minix/servers/vfs/utility.c
Thomas Veerman 13ef7f1f38 Prepare VFS to support back calls from PFS. For security reasons and to support
file descriptor passing, PFS does some back calls to VFS. For example, to
verify the validity of a path provided by a process and to tell VFS it must
copy file descriptors from one process to another.
2010-08-30 13:44:07 +00:00

159 lines
4.6 KiB
C

/* 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
* in_group: determines if group 'grp' is in rfp->fp_sgroups[]
*/
#include "fs.h"
#include <minix/com.h>
#include <minix/endpoint.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include "file.h"
#include "fproc.h"
#include "param.h"
#include "vmnt.h"
/*===========================================================================*
* 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_fullpath'.
* 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, count;
if (len > PATH_MAX) {
err_code = ENAMETOOLONG;
return(EGENERIC);
}
if(len >= sizeof(user_fullpath))
panic("fetch_name: len too much for user_fullpath: %d", len);
/* Check name length for validity. */
if (len <= 0) {
err_code = EINVAL;
return(EGENERIC);
}
if (flag == M3 && len <= M3_STRING) {
/* Just copy the path from the message to 'user_fullpath'. */
rpu = &user_fullpath[0];
rpm = m_in.pathname; /* contained in input message */
count = len;
do { *rpu++ = *rpm++; } while (--count);
r = OK;
} else {
/* String is not contained in the message. Get it from user space. */
r = sys_datacopy(who_e, (vir_bytes) path,
VFS_PROC_NR, (vir_bytes) user_fullpath, (phys_bytes) len);
}
if (user_fullpath[len - 1] != '\0') {
err_code = ENAMETOOLONG;
return(EGENERIC);
}
return(r);
}
/*===========================================================================*
* no_sys *
*===========================================================================*/
PUBLIC int no_sys()
{
/* Somebody has used an illegal system call number */
printf("VFS no_sys: call %d from %d (pid %d)\n", call_nr, who_e, who_p);
return(ENOSYS);
}
/*===========================================================================*
* isokendpt_f *
*===========================================================================*/
PUBLIC int isokendpt_f(char *file, int line, endpoint_t endpoint, int *proc, int fatal)
{
int failed = 0;
endpoint_t ke;
*proc = _ENDPOINT_P(endpoint);
if(endpoint == NONE) {
printf("vfs:%s:%d: endpoint is NONE\n", file, line);
failed = 1;
} else if(*proc < 0 || *proc >= NR_PROCS) {
printf("vfs:%s:%d: proc (%d) from endpoint (%d) out of range\n",
file, line, *proc, endpoint);
failed = 1;
} else if((ke=fproc[*proc].fp_endpoint) != endpoint) {
if(ke == NONE) {
printf("vfs:%s:%d: endpoint (%d) points to NONE slot (%d)\n",
file, line, endpoint, *proc);
assert(fproc[*proc].fp_pid == PID_FREE);
} else {
printf("vfs:%s:%d: proc (%d) from endpoint (%d) doesn't match "
"known endpoint (%d)\n", file, line, *proc, endpoint,
fproc[*proc].fp_endpoint);
assert(fproc[*proc].fp_pid != PID_FREE);
}
failed = 1;
}
if(failed && fatal)
panic("isokendpt_f failed");
return(failed ? EDEADEPT : OK);
}
/*===========================================================================*
* 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 r;
clock_t uptime;
time_t boottime;
r = getuptime2(&uptime, &boottime);
if (r != OK)
panic("clock_time err: %d", r);
return( (time_t) (boottime + (uptime/system_hz)));
}
/*===========================================================================*
* in_group *
*===========================================================================*/
PUBLIC int in_group(struct fproc *rfp, gid_t grp)
{
int i;
for (i = 0; i < rfp->fp_ngroups; i++) {
if (rfp->fp_sgroups[i] == grp) {
return(OK);
}
}
return(EINVAL);
}