| Le guide de l'auteur de pilotes de périphériques pour FreeBSD | ||
|---|---|---|
| Précédent | ||
Cette structure contient quelques informations sur l'état du périphérique et de son pilote. Elle est définie dans /usr/src/sys/sys/devconf.h comme ci-dessous :
struct devconf {
char dc_name[MAXDEVNAME]; /* name */
char dc_descr[MAXDEVDESCR]; /* description */
int dc_unit; /* unit number */
int dc_number; /* unique id */
char dc_pname[MAXDEVNAME]; /* name of the parent device */
int dc_punit; /* unit number of the parent */
int dc_pnumber; /* unique id of the parent */
struct machdep_devconf dc_md; /* machine-dependent stuff */
enum dc_state dc_state; /* state of the device (see above) */
enum dc_class dc_class; /* type of device (see above) */
size_t dc_datalen; /* length of data */
char dc_data[1]; /* variable-length data */
};
Cette structure contient toutes les informations sur un processus. Elle est dans définie /usr/src/sys/sys/proc.h:
/*
* Description of a process.
*
* This structure contains the information needed to manage a thread of
* control, known in UN*X as a process; it has references to
substructures
* containing descriptions of things that the process uses, but may
share
* with related processes. The process structure and the substructures
* are always addressable except for those marked "(PROC ONLY)" below,
* which might be addressable only on a processor on which the process
* is running.
*/
struct proc {
struct proc *p_forw; /* Doubly-linked run/sleep queue. */
struct proc *p_back;
struct proc *p_next; /* Linked list of active procs */
struct proc **p_prev; /* and zombies. */
/* 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 vmspace *p_vmspace; /* Address space. */
struct sigacts *p_sigacts; /* Signal actions, state (PROC ONLY). */
#define p_ucred p_cred->pc_ucred
#define p_rlimit p_limit->pl_rlimit
int p_flag; /* P_* flags. */
char p_stat; /* S* process status. */
char p_pad1[3];
pid_t p_pid; /* Process identifier. */
struct proc *p_hash; /* Hashed based on p_pid for kill+exit+... */
struct proc *p_pgrpnxt; /* Pointer to next process in process group. */
struct proc *p_pptr; /* Pointer to process structure of parent. */
struct proc *p_osptr; /* Pointer to older sibling processes. */
/* The following fields are all zeroed upon creation in fork. */
#define p_startzero p_ysptr
struct proc *p_ysptr; /* Pointer to younger siblings. */
struct proc *p_cptr; /* Pointer to youngest living child. */
pid_t p_oppid; /* Save parent pid during ptrace. XXX */
int p_dupfd; /* Sideways return value from fdopen. XXX */
/* 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. */
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. */
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_pad2[3]; /* alignment */
/* End area that is zeroed on creation. */
#define p_endzero p_startcopy
/* The following fields are all copied upon creation in fork. */
#define p_startcopy p_sigmask
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. */
/* End area that is copied on creation. */
#define p_endcopy p_addr
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 */
};
La structure struct buf est employée pour s'interfacer avec le cache de la mémoire tampon. Elle est dans définie /usr/src/sys/sys/buf.h :
/*
* The buffer header describes an I/O operation in the kernel.
*/
struct buf {
LIST_ENTRY(buf) b_hash; /* Hash chain. */
LIST_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */
TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
struct buf *b_actf, **b_actb; /* Device driver queue when active. */
struct proc *b_proc; /* Associated proc; NULL if kernel. */
volatile long b_flags; /* B_* flags. */
int b_qindex; /* buffer queue index */
int b_error; /* Errno value. */
long b_bufsize; /* Allocated buffer size. */
long b_bcount; /* Valid bytes in buffer. */
long b_resid; /* Remaining I/O. */
dev_t b_dev; /* Device associated with buffer. */
struct {
caddr_t b_addr; /* Memory, superblocks, indirect etc. */
} b_un;
void *b_saveaddr; /* Original b_addr for physio. */
daddr_t b_lblkno; /* Logical block number. */
daddr_t b_blkno; /* Underlying physical block number. */
/* Function to call upon completion. */
void (*b_iodone) __P((struct buf *));
/* For nested b_iodone's. */
struct iodone_chain *b_iodone_chain;
struct vnode *b_vp; /* Device vnode. */
int b_pfcent; /* Center page when swapping cluster. */
int b_dirtyoff; /* Offset in buffer of dirty region. */
int b_dirtyend; /* Offset of end of dirty region. */
struct ucred *b_rcred; /* Read credentials reference. */
struct ucred *b_wcred; /* Write credentials reference. */
int b_validoff; /* Offset in buffer of valid region. */
int b_validend; /* Offset of end of valid region. */
daddr_t b_pblkno; /* physical block number */
caddr_t b_savekva; /* saved kva for transfer while bouncing */
void *b_driver1; /* for private use by the driver */
void *b_driver2; /* for private use by the driver */
void *b_spc;
struct vm_page *b_pages[(MAXPHYS + PAGE_SIZE - 1)/PAGE_SIZE];
int b_npages;
};
Cette structure est utilisée pour déplacer des données entre le
noyau et les espaces utilisateur par les appels système de read() et de write(). Il est dans
défini /usr/src/sys/sys/uio.h :
struct uio {
struct iovec *uio_iov;
int uio_iovcnt;
off_t uio_offset;
int uio_resid;
enum uio_seg uio_segflg;
enum uio_rw uio_rw;
struct proc *uio_procp;
};
plein
FreeBSD Kernel Sources http://www.freebsd.org
NetBSD Kernel Sources http://www.netbsd.org
Writing Device Drivers: Tutorial and Reference; Tim Burke, Mark A. Parenti, Al, Wojtas; Digital Press, ISBN 1-55558-141-2.
Writing A Unix Device Driver; Janet I. Egan, Thomas J. Teixeira; John Wiley & Sons, ISBN 0-471-62859-X.
Writing Device Drivers for SCO Unix; Peter Kettle;
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