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minix/lib/libpuffs/link.c
Ben Gras 2bfeeed885 drop segment from safecopy invocations 
. all invocations were S or D, so can safely be dropped
	  to prepare for the segmentless world
	. still assign D to the SCP_SEG field in the message
	  to make previous kernels usable
2012-06-16 16:22:51 +00:00

557 lines
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#include "fs.h"
#include <stdlib.h>
#include <assert.h>
#include "puffs.h"
#include "puffs_priv.h"
#define SAME 1000
/*===========================================================================*
* fs_ftrunc *
*===========================================================================*/
int fs_ftrunc(void)
{
int r;
struct puffs_node *pn;
off_t start, end;
PUFFS_MAKECRED(pcr, &global_kcred);
if ((pn = puffs_pn_nodewalk(global_pu, 0, &fs_m_in.REQ_INODE_NR)) == NULL)
return(EINVAL);
start = fs_m_in.REQ_TRC_START_LO;
end = fs_m_in.REQ_TRC_END_LO;
if (end == 0) {
struct vattr va;
if (pn->pn_va.va_size == start)
return(OK);
if (global_pu->pu_ops.puffs_node_setattr == NULL)
return(EINVAL);
puffs_vattr_null(&va);
va.va_size = start;
r = global_pu->pu_ops.puffs_node_setattr(global_pu, pn, &va, pcr);
if (r) return(EINVAL);
} else {
/* XXX zerofill the given region. Can we make a hole? */
off_t bytes_left = end - start;
char* rw_buf;
if (global_pu->pu_ops.puffs_node_write == NULL)
return(EINVAL);
/* XXX split into chunks? */
rw_buf = malloc(bytes_left);
if (!rw_buf)
panic("fs_ftrunc: failed to allocated memory\n");
memset(rw_buf, 0, bytes_left);
r = global_pu->pu_ops.puffs_node_write(global_pu, pn, (uint8_t *)rw_buf,
start, (size_t *) &bytes_left, pcr, 0);
free(rw_buf);
if (r) return(EINVAL);
}
update_times(pn, CTIME | MTIME, 0);
return(r);
}
/*===========================================================================*
* fs_link *
*===========================================================================*/
int fs_link()
{
/* Perform the link(name1, name2) system call. */
register int r;
char string[NAME_MAX + 1];
phys_bytes len;
struct puffs_node *pn, *pn_dir, *new_pn;
time_t cur_time;
struct puffs_kcn pkcnp;
PUFFS_MAKECRED(pcr, &global_kcred);
struct puffs_cn pcn = {&pkcnp, (struct puffs_cred *) __UNCONST(pcr), {0,0,0}};
if (global_pu->pu_ops.puffs_node_link == NULL)
return(OK);
/* Copy the link name's last component */
len = fs_m_in.REQ_PATH_LEN;
if (len > NAME_MAX + 1)
return(ENAMETOOLONG);
r = sys_safecopyfrom(VFS_PROC_NR, (cp_grant_id_t) fs_m_in.REQ_GRANT, 0,
(vir_bytes) string, (size_t) len);
if (r != OK) return(r);
NUL(string, len, sizeof(string));
if ((pn = puffs_pn_nodewalk(global_pu, 0, &fs_m_in.REQ_INODE_NR)) == NULL)
return(EINVAL);
/* Check to see if the file has maximum number of links already. */
if (pn->pn_va.va_nlink >= LINK_MAX)
return(EMLINK);
/* Only super_user may link to directories. */
if ((pn->pn_va.va_mode & I_TYPE) == I_DIRECTORY && caller_uid != SU_UID)
return(EPERM);
if ((pn_dir = puffs_pn_nodewalk(global_pu, 0, &fs_m_in.REQ_DIR_INO)) == NULL)
return(EINVAL);
if (pn_dir->pn_va.va_nlink == NO_LINK) {
/* Dir does not actually exist */
return(ENOENT);
}
/* If 'name2' exists in full (even if no space) set 'r' to error. */
if ((new_pn = advance(pn_dir, string, IGN_PERM)) == NULL) {
r = err_code;
if (r == ENOENT) r = OK;
} else {
r = EEXIST;
}
if (r != OK) return(r);
/* Try to link. */
pcn.pcn_namelen = strlen(string);
assert(pcn.pcn_namelen <= MAXPATHLEN);
strcpy(pcn.pcn_name, string);
if (buildpath) {
if (puffs_path_pcnbuild(global_pu, &pcn, pn_dir) != 0)
return(EINVAL);
}
if (global_pu->pu_ops.puffs_node_link(global_pu, pn_dir, pn, &pcn) != 0)
r = EINVAL;
if (buildpath)
global_pu->pu_pathfree(global_pu, &pcn.pcn_po_full);
if (r != OK) return(EINVAL);
cur_time = clock_time();
update_times(pn, CTIME, cur_time);
update_times(pn_dir, MTIME | CTIME, cur_time);
return(OK);
}
/*===========================================================================*
* fs_rdlink *
*===========================================================================*/
int fs_rdlink()
{
register int r; /* return value */
size_t copylen;
struct puffs_node *pn;
char path[PATH_MAX];
PUFFS_MAKECRED(pcr, &global_kcred);
copylen = fs_m_in.REQ_MEM_SIZE < UMAX_FILE_POS ?
fs_m_in.REQ_MEM_SIZE : UMAX_FILE_POS;
assert(copylen <= PATH_MAX);
if ((pn = puffs_pn_nodewalk(global_pu, 0, &fs_m_in.REQ_INODE_NR)) == NULL)
return(EINVAL);
if (!S_ISLNK(pn->pn_va.va_mode))
return(EACCES);
if (global_pu->pu_ops.puffs_node_readlink == NULL)
return(EINVAL);
r = global_pu->pu_ops.puffs_node_readlink(global_pu, pn, pcr, path,
&copylen);
if (r != OK) {
if (r > 0) r = -r;
return(r);
}
r = sys_safecopyto(VFS_PROC_NR, (cp_grant_id_t) fs_m_in.REQ_GRANT,
(vir_bytes) 0, (vir_bytes) path, (size_t) copylen);
if (r == OK)
fs_m_out.RES_NBYTES = copylen;
return(r);
}
/*===========================================================================*
* fs_rename *
*===========================================================================*/
int fs_rename()
{
/* Perform the rename(name1, name2) system call. */
struct puffs_node *old_dirp, *old_ip; /* ptrs to old dir, file pnodes */
struct puffs_node *new_dirp, *new_ip; /* ptrs to new dir, file pnodes */
struct puffs_kcn pkcnp_src;
PUFFS_MAKECRED(pcr_src, &global_kcred);
struct puffs_cn pcn_src = {&pkcnp_src, (struct puffs_cred *) __UNCONST(pcr_src), {0,0,0}};
struct puffs_kcn pkcnp_dest;
PUFFS_MAKECRED(pcr_dest, &global_kcred);
struct puffs_cn pcn_targ = {&pkcnp_dest, (struct puffs_cred *) __UNCONST(pcr_dest), {0,0,0}};
int r = OK; /* error flag; initially no error */
int odir, ndir; /* TRUE iff {old|new} file is dir */
int same_pdir; /* TRUE iff parent dirs are the same */
phys_bytes len;
time_t cur_time;
if (global_pu->pu_ops.puffs_node_rename == NULL)
return(EINVAL);
/* Copy the last component of the old name */
len = fs_m_in.REQ_REN_LEN_OLD; /* including trailing '\0' */
if (len > NAME_MAX + 1)
return(ENAMETOOLONG);
r = sys_safecopyfrom(VFS_PROC_NR, (cp_grant_id_t) fs_m_in.REQ_REN_GRANT_OLD,
(vir_bytes) 0, (vir_bytes) pcn_src.pcn_name, (size_t) len);
if (r != OK) return(r);
NUL(pcn_src.pcn_name, len, sizeof(pcn_src.pcn_name));
pcn_src.pcn_namelen = len - 1;
/* Copy the last component of the new name */
len = fs_m_in.REQ_REN_LEN_NEW; /* including trailing '\0' */
if (len > NAME_MAX + 1)
return(ENAMETOOLONG);
r = sys_safecopyfrom(VFS_PROC_NR, (cp_grant_id_t) fs_m_in.REQ_REN_GRANT_NEW,
(vir_bytes) 0, (vir_bytes) pcn_targ.pcn_name, (size_t) len);
if (r != OK) return(r);
NUL(pcn_targ.pcn_name, len, sizeof(pcn_targ.pcn_name));
pcn_targ.pcn_namelen = len - 1;
/* Get old dir pnode */
if ((old_dirp = puffs_pn_nodewalk(global_pu, 0, &fs_m_in.REQ_REN_OLD_DIR))
== NULL)
return(ENOENT);
old_ip = advance(old_dirp, pcn_src.pcn_name, IGN_PERM);
if (!old_ip) {
return(ENOENT);
}
r = err_code;
if (r == EENTERMOUNT || r == ELEAVEMOUNT) {
old_ip = NULL;
if (r == EENTERMOUNT) r = EXDEV; /* should this fail at all? */
else if (r == ELEAVEMOUNT) r = EINVAL; /* rename on dot-dot */
}
/* Get new dir pnode */
if ((new_dirp = puffs_pn_nodewalk(global_pu, 0, &fs_m_in.REQ_REN_NEW_DIR))
== NULL) {
r = ENOENT;
} else {
if (new_dirp->pn_va.va_nlink == NO_LINK) {
/* Dir does not actually exist */
return(ENOENT);
}
}
/* not required to exist */
new_ip = advance(new_dirp, pcn_targ.pcn_name, IGN_PERM);
/* However, if the check failed because the file does exist, don't continue.
* Note that ELEAVEMOUNT is covered by the dot-dot check later. */
if (err_code == EENTERMOUNT) {
new_ip = NULL;
r = EBUSY;
}
if (old_ip != NULL) {
/* TRUE iff dir */
odir = ((old_ip->pn_va.va_mode & I_TYPE) == I_DIRECTORY);
} else {
odir = FALSE;
}
if (r != OK) return(r);
/* Check for a variety of possible errors. */
same_pdir = (old_dirp == new_dirp);
/* The old or new name must not be . or .. */
if (strcmp(pcn_src.pcn_name, ".") == 0 ||
strcmp(pcn_src.pcn_name, "..") == 0 ||
strcmp(pcn_targ.pcn_name, ".") == 0 ||
strcmp(pcn_targ.pcn_name, "..") == 0) {
r = EINVAL;
}
/* Some tests apply only if the new path exists. */
if (new_ip == NULL) {
if (odir && (new_dirp->pn_va.va_nlink >= SHRT_MAX ||
new_dirp->pn_va.va_nlink >= LINK_MAX) &&
!same_pdir && r == OK) {
r = EMLINK;
}
} else {
if (old_ip == new_ip) r = SAME; /* old=new */
/* dir ? */
ndir = ((new_ip->pn_va.va_mode & I_TYPE) == I_DIRECTORY);
if (odir == TRUE && ndir == FALSE) r = ENOTDIR;
if (odir == FALSE && ndir == TRUE) r = EISDIR;
}
if (r == SAME) {
r = OK;
goto rename_out;
}
if (r != OK) return(r);
/* If a process has another root directory than the system root, we might
* "accidently" be moving it's working directory to a place where it's
* root directory isn't a super directory of it anymore. This can make
* the function chroot useless. If chroot will be used often we should
* probably check for it here. */
/* The rename will probably work. Only two things can go wrong now:
* 1. being unable to remove the new file. (when new file already exists)
* 2. being unable to make the new directory entry. (new file doesn't exists)
* [directory has to grow by one block and cannot because the disk
* is completely full].
* 3. Something (doubtfully) else depending on the FS.
*/
if (buildpath) {
pcn_src.pcn_po_full = old_ip->pn_po;
if (puffs_path_pcnbuild(global_pu, &pcn_targ, new_dirp) != 0)
return(EINVAL);
}
r = global_pu->pu_ops.puffs_node_rename(global_pu, old_dirp, old_ip, &pcn_src,
new_dirp, new_ip, &pcn_targ);
if (r > 0) r = -r;
if (buildpath) {
if (r) {
global_pu->pu_pathfree(global_pu, &pcn_targ.pcn_po_full);
} else {
struct puffs_pathinfo pi;
struct puffs_pathobj po_old;
/* handle this node */
po_old = old_ip->pn_po;
old_ip->pn_po = pcn_targ.pcn_po_full;
if (old_ip->pn_va.va_type != VDIR) {
global_pu->pu_pathfree(global_pu, &po_old);
return(OK);
}
/* handle all child nodes for DIRs */
pi.pi_old = &pcn_src.pcn_po_full;
pi.pi_new = &pcn_targ.pcn_po_full;
PU_LOCK();
if (puffs_pn_nodewalk(global_pu, puffs_path_prefixadj, &pi)
!= NULL) {
/* Actually nomem */
return(EINVAL);
}
PU_UNLOCK();
global_pu->pu_pathfree(global_pu, &po_old);
}
}
rename_out:
cur_time = clock_time();
update_times(old_dirp, MTIME | CTIME, cur_time);
update_times(new_dirp, MTIME | CTIME, cur_time);
/* XXX see release_node comment in fs_unlink */
if (new_ip && new_ip->pn_count == 0) {
release_node(global_pu, new_ip);
}
return(r);
}
static int remove_dir(struct puffs_node *pn_dir, struct puffs_node *pn,
struct puffs_cn *pcn);
static int unlink_file(struct puffs_node *dirp, struct puffs_node *pn,
struct puffs_cn *pcn);
/*===========================================================================*
* fs_unlink *
*===========================================================================*/
int fs_unlink()
{
/* Perform the unlink(name) or rmdir(name) system call. The code for these two
* is almost the same. They differ only in some condition testing. Unlink()
* may be used by the superuser to do dangerous things; rmdir() may not.
*/
int r;
struct puffs_node *pn, *pn_dir;
time_t cur_time;
struct puffs_kcn pkcnp;
struct puffs_cn pcn = {&pkcnp, 0, {0,0,0}};
PUFFS_KCREDTOCRED(pcn.pcn_cred, &global_kcred);
int len;
/* Copy the last component */
len = fs_m_in.REQ_PATH_LEN;
pcn.pcn_namelen = len - 1;
if (pcn.pcn_namelen > NAME_MAX)
return(ENAMETOOLONG);
r = sys_safecopyfrom(VFS_PROC_NR, (cp_grant_id_t) fs_m_in.REQ_GRANT,
(vir_bytes) 0, (vir_bytes) pcn.pcn_name,
(size_t) len);
if (r != OK) return (r);
NUL(pcn.pcn_name, len, sizeof(pcn.pcn_name));
if ((pn_dir = puffs_pn_nodewalk(global_pu, 0, &fs_m_in.REQ_INODE_NR)) == NULL)
return(EINVAL);
/* The last directory exists. Does the file also exist? */
pn = advance(pn_dir, pcn.pcn_name, IGN_PERM);
r = err_code;
/* If error, return pnode. */
if (r != OK) {
/* Mount point? */
if (r == EENTERMOUNT || r == ELEAVEMOUNT) {
r = EBUSY;
}
return(r);
}
/* Now test if the call is allowed, separately for unlink() and rmdir(). */
if (fs_m_in.m_type == REQ_UNLINK) {
/* Only the su may unlink directories, but the su can unlink any dir */
if ((pn->pn_va.va_mode & I_TYPE) == I_DIRECTORY)
r = EPERM;
if (r == OK)
r = unlink_file(pn_dir, pn, &pcn);
} else {
r = remove_dir(pn_dir, pn, &pcn); /* call is RMDIR */
}
if (pn->pn_va.va_nlink != 0) {
cur_time = clock_time();
update_times(pn, CTIME, cur_time);
update_times(pn_dir, MTIME | CTIME, cur_time);
}
/* XXX Ideally, we should check pn->pn_flags & PUFFS_NODE_REMOVED, but
* librefuse doesn't set it (neither manually or via puffs_pn_remove() ).
* Thus we just check that "pn_count == 0". Otherwise release_node()
* will be called in fs_put().
*/
if (pn->pn_count == 0)
release_node(global_pu, pn);
return(r);
}
/*===========================================================================*
* remove_dir *
*===========================================================================*/
static int remove_dir(pn_dir, pn, pcn)
struct puffs_node *pn_dir; /* parent directory */
struct puffs_node *pn; /* directory to be removed */
struct puffs_cn *pcn; /* Name, creads of directory */
{
/* A directory file has to be removed. Five conditions have to met:
* - The file must be a directory
* - The directory must be empty (except for . and ..)
* - The final component of the path must not be . or ..
* - The directory must not be the root of a mounted file system (VFS)
* - The directory must not be anybody's root/working directory (VFS)
*/
/* "." and ".." dentries can be stored in 28 bytes */
#define EMPTY_DIR_DENTRIES_SIZE 28
int r;
char remove_dir_buf[EMPTY_DIR_DENTRIES_SIZE];
struct dirent *dent = (struct dirent*) remove_dir_buf;
int buf_left = EMPTY_DIR_DENTRIES_SIZE;
off_t pos = 0;
int eofflag = 0;
if (global_pu->pu_ops.puffs_node_rmdir == NULL)
return(EINVAL);
if (!S_ISDIR(pn->pn_va.va_mode))
return(ENOTDIR);
/* Check if directory is empty */
r = global_pu->pu_ops.puffs_node_readdir(global_pu, pn, dent, &pos,
(size_t *)&buf_left, pcn->pcn_cred, &eofflag, 0, 0);
if (r) return(EINVAL);
if (!eofflag) return(ENOTEMPTY);
if (strcmp(pcn->pcn_name, ".") == 0 || strcmp(pcn->pcn_name, "..") == 0)
return(EINVAL);
if (pn->pn_va.va_fileid == global_pu->pu_pn_root->pn_va.va_fileid)
return(EBUSY); /* can't remove 'root' */
if (buildpath) {
r = puffs_path_pcnbuild(global_pu, pcn, pn_dir);
if (r) return(EINVAL);
}
r = global_pu->pu_ops.puffs_node_rmdir(global_pu, pn_dir, pn, pcn);
global_pu->pu_pathfree(global_pu, &pcn->pcn_po_full);
if (r) return(EINVAL);
return(OK);
}
/*===========================================================================*
* unlink_file *
*===========================================================================*/
static int unlink_file(dirp, pn, pcn)
struct puffs_node *dirp; /* parent directory of file */
struct puffs_node *pn; /* pnode of file, may be NULL too. */
struct puffs_cn *pcn; /* Name, creads of file */
{
/* Unlink 'file_name'; pn must be the pnode of 'file_name' */
int r;
assert(pn != NULL);
if (global_pu->pu_ops.puffs_node_remove == NULL)
return(EINVAL);
if (S_ISDIR(pn->pn_va.va_mode))
return(EINVAL);
if (buildpath) {
r = puffs_path_pcnbuild(global_pu, pcn, dirp);
if (r)
return(EINVAL);
}
r = global_pu->pu_ops.puffs_node_remove(global_pu, dirp, pn, pcn);
global_pu->pu_pathfree(global_pu, &pcn->pcn_po_full);
if (r) return(EINVAL);
return(OK);
}
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