minix/servers/sm/manager.c

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/* This file contains procedures to manage the system processes.
*
* The entry points into this file are
* do_start:
* do_stop:
* do_exit: a child of this server exited
*
* Changes:
* Jul 22, 2005: Created (Jorrit N. Herder)
*/
#include "sm.h"
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <minix/dmap.h>
extern int errno;
#define EXEC_FAILED 49 /* arbitrary, recognizable status */
#define MAX_PATH_LEN 256 /* maximum path string length */
#define MAX_ARGS_LEN 4096 /* maximum argument string length */
#define MAX_ARG_COUNT 1 /* parsed arguments count */
PRIVATE char command[MAX_PATH_LEN+1];
PRIVATE char arg_buf[MAX_ARGS_LEN+1];
/*===========================================================================*
* do_start *
*===========================================================================*/
PUBLIC int do_start(message *m_ptr)
{
message m;
int child_proc_nr;
int major_nr;
enum dev_style dev_style;
pid_t child_pid;
char *args[MAX_ARG_COUNT+1];
int s;
/* Obtain command name and parameters. */
if (m_ptr->SRV_PATH_LEN > MAX_PATH_LEN) return(E2BIG);
if (OK != (s=sys_datacopy(m_ptr->m_source, (vir_bytes) m_ptr->SRV_PATH_ADDR,
SELF, (vir_bytes) command, m_ptr->SRV_PATH_LEN))) return(s);
command[m_ptr->SRV_PATH_LEN] = '\0';
if (command[0] != '/') return(EINVAL);
if (m_ptr->SRV_ARGS_LEN > 0) {
if (m_ptr->SRV_ARGS_LEN > MAX_ARGS_LEN) return(E2BIG);
if (OK != (s=sys_datacopy(m_ptr->m_source, (vir_bytes) m_ptr->SRV_ARGS_ADDR,
SELF, (vir_bytes) arg_buf, m_ptr->SRV_ARGS_LEN))) return(s);
arg_buf[m_ptr->SRV_ARGS_LEN] = '\0';
args[0] = &arg_buf[0];
args[1] = NULL;
} else {
args[0] = NULL;
}
/* Now try to execute the new system service. Fork a new process. The child
* process will be inhibited from running by the NO_PRIV flag. Only let the
* child run once its privileges have been set by the parent.
*/
if ((s = _taskcall(PM_PROC_NR, FORK, &m)) < 0) /* use raw interface */
report("SM", "_taskcall to PM failed", s); /* to get both */
child_pid = m.m_type; /* - child's pid */
child_proc_nr = m.PR_PROC_NR; /* - process nr */
/* Now branch for parent and child process, and check for error. */
switch(child_pid) { /* see fork(2) */
case 0: /* child process */
execve(command, args, NULL); /* POSIX exec */
report("SM", "warning, exec() failed", errno); /* shouldn't happen */
exit(EXEC_FAILED); /* terminate child */
break;
case -1: /* fork failed */
report("SM", "warning, fork() failed", errno); /* shouldn't happen */
return(errno);
default: /* parent process */
if ((major_nr = m_ptr->SRV_DEV_MAJOR) > 0) { /* set driver map */
dev_style = STYLE_DEV;
if ((s=mapdriver(child_proc_nr, major_nr, dev_style)) < 0) {
#if VERBOSE
printf("SM: '%s %s', major %d, pid %d, proc_nr %d",
command, arg_buf, major_nr, child_pid, child_proc_nr);
#endif
report("SM", "couldn't map driver", errno);
}
}
if ((s = _taskcall(SYSTEM, SYS_PRIVCTL, &m)) < 0) /* set privileges */
report("SM", "_taskcall to SYSTEM failed", s); /* to let child run */
#if VERBOSE
printf("SM: started '%s %s', major %d, pid %d, proc_nr %d",
command, arg_buf, major_nr, child_pid, child_proc_nr);
#endif
/* update tables */
}
return(OK);
}
/*===========================================================================*
* do_stop *
*===========================================================================*/
PUBLIC int do_stop(message *m_ptr)
{
return(ENOSYS);
}
/*===========================================================================*
* do_exit *
*===========================================================================*/
PUBLIC int do_exit(message *m_ptr)
{
pid_t exit_pid;
int exit_status;
#if VERBOSE
printf("SM: got SIGCHLD signal, doing wait to get exited child.\n");
#endif
/* See which child exited and what the exit status is. This is done in a
* loop because multiple childs may have exited, all reported by one
* SIGCHLD signal. The WNOHANG options is used to prevent blocking if,
* somehow, no exited child can be found.
*/
while ( (exit_pid = waitpid(-1, &exit_status, WNOHANG)) != 0 ) {
#if VERBOSE
printf("SM: pid %d,", exit_pid);
if (WIFSIGNALED(exit_status)) {
printf("killed, signal number %d\n", WTERMSIG(exit_status));
} else if (WIFEXITED(exit_status)) {
printf("normal exit, status %d\n", WEXITSTATUS(exit_status));
}
#endif
}
return(OK);
}