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Diffstat (limited to 'daemon.c')
| -rw-r--r-- | daemon.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/daemon.c b/daemon.c new file mode 100644 index 00000000..56aab4ef --- /dev/null +++ b/daemon.c @@ -0,0 +1,221 @@ +/* Copyright 1993-95 by Carl Harris, Jr. + * All rights reserved + * + * Distribute freely, except: don't remove my name from the source or + * documentation (don't take credit for my work), mark your changes (don't + * get me blamed for your possible bugs), don't alter or remove this + * notice. May be sold if buildable source is provided to buyer. No + * warrantee of any kind, express or implied, is included with this + * software; use at your own risk, responsibility for damages (if any) to + * anyone resulting from the use of this software rests entirely with the + * user. + * + * Send bug reports, bug fixes, enhancements, requests, flames, etc., and + * I'll try to keep a version up to date. I can be reached as follows: + * Carl Harris <ceharris@mal.com> + */ + + +/*********************************************************************** + module: daemon + project: popclient + programmer: Carl Harris, ceharris@mal.com + description: This module contains all of the code needed to + turn a process into a daemon for POSIX, SysV, and + BSD systems. + + $Log: daemon.c,v $ + Revision 1.1 1996/06/25 14:32:01 esr + Initial revision + + Revision 1.1 1995/08/14 18:36:38 ceharris + Patches to support POP3's LAST command. + Final revisions for beta3 release. + + ***********************************************************************/ + + +#include <config.h> + +#include <stdio.h> +#include <sys/types.h> +#include <sys/file.h> +#include <signal.h> +#include <fcntl.h> + +#if defined(HAVE_SYS_WAIT_H) +# include <sys/wait.h> +#endif + +#if defined(HAVE_UNISTD_H) +# include <unistd.h> +#endif + + +#include "popclient.h" + + +/****************************************************************** + function: sigchld_handler + description: Process the SIGCHLD (a.k.a SIGCLD) signal by calling + a wait() variant to obtain the exit code of the + terminating process. + arguments: none. + ret. value: none (or undefined if REGSIGTYPE is int). + globals: none. + calls: none. + *****************************************************************/ + +RETSIGTYPE +sigchld_handler () +{ + pid_t pid; + +#if defined(HAVE_UNION_WAIT) + union wait status; +#else + int status; +#endif + +#if defined(HAVE_WAIT3) + while ((pid = wait3(&status, WNOHANG, (struct rusage *) 0)) > 0) + ; /* swallow 'em up. */ +#elif defined(HAVE_WAITPID) + while ((pid = waitpid(-1, &status, WNOHANG)) > 0) + ; /* swallow 'em up. */ +#else /* Zooks! Nothing to do but wait(), and hope we don't block... */ + wait(&status); +#endif + +} + + + +/****************************************************************** + function: daemonize + description: become a daemon process; i.e. detach from the + control terminal, don't reacquire a control terminal, + become process group leader of our own process group, + and set up to catch child process termination signals. + arguments: + options command-line options. + + ret. value: none. + globals: refers to the address of sigchld_handler(). + calls: none. + *****************************************************************/ + +int +daemonize (options) +struct optrec *options; +{ + int fd; + pid_t childpid; + RETSIGTYPE sigchild_handler(); + + /* if we are started by init (process 1) via /etc/inittab we needn't + bother to detach from our process group context */ + + if (getppid() == 1) + goto nottyDetach; + + /* Ignore BSD terminal stop signals */ +#ifdef SIGTTOU + signal(SIGTTOU, SIG_IGN); +#endif +#ifdef SIGTTIN + signal(SIGTTIN, SIG_IGN); +#endif +#ifdef SIGTSTP + signal(SIGTSTP, SIG_IGN); +#endif + + /* In case we were not started in the background, fork and let + the parent exit. Guarantees that the child is not a process + group leader */ + + if ((childpid = fork()) < 0) { + perror("fork"); + return(PS_IOERR); + } + else if (childpid > 0) + exit(0); /* parent */ + + + /* Make ourselves the leader of a new process group with no + controlling terminal */ + +#if defined(HAVE_SETSID) /* POSIX */ + /* POSIX makes this soooo easy to do */ + if (setsid() < 0) { + perror("setsid"); + return(PS_IOERR); + } +#elif defined(SIGTSTP) /* BSD */ + /* change process group */ + setpgrp(0, getpid()); + + /* lose controlling tty */ + if ((fd = open("/dev/tty", O_RDWR)) >= 0) { + ioctl(fd, TIOCNOTTY, (char *) 0); + close(fd); + } +#else /* SVR3 and older */ + /* change process group */ + setpgrp(); + + /* lose controlling tty */ + signal(SIGHUP, SIG_IGN); + if ((childpid = fork) < 0) { + perror("fork"); + return(PS_IOERR); + } + else if (childpid > 0) { + exit(0); /* parent */ + } +#endif + +nottyDetach: + + /* Close any/all open file descriptors */ +#if defined(HAVE_GETDTABLESIZE) + for (fd = getdtablesize()-1; fd >= 0; fd--) +#elif defined(NOFILE) + for (fd = NOFILE-1; fd >= 0; fd--) +#else /* make an educated guess */ + for (fd = 19; fd >= 0; fd--) +#endif + { + close(fd); + } + + /* Reopen stdin descriptor on /dev/null */ + if ((fd = open("/dev/null", O_RDWR)) < 0) { /* stdin */ + perror("open: /dev/null"); + return(PS_IOERR); + } + + + if (dup(fd) < 0) { /* stdout */ + log_perror("dup"); + return(PS_IOERR); + } + if (dup(fd) < 0) { /* stderr */ + log_perror("dup"); + return(PS_IOERR); + } + + /* move to root directory, so we don't prevent filesystem unmounts */ + chdir("/"); + + /* set our umask to something reasonable (we hope) */ +#if defined(DEF_UMASK) + umask(DEF_UMASK); +#else + umask(022); +#endif + + /* set up to catch child process termination signals */ + signal(SIGCLD, sigchild_handler); + +} |