The main purpose of this patch is to fix handling of unpause calls from PM while another call is ongoing. The solution to this problem sparked a full revision of the threading model, consisting of a large number of related changes: - all active worker threads are now always associated with a process, and every process has at most one active thread working for it; - the process lock is always held by a process's worker thread; - a process can now have both normal work and postponed PM work associated to it; - timer expiry and non-postponed PM work is done from the main thread; - filp garbage collection is done from a thread associated with VFS; - reboot calls from PM are now done from a thread associated with PM; - the DS events handler is protected from starting multiple threads; - support for a system worker thread has been removed; - the deadlock recovery thread has been replaced by a parameter to the worker_start() function; the number of worker threads has consequently been increased by one; - saving and restoring of global but per-thread variables is now centralized in worker_suspend() and worker_resume(); err_code is now saved and restored in all cases; - the concept of jobs has been removed, and job_m_in now points to a message stored in the worker thread structure instead; - the PM lock has been removed; - the separate exec lock has been replaced by a lock on the VM process, which was already being locked for exec calls anyway; - PM_UNPAUSE is now processed as a postponed PM request, from a thread associated with the target process; - the FP_DROP_WORK flag has been removed, since it is no longer more than just an optimization and only applied to processes operating on a pipe when getting killed; - assignment to "fp" now takes place only when obtaining new work in the main thread or a worker thread, when resuming execution of a thread, and in the special case of exiting processes during reboot; - there are no longer special cases where the yield() call is used to force a thread to run. Change-Id: I7a97b9b95c2450454a9b5318dfa0e6150d4e6858
180 lines
4.9 KiB
C
180 lines
4.9 KiB
C
/* This file contains a few general purpose utility routines.
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*
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* The entry points into this file are
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* clock_timespec: ask the clock task for the real time
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* copy: copy a block of data
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* fetch_name: go get a path name from user space
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* no_sys: reject a system call that FS does not handle
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* panic: something awful has occurred; MINIX cannot continue
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* conv2: do byte swapping on a 16-bit int
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* conv4: do byte swapping on a 32-bit long
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* in_group: determines if group 'grp' is in rfp->fp_sgroups[]
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*/
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#include "fs.h"
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#include <minix/com.h>
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#include <minix/endpoint.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <time.h>
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#include "file.h"
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#include "param.h"
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#include "vmnt.h"
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/*===========================================================================*
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* copy_name *
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*===========================================================================*/
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inline int copy_name( size_t len, char *dest)
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{
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/* Go get path and put it in 'dest'.
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*/
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if (len > PATH_MAX) { /* 'len' includes terminating-nul */
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err_code = ENAMETOOLONG;
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return(EGENERIC);
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}
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/* Check name length for validity. */
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if (len > SSIZE_MAX) {
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err_code = EINVAL;
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return(EGENERIC);
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}
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if (len <= M3_STRING) {
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/* Just copy the path from the message */
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strncpy(dest, job_m_in.pathname, len);
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} else {
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/* String is not contained in the message. */
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err_code = EINVAL;
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return(EGENERIC);
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}
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if (dest[len - 1] != '\0') {
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err_code = ENAMETOOLONG;
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return(EGENERIC);
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}
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return(OK);
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}
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/*===========================================================================*
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* fetch_name *
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*===========================================================================*/
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int fetch_name(vir_bytes path, size_t len, char *dest)
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{
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/* Go get path and put it in 'dest'. */
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int r;
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if (len > PATH_MAX) { /* 'len' includes terminating-nul */
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err_code = ENAMETOOLONG;
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return(EGENERIC);
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}
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/* Check name length for validity. */
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if (len > SSIZE_MAX) {
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err_code = EINVAL;
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return(EGENERIC);
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}
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/* String is not contained in the message. Get it from user space. */
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r = sys_datacopy(who_e, path, VFS_PROC_NR, (vir_bytes) dest, len);
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if (r != OK) {
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err_code = EINVAL;
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return(r);
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}
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if (dest[len - 1] != '\0') {
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err_code = ENAMETOOLONG;
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return(EGENERIC);
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}
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return(OK);
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}
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/*===========================================================================*
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* no_sys *
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*===========================================================================*/
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int no_sys(message *UNUSED(m_out))
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{
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/* Somebody has used an illegal system call number */
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return(ENOSYS);
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}
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/*===========================================================================*
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* isokendpt_f *
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*===========================================================================*/
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int isokendpt_f(char *file, int line, endpoint_t endpoint, int *proc,
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int fatal)
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{
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int failed = 0;
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endpoint_t ke;
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*proc = _ENDPOINT_P(endpoint);
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if (endpoint == NONE) {
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printf("VFS %s:%d: endpoint is NONE\n", file, line);
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failed = 1;
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} else if (*proc < 0 || *proc >= NR_PROCS) {
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printf("VFS %s:%d: proc (%d) from endpoint (%d) out of range\n",
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file, line, *proc, endpoint);
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failed = 1;
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} else if ((ke = fproc[*proc].fp_endpoint) != endpoint) {
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if(ke == NONE) {
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assert(fproc[*proc].fp_pid == PID_FREE);
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} else {
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printf("VFS %s:%d: proc (%d) from endpoint (%d) doesn't match "
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"known endpoint (%d)\n", file, line, *proc, endpoint,
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fproc[*proc].fp_endpoint);
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assert(fproc[*proc].fp_pid != PID_FREE);
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}
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failed = 1;
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}
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if(failed && fatal)
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panic("isokendpt_f failed");
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return(failed ? EDEADEPT : OK);
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}
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/*===========================================================================*
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* clock_timespec *
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*===========================================================================*/
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struct timespec clock_timespec(void)
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{
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/* This routine returns the time in seconds since 1.1.1970. MINIX is an
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* astrophysically naive system that assumes the earth rotates at a constant
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* rate and that such things as leap seconds do not exist.
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*/
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register int r;
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struct timespec tv;
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clock_t uptime;
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clock_t realtime;
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time_t boottime;
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r = getuptime(&uptime, &realtime, &boottime);
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if (r != OK)
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panic("clock_timespec err: %d", r);
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tv.tv_sec = (time_t) (boottime + (realtime/system_hz));
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/* We do not want to overflow, and system_hz can be as high as 50kHz */
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assert(system_hz < LONG_MAX/40000);
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tv.tv_nsec = (realtime%system_hz) * 40000 / system_hz * 25000;
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return tv;
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}
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/*===========================================================================*
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* in_group *
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*===========================================================================*/
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int in_group(struct fproc *rfp, gid_t grp)
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{
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int i;
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for (i = 0; i < rfp->fp_ngroups; i++)
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if (rfp->fp_sgroups[i] == grp)
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return(OK);
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return(EINVAL);
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}
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