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mach_init(8) [opendarwin man page]

MACH_INIT(8)						    BSD System Manager's Manual 					      MACH_INIT(8)

mach_init -- Mach service naming (bootstrap) daemon SYNOPSIS
mach_init [-D] [-d] [-F] [-r name-in-existing-server] DESCRIPTION
mach_init is a daemon that maintains various mappings between service names and the Mach ports that provide access to those services. Clients of mach_init can register and lookup services, create new mapping subsets, and associate services with declared servers. The mach_init daemon will also be responsible for launching (and/or re-launching) those service providing servers when attempts to use one or more of the associated services is detected. The options are as follows: -D When the -D option is specified, mach_init starts in normal (non-debug) mode. Logging is minimal (only security-related and process launch failures are logged). Core dumps are disabled for launched servers. This is the default. -d When the -d option is specified, mach_init starts in debug mode. Logging is extensive. Core dumps will be taken for any launched servers that crash. -F When the -F option is specified, mach_init forks during initialization so that it doesn't have to be put in the background manually by the caller. -r Using the -r option tells mach_init to register itself in a previously running copy of mach_init under the service name name-in-existing-server. This is most useful when debugging new instances of mach_init itself, but can also be used for robustness or to allow the subsequent mach_init processes to run as a non-root user. As mach_init is often used to launch servers, this could be more secure. However, mach_init will not allow a server declaration to specify a user id different than that of the requesting client (unless the client is running as root). So it shouldn't be required for a secure configuration. Access to mach_init is provided through the bootstrap series of RPC APIs over service ports published by mach_init itself. Each Mach task has an assigned bootstrap port retrieved via task_get_bootstrap_port(). These bootstrap port registrations are inherited across fork(). The service registrations are grouped into subsets, providing a level of security. Only processes with access to the subset's bootstrap port will be able to register/lookup Mach ports within that subset. Lookups from within a subset will search the subset first, then move on to its parent, and then its grand-parent, etc... until a string name match is found or the top of the bootstrap tree is reached. Subsets are sometimes associated with login sessions to protect session-specific ports from being exposed outside the session. The first instance of mach_init is responsible for launching the traditional BSD process control initialization daemon (/sbin/init). SAMPLE USAGE
mach_init -d -r mach_init will start in debug mode, and register itself in an already running instance of mach_init under the service name strap. NOTE
Sending a SIGHUP to a running mach_init will toggle debug mode. SEE ALSO
init(8) Mac OS X March 20, 2002 Mac OS X

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launch(3)						   BSD Library Functions Manual 						 launch(3)

launchd APIs -- interfaces for interacting with a launchd job. SYNOPSIS
#include <launch.h> #include <servers/bootstrap.h> kern_return_t bootstrap_check_in(mach_port_t bp, const name_t service_name, mach_port_t *sp); int launch_activate_socket(const char *name, int **fds, size_t *cnt); DESCRIPTION
A launchd(8) job may have resources that are held on behalf of it while it is not running to facilitate launch-on-demand. These interfaces allow for the job to retrieve these resources as part of its initialization. Currently supported resource types are XPC listener connections, Mach ports, and sockets. Use of XPC with launchd(8) is documented in the xpc(3) family of manual pages. MACH PORTS
The bootstrap_check_in() routine allows for a launchd(8) job to retrieve the receive right to a Mach port that launchd(8) has created on behalf of the job. launchd(8) creates this port and advertises it in the appropriate Mach bootstrap namespace by parsing the MachServices entry of the job's launchd.plist(5). The first argument to bootstrap_check_in() should always be the bootstrap_port() global. The second argument should be the name of the service whose port you wish to retrieve, as specified as an entry in the job's MachServices dictionary. The final argument, upon successful return, will be the name of the receive right corresponding to the port that launchd(8) had advertised in the bootstrap namespace. If the job closes the receive right to the port with mach_port_mod_refs() or exits, the receive right obtained by this routine will be send back to launchd(8) rather than being closed. This allows launchd to resume advertising the same port in the Mach bootstrap namespace and frees clients from the need to re-query for the send right to that port when the job dies. SOCKETS
The launch_activate_socket() routine allows a launchd(8) job to retrieve a set of file descriptors corresponding to a socket service that launchd(8) has created and advertised on behalf of the job by parsing the Sockets entry in the job's launchd.plist(5). The first argument should be the name of the socket entry as specified in the launchd.plist(5). The second argument, upon output, will point to an array of integers whose count is filled into the third argument upon success. This array represents all the sockets that launchd(8) created corre- sponding to the entry in the job's Sockets dictionary. Depending on the properties specified, a single Sockets entry may have multiple descriptors created for it (one for IPv4 and one for IPv6, for example). This array is allocated on the heap, and it is the caller's respon- sibility to call free(3) to dispose of the memory when it is no longer needed. RETURN VALUES
If launch_activate_socket() succeeds, zero is returned. In the event of failure, a non-zero POSIX-compatible error code indicating the nature of the error is returned. This error may be decoded with strerror(3). If bootstrap_check_in() succeeds, KERN_SUCCESS is returned. In the event of failure, a non-zero error code that may be decoded with bootstrap_strerror(). ERRORS
bootstrap_check_in() will fail if: [BOOTSTRAP_UNKNOWN_SERVICE] The Mach service name specified does not exist in the caller's launchd.plist(5). [BOOTSTRAP_SERVICE_ACTIVE] The specified Mach service has already been checked in by the job. launch_activate_socket() will fail if: [ENOENT] The socket name specified does not exist in the caller's launchd.plist(5). [ESRCH] The calling process is not managed by launchd(8). [EALREADY] The specified socket has already been activated. SEE ALSO
xpc(3), xpc_connection_create(3), socket(2), launchd(8), launchd.plist(5). Darwin 31 March, 2014 Darwin
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