2384a85296
For character device i/o, FS does a so-called 'magic' grant to let the driver copy from or to user space. As this is done in FS address space, the driver is told to do this in FS address space. The redirection to the right user process then happens at copy-time in the kernel, using the FS grant table. This also happens for DEV_READ and DEV_WRITE on block devices. For other block device i/o, which happens from/to FS buffers, FS does a 'direct' grant to its own address space for the driver. After the i/o returns, this access has to be K-I-L-L-E-D, revoked. Sometimes this is after a SUSPEND and DEV_REVIVE, in which case the revoking happens in pipe.c. This conversion happens in safe_io_conversion() in device.c, called by dev_io and dev_bio. FS has to pre-allocate its own space for these grant tables. This happens in main.c.
45 lines
2.2 KiB
C
45 lines
2.2 KiB
C
#include <sys/select.h>
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#include <minix/safecopies.h>
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/* This is the per-process information. A slot is reserved for each potential
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* process. Thus NR_PROCS must be the same as in the kernel. It is not
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* possible or even necessary to tell when a slot is free here.
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*/
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EXTERN struct fproc {
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mode_t fp_umask; /* mask set by umask system call */
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struct inode *fp_workdir; /* pointer to working directory's inode */
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struct inode *fp_rootdir; /* pointer to current root dir (see chroot) */
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struct filp *fp_filp[OPEN_MAX];/* the file descriptor table */
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fd_set fp_filp_inuse; /* which fd's are in use? */
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uid_t fp_realuid; /* real user id */
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uid_t fp_effuid; /* effective user id */
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gid_t fp_realgid; /* real group id */
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gid_t fp_effgid; /* effective group id */
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dev_t fp_tty; /* major/minor of controlling tty */
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int fp_fd; /* place to save fd if rd/wr can't finish */
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char *fp_buffer; /* place to save buffer if rd/wr can't finish*/
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int fp_nbytes; /* place to save bytes if rd/wr can't finish */
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int fp_cum_io_partial; /* partial byte count if rd/wr can't finish */
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char fp_suspended; /* set to indicate process hanging */
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char fp_revived; /* set to indicate process being revived */
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int fp_task; /* which task is proc suspended on */
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endpoint_t fp_ioproc; /* proc no. in suspended-on i/o message */
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cp_grant_id_t fp_grant; /* revoke this grant on unsuspend if > -1 */
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char fp_sesldr; /* true if proc is a session leader */
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char fp_execced; /* true if proc has exec()ced after fork */
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pid_t fp_pid; /* process id */
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long fp_cloexec; /* bit map for POSIX Table 6-2 FD_CLOEXEC */
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endpoint_t fp_endpoint; /* kernel endpoint number of this process */
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} fproc[NR_PROCS];
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/* Field values. */
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#define NOT_SUSPENDED 0 /* process is not suspended on pipe or task */
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#define SUSPENDED 1 /* process is suspended on pipe or task */
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#define NOT_REVIVING 0 /* process is not being revived */
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#define REVIVING 1 /* process is being revived from suspension */
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#define PID_FREE 0 /* process slot free */
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/* Check is process number is acceptable - includes system processes. */
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#define isokprocnr(n) ((unsigned)((n)+NR_TASKS) < NR_PROCS + NR_TASKS)
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