AUTHOPEN(1) BSD General Commands Manual AUTHOPEN(1)NAMEauthopen — open file with authorization
SYNOPSISauthopen [-stdoutpipe] [-extauth] filename
authopen [-stdoutpipe] [-extauth] -w [-a] filename
authopen [-stdoutpipe] [-extauth] -c [-x -m mode -w] filename
authopen [-stdoutpipe] [-extauth] -o flags filename
DESCRIPTIONauthopen provides authorization-based file opening services. In its sim‐
plest form, authopen verifies that it is allowed to open filename (using
an appropriate sys.openfile.* authorization right) and then writes the
file to stdout. If -w is specified, authopen will read from stdin and
write to the file.
authopen is designed to be used both from the command line and program‐
matically. The -stdoutpipe flag allows a parent process to receive an
open file descriptor pointing to the file in question.
Before opening filename, authopen will make an authorization request for
a right of the form:
‘.readonly’ rights only allow for read-only file descriptors.
‘.readwrite’ rights allow for read/write file descriptors.
‘.readwritecreate’ rights allow for read/write descriptors and the cre‐
ation of new files.
The -extauth option can be used to provide an AuthorizationRef con‐
structed by the client. This generally prevents authopen from presenting
an authorization dialog containing its own name.
OPTIONS-stdoutpipe specifies that STDOUT_FILENO has been dup2()'d onto a pipe
to a parent process and that an open file descriptor to filename
(with the appropriate access mode) should be sent back across it
using the SCM_RIGHTS extension to sendmsg(2) rather than having
the file itself written to or read from stdin / stdout.
-extauth specifies that authopen should read one AuthorizationExternal‐
Form structure from stdin, convert it to an AuthorizationRef,
and attempt to use it to authorize the open(2) operation. The
authorization should refer to the sys.apenfile right correspond‐
ing to the requested operation. The authorization data will be
read before any additional data supplied on stdin, and will not
be included in data written with -w.
-w instructs authopen to open filename read/write and truncate it.
If -stdoutpipe has not been specified, authopen will then copy
stdin to filename until stdin is closed.
-a append to filename rather than truncating it (truncating is the
-c create the file if it doesn't exist. -m requires -c.
-m mode specify the mode bits if a file is created.
-o flags numerically specify the flags that should be passed to open(2).
-x require that the file being created not exist.
To replace /etc/hostconfig (assuming
sys.openfile.readwrite./etc/hostconfig or better can be obtained):
$ cat tmpdata | authopen-w /etc/hostconfig
ERRORSauthopen will fail if an appropriate sys.openfile.readonly.*,
sys.openfile.readwrite.*, or sys.openfile.readwritecreate.* right cannot
be obtained or if the named path does not exist.
BUGSauthopen should support prefix path authentication such that the right
sys.openfile.*./dev/ could give access to all /dev entries and
sys.openfile.*./dev/disk1 could give access to all disk1-related /dev
authopen should use getopt(3).
SEE ALSOopen(2), Security/Authorization.h, realpath(3), recvmsg(2).
W. Richard Stevens, "Passing File Descriptors", Advanced Programming in
the UNIX Environment.
HISTORYauthopen appeared in Mac OS X 10.1 to assist with the manipulation of
Darwin 28 Feb 2013 Darwin