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authopen(1) [osx man page]

AUTHOPEN(1)						    BSD General Commands Manual 					       AUTHOPEN(1)

authopen -- open file with authorization SYNOPSIS
authopen [-stdoutpipe] [-extauth] filename authopen [-stdoutpipe] [-extauth] -w [-a] filename authopen [-stdoutpipe] [-extauth] -c [-x -m mode -w] filename authopen [-stdoutpipe] [-extauth] -o flags filename authopen -h DESCRIPTION
authopen provides authorization-based file opening services. In its simplest 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 programmatically. 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: sys.openfile.[readonly|readwrite|readwritecreate]./fully/qualified/path '.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 creation of new files. The -extauth option can be used to provide an AuthorizationRef constructed 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 AuthorizationExternalForm 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 corresponding 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 default). -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. EXAMPLES
To replace /etc/hostconfig (assuming sys.openfile.readwrite./etc/hostconfig or better can be obtained): $ cat tmpdata | authopen -w /etc/hostconfig ERRORS
authopen 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. BUGS
authopen 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 entries. authopen should use getopt(3). LOCATION
/usr/libexec/authopen SEE ALSO
open(2), Security/Authorization.h, realpath(3), recvmsg(2). W. Richard Stevens, "Passing File Descriptors", Advanced Programming in the UNIX Environment. HISTORY
authopen appeared in Mac OS X 10.1 to assist with the manipulation of disk devices. Darwin 28 Feb 2013 Darwin

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FOPEN(3)						     Library Functions Manual							  FOPEN(3)

fopen, freopen, fdopen - open a stream SYNOPSIS
#include <stdio.h> FILE *fopen(const char *filename, const char *type) FILE *freopen(const char *filename, const char *type, FILE *stream) FILE *fdopen(int fildes, const char *type) DESCRIPTION
Fopen opens the file named by filename and associates a stream with it. Fopen returns a pointer to be used to identify the stream in sub- sequent operations. Type is a character string having one of the following values: "r" open for reading "w" create for writing "a" append: open for writing at end of file, or create for writing In addition, each type may be followed by a "+" to have the file opened for reading and writing. "r+" positions the stream at the begin- ning of the file, "w+" creates or truncates it, and "a+" positions it at the end. Both reads and writes may be used on read/write streams, with the limitation that an fseek, rewind, or reading an end-of-file must be used between a read and a write or vice-versa. Freopen substitutes the named file in place of the open stream. It returns the original value of stream. The original stream is closed. Freopen is typically used to attach the preopened constant names, stdin, stdout, stderr, to specified files. Fdopen associates a stream with a file descriptor obtained from open, dup, creat, or pipe(2). The type of the stream must agree with the mode of the open file. SEE ALSO
open(2), fclose(3). DIAGNOSTICS
Fopen and freopen return the pointer NULL if filename cannot be accessed, if too many files are already open, or if other resources needed cannot be allocated. BUGS
Fdopen is not portable to systems other than UNIX. The read/write types do not exist on all systems. Those systems without read/write modes will probably treat the type as if the "+" was not present. These are unreliable in any event. 4th Berkeley Distribution May 27, 1986 FOPEN(3)
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