92 lines
3.7 KiB
Text
92 lines
3.7 KiB
Text
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cinit commands, Nico Schottelius 2005-04-28
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cinit allows communication through a socket (see ipc.thoughs for reasons).
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Sockets allow to find out the accessing uid, gid and pid (uses SO_PEERCRED as
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socketoption).
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The communication-protocol is binary, the implementation can be found
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in comm/* mostly (clients use begin_msg() and server sigio() additonally).
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Protocol overview
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Any communication begins with a command. A command is a one byte
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unsigned char. Depending on the command, the communication has its own
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semantics.
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Commands are: (values can be found in cinit.h)
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CMD_START_SVC: I want to start a service.
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CMD_CHG_STATUS: I want to change the status of a service.
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CMD_STOP_SVC: Please shutdown a service and its dependencies.
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CMD_KILL_SVC: Shutdown a service, don't care about its dependencies.
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CMD_RESCUE: Kill everything, and spawn a sulogin shell.**)
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CMD_INIT: Start all services (again possibly).**)
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CMD_HALT: Halt the system*)
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CMD_REBOOT: Reboot the system*)
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CMD_POWEROFF: Power-off the system*)
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*) The commands are not and maybe will never be implemented,
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as they are realized another way (using signals).
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**) Not yet implemented.
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Detailled command-listing
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CMD_START_SVC
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1. int len; /* length of service name, including \0 */
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2. char *svc; /* name of the service, absolute pathname */
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cinit returns:
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a) ok, a SID, a service ID: int svc_id; [ really need int? ]
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b) fail, [currently only fail is returned]
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a) already running
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b) svc_name too long / not allowed
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[ A service identification is used for faster searching in cinit.
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It is also a hint for developers of external software, that they should not
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be able to use CMD_CHG_STATUS, if they didn't start a service.
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They should use CMD_STOP_SVC to stop a service.
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Starting a service is currently done via exec() in the external program or
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a cinit-fork(). ]
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CMD1CHG_STATUS: I want to change the status of a service.
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0. int len;
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1. char *svc;
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2. char status; /* status:
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once: started successfully the service once.
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fail: tried to start once, but the service exit ungracefully
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respawn: I am on it, as soon it exists I'll restart! */
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2. pid_t pid /* the pid of the service, if started once
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or the pid of the service watcher, if respawning */
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cinit returns: MSG_OK|MSG_FAIL (char)
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CMD_STOP_SVC: Please shutdown a service and its dependencies.
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1. int len; /* length of service name, including \0 */
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2. char *svc; /* name of the service, absolute pathname */
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cinit returns: ready...
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CMD_KILL_SVC: Shutdown a service, don't care about its dependencies.
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1. int len; /* length of service name, including \0 */
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2. char *svc; /* name of the service, absolute pathname */
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cinit returns: ready...
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CMD_INIT: Start all services (again possibly).
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cinit returns: ready...
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CMD_RESCUE: Kill everything, and spawn a sulogin shell.
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CMD_HALT: Halt the system.
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CMD_REBOOT: Reboot the system.
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CMD_POWEROFF: Power-off the system.
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