include/wvsubproc.h

   1 /* -*- Mode: C++ -*-
   2  * Worldvisions Weaver Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  *
   5  * A class for reliably starting/stopping subprocesses.
   6  *
   7  * We want to avoid calling system(), since it uses the shell (and
   8  * thus has strange parsing weirdness, environment variable changes,
   9  * and so on).  Plus calling the shell when we need to is just slow.
  10  *
  11  * On the other hand, we want handy features like the ability to wait
  12  * for our child process to die, and the ability to kill it if it
  13  * doesn't (without having to use "killall").
  14  *
  15  * By using setsid(), we also deal with strange situations like
  16  * scripts which launch other programs.  stop() and kill() will kill
  17  * them all. (If you don't want that, use stop_primary() and
  18  * kill_primary().)
  19  */
  20 #ifndef __WVSUBPROC_H
  21 #define __WVSUBPROC_H
  22
  23 #include "wvstringlist.h"
  24
  25 #include <stdarg.h>
  26 #include <signal.h>
  27 #include <time.h>
  28
  29 class WvSubProc
  30 {
  31 public:
  32     DeclareWvList(pid_t);
  33     pid_tList old_pids;
  34
  35     pid_t pid;
  36     bool running;
  37     int estatus;
  38     WvString pidfile, last_cmd, app;
  39     WvStringList last_args, env;
  40
  41     WvSubProc()
  42         { init(); }
  43
  44     WvSubProc(const char cmd[], const char * const *argv)
  45         { init(); startv(cmd, argv); }
  46
  47     virtual ~WvSubProc();
  48
  49 private:
  50     void init();
  51     int _startv(const char cmd[], const char * const *argv);
  52
  53     int memlimit;
  54
  55 public:
  56     void prepare(const char cmd[], ...);
  57     void preparev(const char cmd[], va_list ap);
  58     void preparev(const char cmd[], const char * const *argv);
  59     void preparev(const char cmd[], WvStringList &);
  60
  61     // launch a subprocess, which will be owned by this object.
  62     int start(const char cmd[], ...);
  63
  64     int startv(const char cmd[], const char * const *argv);
  65     virtual int start_again();
  66
  67     virtual int fork(int *waitfd);
  68
  69     // stop (kill -TERM or -KILL as necessary) the subprocess and
  70     // all its children.
  71     virtual void stop(time_t msec_delay, bool kill_children = true);
  72
  73     // wait for the subprocess (and all its children) to die.
  74     virtual void wait(time_t msec_delay, bool wait_children = true);
  75
  76     // figure out the pid from the /var/run pidfile
  77     pid_t pidfile_pid();
  78
  79     /// Sets a limit on the number of megabytes of memory the subprocess will
  80     // use
  81     void setMemLimit(int megs) { memlimit = megs; }
  82
  83     // send a signal to the subprocess and all its children.
  84     void kill(int sig);
  85
  86     // send a signal only to the main subprocess.
  87     void kill_primary(int sig);
  88
  89     // suspend the process temporarily, or resume it.
  90     virtual void suspend()
  91         { kill(SIGSTOP); }
  92     virtual void resume()
  93         { kill(SIGCONT); }
  94 };
  95
  96 DeclareWvList(WvSubProc);
  97
  98 #endif // __WVSUBPROC_H