minix/servers/fs/utility.c

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/* This file contains a few general purpose utility routines.
*
* The entry points into this file are
* clock_time: ask the clock task for the real time
* copy: copy a block of data
* fetch_name: go get a path name from user space
* no_sys: reject a system call that FS does not handle
* panic: something awful has occurred; MINIX cannot continue
* conv2: do byte swapping on a 16-bit int
* conv4: do byte swapping on a 32-bit long
*/
#include "fs.h"
#include <minix/com.h>
endpoint-aware conversion of servers. 'who', indicating caller number in pm and fs and some other servers, has been removed in favour of 'who_e' (endpoint) and 'who_p' (proc nr.). In both PM and FS, isokendpt() convert endpoints to process slot numbers, returning OK if it was a valid and consistent endpoint number. okendpt() does the same but panic()s if it doesn't succeed. (In PM, this is pm_isok..) pm and fs keep their own records of process endpoints in their proc tables, which are needed to make kernel calls about those processes. message field names have changed. fs drivers are endpoints. fs now doesn't try to get out of driver deadlock, as the protocol isn't supposed to let that happen any more. (A warning is printed if ELOCKED is detected though.) fproc[].fp_task (indicating which driver the process is suspended on) became an int. PM and FS now get endpoint numbers of initial boot processes from the kernel. These happen to be the same as the old proc numbers, to let user processes reach them with the old numbers, but FS and PM don't know that. All new processes after INIT, even after the generation number wraps around, get endpoint numbers with generation 1 and higher, so the first instances of the boot processes are the only processes ever to have endpoint numbers in the old proc number range. More return code checks of sys_* functions have been added. IS has become endpoint-aware. Ditched the 'text' and 'data' fields in the kernel dump (which show locations, not sizes, so aren't terribly useful) in favour of the endpoint number. Proc number is still visible. Some other dumps (e.g. dmap, rs) show endpoint numbers now too which got the formatting changed. PM reading segments using rw_seg() has changed - it uses other fields in the message now instead of encoding the segment and process number and fd in the fd field. For that it uses _read_pm() and _write_pm() which to _taskcall()s directly in pm/misc.c. PM now sys_exit()s itself on panic(), instead of sys_abort(). RS also talks in endpoints instead of process numbers.
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#include <minix/endpoint.h>
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#include <unistd.h>
#include "buf.h"
#include "file.h"
#include "fproc.h"
#include "inode.h"
#include "param.h"
PRIVATE int panicking; /* inhibits recursive panics during sync */
/*===========================================================================*
* clock_time *
*===========================================================================*/
PUBLIC time_t clock_time()
{
/* This routine returns the time in seconds since 1.1.1970. MINIX is an
* astrophysically naive system that assumes the earth rotates at a constant
* rate and that such things as leap seconds do not exist.
*/
register int k;
clock_t uptime;
if ( (k=getuptime(&uptime)) != OK) panic(__FILE__,"clock_time err", k);
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return( (time_t) (boottime + (uptime/HZ)));
}
/*===========================================================================*
* fetch_name *
*===========================================================================*/
PUBLIC int fetch_name(path, len, flag)
char *path; /* pointer to the path in user space */
int len; /* path length, including 0 byte */
int flag; /* M3 means path may be in message */
{
/* Go get path and put it in 'user_path'.
* If 'flag' = M3 and 'len' <= M3_STRING, the path is present in 'message'.
* If it is not, go copy it from user space.
*/
register char *rpu, *rpm;
int r;
/* Check name length for validity. */
if (len <= 0) {
err_code = EINVAL;
return(EGENERIC);
}
if (len > PATH_MAX) {
err_code = ENAMETOOLONG;
return(EGENERIC);
}
if (flag == M3 && len <= M3_STRING) {
/* Just copy the path from the message to 'user_path'. */
rpu = &user_path[0];
rpm = m_in.pathname; /* contained in input message */
do { *rpu++ = *rpm++; } while (--len);
r = OK;
} else {
/* String is not contained in the message. Get it from user space. */
endpoint-aware conversion of servers. 'who', indicating caller number in pm and fs and some other servers, has been removed in favour of 'who_e' (endpoint) and 'who_p' (proc nr.). In both PM and FS, isokendpt() convert endpoints to process slot numbers, returning OK if it was a valid and consistent endpoint number. okendpt() does the same but panic()s if it doesn't succeed. (In PM, this is pm_isok..) pm and fs keep their own records of process endpoints in their proc tables, which are needed to make kernel calls about those processes. message field names have changed. fs drivers are endpoints. fs now doesn't try to get out of driver deadlock, as the protocol isn't supposed to let that happen any more. (A warning is printed if ELOCKED is detected though.) fproc[].fp_task (indicating which driver the process is suspended on) became an int. PM and FS now get endpoint numbers of initial boot processes from the kernel. These happen to be the same as the old proc numbers, to let user processes reach them with the old numbers, but FS and PM don't know that. All new processes after INIT, even after the generation number wraps around, get endpoint numbers with generation 1 and higher, so the first instances of the boot processes are the only processes ever to have endpoint numbers in the old proc number range. More return code checks of sys_* functions have been added. IS has become endpoint-aware. Ditched the 'text' and 'data' fields in the kernel dump (which show locations, not sizes, so aren't terribly useful) in favour of the endpoint number. Proc number is still visible. Some other dumps (e.g. dmap, rs) show endpoint numbers now too which got the formatting changed. PM reading segments using rw_seg() has changed - it uses other fields in the message now instead of encoding the segment and process number and fd in the fd field. For that it uses _read_pm() and _write_pm() which to _taskcall()s directly in pm/misc.c. PM now sys_exit()s itself on panic(), instead of sys_abort(). RS also talks in endpoints instead of process numbers.
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r = sys_datacopy(who_e, (vir_bytes) path,
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FS_PROC_NR, (vir_bytes) user_path, (phys_bytes) len);
}
return(r);
}
/*===========================================================================*
* no_sys *
*===========================================================================*/
PUBLIC int no_sys()
{
/* Somebody has used an illegal system call number */
return(EINVAL);
}
/*===========================================================================*
* panic *
*===========================================================================*/
PUBLIC void panic(who, mess, num)
char *who; /* who caused the panic */
char *mess; /* panic message string */
int num; /* number to go with it */
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{
/* Something awful has happened. Panics are caused when an internal
* inconsistency is detected, e.g., a programming error or illegal value of a
* defined constant.
*/
if (panicking) return; /* do not panic during a sync */
panicking = TRUE; /* prevent another panic during the sync */
printf("FS panic (%s): %s ", who, mess);
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if (num != NO_NUM) printf("%d",num);
(void) do_sync(); /* flush everything to the disk */
sys_exit(1);
}
/*===========================================================================*
* conv2 *
*===========================================================================*/
PUBLIC unsigned conv2(norm, w)
int norm; /* TRUE if no swap, FALSE for byte swap */
int w; /* promotion of 16-bit word to be swapped */
{
/* Possibly swap a 16-bit word between 8086 and 68000 byte order. */
if (norm) return( (unsigned) w & 0xFFFF);
return( ((w&BYTE) << 8) | ( (w>>8) & BYTE));
}
/*===========================================================================*
* conv4 *
*===========================================================================*/
PUBLIC long conv4(norm, x)
int norm; /* TRUE if no swap, FALSE for byte swap */
long x; /* 32-bit long to be byte swapped */
{
/* Possibly swap a 32-bit long between 8086 and 68000 byte order. */
unsigned lo, hi;
long l;
if (norm) return(x); /* byte order was already ok */
lo = conv2(FALSE, (int) x & 0xFFFF); /* low-order half, byte swapped */
hi = conv2(FALSE, (int) (x>>16) & 0xFFFF); /* high-order half, swapped */
l = ( (long) lo <<16) | hi;
return(l);
}
endpoint-aware conversion of servers. 'who', indicating caller number in pm and fs and some other servers, has been removed in favour of 'who_e' (endpoint) and 'who_p' (proc nr.). In both PM and FS, isokendpt() convert endpoints to process slot numbers, returning OK if it was a valid and consistent endpoint number. okendpt() does the same but panic()s if it doesn't succeed. (In PM, this is pm_isok..) pm and fs keep their own records of process endpoints in their proc tables, which are needed to make kernel calls about those processes. message field names have changed. fs drivers are endpoints. fs now doesn't try to get out of driver deadlock, as the protocol isn't supposed to let that happen any more. (A warning is printed if ELOCKED is detected though.) fproc[].fp_task (indicating which driver the process is suspended on) became an int. PM and FS now get endpoint numbers of initial boot processes from the kernel. These happen to be the same as the old proc numbers, to let user processes reach them with the old numbers, but FS and PM don't know that. All new processes after INIT, even after the generation number wraps around, get endpoint numbers with generation 1 and higher, so the first instances of the boot processes are the only processes ever to have endpoint numbers in the old proc number range. More return code checks of sys_* functions have been added. IS has become endpoint-aware. Ditched the 'text' and 'data' fields in the kernel dump (which show locations, not sizes, so aren't terribly useful) in favour of the endpoint number. Proc number is still visible. Some other dumps (e.g. dmap, rs) show endpoint numbers now too which got the formatting changed. PM reading segments using rw_seg() has changed - it uses other fields in the message now instead of encoding the segment and process number and fd in the fd field. For that it uses _read_pm() and _write_pm() which to _taskcall()s directly in pm/misc.c. PM now sys_exit()s itself on panic(), instead of sys_abort(). RS also talks in endpoints instead of process numbers.
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/*===========================================================================*
* isokendpt_f *
*===========================================================================*/
PUBLIC int isokendpt_f(char *file, int line, int endpoint, int *proc, int fatal)
{
int failed = 0;
*proc = _ENDPOINT_P(endpoint);
if(*proc < 0 || *proc >= NR_PROCS) {
printf("FS:%s:%d: proc (%d) from endpoint (%d) out of range\n",
file, line, *proc, endpoint);
failed = 1;
} else if(fproc[*proc].fp_endpoint != endpoint) {
printf("FS:%s:%d: proc (%d) from endpoint (%d) doesn't match "
"known endpoint (%d)\n",
file, line, *proc, endpoint, fproc[*proc].fp_endpoint);
failed = 1;
}
if(failed && fatal)
panic(__FILE__, "isokendpt_f failed", NO_NUM);
return failed ? EDEADSRCDST : OK;
}