#define SYS_syscall 0
#define SYS_exit 1
#define SYS_fork 2
#define SYS_read 3
#define SYS_write 4
#define SYS_open 5
#define SYS_close 6
#define SYS_wait4 7
/* 8 is old creat */
#define SYS_link 9
#define SYS_unlink 10
/* 11 is obsolete execv */
#define SYS_chdir 12
#define SYS_fchdir 13
#define SYS_mknod 14
#define SYS_chmod 15
#define SYS_chown 16
#define SYS_break 17
#define SYS_getfsstat 18
/* 19 is old lseek */
#define SYS_getpid 20
Για παράδειγμα ο παρακάτω κώδικας του πυρήνα υλοποιεί την κλήση getpid:
int
getpid(p, uap)
struct proc *p;
struct getpid_args *uap;
{
p->p_retval[0] = p->p_pid;
return (0);
}
struct proc {
TAILQ_ENTRY(proc) p_procq; /* run/sleep queue. */
LIST_ENTRY(proc) p_list; /* List of all processes. */
/* substructures: */
struct pcred *p_cred; /* Process owner's identity. */
struct filedesc *p_fd; /* Ptr to open files structure. */
struct pstats *p_stats; /* Accounting/statistics (PROC ONLY). */
struct plimit *p_limit; /* Process limits. */
struct vm_object *p_upages_obj;/* Upages object */
struct sigacts *p_sigacts; /* Signal actions, state (PROC ONLY). */
int p_flag; /* P_* flags. */
char p_stat; /* S* process status. */
char p_pad1[3];
pid_t p_pid; /* Process identifier. */
LIST_ENTRY(proc) p_hash; /* Hash chain. */
LIST_ENTRY(proc) p_pglist; /* List of processes in pgrp. */
struct proc *p_pptr; /* Pointer to parent process. */
LIST_ENTRY(proc) p_sibling; /* List of sibling processes. */
LIST_HEAD(, proc) p_children; /* Pointer to list of children. */
struct callout_handle p_ithandle; /*
* Callout handle for scheduling
* p_realtimer.
*/
pid_t p_oppid; /* Save parent pid during ptrace. XXX */
int p_dupfd; /* Sideways return value from fdopen. XXX */
struct vmspace *p_vmspace; /* Address space. */
/* scheduling */
u_int p_estcpu; /* Time averaged value of p_cpticks. */
int p_cpticks; /* Ticks of cpu time. */
fixpt_t p_pctcpu; /* %cpu for this process during p_swtime */
void *p_wchan; /* Sleep address. */
const char *p_wmesg; /* Reason for sleep. */
u_int p_swtime; /* Time swapped in or out. */
u_int p_slptime; /* Time since last blocked. */
struct itimerval p_realtimer; /* Alarm timer. */
struct timeval p_rtime; /* Real time. */
u_quad_t p_uticks; /* Statclock hits in user mode. */
u_quad_t p_sticks; /* Statclock hits in system mode. */
u_quad_t p_iticks; /* Statclock hits processing intr. */
struct timeval *p_sleepend; /* Wake time for nanosleep & friends */
int p_traceflag; /* Kernel trace points. */
struct vnode *p_tracep; /* Trace to vnode. */
int p_siglist; /* Signals arrived but not delivered. */
struct vnode *p_textvp; /* Vnode of executable. */
char p_lock; /* Process lock (prevent swap) count. */
char p_oncpu; /* Which cpu we are on */
char p_lastcpu; /* Last cpu we were on */
char p_pad2; /* alignment */
short p_locks; /* DEBUG: lockmgr count of held locks */
short p_simple_locks; /* DEBUG: count of held simple locks */
register_t p_retval[2]; /* syscall aux returns */
sigset_t p_sigmask; /* Current signal mask. */
sigset_t p_sigignore; /* Signals being ignored. */
sigset_t p_sigcatch; /* Signals being caught by user. */
u_char p_priority; /* Process priority. */
u_char p_usrpri; /* User-priority based on p_cpu and p_nice. */
char p_nice; /* Process "nice" value. */
char p_comm[MAXCOMLEN+1];
struct pgrp *p_pgrp; /* Pointer to process group. */
struct sysentvec *p_sysent; /* System call dispatch information. */
struct rtprio p_rtprio; /* Realtime priority. */
struct user *p_addr; /* Kernel virtual addr of u-area (PROC ONLY). */
struct mdproc p_md; /* Any machine-dependent fields. */
u_short p_xstat; /* Exit status for wait; also stop signal. */
u_short p_acflag; /* Accounting flags. */
struct rusage *p_ru; /* Exit information. XXX */
int p_nthreads; /* number of threads (only in leader) */
void *p_aioinfo; /* ASYNC I/O info */
int p_wakeup; /* thread id */
struct proc *p_peers;
struct proc *p_leader;
};
Κάθε διεργασία μπορεί να βρίσκεται σε μια από τις παρακάτω καταστάσεις:
#define SIDL 1 /* Process being created by fork. */ #define SRUN 2 /* Currently runnable. */ #define SSLEEP 3 /* Sleeping on an address. */ #define SSTOP 4 /* Process debugging or suspension. */ #define SZOMB 5 /* Awaiting collection by parent. */
struct inode {
struct lock i_lock; /* Inode lock. >Keep this first< */
LIST_ENTRY(inode) i_hash;/* Hash chain. */
struct vnode *i_vnode;/* Vnode associated with this inode. */
struct vnode *i_devvp;/* Vnode for block I/O. */
u_int32_t i_flag; /* flags, see below */
dev_t i_dev; /* Device associated with the inode. */
ino_t i_number; /* The identity of the inode. */
union { /* Associated filesystem. */
struct fs *fs; /* FFS */
struct lfs *lfs; /* LFS */
struct ext2_sb_info *e2fs; /* EXT2FS */
} inode_u;
struct dquot *i_dquot[MAXQUOTAS]; /* Dquot structures. */
u_quad_t i_modrev; /* Revision level for NFS lease. */
struct lockf *i_lockf;/* Head of byte-level lock list. */
/*
* The on-disk dinode itself.
*/
struct dinode i_din; /* 128 bytes of the on-disk dinode. */
};
Επιπλεόν το τμήμα κάθε πίνακα δεικτών που βρίσκεται στο δίσκο
περιέχει τα ιδιοχαρακτηριστικά του αρχείου,
δείκτες για τα τμήματα που περιέχουν δεδομένα του αρχείου,
καθώς και δείκτες σε τμήματα που περιέχουν δείκτες σε
τμήματα που περιέχουν δεδομένα του αρχείου.
struct dinode {
u_int16_t di_mode; /* 0: IFMT, permissions; see below. */
int16_t di_nlink; /* 2: File link count. */
u_int64_t di_size; /* 8: File byte count. */
int32_t di_atime; /* 16: Last access time. */
int32_t di_atimensec; /* 20: Last access time. */
int32_t di_mtime; /* 24: Last modified time. */
int32_t di_mtimensec; /* 28: Last modified time. */
int32_t di_ctime; /* 32: Last inode change time. */
int32_t di_ctimensec; /* 36: Last inode change time. */
ufs_daddr_t di_db[NDADDR]; /* 40: Direct disk blocks. */
ufs_daddr_t di_ib[NIADDR]; /* 88: Indirect disk blocks. */
u_int32_t di_flags; /* 100: Status flags (chflags). */
int32_t di_blocks; /* 104: Blocks actually held. */
int32_t di_gen; /* 108: Generation number. */
u_int32_t di_uid; /* 112: File owner. */
u_int32_t di_gid; /* 116: File group. */
int32_t di_spare[2]; /* 120: Reserved; currently unused */
};
struct direct {
u_int32_t d_ino; /* inode number of entry */
u_int16_t d_reclen; /* length of this record */
u_int8_t d_type; /* file type, see below */
u_int8_t d_namlen; /* length of string in d_name */
char d_name[MAXNAMLEN + 1];/* name with length <= MAXNAMLEN */
};
Σε κάθε κατάλογο μπορούν να φυλαχθούν οι παρακάτω τύποι αρχείων:
#define DT_UNKNOWN 0 /* Άγνωστο */ #define DT_FIFO 1 /* Ουρά FIFO (σωλήνωση) */ #define DT_CHR 2 /* Συσκευή χαρακτήρων */ #define DT_DIR 4 /* Κατάλογος */ #define DT_BLK 6 /* Συσκευή τμημάτων */ #define DT_REG 8 /* Κανονικό αρχείο */ #define DT_LNK 10 /* Δεσμός */ #define DT_SOCK 12 /* Διαδιεργασιακή σύνδεση */
access(struct vop_access_args *); advlock(struct vop_advlock_args *); chmod(struct vnode *, int, struct ucred *, struct proc *); chown(struct vnode *, uid_t, gid_t, struct ucred *, struct proc *); close(struct vop_close_args *); create(struct vop_create_args *); getattr(struct vop_getattr_args *); link(struct vop_link_args *); makeinode(int mode, struct vnode *, struct vnode **, struct componentname *); missingop(struct vop_generic_args *ap); mkdir(struct vop_mkdir_args *); mknod(struct vop_mknod_args *); mmap(struct vop_mmap_args *); open(struct vop_open_args *); print(struct vop_print_args *); readdir(struct vop_readdir_args *); readlink(struct vop_readlink_args *); remove(struct vop_remove_args *); rename(struct vop_rename_args *); rmdir(struct vop_rmdir_args *); setattr(struct vop_setattr_args *); strategy(struct vop_strategy_args *); symlink(struct vop_symlink_args *);
struct vm_page {
TAILQ_ENTRY(vm_page) pageq; /* queue info for FIFO queue or free list (P) */
TAILQ_ENTRY(vm_page) hashq; /* hash table links (O) */
TAILQ_ENTRY(vm_page) listq; /* pages in same object (O) */
vm_object_t object; /* which object am I in (O,P) */
vm_pindex_t pindex; /* offset into object (O,P) */
vm_offset_t phys_addr; /* physical address of page */
u_short queue; /* page queue index */
u_short flags, /* see below */
pc; /* page color */
u_short wire_count; /* wired down maps refs (P) */
short hold_count; /* page hold count */
u_char act_count; /* page usage count */
u_char busy; /* page busy count */
/* NOTE that these must support one bit per DEV_BSIZE in a page!!! */
/* so, on normal X86 kernels, they must be at least 8 bits wide */
u_char valid; /* map of valid DEV_BSIZE chunks */
u_char dirty; /* map of dirty DEV_BSIZE chunks */
};
Αντίστοιχα η σελίδα μπορεί να βρίσκεται σε μια από τις παρακάτω καταστάσεις:
#define PG_BUSY 0x01 /* page is in transit (O) */ #define PG_WANTED 0x02 /* someone is waiting for page (O) */ #define PG_TABLED 0x04 /* page is in VP table (O) */ #define PG_FICTITIOUS 0x08 /* physical page doesn't exist (O) */ #define PG_WRITEABLE 0x10 /* page is mapped writeable */ #define PG_MAPPED 0x20 /* page is mapped */ #define PG_ZERO 0x40 /* page is zeroed */ #define PG_REFERENCED 0x80 /* page has been referenced */ #define PG_CLEANCHK 0x100 /* page has been checked for cleaning */Όλες οι σελίδες ανοίκουν σε μια από 5 διαφορετικές λίστες ταξινομημένες σύμφωνα με το κριτήριο LRU (Least Recently Used - Λιγότερο πρόσφατη χρησιμοποιημένη).
Τελευταία αλλαγή: Δευτέρα, 2 Αυγούστου 2004 12:27 πμ
Εκτός αν αναφέρεται κάτι διαφορετικό, όλο το πρωτότυπο υλικό της σελίδας αυτής
του οποίου δημιουργός είναι ο Διομήδης Σπινέλλης παρέχεται σύμφωνα με τους
όρους της άδειας
«Creative Commons Attribution-Share Alike 3.0 Greece License».