minix/servers/vfs/misc.c
Thomas Veerman 958b25be50 - Introduce support for sticky bit.
- Revise VFS-FS protocol and update VFS/MFS/ISOFS accordingly.
- Clean up MFS by removing old, dead code (backwards compatibility is broken by
  the new VFS-FS protocol, anyway) and rewrite other parts. Also, make sure all
  functions have proper banners and prototypes.
- VFS should always provide a (syntactically) valid path to the FS; no need for
  the FS to do sanity checks when leaving/entering mount points.
- Fix several bugs in MFS:
  - Several path lookup bugs in MFS.
  - A link can be too big for the path buffer.
  - A mountpoint can become inaccessible when the creation of a new inode
    fails, because the inode already exists and is a mountpoint.
- Introduce support for supplemental groups.
- Add test 46 to test supplemental group functionality (and removed obsolete
  suppl. tests from test 2).
- Clean up VFS (not everything is done yet).
- ISOFS now opens device read-only. This makes the -r flag in the mount command
  unnecessary (but will still report to be mounted read-write).
- Introduce PipeFS. PipeFS is a new FS that handles all anonymous and
  named pipes. However, named pipes still reside on the (M)FS, as they are part
  of the file system on disk. To make this work VFS now has a concept of
  'mapped' inodes, which causes read, write, truncate and stat requests to be
  redirected to the mapped FS, and all other requests to the original FS.
2009-12-20 20:27:14 +00:00

642 lines
18 KiB
C

/* This file contains a collection of miscellaneous procedures. Some of them
* perform simple system calls. Some others do a little part of system calls
* that are mostly performed by the Memory Manager.
*
* The entry points into this file are
* do_dup: perform the DUP system call
* do_fcntl: perform the FCNTL system call
* do_sync: perform the SYNC system call
* do_fsync: perform the FSYNC system call
* do_reboot: sync disks and prepare for shutdown
* do_fork: adjust the tables after MM has performed a FORK system call
* do_exec: handle files with FD_CLOEXEC on after MM has done an EXEC
* do_exit: a process has exited; note that in the tables
* do_set: set uid or gid for some process
* do_revive: revive a process that was waiting for something (e.g. TTY)
* do_svrctl: file system control
* do_getsysinfo: request copy of FS data structure
* pm_dumpcore: create a core dump
*/
#include "fs.h"
#include <fcntl.h>
#include <assert.h>
#include <unistd.h> /* cc runs out of memory with unistd.h :-( */
#include <minix/callnr.h>
#include <minix/safecopies.h>
#include <minix/endpoint.h>
#include <minix/com.h>
#include <minix/u64.h>
#include <sys/ptrace.h>
#include <sys/svrctl.h>
#include "file.h"
#include "fproc.h"
#include "param.h"
#include <minix/vfsif.h>
#include "vnode.h"
#include "vmnt.h"
#define CORE_NAME "core"
#define CORE_MODE 0777 /* mode to use on core image files */
#if ENABLE_SYSCALL_STATS
PUBLIC unsigned long calls_stats[NCALLS];
#endif
FORWARD _PROTOTYPE( void free_proc, (struct fproc *freed, int flags) );
FORWARD _PROTOTYPE( void unmount_all, (void) );
/*
FORWARD _PROTOTYPE( int dumpcore, (int proc_e, struct mem_map *seg_ptr) );
FORWARD _PROTOTYPE( int write_bytes, (struct inode *rip, off_t off,
char *buf, size_t bytes) );
FORWARD _PROTOTYPE( int write_seg, (struct inode *rip, off_t off, int proc_e,
int seg, off_t seg_off, phys_bytes seg_bytes) );
*/
#define FP_EXITING 1
/*===========================================================================*
* do_getsysinfo *
*===========================================================================*/
PUBLIC int do_getsysinfo()
{
struct fproc *proc_addr;
vir_bytes src_addr, dst_addr;
size_t len;
int s;
/* Only su may call do_getsysinfo. This call may leak information (and is not
* stable enough to be part of the API/ABI).
*/
if (!super_user) return(EPERM);
switch(m_in.info_what) {
case SI_PROC_ADDR:
proc_addr = &fproc[0];
src_addr = (vir_bytes) &proc_addr;
len = sizeof(struct fproc *);
break;
case SI_PROC_TAB:
src_addr = (vir_bytes) fproc;
len = sizeof(struct fproc) * NR_PROCS;
break;
case SI_DMAP_TAB:
src_addr = (vir_bytes) dmap;
len = sizeof(struct dmap) * NR_DEVICES;
break;
#if ENABLE_SYSCALL_STATS
case SI_CALL_STATS:
src_addr = (vir_bytes) calls_stats;
len = sizeof(calls_stats);
break;
#endif
default:
return(EINVAL);
}
dst_addr = (vir_bytes) m_in.info_where;
if (OK != (s = sys_datacopy(SELF, src_addr, who_e, dst_addr, len))) return(s);
return(OK);
}
/*===========================================================================*
* do_dup *
*===========================================================================*/
PUBLIC int do_dup()
{
/* Perform the dup(fd) or dup2(fd,fd2) system call. These system calls are
* obsolete. In fact, it is not even possible to invoke them using the
* current library because the library routines call fcntl(). They are
* provided to permit old binary programs to continue to run.
*/
register int rfd;
register struct filp *f;
struct filp *dummy;
int r;
/* Is the file descriptor valid? */
rfd = m_in.fd & ~DUP_MASK; /* kill off dup2 bit, if on */
if ((f = get_filp(rfd)) == NIL_FILP) return(err_code);
/* Distinguish between dup and dup2. */
if (m_in.fd == rfd) { /* bit not on */
/* dup(fd) */
if ((r = get_fd(0, 0, &m_in.fd2, &dummy)) != OK) return(r);
} else {
/* dup2(fd, fd2) */
if (m_in.fd2 < 0 || m_in.fd2 >= OPEN_MAX) return(EBADF);
if (rfd == m_in.fd2) return(m_in.fd2); /* ignore the call: dup2(x, x) */
m_in.fd = m_in.fd2; /* prepare to close fd2 */
(void) do_close(); /* cannot fail */
}
/* Success. Set up new file descriptors. */
f->filp_count++;
fp->fp_filp[m_in.fd2] = f;
FD_SET(m_in.fd2, &fp->fp_filp_inuse);
return(m_in.fd2);
}
/*===========================================================================*
* do_fcntl *
*===========================================================================*/
PUBLIC int do_fcntl()
{
/* Perform the fcntl(fd, request, ...) system call. */
register struct filp *f;
int new_fd, r, fl;
long cloexec_mask; /* bit map for the FD_CLOEXEC flag */
long clo_value; /* FD_CLOEXEC flag in proper position */
struct filp *dummy;
/* Is the file descriptor valid? */
if ((f = get_filp(m_in.fd)) == NIL_FILP) return(err_code);
switch (m_in.request) {
case F_DUPFD:
/* This replaces the old dup() system call. */
if (m_in.addr < 0 || m_in.addr >= OPEN_MAX) return(EINVAL);
if ((r = get_fd(m_in.addr, 0, &new_fd, &dummy)) != OK) return(r);
f->filp_count++;
fp->fp_filp[new_fd] = f;
return(new_fd);
case F_GETFD:
/* Get close-on-exec flag (FD_CLOEXEC in POSIX Table 6-2). */
return( FD_ISSET(m_in.fd, &fp->fp_cloexec_set) ? FD_CLOEXEC : 0);
case F_SETFD:
/* Set close-on-exec flag (FD_CLOEXEC in POSIX Table 6-2). */
if(m_in.addr & FD_CLOEXEC)
FD_SET(m_in.fd, &fp->fp_cloexec_set);
else
FD_CLR(m_in.fd, &fp->fp_cloexec_set);
return(OK);
case F_GETFL:
/* Get file status flags (O_NONBLOCK and O_APPEND). */
fl = f->filp_flags & (O_NONBLOCK | O_APPEND | O_ACCMODE);
return(fl);
case F_SETFL:
/* Set file status flags (O_NONBLOCK and O_APPEND). */
fl = O_NONBLOCK | O_APPEND | O_REOPEN;
f->filp_flags = (f->filp_flags & ~fl) | (m_in.addr & fl);
return(OK);
case F_GETLK:
case F_SETLK:
case F_SETLKW:
/* Set or clear a file lock. */
r = lock_op(f, m_in.request);
return(r);
case F_FREESP:
{
/* Free a section of a file. Preparation is done here, actual freeing
* in freesp_inode().
*/
off_t start, end;
struct flock flock_arg;
signed long offset;
/* Check if it's a regular file. */
if((f->filp_vno->v_mode & I_TYPE) != I_REGULAR) return(EINVAL);
if (!(f->filp_mode & W_BIT)) return(EBADF);
/* Copy flock data from userspace. */
if((r = sys_datacopy(who_e, (vir_bytes) m_in.name1, SELF,
(vir_bytes) &flock_arg, (phys_bytes) sizeof(flock_arg))) != OK)
return(r);
/* Convert starting offset to signed. */
offset = (signed long) flock_arg.l_start;
/* Figure out starting position base. */
switch(flock_arg.l_whence) {
case SEEK_SET: start = 0; if(offset < 0) return EINVAL; break;
case SEEK_CUR:
if (ex64hi(f->filp_pos) != 0)
panic(__FILE__, "do_fcntl: position in file too high",
NO_NUM);
start = ex64lo(f->filp_pos);
break;
case SEEK_END: start = f->filp_vno->v_size; break;
default: return EINVAL;
}
/* Check for overflow or underflow. */
if(offset > 0 && start + offset < start) return EINVAL;
if(offset < 0 && start + offset > start) return EINVAL;
start += offset;
if(flock_arg.l_len > 0) {
end = start + flock_arg.l_len;
if(end <= start) return EINVAL;
} else {
end = 0;
}
return req_ftrunc(f->filp_vno->v_fs_e, f->filp_vno->v_inode_nr, start,
end);
}
default:
return(EINVAL);
}
}
/*===========================================================================*
* do_sync *
*===========================================================================*/
PUBLIC int do_sync()
{
struct vmnt *vmp;
for (vmp = &vmnt[1]; vmp < &vmnt[NR_MNTS]; ++vmp)
if (vmp->m_dev != NO_DEV)
req_sync(vmp->m_fs_e);
return(OK);
}
/*===========================================================================*
* do_fsync *
*===========================================================================*/
PUBLIC int do_fsync()
{
/* Perform the fsync() system call. For now, don't be unnecessarily smart. */
do_sync();
return(OK);
}
/*===========================================================================*
* unmount_all *
*===========================================================================*/
PRIVATE void unmount_all(void)
{
/* Unmount all filesystems. File systems are mounted on other file systems,
* so you have to pull off the loose bits repeatedly to get it all undone.
*/
int i;
for (i= 0; i < NR_MNTS; i++) {
struct vmnt *vmp;
/* Unmount at least one. */
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; vmp++) {
if (vmp->m_dev != NO_DEV)
unmount(vmp->m_dev);
}
}
}
/*===========================================================================*
* pm_reboot *
*===========================================================================*/
PUBLIC void pm_reboot()
{
/* Perform the FS side of the reboot call. */
int i;
do_sync();
SANITYCHECK;
/* Do exit processing for all leftover processes and servers,
* but don't actually exit them (if they were really gone, PM
* will tell us about it).
*/
for (i = 0; i < NR_PROCS; i++)
if((m_in.endpt1 = fproc[i].fp_endpoint) != NONE) {
/* No FP_EXITING, just free the resources, otherwise
* consistency check for fp_endpoint (set to NONE) will
* fail if process wants to do something in the (short)
* future.
*/
free_proc(&fproc[i], 0);
}
SANITYCHECK;
unmount_all();
SANITYCHECK;
}
/*===========================================================================*
* pm_fork *
*===========================================================================*/
PUBLIC void pm_fork(pproc, cproc, cpid)
int pproc; /* Parent process */
int cproc; /* Child process */
int cpid; /* Child process id */
{
/* Perform those aspects of the fork() system call that relate to files.
* In particular, let the child inherit its parent's file descriptors.
* The parent and child parameters tell who forked off whom. The file
* system uses the same slot numbers as the kernel. Only MM makes this call.
*/
register struct fproc *cp;
int i, parentno, childno;
/* Check up-to-dateness of fproc. */
okendpt(pproc, &parentno);
/* PM gives child endpoint, which implies process slot information.
* Don't call isokendpt, because that will verify if the endpoint
* number is correct in fproc, which it won't be.
*/
childno = _ENDPOINT_P(cproc);
if(childno < 0 || childno >= NR_PROCS)
panic(__FILE__, "FS: bogus child for forking", m_in.child_endpt);
if(fproc[childno].fp_pid != PID_FREE)
panic(__FILE__, "FS: forking on top of in-use child", childno);
/* Copy the parent's fproc struct to the child. */
fproc[childno] = fproc[parentno];
/* Increase the counters in the 'filp' table. */
cp = &fproc[childno];
fp = &fproc[parentno];
for (i = 0; i < OPEN_MAX; i++)
if (cp->fp_filp[i] != NIL_FILP) cp->fp_filp[i]->filp_count++;
/* Fill in new process and endpoint id. */
cp->fp_pid = cpid;
cp->fp_endpoint = cproc;
/* A forking process never has an outstanding grant,
* as it isn't blocking on i/o.
*/
if(GRANT_VALID(fp->fp_grant)) {
printf("vfs: fork: fp (endpoint %d) has grant %d\n", fp->fp_endpoint, fp->fp_grant);
panic(__FILE__, "fp contains valid grant", NO_NUM);
}
if(GRANT_VALID(cp->fp_grant)) {
printf("vfs: fork: cp (endpoint %d) has grant %d\n", cp->fp_endpoint, cp->fp_grant);
panic(__FILE__, "cp contains valid grant", NO_NUM);
}
/* A child is not a process leader. */
cp->fp_sesldr = 0;
/* This child has not exec()ced yet. */
cp->fp_execced = 0;
/* Record the fact that both root and working dir have another user. */
if(cp->fp_rd) dup_vnode(cp->fp_rd);
if(cp->fp_wd) dup_vnode(cp->fp_wd);
}
/*===========================================================================*
* free_proc *
*===========================================================================*/
PRIVATE void free_proc(struct fproc *exiter, int flags)
{
int i;
register struct fproc *rfp;
register struct filp *rfilp;
register struct vnode *vp;
dev_t dev;
SANITYCHECK;
fp = exiter; /* get_filp() needs 'fp' */
if(fp->fp_endpoint == NONE) {
panic(__FILE__, "free_proc: already free", NO_NUM);
}
if (fp_is_blocked(fp)) {
SANITYCHECK;
unpause(fp->fp_endpoint);
SANITYCHECK;
}
SANITYCHECK;
/* Loop on file descriptors, closing any that are open. */
for (i = 0; i < OPEN_MAX; i++) {
(void) close_fd(fp, i);
}
/* Check if any process is SUSPENDed on this driver.
* If a driver exits, unmap its entries in the dmap table.
* (unmapping has to be done after the first step, because the
* dmap table is used in the first step.)
*/
unsuspend_by_endpt(fp->fp_endpoint);
/* Release root and working directories. */
if(fp->fp_rd) { put_vnode(fp->fp_rd); fp->fp_rd = NIL_VNODE; }
if(fp->fp_wd) { put_vnode(fp->fp_wd); fp->fp_wd = NIL_VNODE; }
/* The rest of these actions is only done when processes actually
* exit.
*/
if(!(flags & FP_EXITING)) {
SANITYCHECK;
return;
}
/* Invalidate endpoint number for error and sanity checks. */
fp->fp_endpoint = NONE;
/* If a session leader exits and it has a controlling tty, then revoke
* access to its controlling tty from all other processes using it.
*/
if (fp->fp_sesldr && fp->fp_tty != 0) {
dev = fp->fp_tty;
for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if(rfp->fp_pid == PID_FREE) continue;
if (rfp->fp_tty == dev) rfp->fp_tty = 0;
for (i = 0; i < OPEN_MAX; i++) {
if ((rfilp = rfp->fp_filp[i]) == NIL_FILP) continue;
if (rfilp->filp_mode == FILP_CLOSED) continue;
vp = rfilp->filp_vno;
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL) continue;
if ((dev_t) vp->v_sdev != dev) continue;
(void) dev_close(dev, rfilp-filp);
/* Ignore any errors, even SUSPEND. */
rfilp->filp_mode = FILP_CLOSED;
}
}
}
/* Exit done. Mark slot as free. */
fp->fp_pid = PID_FREE;
SANITYCHECK;
}
/*===========================================================================*
* pm_exit *
*===========================================================================*/
PUBLIC void pm_exit(proc)
int proc;
{
int exitee_p;
/* Perform the file system portion of the exit(status) system call. */
/* Nevertheless, pretend that the call came from the user. */
okendpt(proc, &exitee_p);
free_proc(&fproc[exitee_p], FP_EXITING);
}
/*===========================================================================*
* pm_setgid *
*===========================================================================*/
PUBLIC void pm_setgid(proc_e, egid, rgid)
int proc_e;
int egid;
int rgid;
{
register struct fproc *tfp;
int slot;
okendpt(proc_e, &slot);
tfp = &fproc[slot];
tfp->fp_effgid = egid;
tfp->fp_realgid = rgid;
}
/*===========================================================================*
* pm_setgroups *
*===========================================================================*/
PUBLIC void pm_setgroups(proc_e, ngroups, groups)
int proc_e;
int ngroups;
gid_t *groups;
{
struct fproc *rfp;
int slot, i;
okendpt(proc_e, &slot);
rfp = &fproc[slot];
if (ngroups * sizeof(gid_t) > sizeof(rfp->fp_sgroups))
panic(__FILE__, "VFS: pm_setgroups: too much data to copy\n", NO_NUM);
if(sys_datacopy(who_e, (vir_bytes) groups, SELF, (vir_bytes) rfp->fp_sgroups,
ngroups * sizeof(gid_t)) == OK) {
rfp->fp_ngroups = ngroups;
} else
panic(__FILE__, "VFS: pm_setgroups: datacopy failed\n", NO_NUM);
}
/*===========================================================================*
* pm_setuid *
*===========================================================================*/
PUBLIC void pm_setuid(proc_e, euid, ruid)
int proc_e;
int euid;
int ruid;
{
register struct fproc *tfp;
int slot;
okendpt(proc_e, &slot);
tfp = &fproc[slot];
tfp->fp_effuid = euid;
tfp->fp_realuid = ruid;
}
/*===========================================================================*
* do_svrctl *
*===========================================================================*/
PUBLIC int do_svrctl()
{
switch (m_in.svrctl_req) {
case FSSIGNON: {
/* A server in user space calls in to manage a device. */
struct fssignon device;
int r, major, proc_nr_n;
if (fp->fp_effuid != SU_UID && fp->fp_effuid != SERVERS_UID)
return(EPERM);
/* Try to copy request structure to FS. */
if ((r = sys_datacopy(who_e, (vir_bytes) m_in.svrctl_argp,
FS_PROC_NR, (vir_bytes) &device,
(phys_bytes) sizeof(device))) != OK)
return(r);
if (isokendpt(who_e, &proc_nr_n) != OK)
return(EINVAL);
/* Try to update device mapping. */
major = (device.dev >> MAJOR) & BYTE;
r=map_driver(major, who_e, device.style, 0 /* !force */);
if (r == OK)
{
/* If a driver has completed its exec(), it can be announced
* to be up.
*/
if(fproc[proc_nr_n].fp_execced) {
/* Reply before calling dev_up */
#if 0
printf("do_svrctl: replying before dev_up\n");
#endif
reply(who_e, r);
dev_up(major);
r= SUSPEND;
} else {
dmap[major].dmap_flags |= DMAP_BABY;
}
}
return(r);
}
case FSDEVUNMAP: {
struct fsdevunmap fdu;
int r, major;
/* Try to copy request structure to FS. */
if ((r = sys_datacopy(who_e, (vir_bytes) m_in.svrctl_argp,
FS_PROC_NR, (vir_bytes) &fdu,
(phys_bytes) sizeof(fdu))) != OK)
return(r);
major = (fdu.dev >> MAJOR) & BYTE;
r=map_driver(major, NONE, 0, 0);
return(r);
}
default:
return(EINVAL);
}
}
/*===========================================================================*
* pm_dumpcore *
*===========================================================================*/
PUBLIC int pm_dumpcore(proc_e, seg_ptr)
int proc_e;
struct mem_map *seg_ptr;
{
int r, proc_s;
/* Terminate the process */
okendpt(proc_e, &proc_s);
free_proc(&fproc[proc_s], FP_EXITING);
return OK;
}