/* * 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/mm.h>#include <linux/slab.h>#include <linux/acct.h>#include <linux/capability.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 <linux/mount.h>#include <asm/uaccess.h>#include <asm/div64.h>#include <linux/blkdev.h> /* sector_div */#include <linux/pid_namespace.h> /* * 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(struct bsd_acct_struct *acct, struct pid_namespace *ns, 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 bsd_acct_struct { int active; unsigned long needcheck; struct file *file; struct pid_namespace *ns; struct list_head list;}; static DEFINE_SPINLOCK(acct_lock);static LIST_HEAD(acct_list); /* * Check the amount of free space and suspend/resume accordingly. */static int check_free_space(struct bsd_acct_struct *acct, struct file *file){ struct kstatfs sbuf; int res; int act; u64 resume; u64 suspend; spin_lock(&acct_lock); res = acct->active; if (!file || time_is_before_jiffies(acct->needcheck)) goto out; spin_unlock(&acct_lock); /* May block */ if (vfs_statfs(&file->f_path, &sbuf)) return res; suspend = sbuf.f_blocks * SUSPEND; resume = sbuf.f_blocks * RESUME; do_div(suspend, 100); do_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->file under us we'ld better be * silent and _not_ touch anything. */ spin_lock(&acct_lock); if (file != acct->file) { if (act) res = act>0; goto out; } if (acct->active) { if (act < 0) { acct->active = 0; printk(KERN_INFO "Process accounting paused\n"); } } else { if (act > 0) { acct->active = 1; printk(KERN_INFO "Process accounting resumed\n"); } } acct->needcheck = jiffies + ACCT_TIMEOUT*HZ; res = acct->active;out: spin_unlock(&acct_lock); return res;} /* * Close the old accounting file (if currently open) and then replace * it with file (if non-NULL). * * NOTE: acct_lock MUST be held on entry and exit. */static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file, struct pid_namespace *ns){ struct file *old_acct = NULL; struct pid_namespace *old_ns = NULL; if (acct->file) { old_acct = acct->file; old_ns = acct->ns; acct->active = 0; acct->file = NULL; acct->ns = NULL; list_del(&acct->list); } if (file) { acct->file = file; acct->ns = ns; acct->needcheck = jiffies + ACCT_TIMEOUT*HZ; acct->active = 1; list_add(&acct->list, &acct_list); } if (old_acct) { mnt_unpin(old_acct->f_path.mnt); spin_unlock(&acct_lock); do_acct_process(acct, old_ns, old_acct); filp_close(old_acct, NULL); spin_lock(&acct_lock); }} static int acct_on(struct filename *pathname){ struct file *file; struct vfsmount *mnt; struct pid_namespace *ns; struct bsd_acct_struct *acct = NULL; /* Difference from BSD - they don't do O_APPEND */ file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0); if (IS_ERR(file)) return PTR_ERR(file); if (!S_ISREG(file_inode(file)->i_mode)) { filp_close(file, NULL); return -EACCES; } if (!file->f_op->write) { filp_close(file, NULL); return -EIO; } ns = task_active_pid_ns(current); if (ns->bacct == NULL) { acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL); if (acct == NULL) { filp_close(file, NULL); return -ENOMEM; } } spin_lock(&acct_lock); if (ns->bacct == NULL) { ns->bacct = acct; acct = NULL; } mnt = file->f_path.mnt; mnt_pin(mnt); acct_file_reopen(ns->bacct, file, ns); spin_unlock(&acct_lock); mntput(mnt); /* it's pinned, now give up active reference */ kfree(acct); return 0;} /** * sys_acct - enable/disable process accounting * @name: file name for accounting records or NULL to shutdown accounting * * Returns 0 for success or negative errno values for failure. * * 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. */SYSCALL_DEFINE1(acct, const char __user *, name){ int error = 0; if (!capable(CAP_SYS_PACCT)) return -EPERM; if (name) { struct filename *tmp = getname(name); if (IS_ERR(tmp)) return (PTR_ERR(tmp)); error = acct_on(tmp); putname(tmp); } else { struct bsd_acct_struct *acct; acct = task_active_pid_ns(current)->bacct; if (acct == NULL) return 0; spin_lock(&acct_lock); acct_file_reopen(acct, NULL, NULL); spin_unlock(&acct_lock); } return error;} /** * acct_auto_close - turn off a filesystem's accounting if it is on * @m: vfsmount being shut down * * If the accounting is turned on for a file in the subtree pointed to * to by m, turn accounting off. Done when m is about to die. */void acct_auto_close_mnt(struct vfsmount *m){ struct bsd_acct_struct *acct; spin_lock(&acct_lock);restart: list_for_each_entry(acct, &acct_list, list) if (acct->file && acct->file->f_path.mnt == m) { acct_file_reopen(acct, NULL, NULL); goto restart; } spin_unlock(&acct_lock);} /** * acct_auto_close - turn off a filesystem's accounting if it is on * @sb: super block for the filesystem * * If the accounting is turned on for a file in the filesystem pointed * to by sb, turn accounting off. */void acct_auto_close(struct super_block *sb){ struct bsd_acct_struct *acct; spin_lock(&acct_lock);restart: list_for_each_entry(acct, &acct_list, list) if (acct->file && acct->file->f_path.dentry->d_sb == sb) { acct_file_reopen(acct, NULL, NULL); goto restart; } spin_unlock(&acct_lock);} void acct_exit_ns(struct pid_namespace *ns){ struct bsd_acct_struct *acct = ns->bacct; if (acct == NULL) return; spin_lock(&acct_lock); if (acct->file != NULL) acct_file_reopen(acct, NULL, NULL); spin_unlock(&acct_lock); kfree(acct);} /* * 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() or when switching to a different output file. */ /* * do_acct_process does all actual work. Caller holds the reference to file. */static void do_acct_process(struct bsd_acct_struct *acct, struct pid_namespace *ns, struct file *file){ struct pacct_struct *pacct = ¤t->signal->pacct; acct_t ac; mm_segment_t fs; unsigned long flim; u64 elapsed; u64 run_time; struct timespec uptime; struct tty_struct *tty; const struct cred *orig_cred; /* Perform file operations on behalf of whoever enabled accounting */ orig_cred = override_creds(file->f_cred); /* * First check to see if there is enough free_space to continue * the process accounting system. */ if (!check_free_space(acct, file)) goto out; /* * Fill the accounting struct with the needed info as recorded * by the different kernel functions. */ memset(&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->group_leader->start_time.tv_sec * NSEC_PER_SEC + current->group_leader->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 {Lines 1–500 of 647. Load more
/* * 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/mm.h> #include <linux/slab.h> #include <linux/acct.h> #include <linux/capability.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 <linux/mount.h> #include <asm/uaccess.h> #include <asm/div64.h> #include <linux/blkdev.h> /* sector_div */ #include <linux/pid_namespace.h> /* * 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(struct bsd_acct_struct *acct, struct pid_namespace *ns, 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 bsd_acct_struct { int active; unsigned long needcheck; struct file *file; struct pid_namespace *ns; struct list_head list; }; static DEFINE_SPINLOCK(acct_lock); static LIST_HEAD(acct_list); /* * Check the amount of free space and suspend/resume accordingly. */ static int check_free_space(struct bsd_acct_struct *acct, struct file *file) { struct kstatfs sbuf; int res; int act; u64 resume; u64 suspend; spin_lock(&acct_lock); res = acct->active; if (!file || time_is_before_jiffies(acct->needcheck)) goto out; spin_unlock(&acct_lock); /* May block */ if (vfs_statfs(&file->f_path, &sbuf)) return res; suspend = sbuf.f_blocks * SUSPEND; resume = sbuf.f_blocks * RESUME; do_div(suspend, 100); do_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->file under us we'ld better be * silent and _not_ touch anything. */ spin_lock(&acct_lock); if (file != acct->file) { if (act) res = act>0; goto out; } if (acct->active) { if (act < 0) { acct->active = 0; printk(KERN_INFO "Process accounting paused\n"); } } else { if (act > 0) { acct->active = 1; printk(KERN_INFO "Process accounting resumed\n"); } } acct->needcheck = jiffies + ACCT_TIMEOUT*HZ; res = acct->active; out: spin_unlock(&acct_lock); return res; } /* * Close the old accounting file (if currently open) and then replace * it with file (if non-NULL). * * NOTE: acct_lock MUST be held on entry and exit. */ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file, struct pid_namespace *ns) { struct file *old_acct = NULL; struct pid_namespace *old_ns = NULL; if (acct->file) { old_acct = acct->file; old_ns = acct->ns; acct->active = 0; acct->file = NULL; acct->ns = NULL; list_del(&acct->list); } if (file) { acct->file = file; acct->ns = ns; acct->needcheck = jiffies + ACCT_TIMEOUT*HZ; acct->active = 1; list_add(&acct->list, &acct_list); } if (old_acct) { mnt_unpin(old_acct->f_path.mnt); spin_unlock(&acct_lock); do_acct_process(acct, old_ns, old_acct); filp_close(old_acct, NULL); spin_lock(&acct_lock); } } static int acct_on(struct filename *pathname) { struct file *file; struct vfsmount *mnt; struct pid_namespace *ns; struct bsd_acct_struct *acct = NULL; /* Difference from BSD - they don't do O_APPEND */ file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0); if (IS_ERR(file)) return PTR_ERR(file); if (!S_ISREG(file_inode(file)->i_mode)) { filp_close(file, NULL); return -EACCES; } if (!file->f_op->write) { filp_close(file, NULL); return -EIO; } ns = task_active_pid_ns(current); if (ns->bacct == NULL) { acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL); if (acct == NULL) { filp_close(file, NULL); return -ENOMEM; } } spin_lock(&acct_lock); if (ns->bacct == NULL) { ns->bacct = acct; acct = NULL; } mnt = file->f_path.mnt; mnt_pin(mnt); acct_file_reopen(ns->bacct, file, ns); spin_unlock(&acct_lock); mntput(mnt); /* it's pinned, now give up active reference */ kfree(acct); return 0; } /** * sys_acct - enable/disable process accounting * @name: file name for accounting records or NULL to shutdown accounting * * Returns 0 for success or negative errno values for failure. * * 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. */ SYSCALL_DEFINE1(acct, const char __user *, name) { int error = 0; if (!capable(CAP_SYS_PACCT)) return -EPERM; if (name) { struct filename *tmp = getname(name); if (IS_ERR(tmp)) return (PTR_ERR(tmp)); error = acct_on(tmp); putname(tmp); } else { struct bsd_acct_struct *acct; acct = task_active_pid_ns(current)->bacct; if (acct == NULL) return 0; spin_lock(&acct_lock); acct_file_reopen(acct, NULL, NULL); spin_unlock(&acct_lock); } return error; } /** * acct_auto_close - turn off a filesystem's accounting if it is on * @m: vfsmount being shut down * * If the accounting is turned on for a file in the subtree pointed to * to by m, turn accounting off. Done when m is about to die. */ void acct_auto_close_mnt(struct vfsmount *m) { struct bsd_acct_struct *acct; spin_lock(&acct_lock); restart: list_for_each_entry(acct, &acct_list, list) if (acct->file && acct->file->f_path.mnt == m) { acct_file_reopen(acct, NULL, NULL); goto restart; } spin_unlock(&acct_lock); } /** * acct_auto_close - turn off a filesystem's accounting if it is on * @sb: super block for the filesystem * * If the accounting is turned on for a file in the filesystem pointed * to by sb, turn accounting off. */ void acct_auto_close(struct super_block *sb) { struct bsd_acct_struct *acct; spin_lock(&acct_lock); restart: list_for_each_entry(acct, &acct_list, list) if (acct->file && acct->file->f_path.dentry->d_sb == sb) { acct_file_reopen(acct, NULL, NULL); goto restart; } spin_unlock(&acct_lock); } void acct_exit_ns(struct pid_namespace *ns) { struct bsd_acct_struct *acct = ns->bacct; if (acct == NULL) return; spin_lock(&acct_lock); if (acct->file != NULL) acct_file_reopen(acct, NULL, NULL); spin_unlock(&acct_lock); kfree(acct); } /* * 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() or when switching to a different output file. */ /* * do_acct_process does all actual work. Caller holds the reference to file. */ static void do_acct_process(struct bsd_acct_struct *acct, struct pid_namespace *ns, struct file *file) { struct pacct_struct *pacct = ¤t->signal->pacct; acct_t ac; mm_segment_t fs; unsigned long flim; u64 elapsed; u64 run_time; struct timespec uptime; struct tty_struct *tty; const struct cred *orig_cred; /* Perform file operations on behalf of whoever enabled accounting */ orig_cred = override_creds(file->f_cred); /* * First check to see if there is enough free_space to continue * the process accounting system. */ if (!check_free_space(acct, file)) goto out; /* * Fill the accounting struct with the needed info as recorded * by the different kernel functions. */ memset(&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->group_leader->start_time.tv_sec * NSEC_PER_SEC + current->group_leader->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 {