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/* This file contains a few general purpose utility routines.
*
* The entry points into this file are
* copy_path: copy a path name from a path request from userland
* fetch_name: go get a path name from user space
* panic: something awful has occurred; MINIX cannot continue
* in_group: determines if group 'grp' is in rfp->fp_sgroups[]
*/
#include "fs.h"
#include <minix/callnr.h>
#include <minix/endpoint.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <time.h>
#include "file.h"
#include "vmnt.h"
/*===========================================================================*
* copy_path *
*===========================================================================*/
int copy_path(char *dest, size_t size)
{
/* Go get the path for a path request. Put the result in in 'dest', which
* should be at least PATH_MAX in size.
*/
vir_bytes name;
size_t len;
assert(size >= PATH_MAX);
name = job_m_in.m_lc_vfs_path.name;
len = job_m_in.m_lc_vfs_path.len;
if (len > size) { /* 'len' includes terminating-nul */
err_code = ENAMETOOLONG;
return(EGENERIC);
}
/* Is the string contained in the message? If not, perform a normal copy. */
if (len > M_PATH_STRING_MAX)
return fetch_name(name, len, dest);
/* Just copy the path from the message */
strncpy(dest, job_m_in.m_lc_vfs_path.buf, len);
if (dest[len - 1] != '\0') {
err_code = ENAMETOOLONG;
return(EGENERIC);
}
return(OK);
}
/*===========================================================================*
* fetch_name *
*===========================================================================*/
int fetch_name(vir_bytes path, size_t len, char *dest)
{
/* Go get path and put it in 'dest'. */
int r;
if (len > PATH_MAX) { /* 'len' includes terminating-nul */
err_code = ENAMETOOLONG;
return(EGENERIC);
}
/* Check name length for validity. */
if (len > SSIZE_MAX) {
err_code = EINVAL;
return(EGENERIC);
}
/* String is not contained in the message. Get it from user space. */
r = sys_datacopy_wrapper(who_e, path, VFS_PROC_NR, (vir_bytes) dest, len);
if (r != OK) {
err_code = EINVAL;
return(r);
}
if (dest[len - 1] != '\0') {
err_code = ENAMETOOLONG;
return(EGENERIC);
}
return(OK);
}
/*===========================================================================*
* isokendpt_f *
*===========================================================================*/
int isokendpt_f(const 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) {
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);
}
/*===========================================================================*
* in_group *
*===========================================================================*/
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);
}
/*===========================================================================*
* sys_datacopy_wrapper *
*===========================================================================*/
int sys_datacopy_wrapper(endpoint_t src, vir_bytes srcv,
endpoint_t dst, vir_bytes dstv, size_t len)
{
/* Safe function to copy data from or to a user buffer.
* VFS has to be a bit more careful as a regular copy
* might trigger VFS action needed by VM while it's
* blocked on the kernel call. This wrapper tries the
* copy, invokes VM itself asynchronously if necessary,
* then tries the copy again.
*
* This function assumes it's between VFS and a user process,
* and therefore one of the endpoints is SELF (VFS).
*/
int r;
endpoint_t them = NONE;
vir_bytes themv = -1;
int writable = -1;
r = sys_datacopy_try(src, srcv, dst, dstv, len);
if(src == VFS_PROC_NR) src = SELF;
if(dst == VFS_PROC_NR) dst = SELF;
assert(src == SELF || dst == SELF);
if(src == SELF) { them = dst; themv = dstv; writable = 1; }
if(dst == SELF) { them = src; themv = srcv; writable = 0; }
assert(writable >= 0);
assert(them != SELF);
if(r == EFAULT) {
/* The copy has failed with EFAULT, this means the kernel has
* given up but it might not be a legitimate error. Ask VM.
*/
if((r=vm_vfs_procctl_handlemem(them, themv, len, writable)) != OK) {
return r;
}
r = sys_datacopy_try(src, srcv, dst, dstv, len);
}
return r;
}
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