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#include <asm/cachectl.h> int cacheflush(char *addr,intnbytes,intcache);
DESCRIPTION
cacheflush flushes contents of indicated cache(s) for user addresses in the range addr to (addr+nbytes-1). The cache may be one of the following:
| ICACHE | Flush the instruction cache. |
| DCACHE | Write back to memory and invalidate the affected valid cache lines. |
| BCACHE | Same as (ICACHE|DCACHE). |
RETURN VALUE
cacheflush returns 0 on success or -1 on error. If errors are detected, errno will indicate the error.
ERRORS
| EINVAL | The cache parameter is not one of ICACHE, DCACHE, or BCACHE. |
| EFAULT | Some or all of the address range addr to (addr+nbytes-1) is not accessible. |
BUGS
The current implementation ignores the addr and nbytes parameters. Therefore, the whole cache is always flushed.
NOTE
This system call is only available on MIPS-based systems.
SEE ALSO
cachectl(2)
Linux, 27 June 95
chdir, fchdir—Changes the working directory
SYNOPSIS
#include <unistd.h> int chdir(const char *path); int fchdir(int fd);
DESCRIPTION
chdir changes the current directory to that specified in path.
fchdir is identical to chdir, only the directory is given as an open file descriptor.
RETURN VALUE
On success, 0 is returned. On error, _1 is returned, and errno is set appropriately.
ERRORS
Depending on the file system, other errors can be returned. The more general errors are listed here:
| EPERM | The process does not have execute permission on the directory. |
| EFAULT | path points outside your accessible address space. |
| ENAMETOOLONG | path is too long. |
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| EBADF | fd is not a valid file descriptor. |
| ENOENT | The file does not exist. |
| ENOMEM | Insufficient kernel memory was available. |
| ENOTDIR | A component of the path prefix is not a directory. |
| EACCES | Search permission is denied on a component of the path prefix. |
| ELOOP | path contains a circular reference (that is, via a symbolic link) |
SEE ALSO
getcwd(3), chroot(2)
Linux 1.2.4, 15 April 1995
chmod, fchmod—Changes permissions of a file
SYNOPSIS
#include <sys/types.h> #include <sys/stat.h> int chmod(const char *path,modetmode); int fchmod(int fildes,modetmode);
DESCRIPTION
The mode of the file given by path or referenced by filedes is changed.
Modes are specified by oring the following:
| S_ISUID | 04000 Set user ID on execution |
| S_ISGID | 02000 Set group ID on execution |
| S_ISVTX | 01000 Sticky bit |
| S_IRUSR (S_IREAD) | 00400 Read by owner |
| S_IWUSR (S_IWRITE) | 00200 Write by owner |
| S_IXUSR (S_IEXEC) | 00100 Execute/search by owner |
| S_IRGRP | 00040 Read by group |
| S_IWGRP | 00020 Write by group |
| S_IXGRP | 00010 Execute/search by group |
| S_IROTH | 00004 Read by others |
| S_IWOTH | 00002 Write by others |
| S_IXOTH | 00001 Execute/search by others |
| The effective UID of the process must be 0 or must match the owner of the file. | |
| The effective UID or GID must be appropriate for setting execution bits. | |
| Depending on the file system, set user ID and set group ID execution bits may be turned off if a file is written. On some file systems, only the superuser can set the sticky bit, which may have a special meaning (that is, for directories, a file can only be deleted by the owner or the superuser). |
RETURN VALUE
On success, 0 is returned. On error, _1 is returned and errno is set appropriately.
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ERRORS
Depending on the file system, other errors can be returned. The more general errors for chmod are listed here:
| EPERM | The effective UID does not match the owner of the file and is not 0. |
| EROFS | The named file resides on a read-only file system. |
| EFAULT | path points outside your accessible address space. |
| ENAMETOOLONG | path is too long. |
| ENOENT | The file does not exist. |
| ENOMEM | Insufficient kernel memory was available. |
| ENOTDIR | A component of the path prefix is not a directory. |
| EACCES | Search permission is denied on a component of the path prefix. |
| ELOOP | path contains a circular reference (that is, via a symbolic link) |
The general errors for fchmod are listed here:
| EBADF | The descriptor is not value. |
| ENOENT | See above. |
| EPERM | See above. |
| EROFS | See above. |
SEE ALSO
open(2), chown(2), stat(2)
Linux 0.99.11, 21 July 1993
chown, fchown—Changes ownership of a file
SYNOPSIS
#include <sys/types.h> #include <unistd.h> int chown(const char *path, uid t owner, gid_t group); int fchown(int fd, uid t owner, gid_t group);
DESCRIPTION
The owner of the file specified by path or by fd is changed. Only the superuser may change the owner of a file. The owner of a file may change the group of the file to any group of which that owner is a member. The superuser may change the group arbitrarily.
If the owner or group is specified as _1, that ID is not changed.
RETURN VALUE
On success, 0 is returned. On error, _1 is returned and errno is set appropriately.
ERRORS
Depending on the file system, other errors can be returned. The more general errors for chown are listed here:
| EPERM | The effective UID does not match the owner of the file, and is not 0; or the owner or group were specified incorrectly. |
| EROFS | The named file resides on a read-only file system. |
| EFAULT | path points outside your accessible address space. |
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| ENAMETOOLONG | path is too long. |
| ENOENT | The file does not exist. |
| ENOMEM | Insufficient kernel memory was available. |
| ENOTDIR | A component of the path prefix is not a directory. |
| EACCES | Search permission is denied on a component of the path prefix. |
| ELOOP | path contains a circular reference (that is, via a symbolic link). |
The general errors for fchown are listed here:
| EBADF | The descriptor is not value. |
| ENOENT | See above. |
| EPERM | See above. |
| EROFS | See above. |
NOTES
chown does not follow symbolic links. The prototype for fchown is only available if USE BSD is defined.
SEE ALSO
chmod(2), flock(2)
Linux 0.99.11, 21 July 1993
chroot—Changes root directory
SYNOPSIS
#include <unistd.h> int chroot(const char *path);
DESCRIPTION
chroot changes the root directory to that specified in path. This directory will be used for pathnames beginning with /. The root directory is inherited by all children of the current process.
Only the superuser may change the root directory.
Note that this call does not change the current working directory, so that . can be outside the tree rooted at /.
RETURN VALUE
On success, 0 is returned. On error, _1 is returned and errno is set appropriately.
ERRORS
Depending on the file system, other errors can be returned. The more general errors are listed here:
| EPERM | The effective UID does not match the owner of the file, and is not 0; or the owner or group were specified incorrectly. |
| EROFS | The named file resides on a read-only file system. |
| EFAULT | path points outside your accessible address space. |
| ENAMETOOLONG | path is too long. |
| ENOENT | The file does not exist. |
| ENOMEM | Insufficient kernel memory was available. |