minix/lib/libsffs/stat.c

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/* This file contains file metadata retrieval and manipulation routines.
*
* The entry points into this file are:
* get_mode return a file's mode
* do_stat perform the STAT file system call
* do_chmod perform the CHMOD file system call
* do_utime perform the UTIME file system call
*
* Created:
* April 2009 (D.C. van Moolenbroek)
*/
#include "inc.h"
/*===========================================================================*
* get_mode *
*===========================================================================*/
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mode_t get_mode(ino, mode)
struct inode *ino;
int mode;
{
/* Return the mode for an inode, given the inode and the retrieved mode.
*/
mode &= S_IRWXU;
mode = mode | (mode >> 3) | (mode >> 6);
if (IS_DIR(ino))
mode = S_IFDIR | (mode & sffs_params->p_dir_mask);
else
mode = S_IFREG | (mode & sffs_params->p_file_mask);
if (state.s_read_only)
mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
return mode;
}
/*===========================================================================*
* do_stat *
*===========================================================================*/
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int do_stat()
{
/* Retrieve inode status.
*/
struct inode *ino;
struct sffs_attr attr;
struct stat stat;
char path[PATH_MAX];
ino_t ino_nr;
int r;
ino_nr = m_in.REQ_INODE_NR;
/* Don't increase the inode refcount: it's already open anyway */
if ((ino = find_inode(ino_nr)) == NULL)
return EINVAL;
attr.a_mask = SFFS_ATTR_MODE | SFFS_ATTR_SIZE | SFFS_ATTR_CRTIME |
SFFS_ATTR_ATIME | SFFS_ATTR_MTIME | SFFS_ATTR_CTIME;
if ((r = verify_inode(ino, path, &attr)) != OK)
return r;
memset(&stat, 0, sizeof(struct stat));
stat.st_dev = state.s_dev;
stat.st_ino = ino_nr;
stat.st_mode = get_mode(ino, attr.a_mode);
stat.st_uid = sffs_params->p_uid;
stat.st_gid = sffs_params->p_gid;
stat.st_rdev = NO_DEV;
if (cmp64u(attr.a_size, LONG_MAX) > 0)
stat.st_size = LONG_MAX;
else
stat.st_size = ex64lo(attr.a_size);
stat.st_atimespec = attr.a_atime;
stat.st_mtimespec = attr.a_mtime;
stat.st_ctimespec = attr.a_ctime;
stat.st_birthtimespec = attr.a_crtime;
stat.st_blocks = stat.st_size / S_BLKSIZE;
if (stat.st_size % S_BLKSIZE != 0)
stat.st_blocks += 1;
stat.st_blksize = BLOCK_SIZE;
/* We could make this more accurate by iterating over directory inodes'
* children, counting how many of those are directories as well.
* It's just not worth it.
*/
stat.st_nlink = 0;
if (ino->i_parent != NULL) stat.st_nlink++;
if (IS_DIR(ino)) {
stat.st_nlink++;
if (HAS_CHILDREN(ino)) stat.st_nlink++;
}
return sys_safecopyto(m_in.m_source, m_in.REQ_GRANT, 0,
(vir_bytes) &stat, sizeof(stat));
}
/*===========================================================================*
* do_chmod *
*===========================================================================*/
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int do_chmod()
{
/* Change file mode.
*/
struct inode *ino;
char path[PATH_MAX];
struct sffs_attr attr;
int r;
if (state.s_read_only)
return EROFS;
if ((ino = find_inode(m_in.REQ_INODE_NR)) == NULL)
return EINVAL;
if ((r = verify_inode(ino, path, NULL)) != OK)
return r;
/* Set the new file mode. */
attr.a_mask = SFFS_ATTR_MODE;
attr.a_mode = m_in.REQ_MODE; /* no need to convert in this direction */
if ((r = sffs_table->t_setattr(path, &attr)) != OK)
return r;
/* We have no idea what really happened. Query for the mode again. */
if ((r = verify_path(path, ino, &attr, NULL)) != OK)
return r;
m_out.RES_MODE = get_mode(ino, attr.a_mode);
return OK;
}
/*===========================================================================*
* do_utime *
*===========================================================================*/
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int do_utime()
{
/* Set file times.
*/
struct inode *ino;
char path[PATH_MAX];
struct sffs_attr attr;
int r;
if (state.s_read_only)
return EROFS;
if ((ino = find_inode(m_in.REQ_INODE_NR)) == NULL)
return EINVAL;
if ((r = verify_inode(ino, path, NULL)) != OK)
return r;
attr.a_mask = 0;
switch(m_in.REQ_ACNSEC) {
case UTIME_OMIT: /* do not touch */
break;
case UTIME_NOW:
/* XXX VFS should have time() into ACTIME, for compat; we trust it! */
m_in.REQ_ACNSEC = 0;
/*FALLTHROUGH*/
default:
/* cases m_in.REQ_ACNSEC < 0 || m_in.REQ_ACNSEC >= 1E9
* are caught by VFS to cooperate with old instances of EXT2
*/
attr.a_atime.tv_sec = m_in.REQ_ACTIME;
attr.a_atime.tv_nsec = m_in.REQ_ACNSEC;
attr.a_mask |= SFFS_ATTR_ATIME;
break;
}
switch(m_in.REQ_MODNSEC) {
case UTIME_OMIT: /* do not touch */
break;
case UTIME_NOW:
/* XXX VFS should have time() into MODTIME, for compat; we trust it! */
m_in.REQ_MODNSEC = 0;
/*FALLTHROUGH*/
default:
/* cases m_in.REQ_MODNSEC < 0 || m_in.REQ_MODNSEC >= 1E9
* are caught by VFS to cooperate with old instances
*/
attr.a_mtime.tv_sec = m_in.REQ_MODTIME;
attr.a_mtime.tv_nsec = m_in.REQ_MODNSEC;
attr.a_mask |= SFFS_ATTR_MTIME;
break;
}
return sffs_table->t_setattr(path, &attr);
}