#include <stdio.h>
#include <errno.h>
#include <signal.h>
+#include <string.h>
#include <sys/types.h>
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#include "fetchmail.h"
#include "tunable.h"
-RETSIGTYPE
+static RETSIGTYPE
sigchld_handler (int sig)
/* process SIGCHLD to obtain the exit code of the terminating process */
{
- pid_t pid;
-
#if defined(HAVE_WAITPID) /* the POSIX way */
int status;
- while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
+ while (waitpid(-1, &status, WNOHANG) > 0)
continue; /* swallow 'em up. */
#elif defined(HAVE_WAIT3) /* the BSD way */
+ pid_t pid;
#if defined(HAVE_UNION_WAIT) && !defined(__FreeBSD__)
union wait status;
#else
wait(&status);
#endif
+ lastsig = SIGCHLD;
+ (void)sig;
+}
+
+RETSIGTYPE null_signal_handler(int sig) { (void)sig; }
+
+SIGHANDLERTYPE set_signal_handler(int sig, SIGHANDLERTYPE handler)
+/*
+ * This function is called by other parts of the program to
+ * setup the signal handler after a change to the signal context.
+ * This is done to improve robustness of the signal handling code.
+ * It has the same prototype as signal(2).
+ */
+{
+ SIGHANDLERTYPE rethandler;
+#ifdef HAVE_SIGACTION
+ struct sigaction sa_new, sa_old;
+
+ memset (&sa_new, 0, sizeof sa_new);
+ sigemptyset (&sa_new.sa_mask);
+ sa_new.sa_handler = handler;
+ sa_new.sa_flags = 0;
+#ifdef SA_RESTART /* SunOS 4.1 portability hack */
+ /* system call should restart on all signals except SIGALRM */
+ if (sig != SIGALRM)
+ sa_new.sa_flags |= SA_RESTART;
+#endif
+#ifdef SA_NOCLDSTOP /* SunOS 4.1 portability hack */
+ if (sig == SIGCHLD)
+ sa_new.sa_flags |= SA_NOCLDSTOP;
+#endif
+ sigaction(sig, &sa_new, &sa_old);
+ rethandler = sa_old.sa_handler;
+#if defined(SIGPWR)
+ if (sig == SIGCHLD)
+ sigaction(SIGPWR, &sa_new, NULL);
+#endif
+#else /* HAVE_SIGACTION */
+ rethandler = signal(sig, handler);
+#if defined(SIGPWR)
+ if (sig == SIGCHLD)
+ signal(SIGPWR, handler);
+#endif
+ /* system call should restart on all signals except SIGALRM */
+ siginterrupt(sig, sig == SIGALRM);
+#endif /* HAVE_SIGACTION */
+ return rethandler;
+}
+
+void deal_with_sigchld(void)
+{
+ set_signal_handler(SIGCHLD, sigchld_handler);
}
int
-daemonize (const char *logfile, void (*termhook)(int))
+daemonize (const char *logfile)
/* detach from control TTY, become process group leader, catch SIGCHLD */
{
- int fd;
+ int fd, logfd;
pid_t childpid;
- RETSIGTYPE sigchld_handler(int);
/* if we are started by init (process 1) via /etc/inittab we needn't
bother to detach from our process group context */
/* Ignore BSD terminal stop signals */
#ifdef SIGTTOU
- signal(SIGTTOU, SIG_IGN);
+ set_signal_handler(SIGTTOU, SIG_IGN);
#endif
#ifdef SIGTTIN
- signal(SIGTTIN, SIG_IGN);
+ set_signal_handler(SIGTTIN, SIG_IGN);
#endif
#ifdef SIGTSTP
- signal(SIGTSTP, SIG_IGN);
+ set_signal_handler(SIGTSTP, SIG_IGN);
#endif
/* In case we were not started in the background, fork and let
group leader */
if ((childpid = fork()) < 0) {
- report(stderr, errno, "fork\n");
+ report(stderr, "fork (%s)\n", strerror(errno));
return(PS_IOERR);
}
else if (childpid > 0)
#if defined(HAVE_SETSID) /* POSIX */
/* POSIX makes this soooo easy to do */
if (setsid() < 0) {
- report(stderr, errno, "setsid\n");
+ report(stderr, "setsid (%s)\n", strerror(errno));
return(PS_IOERR);
}
#elif defined(SIGTSTP) /* BSD */
/* lose controlling tty */
if ((fd = open("/dev/tty", O_RDWR)) >= 0) {
ioctl(fd, TIOCNOTTY, (char *) 0);
- close(fd);
+ close(fd); /* not checking should be safe, there were no writes */
}
#else /* SVR3 and older */
/* change process group */
#endif
/* lose controlling tty */
- signal(SIGHUP, SIG_IGN);
+ set_signal_handler(SIGHUP, SIG_IGN);
if ((childpid = fork()) < 0) {
- report(stderr, errno, "fork\n");
+ report(stderr, "fork (%s)\n", strerror(errno));
return(PS_IOERR);
}
else if (childpid > 0) {
nottyDetach:
+ (void)close(0);
+
+ /* Reopen stdin descriptor on /dev/null */
+ if (open("/dev/null", O_RDWR) < 0) { /* stdin */
+ report(stderr, "cannot open /dev/null: %s\n", strerror(errno));
+ return(PS_IOERR);
+ }
+
+ if (logfile)
+ {
+ if ((logfd = open(logfile, O_CREAT|O_WRONLY|O_APPEND, 0666)) < 0) { /* stdout */
+ report(stderr, "cannot open %s: %s\n", logfile, strerror(errno));
+ return PS_IOERR;
+ }
+ } else
+ logfd = 0; /* else use /dev/null */
+
/* Close any/all open file descriptors */
#if defined(HAVE_GETDTABLESIZE)
- for (fd = getdtablesize()-1; fd >= 0; fd--)
+ fd = getdtablesize() - 1;
#elif defined(NOFILE)
- for (fd = NOFILE-1; fd >= 0; fd--)
+ fd = NOFILE - 1;
#else /* make an educated guess */
- for (fd = 19; fd >= 0; fd--)
+ fd = 1023;
#endif
- {
- close(fd);
- }
-
- /* Reopen stdin descriptor on /dev/null */
- if ((fd = open("/dev/null", O_RDWR)) < 0) { /* stdin */
- report(stderr, errno, "open: /dev/null\n");
- return(PS_IOERR);
+ while (fd >= 1) {
+ if (fd != logfd)
+ close(fd); /* not checking this should be safe, no writes */
+ -- fd;
}
- if (logfile)
- fd = open(logfile, O_CREAT|O_WRONLY|O_APPEND, 0666); /* stdout */
- else
- if (dup(fd) < 0) { /* stdout */
- report(stderr, errno, "dup\n");
+ if (dup(logfd) < 0 /* stdout */
+ || ((logfd == 0 || logfd >= 3) && dup(logfd) < 0)) { /* stderr */
+ report(stderr, "dup (%s)\n", strerror(errno));
return(PS_IOERR);
- }
- if (dup(fd) < 0) { /* stderr */
- report(stderr, errno, "dup\n");
- return(PS_IOERR);
}
+#ifdef HAVE_GETCWD
/* move to root directory, so we don't prevent filesystem unmounts */
chdir("/");
+#endif
/* set our umask to something reasonable (we hope) */
#if defined(DEF_UMASK)
umask(022);
#endif
- /* set up to catch child process termination signals */
- signal(SIGCHLD, sigchld_handler);
-#if defined(SIGPWR)
- signal(SIGPWR, sigchld_handler);
-#endif
+ deal_with_sigchld();
return(0);
}
+flag is_a_file(int fd)
+/* is the given fd attached to a file? (used to control logging) */
+{
+ struct stat stbuf;
+
+ /*
+ * We'd like just to return 1 on (S_IFREG | S_IFBLK),
+ * but weirdly enough, Linux ptys seem to have S_IFBLK
+ * so this test would fail when run on an xterm.
+ */
+ if (isatty(fd) || fstat(fd, &stbuf))
+ return(0);
+ else if (stbuf.st_mode & (S_IFREG))
+ return(1);
+ return(0);
+}
+
/* daemon.c ends here */
projects / ~andy / fetchmail / blobdiff