minix/servers/vfs/stadir.c

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/* This file contains the code for performing four system calls relating to
* status and directories.
*
* The entry points into this file are
* do_chdir: perform the CHDIR system call
* do_chroot: perform the CHROOT system call
* do_stat: perform the STAT system call
* do_fstat: perform the FSTAT system call
* do_fstatfs: perform the FSTATFS system call
* do_lstat: perform the LSTAT system call
*
* Changes for VFS:
* Jul 2006 (Balazs Gerofi)
*/
#include "fs.h"
#include <sys/stat.h>
#include <sys/statfs.h>
#include <minix/com.h>
#include <minix/u64.h>
#include <string.h>
#include "file.h"
#include "fproc.h"
#include "param.h"
#include <minix/vfsif.h>
#include "vnode.h"
#include "vmnt.h"
FORWARD _PROTOTYPE( int change, (struct vnode **iip, char *name_ptr, int len));
FORWARD _PROTOTYPE( int change_into, (struct vnode **iip, struct vnode *vp));
/*===========================================================================*
* do_fchdir *
*===========================================================================*/
PUBLIC int do_fchdir()
{
/* Change directory on already-opened fd. */
struct filp *rfilp;
int r;
/* Is the file descriptor valid? */
if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) return(err_code);
/* Is it a dir? */
if ((rfilp->filp_vno->v_mode & I_TYPE) != I_DIRECTORY)
return ENOTDIR;
/* Issue request and handle error */
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r = forbidden(rfilp->filp_vno, X_BIT);
if (r != OK) return r;
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rfilp->filp_vno->v_ref_count++; /* change_into expects a reference */
return change_into(&fp->fp_wd, rfilp->filp_vno);
}
/*===========================================================================*
* do_chdir *
*===========================================================================*/
PUBLIC int do_chdir()
{
/* Change directory. This function is also called by MM to simulate a chdir
* in order to do EXEC, etc. It also changes the root directory, the uids and
* gids, and the umask.
*/
int r;
register struct fproc *rfp;
if (who_e == PM_PROC_NR) {
int slot;
if(isokendpt(m_in.endpt1, &slot) != OK)
return EINVAL;
rfp = &fproc[slot];
put_vnode(fp->fp_rd);
dup_vnode(fp->fp_rd = rfp->fp_rd);
put_vnode(fp->fp_wd);
dup_vnode(fp->fp_wd = rfp->fp_wd);
/* MM uses access() to check permissions. To make this work, pretend
* that the user's real ids are the same as the user's effective ids.
* FS calls other than access() do not use the real ids, so are not
* affected.
*/
fp->fp_realuid =
fp->fp_effuid = rfp->fp_effuid;
fp->fp_realgid =
fp->fp_effgid = rfp->fp_effgid;
fp->fp_umask = rfp->fp_umask;
return(OK);
}
/* Perform the chdir(name) system call. */
r = change(&fp->fp_wd, m_in.name, m_in.name_length);
return(r);
}
/*===========================================================================*
* do_chroot *
*===========================================================================*/
PUBLIC int do_chroot()
{
/* Perform the chroot(name) system call. */
register int r;
if (!super_user) return(EPERM); /* only su may chroot() */
r = change(&fp->fp_rd, m_in.name, m_in.name_length);
return(r);
}
/*===========================================================================*
* change *
*===========================================================================*/
PRIVATE int change(iip, name_ptr, len)
struct vnode **iip; /* pointer to the inode pointer for the dir */
char *name_ptr; /* pointer to the directory name to change to */
int len; /* length of the directory name string */
{
/* Do the actual work for chdir() and chroot(). */
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struct vnode *vp;
struct lookup_req lookup_req;
int r;
if (fetch_name(name_ptr, len, M3) != OK) return(err_code);
/* Fill in lookup request fields */
lookup_req.path = user_fullpath;
lookup_req.lastc = NULL;
lookup_req.flags = EAT_PATH;
/* Request lookup */
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if ((r = lookup_vp(&lookup_req, &vp)) != OK) return r;
/* Is it a dir? */
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if ((vp->v_mode & I_TYPE) != I_DIRECTORY)
{
put_vnode(vp);
return ENOTDIR;
}
Mostly bugfixes of bugs triggered by the test set. bugfixes: SYSTEM: . removed rc->p_priv->s_flags = 0; for the priv struct shared by all user processes in get_priv(). this should only be done once. doing a SYS_PRIV_USER in sys_privctl() caused the flags of all user processes to be reset, so they were no longer PREEMPTIBLE. this happened when RS executed a policy script. (this broke test1 in the test set) VFS/MFS: . chown can change the mode of a file, and chmod arguments are only part of the full file mode so the full filemode is slightly magic. changed these calls so that the final modes are returned to VFS, so that the vnode can be kept up-to-date. (this broke test11 in the test set) MFS: . lookup() checked for sizeof(string) instead of sizeof(user_path), truncating long path names (caught by test 23) . truncate functions neglected to update ctime (this broke test16) VFS: . corner case of an empty filename lookup caused fields of a request not to be filled in in the lookup functions, not making it clear that the lookup had failed, causing messages to garbage processes, causing strange failures. (caught by test 30) . trust v_size in vnode when doing reads or writes on non-special files, truncating i/o where necessary; this is necessary for pipes, as MFS can't tell when a pipe has been truncated without it being told explicitly each time. when the last reader/writer on a pipe closes, tell FS about the new size using truncate_vn(). (this broke test 25, among others) . permission check for chdir() had disappeared; added a forbidden() call (caught by test 23) new code, shouldn't change anything: . introduced RTS_SET, RTS_UNSET, and RTS_ISSET macro's, and their LOCK variants. These macros set and clear the p_rts_flags field, causing a lot of duplicated logic like old_flags = rp->p_rts_flags; /* save value of the flags */ rp->p_rts_flags &= ~NO_PRIV; if (old_flags != 0 && rp->p_rts_flags == 0) lock_enqueue(rp); to change into the simpler RTS_LOCK_UNSET(rp, NO_PRIV); so the macros take care of calling dequeue() and enqueue() (or lock_*()), as the case may be). This makes the code a bit more readable and a bit less fragile. . removed return code from do_clocktick in CLOCK as it currently never replies . removed some debug code from VFS . fixed grant debug message in device.c preemptive checks, tests, changes: . added return code checks of receive() to SYSTEM and CLOCK . O_TRUNC should never arrive at MFS (added sanity check and removed O_TRUNC code) . user_path declared with PATH_MAX+1 to let it be null-terminated . checks in MFS to see if strings passed by VFS are null-terminated IS: . static irq name table thrown out
2007-02-01 18:50:02 +01:00
/* Access check */
r = forbidden(vp, X_BIT);
if (r != OK) {
put_vnode(vp);
return r;
}
return change_into(iip, vp);
}
/*===========================================================================*
* change_into *
*===========================================================================*/
PRIVATE int change_into(iip, vp)
struct vnode **iip; /* pointer to the inode pointer for the dir */
struct vnode *vp; /* this is what the inode has to become */
{
/* Everything is OK. Make the change. */
put_vnode(*iip); /* release the old directory */
*iip = vp; /* acquire the new one */
return(OK);
}
/*===========================================================================*
* do_stat *
*===========================================================================*/
PUBLIC int do_stat()
{
/* Perform the stat(name, buf) system call. */
struct node_details res;
struct lookup_req lookup_req;
int r;
if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
/* Fill in lookup request fields */
lookup_req.path = user_fullpath;
lookup_req.lastc = NULL;
lookup_req.flags = EAT_PATH;
/* Request lookup */
if ((r = lookup(&lookup_req, &res)) != OK) return r;
/* Issue request */
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return req_stat(res.fs_e, res.inode_nr, who_e, m_in.name2, 0);
}
/*===========================================================================*
* do_fstat *
*===========================================================================*/
PUBLIC int do_fstat()
{
/* Perform the fstat(fd, buf) system call. */
register struct filp *rfilp;
int pipe_pos = 0;
/* Is the file descriptor valid? */
if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) {
return(err_code);
}
/* If we read from a pipe, send position too */
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pipe_pos= 0;
if (rfilp->filp_vno->v_pipe == I_PIPE) {
if (rfilp->filp_mode & R_BIT)
if (ex64hi(rfilp->filp_pos) != 0)
{
panic(__FILE__, "do_fstat: bad position in pipe",
NO_NUM);
}
pipe_pos = ex64lo(rfilp->filp_pos);
}
/* Issue request */
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return req_stat(rfilp->filp_vno->v_fs_e, rfilp->filp_vno->v_inode_nr,
who_e, m_in.buffer, pipe_pos);
}
/*===========================================================================*
* do_fstatfs *
*===========================================================================*/
PUBLIC int do_fstatfs()
{
/* Perform the fstatfs(fd, buf) system call. */
register struct filp *rfilp;
/* Is the file descriptor valid? */
if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) return(err_code);
/* Issue request */
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return req_fstatfs(rfilp->filp_vno->v_fs_e, rfilp->filp_vno->v_inode_nr,
who_e, m_in.buffer);
}
/*===========================================================================*
* do_lstat *
*===========================================================================*/
PUBLIC int do_lstat()
{
/* Perform the lstat(name, buf) system call. */
struct node_details res;
struct lookup_req lookup_req;
int r;
if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
/* Fill in lookup request fields */
lookup_req.path = user_fullpath;
lookup_req.lastc = NULL;
lookup_req.flags = EAT_PATH_OPAQUE;
/* Request lookup */
if ((r = lookup(&lookup_req, &res)) != OK) return r;
/* Issue request */
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return req_stat(res.fs_e, res.inode_nr, who_e, m_in.name2, 0);
}