#include "fetchmail.h"
#include "tunable.h"
-RETSIGTYPE
+static RETSIGTYPE
sigchld_handler (int sig)
/* process SIGCHLD to obtain the exit code of the terminating process */
{
- extern volatile int lastsig; /* last signal received */
pid_t pid;
-
#if defined(HAVE_WAITPID) /* the POSIX way */
int status;
wait(&status);
#endif
lastsig = SIGCHLD;
+ (void)sig;
}
-void deal_with_sigchld(void)
+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).
+ */
{
- RETSIGTYPE sigchld_handler(int);
+ SIGHANDLERTYPE rethandler;
#ifdef HAVE_SIGACTION
- struct sigaction sa_new;
+ struct sigaction sa_new, sa_old;
memset (&sa_new, 0, sizeof sa_new);
sigemptyset (&sa_new.sa_mask);
- /* sa_new.sa_handler = SIG_IGN; pointless */
-
- /* set up to catch child process termination signals */
- sa_new.sa_handler = sigchld_handler;
+ sa_new.sa_handler = handler;
+ sa_new.sa_flags = 0;
#ifdef SA_RESTART /* SunOS 4.1 portability hack */
- sa_new.sa_flags = SA_RESTART;
+ /* 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 (SIGCHLD, &sa_new, NULL);
+ sigaction(sig, &sa_new, &sa_old);
+ rethandler = sa_old.sa_handler;
#if defined(SIGPWR)
- sigaction (SIGPWR, &sa_new, NULL);
+ if (sig == SIGCHLD)
+ sigaction(SIGPWR, &sa_new, NULL);
#endif
-#else
- signal(SIGCHLD, sigchld_handler);
+#else /* HAVE_SIGACTION */
+ rethandler = signal(sig, handler);
#if defined(SIGPWR)
- signal(SIGPWR, sigchld_handler);
+ 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;
-#ifdef HAVE_SIGACTION
- struct sigaction sa_new;
-#endif /* HAVE_SIGACTION */
/* if we are started by init (process 1) via /etc/inittab we needn't
bother to detach from our process group context */
goto nottyDetach;
/* Ignore BSD terminal stop signals */
-#ifdef HAVE_SIGACTION
- memset (&sa_new, 0, sizeof sa_new);
- sigemptyset (&sa_new.sa_mask);
- sa_new.sa_handler = SIG_IGN;
-#ifdef SA_RESTART /* SunOS 4.1 portability hack */
- sa_new.sa_flags = SA_RESTART;
-#endif
-#endif /* HAVE_SIGACTION */
#ifdef SIGTTOU
-#ifndef HAVE_SIGACTION
- signal(SIGTTOU, SIG_IGN);
-#else
- sigaction (SIGTTOU, &sa_new, NULL);
-#endif /* HAVE_SIGACTION */
+ set_signal_handler(SIGTTOU, SIG_IGN);
#endif
#ifdef SIGTTIN
-#ifndef HAVE_SIGACTION
- signal(SIGTTIN, SIG_IGN);
-#else
- sigaction (SIGTTIN, &sa_new, NULL);
-#endif /* HAVE_SIGACTION */
+ set_signal_handler(SIGTTIN, SIG_IGN);
#endif
#ifdef SIGTSTP
-#ifndef HAVE_SIGACTION
- signal(SIGTSTP, SIG_IGN);
-#else
- sigaction (SIGTSTP, &sa_new, NULL);
-#endif /* HAVE_SIGACTION */
+ set_signal_handler(SIGTSTP, SIG_IGN);
#endif
/* In case we were not started in the background, fork and let
#endif
/* lose controlling tty */
-#ifndef HAVE_SIGACTION
- signal(SIGHUP, SIG_IGN);
-#else
- sigaction (SIGHUP, &sa_new, NULL);
-#endif /* HAVE_SIGACTION */
+ set_signal_handler(SIGHUP, SIG_IGN);
if ((childpid = fork()) < 0) {
- report(stderr, "fork (%)\n", strerror(errno));
+ report(stderr, "fork (%s)\n", strerror(errno));
return(PS_IOERR);
}
else if (childpid > 0) {
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); /* not checking this should be safe, no writes */
- }
+ (void)close(0);
/* Reopen stdin descriptor on /dev/null */
if ((fd = open("/dev/null", O_RDWR)) < 0) { /* stdin */
- report(stderr, "open: /dev/null (%s)\n", strerror(errno));
+ report(stderr, "cannot open /dev/null: %s\n", strerror(errno));
return(PS_IOERR);
}
if (logfile)
- fd = open(logfile, O_CREAT|O_WRONLY|O_APPEND, 0666); /* stdout */
- else
- if (dup(fd) < 0) { /* stdout */
+ {
+ 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)
+ fd = getdtablesize() - 1;
+#elif defined(NOFILE)
+ fd = NOFILE - 1;
+#else /* make an educated guess */
+ fd = 1023;
+#endif
+ while (fd >= 1) {
+ if (fd != logfd)
+ close(fd); /* not checking this should be safe, no writes */
+ -- fd;
+ }
+
+ 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, "dup (%s)\n", strerror(errno));
- 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)
return(0);
}
-flag isafile(int fd)
+flag is_a_file(int fd)
/* is the given fd attached to a file? (used to control logging) */
{
struct stat stbuf;