mkdir.3p (7840B)
- '\" et
- .TH MKDIR "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
- .\"
- .SH PROLOG
- This manual page is part of the POSIX Programmer's Manual.
- The Linux implementation of this interface may differ (consult
- the corresponding Linux manual page for details of Linux behavior),
- or the interface may not be implemented on Linux.
- .\"
- .SH NAME
- mkdir, mkdirat
- \(em make a directory
- .SH SYNOPSIS
- .LP
- .nf
- #include <sys/stat.h>
- .P
- int mkdir(const char *\fIpath\fP, mode_t \fImode\fP);
- .P
- #include <fcntl.h>
- .P
- int mkdirat(int \fIfd\fP, const char *\fIpath\fP, mode_t \fImode\fP);
- .fi
- .SH DESCRIPTION
- The
- \fImkdir\fR()
- function shall create a new directory with name
- .IR path .
- The file permission bits of the new directory shall be initialized from
- .IR mode .
- These file permission bits of the
- .IR mode
- argument shall be modified by the process' file creation mask.
- .P
- When bits in
- .IR mode
- other than the file permission bits are set, the meaning of these
- additional bits is implementation-defined.
- .P
- The directory's user ID shall be set to the process' effective user ID.
- The directory's group ID shall be set to the group ID of the parent
- directory or to the effective group ID of the process. Implementations
- shall provide a way to initialize the directory's group ID to the group
- ID of the parent directory. Implementations may, but need not, provide
- an implementation-defined way to initialize the directory's group ID to
- the effective group ID of the calling process.
- .P
- The newly created directory shall be an empty directory.
- .P
- If
- .IR path
- names a symbolic link,
- \fImkdir\fR()
- shall fail and set
- .IR errno
- to
- .BR [EEXIST] .
- .P
- Upon successful completion,
- \fImkdir\fR()
- shall mark for update the last data access, last data modification,
- and last file status change timestamps of the directory. Also, the last
- data modification and last file status change timestamps of the directory
- that contains the new entry shall be marked for update.
- .P
- The
- \fImkdirat\fR()
- function shall be equivalent to the
- \fImkdir\fR()
- function except in the case where
- .IR path
- specifies a relative path. In this case the newly created directory is
- created relative to the directory associated with the file descriptor
- .IR fd
- instead of the current working directory. If the access mode of the
- open file description associated with the file descriptor is not
- O_SEARCH, the function shall check whether directory searches are
- permitted using the current permissions of the directory underlying
- the file descriptor. If the access mode is O_SEARCH, the function
- shall not perform the check.
- .P
- If
- \fImkdirat\fR()
- is passed the special value AT_FDCWD in the
- .IR fd
- parameter, the current working directory shall be used and the behavior
- shall be identical to a call to
- \fImkdir\fR().
- .SH "RETURN VALUE"
- Upon successful completion, these functions shall return 0.
- Otherwise, these functions shall return \-1 and set
- .IR errno
- to indicate the error. If \-1 is returned, no directory shall be created.
- .SH ERRORS
- These functions shall fail if:
- .TP
- .BR EACCES
- Search permission is denied on a component of the path prefix, or write
- permission is denied on the parent directory of the directory to be
- created.
- .TP
- .BR EEXIST
- The named file exists.
- .TP
- .BR ELOOP
- A loop exists in symbolic links encountered during resolution of the
- .IR path
- argument.
- .TP
- .BR EMLINK
- The link count of the parent directory would exceed
- {LINK_MAX}.
- .TP
- .BR ENAMETOOLONG
- .br
- The length of a component of a pathname is longer than
- {NAME_MAX}.
- .TP
- .BR ENOENT
- A component of the path prefix specified by
- .IR path
- does not name an existing directory or
- .IR path
- is an empty string.
- .TP
- .BR ENOSPC
- The file system does not contain enough space to hold the contents of
- the new directory or to extend the parent directory of the new
- directory.
- .TP
- .BR ENOTDIR
- A component of the path prefix names an existing file that is neither
- a directory nor a symbolic link to a directory.
- .TP
- .BR EROFS
- The parent directory resides on a read-only file system.
- .P
- In addition, the
- \fImkdirat\fR()
- function shall fail if:
- .TP
- .BR EACCES
- The access mode of the open file description associated with
- .IR fd
- is not O_SEARCH and the permissions of the directory underlying
- .IR fd
- do not permit directory searches.
- .TP
- .BR EBADF
- The
- .IR path
- argument does not specify an absolute path and the
- .IR fd
- argument is neither AT_FDCWD nor a valid file descriptor open for reading
- or searching.
- .TP
- .BR ENOTDIR
- The
- .IR path
- argument is not an absolute path and
- .IR fd
- is a file descriptor associated with a non-directory file.
- .P
- These functions may fail if:
- .TP
- .BR ELOOP
- More than
- {SYMLOOP_MAX}
- symbolic links were encountered during resolution of the
- .IR path
- argument.
- .TP
- .BR ENAMETOOLONG
- .br
- The length of a pathname exceeds
- {PATH_MAX},
- or pathname resolution of a symbolic link produced an intermediate
- result with a length that exceeds
- {PATH_MAX}.
- .LP
- .IR "The following sections are informative."
- .SH EXAMPLES
- .SS "Creating a Directory"
- .P
- The following example shows how to create a directory named
- .BR /home/cnd/mod1 ,
- with read/write/search permissions for owner and group, and with
- read/search permissions for others.
- .sp
- .RS 4
- .nf
- #include <sys/types.h>
- #include <sys/stat.h>
- .P
- int status;
- \&...
- status = mkdir("/home/cnd/mod1", S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
- .fi
- .P
- .RE
- .SH "APPLICATION USAGE"
- None.
- .SH RATIONALE
- The
- \fImkdir\fR()
- function originated in 4.2 BSD and was added to System V in Release 3.0.
- .P
- 4.3 BSD detects
- .BR [ENAMETOOLONG] .
- .P
- The POSIX.1\(hy1990 standard required that the group ID of a newly created directory be
- set to the group ID of its parent directory or to the effective group
- ID of the creating process. FIPS 151\(hy2 required that implementations provide
- a way to have the group ID be set to the group ID of the containing
- directory, but did not prohibit implementations also supporting a way
- to set the group ID to the effective group ID of the creating process.
- Conforming applications should not assume which group ID will be used. If
- it matters, an application can use
- \fIchown\fR()
- to set the group ID after the directory is created, or determine under
- what conditions the implementation will set the desired group ID.
- .P
- The purpose of the
- \fImkdirat\fR()
- function is to create a directory in directories other than the
- current working directory without exposure to race conditions. Any part
- of the path of a file could be changed in parallel to the call to
- \fImkdir\fR(),
- resulting in unspecified behavior. By opening a file descriptor for
- the target directory and using the
- \fImkdirat\fR()
- function it can be guaranteed that the newly created directory is
- located relative to the desired directory.
- .SH "FUTURE DIRECTIONS"
- None.
- .SH "SEE ALSO"
- .IR "\fIchmod\fR\^(\|)",
- .IR "\fImkdtemp\fR\^(\|)",
- .IR "\fImknod\fR\^(\|)",
- .IR "\fIumask\fR\^(\|)"
- .P
- The Base Definitions volume of POSIX.1\(hy2017,
- .IR "\fB<fcntl.h>\fP",
- .IR "\fB<sys_stat.h>\fP",
- .IR "\fB<sys_types.h>\fP"
- .\"
- .SH COPYRIGHT
- Portions of this text are reprinted and reproduced in electronic form
- from IEEE Std 1003.1-2017, Standard for Information Technology
- -- Portable Operating System Interface (POSIX), The Open Group Base
- Specifications Issue 7, 2018 Edition,
- Copyright (C) 2018 by the Institute of
- Electrical and Electronics Engineers, Inc and The Open Group.
- In the event of any discrepancy between this version and the original IEEE and
- The Open Group Standard, the original IEEE and The Open Group Standard
- is the referee document. The original Standard can be obtained online at
- http://www.opengroup.org/unix/online.html .
- .PP
- Any typographical or formatting errors that appear
- in this page are most likely
- to have been introduced during the conversion of the source files to
- man page format. To report such errors, see
- https://www.kernel.org/doc/man-pages/reporting_bugs.html .