file of the FreeBSD operating system. The encoding + * is a 13-bit fraction with a 3-bit (base 8) exponent. + */ + +#define MANTSIZE 13 /* 13 bit mantissa. */ +#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ +#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ + +static comp_t encode_comp_t(unsigned long value) +{ + int exp, rnd; + + exp = rnd = 0; + while (value > MAXFRACT) { + rnd = value & (1 << (EXPSIZE - 1)); /* Round up? */ + value >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ + exp++; + } + + /* + * If we need to round up, do it (and handle overflow correctly). + */ + if (rnd && (++value > MAXFRACT)) { + value >>= EXPSIZE; + exp++; + } + + /* + * Clean it up and polish it off. + */ + exp <<= MANTSIZE; /* Shift the exponent into place */ + exp += value; /* and add on the mantissa. */ + return exp; +} + +#if ACCT_VERSION==1 || ACCT_VERSION==2 +/* + * encode an u64 into a comp2_t (24 bits) + * + * Format: 5 bit base 2 exponent, 20 bits mantissa. + * The leading bit of the mantissa is not stored, but implied for + * non-zero exponents. + * Largest encodable value is 50 bits. + */ + +#define MANTSIZE2 20 /* 20 bit mantissa. */ +#define EXPSIZE2 5 /* 5 bit base 2 exponent. */ +#define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */ +#define MAXEXP2 ((1 <<EXPSIZE2) - 1) /* Maximum exponent. */ + +static comp2_t encode_comp2_t(u64 value) +{ + int exp, rnd; + + exp = (value > (MAXFRACT2>>1)); + rnd = 0; + while (value > MAXFRACT2) { + rnd = value & 1; + value >>= 1; + exp++; + } + + /* + * If we need to round up, do it (and handle overflow correctly). + */ + if (rnd && (++value > MAXFRACT2)) { + value >>= 1; + exp++; + } + + if (exp > MAXEXP2) { + /* Overflow. Return largest representable number instead. */ + return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1; + } else { + return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1)); + } +} +#endif + +#if ACCT_VERSION==3 +/* + * encode an u64 into a 32 bit IEEE float + */ +static u32 encode_float(u64 value) +{ + unsigned exp = 190; + unsigned u; + + if (value==0) return 0; + while ((s64)value > 0){ + value <<= 1; + exp--; + } + u = (u32)(value >> 40) & 0x7fffffu; + return u | (exp << 23); +} +#endif + +/* + * Write an accounting entry for an exiting process + * + * The acct_process() call is the workhorse of the process + * accounting system. The struct acct is built here and then written + * into the accounting file. This function should only be called from + * do_exit(). + */ + +/* + * do_acct_process does all actual work. Caller holds the reference to file. + */ +static void do_acct_process(long exitcode, struct file *file) +{ + acct_t ac; + mm_segment_t fs; + unsigned long vsize; + unsigned long flim; + u64 elapsed; + u64 run_time; + struct timespec uptime; + + /* + * First check to see if there is enough free_space to continue + * the process accounting system. + */ + if (!check_free_space(file)) + return; + + /* + * Fill the accounting struct with the needed info as recorded + * by the different kernel functions. + */ + memset((caddr_t)&ac, 0, sizeof(acct_t)); + + ac.ac_version = ACCT_VERSION | ACCT_BYTEORDER; + strlcpy(ac.ac_comm, current->comm, sizeof(ac.ac_comm)); + + /* calculate run_time in nsec*/ + do_posix_clock_monotonic_gettime(&uptime); + run_time = (u64)uptime.tv_sec*NSEC_PER_SEC + uptime.tv_nsec; + run_time -= (u64)current->start_time.tv_sec*NSEC_PER_SEC + + current->start_time.tv_nsec; + /* convert nsec -> AHZ */ + elapsed = nsec_to_AHZ(run_time); +#if ACCT_VERSION==3 + ac.ac_etime = encode_float(elapsed); +#else + ac.ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ? + (unsigned long) elapsed : (unsigned long) -1l); +#endif +#if ACCT_VERSION==1 || ACCT_VERSION==2 + { + /* new enlarged etime field */ + comp2_t etime = encode_comp2_t(elapsed); + ac.ac_etime_hi = etime >> 16; + ac.ac_etime_lo = (u16) etime; + } +#endif + do_div(elapsed, AHZ); + ac.ac_btime = xtime.tv_sec - elapsed; + ac.ac_utime = encode_comp_t(jiffies_to_AHZ( + current->signal->utime + + current->group_leader->utime)); + ac.ac_stime = encode_comp_t(jiffies_to_AHZ( + current->signal->stime + + current->group_leader->stime)); + /* we really need to bite the bullet and change layout */ + ac.ac_uid = current->uid; + ac.ac_gid = current->gid; +#if ACCT_VERSION==2 + ac.ac_ahz = AHZ; +#endif +#if ACCT_VERSION==1 || ACCT_VERSION==2 + /* backward-compatible 16 bit fields */ + ac.ac_uid16 = current->uid; + ac.ac_gid16 = current->gid; +#endif +#if ACCT_VERSION==3 + ac.ac_pid = current->tgid; + ac.ac_ppid = current->parent->tgid; +#endif + + read_lock(&tasklist_lock); /* pin current->signal */ + ac.ac_tty = current->signal->tty ? + old_encode_dev(tty_devnum(current->signal->tty)) : 0; + read_unlock(&tasklist_lock); + + ac.ac_flag = 0; + if (current->flags & PF_FORKNOEXEC) + ac.ac_flag |= AFORK; + if (current->flags & PF_SUPERPRIV) + ac.ac_flag |= ASU; + if (current->flags & PF_DUMPCORE) + ac.ac_flag |= ACORE; + if (current->flags & PF_SIGNALED) + ac.ac_flag |= AXSIG; + + vsize = 0; + if (current->mm) { + struct vm_area_struct *vma; + down_read(¤t->mm->mmap_sem); + vma = current->mm->mmap; + while (vma) { + vsize += vma->vm_end - vma->vm_start; + vma = vma->vm_next; + } + up_read(¤t->mm->mmap_sem); + } + vsize = vsize / 1024; + ac.ac_mem = encode_comp_t(vsize); + ac.ac_io = encode_comp_t(0 /* current->io_usage */); /* %% */ + ac.ac_rw = encode_comp_t(ac.ac_io / 1024); + ac.ac_minflt = encode_comp_t(current->signal->min_flt + + current->group_leader->min_flt); + ac.ac_majflt = encode_comp_t(current->signal->maj_flt + + current->group_leader->maj_flt); + ac.ac_swaps = encode_comp_t(0); + ac.ac_exitcode = exitcode; + + /* + * Kernel segment override to datasegment and write it + * to the accounting file. + */ + fs = get_fs(); + set_fs(KERNEL_DS); + /* + * Accounting records are not subject to resource limits. + */ + flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; + current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; + file->f_op->write(file, (char *)&ac, + sizeof(acct_t), &file->f_pos); + current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim; + set_fs(fs); +} + +/* + * acct_process - now just a wrapper around do_acct_process + */ +void acct_process(long exitcode) +{ + struct file *file = NULL; + + /* + * accelerate the common fastpath: + */ + if (!acct_globals.file) + return; + + spin_lock(&acct_globals.lock); + file = acct_globals.file; + if (unlikely(!file)) { + spin_unlock(&acct_globals.lock); + return; + } + get_file(file); + spin_unlock(&acct_globals.lock); + + do_acct_process(exitcode, file); + fput(file); +} + + +/* + * acct_update_integrals + * - update mm integral fields in task_struct + */ +void acct_update_integrals(struct task_struct *tsk) +{ + if (likely(tsk->mm)) { + long delta = tsk->stime - tsk->acct_stimexpd; + + if (delta == 0) + return; + tsk->acct_stimexpd = tsk->stime; + tsk->acct_rss_mem1 += delta * get_mm_counter(tsk->mm, rss); + tsk->acct_vm_mem1 += delta * tsk->mm->total_vm; + } +} + +/* + * acct_clear_integrals + * - clear the mm integral fields in task_struct + */ +void acct_clear_integrals(struct task_struct *tsk) +{ + if (tsk) { + tsk->acct_stimexpd = 0; + tsk->acct_rss_mem1 = 0; + tsk->acct_vm_mem1 = 0; + } +} |