minix/kernel/system/do_kill.c

/* The kernel call that is implemented in this file:
 *   m_type:	SYS_KILL
 *
 * The parameters for this kernel call are:
 *     m2_i1:	SIG_ENDPT  	# process to signal/ pending		
 *     m2_i2:	SIG_NUMBER	# signal number to send to process
 */

#include "../system.h"
#include <signal.h>

#if USE_KILL

/*===========================================================================*
 *			          do_kill				     *
 *===========================================================================*/
PUBLIC int do_kill(m_ptr)
message *m_ptr;			/* pointer to request message */
{
/* Handle sys_kill(). Cause a signal to be sent to a process. The PM is the
 * central server where all signals are processed and handler policies can
 * be registered. Any request, except for PM requests, is added to the map
 * of pending signals and the PM is informed about the new signal.
 * Since system servers cannot use normal POSIX signal handlers (because they
 * are usually blocked on a RECEIVE), they can request the PM to transform 
 * signals into messages. This is done by the PM with a call to sys_kill(). 
 */
  proc_nr_t proc_nr, proc_nr_e;
  int sig_nr = m_ptr->SIG_NUMBER;

  proc_nr_e= m_ptr->SIG_ENDPT;

  if (!isokendpt(proc_nr_e, &proc_nr)) return(EINVAL);
  if (sig_nr >= _NSIG) return(EINVAL);
  if (iskerneln(proc_nr)) return(EPERM);

  /* Set pending signal to be processed by the PM. */
  cause_sig(proc_nr, sig_nr);
  if (sig_nr == SIGKILL)
	clear_endpoint(proc_addr(proc_nr));
  return(OK);
}

#endif /* USE_KILL */
Al's system call -> kernel call renaming 2005-10-14 10:58:59 +02:00			`/* The kernel call that is implemented in this file:`
System processes can be signaled; signals are transformed in SYS_EVENT message that passes signal map along. This mechanisms is also used for nonuser signals like SIGKMESS, SIGKSTOP, SIGKSIG. Revised comments of many system call handlers. Renamed setpriority to nice. 2005-07-19 14:21:36 +02:00			`* m_type: SYS_KILL`
Reorganized system call library; uses separate file per call now. New configuration header file to include/ exclude functionality. Extracted privileged features from struct proc and create new struct priv. Renamed various system calls for readability. 2005-07-14 17:12:12 +02:00			`*`
Al's system call -> kernel call renaming 2005-10-14 10:58:59 +02:00			`* The parameters for this kernel call are:`
'proc number' is process slot, 'endpoint' are generation-aware process instance numbers, encoded and decoded using macros in <minix/endpoint.h>. proc number -> endpoint migration . proc_nr in the interrupt hook is now an endpoint, proc_nr_e. . m_source for messages and notifies is now an endpoint, instead of proc number. . isokendpt() converts an endpoint to a process number, returns success (but fails if the process number is out of range, the process slot is not a living process, or the given endpoint number does not match the endpoint number in the process slot, indicating an old process). . okendpt() is the same as isokendpt(), but panic()s if the conversion fails. This is mainly used for decoding message.m_source endpoints, and other endpoint numbers in kernel data structures, which should always be correct. . if DEBUG_ENABLE_IPC_WARNINGS is enabled, isokendpt() and okendpt() get passed the __FILE__ and __LINE__ of the calling lines, and print messages about what is wrong with the endpoint number (out of range proc, empty proc, or inconsistent endpoint number), with the caller, making finding where the conversion failed easy without having to include code for every call to print where things went wrong. Sometimes this is harmless (wrong arg to a kernel call), sometimes it's a fatal internal inconsistency (bogus m_source). . some process table fields have been appended an _e to indicate it's become and endpoint. . process endpoint is stored in p_endpoint, without generation number. it turns out the kernel never needs the generation number, except when fork()ing, so it's decoded then. . kernel calls all take endpoints as arguments, not proc numbers. the one exception is sys_fork(), which needs to know in which slot to put the child. 2006-03-03 11:00:02 +01:00			`* m2_i1: SIG_ENDPT # process to signal/ pending`
System processes can be signaled; signals are transformed in SYS_EVENT message that passes signal map along. This mechanisms is also used for nonuser signals like SIGKMESS, SIGKSTOP, SIGKSIG. Revised comments of many system call handlers. Renamed setpriority to nice. 2005-07-19 14:21:36 +02:00			`* m2_i2: SIG_NUMBER # signal number to send to process`
Reorganized system call library; uses separate file per call now. New configuration header file to include/ exclude functionality. Extracted privileged features from struct proc and create new struct priv. Renamed various system calls for readability. 2005-07-14 17:12:12 +02:00			`*/`

			`#include "../system.h"`
			`#include <signal.h>`

			`#if USE_KILL`

			`/===========================================================================`
			`* do_kill *`
			`===========================================================================/`
			`PUBLIC int do_kill(m_ptr)`
			`message m_ptr; / pointer to request message */`
			`{`
System processes can be signaled; signals are transformed in SYS_EVENT message that passes signal map along. This mechanisms is also used for nonuser signals like SIGKMESS, SIGKSTOP, SIGKSIG. Revised comments of many system call handlers. Renamed setpriority to nice. 2005-07-19 14:21:36 +02:00			`/* Handle sys_kill(). Cause a signal to be sent to a process. The PM is the`
			`* central server where all signals are processed and handler policies can`
			`* be registered. Any request, except for PM requests, is added to the map`
			`* of pending signals and the PM is informed about the new signal.`
			`* Since system servers cannot use normal POSIX signal handlers (because they`
			`* are usually blocked on a RECEIVE), they can request the PM to transform`
			`* signals into messages. This is done by the PM with a call to sys_kill().`
Reorganized system call library; uses separate file per call now. New configuration header file to include/ exclude functionality. Extracted privileged features from struct proc and create new struct priv. Renamed various system calls for readability. 2005-07-14 17:12:12 +02:00			`*/`
Allow a process to kill itself. Remove the endpoint of a process that kills itself before reporting the singal to pm. 2006-03-15 13:01:59 +01:00			`proc_nr_t proc_nr, proc_nr_e;`
System processes can be signaled; signals are transformed in SYS_EVENT message that passes signal map along. This mechanisms is also used for nonuser signals like SIGKMESS, SIGKSTOP, SIGKSIG. Revised comments of many system call handlers. Renamed setpriority to nice. 2005-07-19 14:21:36 +02:00			`int sig_nr = m_ptr->SIG_NUMBER;`

Allow a process to kill itself. Remove the endpoint of a process that kills itself before reporting the singal to pm. 2006-03-15 13:01:59 +01:00			`proc_nr_e= m_ptr->SIG_ENDPT;`

			`if (!isokendpt(proc_nr_e, &proc_nr)) return(EINVAL);`
fix _NSIG usage 2009-11-28 14:20:50 +01:00			`if (sig_nr >= _NSIG) return(EINVAL);`
- Kernel call handlers cleaned up. More strict checking of input parameters. - Moved generic_handler() from system.c to system/do_irqctl.c. - Set privileges of system processes somewhat stricter. 2005-07-29 17:26:23 +02:00			`if (iskerneln(proc_nr)) return(EPERM);`
System processes can be signaled; signals are transformed in SYS_EVENT message that passes signal map along. This mechanisms is also used for nonuser signals like SIGKMESS, SIGKSTOP, SIGKSIG. Revised comments of many system call handlers. Renamed setpriority to nice. 2005-07-19 14:21:36 +02:00
Jorrit's ... "progress?" 2006-03-10 17:10:05 +01:00			`/* Set pending signal to be processed by the PM. */`
			`cause_sig(proc_nr, sig_nr);`
Don't allow sys_kill to SELF alltogether. 2007-02-23 14:01:55 +01:00			`if (sig_nr == SIGKILL)`
Allow a process to kill itself. Remove the endpoint of a process that kills itself before reporting the singal to pm. 2006-03-15 13:01:59 +01:00			`clear_endpoint(proc_addr(proc_nr));`
Reorganized system call library; uses separate file per call now. New configuration header file to include/ exclude functionality. Extracted privileged features from struct proc and create new struct priv. Renamed various system calls for readability. 2005-07-14 17:12:12 +02:00			`return(OK);`
			`}`

			`#endif /* USE_KILL */`