- introduce new call numbers, names, and field aliases; - initialize request messages to zero for all ABI calls; - format callnr.h in the same way as com.h; - redo call tables in both servers; - remove param.h namespace pollution in the servers; - make brk(2) go to VM directly, rather than through PM; - remove obsolete BRK, UTIME, and WAIT calls; - clean up path copying routine in VFS; - move remaining system calls from libminlib to libc; - correct some errno-related mistakes in libc routines. Change-Id: I2d8ec5d061cd7e0b30c51ffd77aa72ebf84e2565
510 lines
15 KiB
C
510 lines
15 KiB
C
/* This file handles the LINK and UNLINK system calls. It also deals with
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* deallocating the storage used by a file when the last UNLINK is done to a
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* file and the blocks must be returned to the free block pool.
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*
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* The entry points into this file are
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* do_link: perform the LINK system call
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* do_unlink: perform the UNLINK and RMDIR system calls
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* do_rename: perform the RENAME system call
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* do_truncate: perform the TRUNCATE system call
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* do_ftruncate: perform the FTRUNCATE system call
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* do_rdlink: perform the RDLNK system call
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*/
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#include "fs.h"
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#include <sys/stat.h>
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#include <string.h>
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#include <minix/com.h>
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#include <minix/callnr.h>
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#include <minix/vfsif.h>
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#include <sys/dirent.h>
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#include <assert.h>
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#include "file.h"
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#include "path.h"
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#include "vnode.h"
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#include "scratchpad.h"
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/*===========================================================================*
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* do_link *
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*===========================================================================*/
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int do_link(void)
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{
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/* Perform the link(name1, name2) system call. */
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int r = OK;
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struct vnode *vp = NULL, *dirp = NULL;
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struct vmnt *vmp1 = NULL, *vmp2 = NULL;
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char fullpath[PATH_MAX];
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struct lookup resolve;
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vir_bytes vname1, vname2;
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size_t vname1_length, vname2_length;
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vname1 = (vir_bytes) job_m_in.VFS_LINK_NAME1;
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vname1_length = job_m_in.VFS_LINK_LEN1;
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vname2 = (vir_bytes) job_m_in.VFS_LINK_NAME2;
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vname2_length = job_m_in.VFS_LINK_LEN2;
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lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp1, &vp);
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resolve.l_vmnt_lock = VMNT_WRITE;
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resolve.l_vnode_lock = VNODE_READ;
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/* See if 'name1' (file to be linked to) exists. */
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if (fetch_name(vname1, vname1_length, fullpath) != OK) return(err_code);
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if ((vp = eat_path(&resolve, fp)) == NULL) return(err_code);
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/* Does the final directory of 'name2' exist? */
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lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp2, &dirp);
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resolve.l_vmnt_lock = VMNT_READ;
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resolve.l_vnode_lock = VNODE_WRITE;
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if (fetch_name(vname2, vname2_length, fullpath) != OK)
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r = err_code;
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else if ((dirp = last_dir(&resolve, fp)) == NULL)
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r = err_code;
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if (r != OK) {
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unlock_vnode(vp);
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unlock_vmnt(vmp1);
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put_vnode(vp);
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return(r);
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}
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/* Check for links across devices. */
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if (vp->v_fs_e != dirp->v_fs_e)
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r = EXDEV;
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else
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r = forbidden(fp, dirp, W_BIT | X_BIT);
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if (r == OK)
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r = req_link(vp->v_fs_e, dirp->v_inode_nr, fullpath,
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vp->v_inode_nr);
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unlock_vnode(vp);
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unlock_vnode(dirp);
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if (vmp2 != NULL) unlock_vmnt(vmp2);
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unlock_vmnt(vmp1);
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put_vnode(vp);
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put_vnode(dirp);
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return(r);
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}
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/*===========================================================================*
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* do_unlink *
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*===========================================================================*/
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int do_unlink(void)
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{
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/* Perform the unlink(name) or rmdir(name) system call. The code for these two
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* is almost the same. They differ only in some condition testing. Unlink()
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* may be used by the superuser to do dangerous things; rmdir() may not.
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* The syscall might provide 'name' embedded in the message.
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*/
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struct vnode *dirp, *dirp_l, *vp;
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struct vmnt *vmp, *vmp2;
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int r;
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char fullpath[PATH_MAX];
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struct lookup resolve, stickycheck;
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if (copy_path(fullpath, sizeof(fullpath)) != OK)
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return(err_code);
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lookup_init(&resolve, fullpath, PATH_RET_SYMLINK, &vmp, &dirp_l);
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resolve.l_vmnt_lock = VMNT_WRITE;
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resolve.l_vnode_lock = VNODE_WRITE;
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/* Get the last directory in the path. */
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if ((dirp = last_dir(&resolve, fp)) == NULL) return(err_code);
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/* Make sure that the object is a directory */
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if (!S_ISDIR(dirp->v_mode)) {
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unlock_vnode(dirp);
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unlock_vmnt(vmp);
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put_vnode(dirp);
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return(ENOTDIR);
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}
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/* The caller must have both search and execute permission */
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if ((r = forbidden(fp, dirp, X_BIT | W_BIT)) != OK) {
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unlock_vnode(dirp);
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unlock_vmnt(vmp);
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put_vnode(dirp);
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return(r);
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}
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/* Also, if the sticky bit is set, only the owner of the file or a privileged
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user is allowed to unlink */
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if ((dirp->v_mode & S_ISVTX) == S_ISVTX) {
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/* Look up inode of file to unlink to retrieve owner */
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lookup_init(&stickycheck, resolve.l_path, PATH_RET_SYMLINK, &vmp2, &vp);
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stickycheck.l_vmnt_lock = VMNT_READ;
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stickycheck.l_vnode_lock = VNODE_READ;
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vp = advance(dirp, &stickycheck, fp);
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assert(vmp2 == NULL);
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if (vp != NULL) {
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if (vp->v_uid != fp->fp_effuid && fp->fp_effuid != SU_UID)
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r = EPERM;
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unlock_vnode(vp);
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put_vnode(vp);
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} else
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r = err_code;
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if (r != OK) {
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unlock_vnode(dirp);
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unlock_vmnt(vmp);
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put_vnode(dirp);
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return(r);
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}
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}
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upgrade_vmnt_lock(vmp);
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if (job_call_nr == VFS_UNLINK)
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r = req_unlink(dirp->v_fs_e, dirp->v_inode_nr, fullpath);
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else
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r = req_rmdir(dirp->v_fs_e, dirp->v_inode_nr, fullpath);
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unlock_vnode(dirp);
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unlock_vmnt(vmp);
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put_vnode(dirp);
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return(r);
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}
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/*===========================================================================*
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* do_rename *
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*===========================================================================*/
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int do_rename(void)
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{
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/* Perform the rename(name1, name2) system call. */
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int r = OK, r1;
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struct vnode *old_dirp = NULL, *new_dirp = NULL, *new_dirp_l = NULL, *vp;
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struct vmnt *oldvmp, *newvmp, *vmp2;
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char old_name[PATH_MAX];
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char fullpath[PATH_MAX];
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struct lookup resolve, stickycheck;
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vir_bytes vname1, vname2;
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size_t vname1_length, vname2_length;
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vname1 = (vir_bytes) job_m_in.VFS_LINK_NAME1;
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vname1_length = job_m_in.VFS_LINK_LEN1;
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vname2 = (vir_bytes) job_m_in.VFS_LINK_NAME2;
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vname2_length = job_m_in.VFS_LINK_LEN2;
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lookup_init(&resolve, fullpath, PATH_RET_SYMLINK, &oldvmp, &old_dirp);
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/* Do not yet request exclusive lock on vmnt to prevent deadlocks later on */
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resolve.l_vmnt_lock = VMNT_WRITE;
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resolve.l_vnode_lock = VNODE_WRITE;
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/* See if 'name1' (existing file) exists. Get dir and file inodes. */
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if (fetch_name(vname1, vname1_length, fullpath) != OK) return(err_code);
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if ((old_dirp = last_dir(&resolve, fp)) == NULL) return(err_code);
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/* If the sticky bit is set, only the owner of the file or a privileged
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user is allowed to rename */
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if ((old_dirp->v_mode & S_ISVTX) == S_ISVTX) {
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/* Look up inode of file to unlink to retrieve owner */
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lookup_init(&stickycheck, resolve.l_path, PATH_RET_SYMLINK, &vmp2, &vp);
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stickycheck.l_vmnt_lock = VMNT_READ;
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stickycheck.l_vnode_lock = VNODE_READ;
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vp = advance(old_dirp, &stickycheck, fp);
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assert(vmp2 == NULL);
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if (vp != NULL) {
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if(vp->v_uid != fp->fp_effuid && fp->fp_effuid != SU_UID)
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r = EPERM;
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unlock_vnode(vp);
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put_vnode(vp);
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} else
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r = err_code;
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if (r != OK) {
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unlock_vnode(old_dirp);
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unlock_vmnt(oldvmp);
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put_vnode(old_dirp);
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return(r);
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}
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}
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/* Save the last component of the old name */
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if (strlen(fullpath) >= sizeof(old_name)) {
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unlock_vnode(old_dirp);
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unlock_vmnt(oldvmp);
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put_vnode(old_dirp);
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return(ENAMETOOLONG);
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}
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strlcpy(old_name, fullpath, PATH_MAX);
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/* See if 'name2' (new name) exists. Get dir inode */
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lookup_init(&resolve, fullpath, PATH_RET_SYMLINK, &newvmp, &new_dirp_l);
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resolve.l_vmnt_lock = VMNT_READ;
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resolve.l_vnode_lock = VNODE_WRITE;
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if (fetch_name(vname2, vname2_length, fullpath) != OK) r = err_code;
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else if ((new_dirp = last_dir(&resolve, fp)) == NULL) r = err_code;
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/* We used a separate vnode pointer to see whether we obtained a lock on the
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* new_dirp vnode. If the new directory and old directory are the same, then
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* the VNODE_WRITE lock on new_dirp will fail. In that case, new_dirp_l will
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* be NULL, but new_dirp will not.
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*/
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if (new_dirp == old_dirp) assert(new_dirp_l == NULL);
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if (r != OK) {
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unlock_vnode(old_dirp);
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unlock_vmnt(oldvmp);
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put_vnode(old_dirp);
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return(r);
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}
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/* Both parent directories must be on the same device. */
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if (old_dirp->v_fs_e != new_dirp->v_fs_e) r = EXDEV;
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/* Parent dirs must be writable, searchable and on a writable device */
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if ((r1 = forbidden(fp, old_dirp, W_BIT|X_BIT)) != OK ||
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(r1 = forbidden(fp, new_dirp, W_BIT|X_BIT)) != OK) r = r1;
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if (r == OK) {
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upgrade_vmnt_lock(oldvmp); /* Upgrade to exclusive access */
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r = req_rename(old_dirp->v_fs_e, old_dirp->v_inode_nr, old_name,
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new_dirp->v_inode_nr, fullpath);
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}
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unlock_vnode(old_dirp);
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unlock_vmnt(oldvmp);
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if (new_dirp_l) unlock_vnode(new_dirp_l);
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if (newvmp) unlock_vmnt(newvmp);
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put_vnode(old_dirp);
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put_vnode(new_dirp);
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return(r);
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}
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/*===========================================================================*
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* do_truncate *
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*===========================================================================*/
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int do_truncate(void)
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{
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/* truncate_vnode() does the actual work of do_truncate() and do_ftruncate().
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* do_truncate() and do_ftruncate() have to get hold of the inode, either
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* by name or fd, do checks on it, and call truncate_inode() to do the
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* work.
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*/
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struct vnode *vp;
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struct vmnt *vmp;
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int r;
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char fullpath[PATH_MAX];
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struct lookup resolve;
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off_t length;
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vir_bytes vname;
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size_t vname_length;
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vname = (vir_bytes) job_m_in.VFS_TRUNCATE_NAME;
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vname_length = job_m_in.VFS_TRUNCATE_LEN;
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lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp, &vp);
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resolve.l_vmnt_lock = VMNT_READ;
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resolve.l_vnode_lock = VNODE_WRITE;
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length = (off_t) make64(job_m_in.VFS_TRUNCATE_OFF_LO,
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job_m_in.VFS_TRUNCATE_OFF_HI);
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if (length < 0) return(EINVAL);
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/* Temporarily open file */
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if (fetch_name(vname, vname_length, fullpath) != OK) return(err_code);
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if ((vp = eat_path(&resolve, fp)) == NULL) return(err_code);
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/* Ask FS to truncate the file */
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if ((r = forbidden(fp, vp, W_BIT)) == OK) {
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/* If the file size does not change, do not make the actual call. This
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* ensures that the file times are retained when the file size remains
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* the same, which is a POSIX requirement.
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*/
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if (S_ISREG(vp->v_mode) && vp->v_size == length)
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r = OK;
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else
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r = truncate_vnode(vp, length);
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}
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unlock_vnode(vp);
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unlock_vmnt(vmp);
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put_vnode(vp);
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return(r);
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}
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/*===========================================================================*
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* do_ftruncate *
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*===========================================================================*/
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int do_ftruncate(void)
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{
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/* As with do_truncate(), truncate_vnode() does the actual work. */
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struct filp *rfilp;
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struct vnode *vp;
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int r;
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off_t length;
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scratch(fp).file.fd_nr = job_m_in.VFS_TRUNCATE_FD;
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length = (off_t) make64(job_m_in.VFS_TRUNCATE_OFF_LO,
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job_m_in.VFS_TRUNCATE_OFF_HI);
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if (length < 0) return(EINVAL);
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/* File is already opened; get a vnode pointer from filp */
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if ((rfilp = get_filp(scratch(fp).file.fd_nr, VNODE_WRITE)) == NULL)
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return(err_code);
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vp = rfilp->filp_vno;
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if (!(rfilp->filp_mode & W_BIT))
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r = EBADF;
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else if (S_ISREG(vp->v_mode) && vp->v_size == length)
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/* If the file size does not change, do not make the actual call. This
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* ensures that the file times are retained when the file size remains
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* the same, which is a POSIX requirement.
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*/
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r = OK;
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else
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r = truncate_vnode(vp, length);
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unlock_filp(rfilp);
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return(r);
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}
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/*===========================================================================*
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* truncate_vnode *
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*===========================================================================*/
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int truncate_vnode(vp, newsize)
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struct vnode *vp;
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off_t newsize;
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{
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/* Truncate a regular file or a pipe */
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int r;
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assert(tll_locked_by_me(&vp->v_lock));
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if (!S_ISREG(vp->v_mode) && !S_ISFIFO(vp->v_mode)) return(EINVAL);
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/* We must not compare the old and the new size here: this function may be
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* called for open(2), which requires an update to the file times if O_TRUNC
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* is given, even if the file size remains the same.
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*/
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if ((r = req_ftrunc(vp->v_fs_e, vp->v_inode_nr, newsize, 0)) == OK)
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vp->v_size = newsize;
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return(r);
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}
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/*===========================================================================*
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* do_slink *
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*===========================================================================*/
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int do_slink(void)
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{
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/* Perform the symlink(name1, name2) system call. */
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int r;
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struct vnode *vp;
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struct vmnt *vmp;
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char fullpath[PATH_MAX];
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struct lookup resolve;
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vir_bytes vname1, vname2;
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size_t vname1_length, vname2_length;
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lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp, &vp);
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resolve.l_vmnt_lock = VMNT_WRITE;
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resolve.l_vnode_lock = VNODE_WRITE;
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vname1 = (vir_bytes) job_m_in.VFS_LINK_NAME1;
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vname1_length = job_m_in.VFS_LINK_LEN1;
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vname2 = (vir_bytes) job_m_in.VFS_LINK_NAME2;
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vname2_length = job_m_in.VFS_LINK_LEN2;
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if (vname1_length <= 1) return(ENOENT);
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if (vname1_length >= SYMLINK_MAX) return(ENAMETOOLONG);
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/* Get dir inode of 'name2' */
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if (fetch_name(vname2, vname2_length, fullpath) != OK) return(err_code);
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if ((vp = last_dir(&resolve, fp)) == NULL) return(err_code);
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if ((r = forbidden(fp, vp, W_BIT|X_BIT)) == OK) {
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r = req_slink(vp->v_fs_e, vp->v_inode_nr, fullpath, who_e,
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vname1, vname1_length - 1, fp->fp_effuid,
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fp->fp_effgid);
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}
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unlock_vnode(vp);
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unlock_vmnt(vmp);
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put_vnode(vp);
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return(r);
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}
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/*===========================================================================*
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* rdlink_direct *
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*===========================================================================*/
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int rdlink_direct(orig_path, link_path, rfp)
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char *orig_path;
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char link_path[PATH_MAX]; /* should have length PATH_MAX */
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struct fproc *rfp;
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{
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/* Perform a readlink()-like call from within the VFS */
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int r;
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struct vnode *vp;
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struct vmnt *vmp;
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struct lookup resolve;
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lookup_init(&resolve, link_path, PATH_RET_SYMLINK, &vmp, &vp);
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resolve.l_vmnt_lock = VMNT_READ;
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resolve.l_vnode_lock = VNODE_READ;
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/* Temporarily open the file containing the symbolic link. Use link_path
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* for temporary storage to keep orig_path untouched. */
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strncpy(link_path, orig_path, PATH_MAX); /* PATH_MAX includes '\0' */
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link_path[PATH_MAX - 1] = '\0';
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if ((vp = eat_path(&resolve, rfp)) == NULL) return(err_code);
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|
|
|
/* Make sure this is a symbolic link */
|
|
if (!S_ISLNK(vp->v_mode))
|
|
r = EINVAL;
|
|
else
|
|
r = req_rdlink(vp->v_fs_e, vp->v_inode_nr, NONE, (vir_bytes) link_path,
|
|
PATH_MAX - 1, 1);
|
|
|
|
if (r > 0) link_path[r] = '\0'; /* Terminate string when succesful */
|
|
|
|
unlock_vnode(vp);
|
|
unlock_vmnt(vmp);
|
|
put_vnode(vp);
|
|
|
|
return r;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* do_rdlink *
|
|
*===========================================================================*/
|
|
int do_rdlink(void)
|
|
{
|
|
/* Perform the readlink(name, buf, bufsize) system call. */
|
|
int r;
|
|
struct vnode *vp;
|
|
struct vmnt *vmp;
|
|
char fullpath[PATH_MAX];
|
|
struct lookup resolve;
|
|
vir_bytes vname;
|
|
size_t vname_length, buf_size;
|
|
vir_bytes buf;
|
|
|
|
vname = (vir_bytes) job_m_in.VFS_READLINK_NAME;
|
|
vname_length = job_m_in.VFS_READLINK_NAMELEN;
|
|
buf = (vir_bytes) job_m_in.VFS_READLINK_BUF;
|
|
buf_size = (size_t) job_m_in.VFS_READLINK_BUFSIZE;
|
|
if (buf_size > SSIZE_MAX) return(EINVAL);
|
|
|
|
lookup_init(&resolve, fullpath, PATH_RET_SYMLINK, &vmp, &vp);
|
|
resolve.l_vmnt_lock = VMNT_READ;
|
|
resolve.l_vnode_lock = VNODE_READ;
|
|
|
|
/* Temporarily open the file containing the symbolic link */
|
|
if (fetch_name(vname, vname_length, fullpath) != OK) return(err_code);
|
|
if ((vp = eat_path(&resolve, fp)) == NULL) return(err_code);
|
|
|
|
/* Make sure this is a symbolic link */
|
|
if (!S_ISLNK(vp->v_mode))
|
|
r = EINVAL;
|
|
else
|
|
r = req_rdlink(vp->v_fs_e, vp->v_inode_nr, who_e, buf, buf_size, 0);
|
|
|
|
unlock_vnode(vp);
|
|
unlock_vmnt(vmp);
|
|
put_vnode(vp);
|
|
|
|
return(r);
|
|
}
|