/* $Cambridge: exim/exim-src/src/os.c,v 1.6 2007/01/08 10:50:18 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
/* Copyright (c) University of Cambridge 1995 - 2007 */
/* See the file NOTICE for conditions of use and distribution. */
#ifdef STAND_ALONE
#include <signal.h>
#include <stdio.h>
#include <time.h>
#endif
/* This source file contains "default" system-dependent functions which
provide functionality (or lack of it) in cases where the OS-specific os.c
file has not. Some of them are tailored by macros defined in os.h files. */
#ifndef OS_RESTARTING_SIGNAL
/*************************************************
* Set up restarting signal *
*************************************************/
/* This function has the same functionality as the ANSI C signal() function,
except that it arranges that, if the signal happens during a system call, the
system call gets restarted. (Also, it doesn't return a result.) Different
versions of Unix have different defaults, and different ways of setting up a
restarting signal handler. If the functionality is not available, the signal
should be set to be ignored. This function is used only for catching SIGUSR1.
*/
void
os_restarting_signal(int sig, void (*handler)(int))
{
/* Many systems have the SA_RESTART sigaction for specifying that a signal
should restart system calls. These include SunOS5, AIX, BSDI, IRIX, FreeBSD,
OSF1, Linux and HP-UX 10 (but *not* HP-UX 9). */
#ifdef SA_RESTART
struct sigaction act;
act.sa_handler = handler;
sigemptyset(&(act.sa_mask));
act.sa_flags = SA_RESTART;
sigaction(sig, &act, NULL);
#ifdef STAND_ALONE
printf("Used SA_RESTART\n");
#endif
/* SunOS4 and Ultrix default to non-interruptable signals, with SV_INTERRUPT
for making them interruptable. This seems to be a dying fashion. */
#elif defined SV_INTERRUPT
signal(sig, handler);
#ifdef STAND_ALONE
printf("Used default signal()\n");
#endif
/* If neither SA_RESTART nor SV_INTERRUPT is available we don't know how to
set up a restarting signal, so simply suppress the facility. */
#else
signal(sig, SIG_IGN);
#ifdef STAND_ALONE
printf("Used SIG_IGN\n");
#endif
#endif
}
#endif /* OS_RESTARTING_SIGNAL */
#ifndef OS_NON_RESTARTING_SIGNAL
/*************************************************
* Set up non-restarting signal *
*************************************************/
/* This function has the same functionality as the ANSI C signal() function,
except that it arranges that, if the signal happens during a system call, the
system call gets interrupted. (Also, it doesn't return a result.) Different
versions of Unix have different defaults, and different ways of setting up a
non-restarting signal handler. For systems for which we don't know what to do,
just use the normal signal() function and hope for the best. */
void
os_non_restarting_signal(int sig, void (*handler)(int))
{
/* Many systems have the SA_RESTART sigaction for specifying that a signal
should restart system calls. These include SunOS5, AIX, BSDI, IRIX, FreeBSD,
OSF1, Linux and HP-UX 10 (but *not* HP-UX 9). */
#ifdef SA_RESTART
struct sigaction act;
act.sa_handler = handler;
sigemptyset(&(act.sa_mask));
act.sa_flags = 0;
sigaction(sig, &act, NULL);
#ifdef STAND_ALONE
printf("Used sigaction() with flags = 0\n");
#endif
/* SunOS4 and Ultrix default to non-interruptable signals, with SV_INTERRUPT
for making them interruptable. This seems to be a dying fashion. */
#elif defined SV_INTERRUPT
struct sigvec sv;
sv.sv_handler = handler;
sv.sv_flags = SV_INTERRUPT;
sv.sv_mask = -1;
sigvec(sig, &sv, NULL);
#ifdef STAND_ALONE
printf("Used sigvec() with flags = SV_INTERRUPT\n");
#endif
/* If neither SA_RESTART nor SV_INTERRUPT is available we don't know how to
set up a restarting signal, so just use the standard signal() function. */
#else
signal(sig, handler);
#ifdef STAND_ALONE
printf("Used default signal()\n");
#endif
#endif
}
#endif /* OS_NON_RESTARTING_SIGNAL */
#ifdef STRERROR_FROM_ERRLIST
/*************************************************
* Provide strerror() for non-ANSI libraries *
*************************************************/
/* Some old-fashioned systems still around (e.g. SunOS4) don't have strerror()
in their libraries, but can provide the same facility by this simple
alternative function. */
char *
strerror(int n)
{
if (n < 0 || n >= sys_nerr) return "unknown error number";
return sys_errlist[n];
}
#endif /* STRERROR_FROM_ERRLIST */
#ifndef OS_STRSIGNAL
/*************************************************
* Provide strsignal() for systems without *
*************************************************/
/* Some systems have strsignal() to turn signal numbers into names; others
may have other means of doing this. This function is used for those systems
that have nothing. It provides a basic translation for the common standard
signal numbers. I've been extra cautious with the ifdef's here. Probably more
than is necessary... */
char *
os_strsignal(int n)
{
switch (n)
{
#ifdef SIGHUP
case SIGHUP: return "hangup";
#endif
#ifdef SIGINT
case SIGINT: return "interrupt";
#endif
#ifdef SIGQUIT
case SIGQUIT: return "quit";
#endif
#ifdef SIGILL
case SIGILL: return "illegal instruction";
#endif
#ifdef SIGTRAP
case SIGTRAP: return "trace trap";
#endif
#ifdef SIGABRT
case SIGABRT: return "abort";
#endif
#ifdef SIGEMT
case SIGEMT: return "EMT instruction";
#endif
#ifdef SIGFPE
case SIGFPE: return "arithmetic exception";
#endif
#ifdef SIGKILL
case SIGKILL: return "killed";
#endif
#ifdef SIGBUS
case SIGBUS: return "bus error";
#endif
#ifdef SIGSEGV
case SIGSEGV: return "segmentation fault";
#endif
#ifdef SIGSYS
case SIGSYS: return "bad system call";
#endif
#ifdef SIGPIPE
case SIGPIPE: return "broken pipe";
#endif
#ifdef SIGALRM
case SIGALRM: return "alarm";
#endif
#ifdef SIGTERM
case SIGTERM: return "terminated";
#endif
#ifdef SIGUSR1
case SIGUSR1: return "user signal 1";
#endif
#ifdef SIGUSR2
case SIGUSR2: return "user signal 2";
#endif
#ifdef SIGCHLD
case SIGCHLD: return "child stop or exit";
#endif
#ifdef SIGPWR
case SIGPWR: return "power fail/restart";
#endif
#ifdef SIGURG
case SIGURG: return "urgent condition on I/O channel";
#endif
#ifdef SIGSTOP
case SIGSTOP: return "stop";
#endif
#ifdef SIGTSTP
case SIGTSTP: return "stop from tty";
#endif
#ifdef SIGXCPU
case SIGXCPU: return "exceeded CPU limit";
#endif
#ifdef SIGXFSZ
case SIGXFSZ: return "exceeded file size limit";
#endif
default: return "unrecognized signal number";
}
}
#endif /* OS_STRSIGNAL */
#ifndef OS_STREXIT
/*************************************************
* Provide strexit() for systems without *
*************************************************/
/* Actually, I don't know of any system that has a strexit() function to turn
exit codes into text, but this function is implemented this way so that if any
OS does have such a thing, it could be used instead of this build-in one. */
char *
os_strexit(int n)
{
switch (n)
{
/* On systems without sysexits.h we can assume only those exit codes
that are given a default value in exim.h. */
#ifndef NO_SYSEXITS
case EX_USAGE: return "(could mean usage or syntax error)";
case EX_DATAERR: return "(could mean error in input data)";
case EX_NOINPUT: return "(could mean input data missing)";
case EX_NOUSER: return "(could mean user nonexistent)";
case EX_NOHOST: return "(could mean host nonexistent)";
case EX_SOFTWARE: return "(could mean internal software error)";
case EX_OSERR: return "(could mean internal operating system error)";
case EX_OSFILE: return "(could mean system file missing)";
case EX_IOERR: return "(could mean input/output error)";
case EX_PROTOCOL: return "(could mean protocol error)";
case EX_NOPERM: return "(could mean permission denied)";
#endif
case EX_EXECFAILED: return "(could mean unable to exec or command does not exist)";
case EX_UNAVAILABLE: return "(could mean service or program unavailable)";
case EX_CANTCREAT: return "(could mean can't create output file)";
case EX_TEMPFAIL: return "(could mean temporary error)";
case EX_CONFIG: return "(could mean configuration error)";
default: return "";
}
}
#endif /* OS_STREXIT */
/***********************************************************
* Load average function *
***********************************************************/
/* Although every Unix seems to have a different way of getting the load
average, a number of them have things in common. Some common variants are
provided below, but if an OS has unique requirements it can be handled in
a specific os.c file. What is required is a function called os_getloadavg
which takes no arguments and passes back the load average * 1000 as an int,
or -1 if no data is available. */
/* ----------------------------------------------------------------------- */
/* If the OS has got a BSD getloadavg() function, life is very easy. */
#if !defined(OS_LOAD_AVERAGE) && defined(HAVE_BSD_GETLOADAVG)
#define OS_LOAD_AVERAGE
int
os_getloadavg(void)
{
double avg;
int loads = getloadavg (&avg, 1);
if (loads != 1) return -1;
return (int)(avg * 1000.0);
}
#endif
/* ----------------------------------------------------------------------- */
/* ----------------------------------------------------------------------- */
/* Only SunOS5 has the kstat functions as far as I know, but put the code
here as there is the -hal variant, and other systems might follow this road one
day. */
#if !defined(OS_LOAD_AVERAGE) && defined(HAVE_KSTAT)
#define OS_LOAD_AVERAGE
#include <kstat.h>
int
os_getloadavg(void)
{
int avg;
kstat_ctl_t *kc;
kstat_t *ksp;
kstat_named_t *kn;
if ((kc = kstat_open()) == NULL ||
(ksp = kstat_lookup(kc, LOAD_AVG_KSTAT_MODULE, 0, LOAD_AVG_KSTAT))
== NULL ||
kstat_read(kc, ksp, NULL) < 0 ||
(kn = kstat_data_lookup(ksp, LOAD_AVG_SYMBOL)) == NULL)
return -1;
avg = (int)(((double)(kn->LOAD_AVG_FIELD)/FSCALE) * 1000.0);
kstat_close(kc);
return avg;
}
#endif
/* ----------------------------------------------------------------------- */
/* ----------------------------------------------------------------------- */
/* Handle OS where a kernel symbol has to be read from /dev/kmem */
#if !defined(OS_LOAD_AVERAGE) && defined(HAVE_DEV_KMEM)
#define OS_LOAD_AVERAGE
#include <nlist.h>
static int avg_kd = -1;
static long avg_offset;
int
os_getloadavg(void)
{
LOAD_AVG_TYPE avg;
if (avg_kd < 0)
{
struct nlist nl[2];
nl[0].n_name = LOAD_AVG_SYMBOL;
nl[1].n_name = "";
nlist (KERNEL_PATH, nl);
avg_offset = (long)nl[0].n_value;
avg_kd = open ("/dev/kmem", 0);
if (avg_kd < 0) return -1;
(void) fcntl(avg_kd, F_SETFD, FD_CLOEXEC);
}
if (lseek (avg_kd, avg_offset, 0) == -1L
|| read (avg_kd, (char *)(&avg), sizeof (avg)) != sizeof(avg))
return -1;
return (int)(((double)avg/FSCALE)*1000.0);
}
#endif
/* ----------------------------------------------------------------------- */
/* ----------------------------------------------------------------------- */
/* If nothing is known about this OS, then the load average facility is
not available. */
#ifndef OS_LOAD_AVERAGE
int
os_getloadavg(void)
{
return -1;
}
#endif
/* ----------------------------------------------------------------------- */
#if !defined FIND_RUNNING_INTERFACES
/*************************************************
* Find all the running network interfaces *
*************************************************/
/* Finding all the running interfaces is something that has os-dependent
tweaks, even in the IPv4 case, and it gets worse for IPv6, which is why this
code is now in the os-dependent source file. There is a common function which
works on most OS (except IRIX) for IPv4 interfaces, and, with some variations
controlled by macros, on at least one OS for IPv6 and IPv4 interfaces. On Linux
with IPv6, the common function is used for the IPv4 interfaces and additional
code used for IPv6. Consequently, the real function is called
os_common_find_running_interfaces() so that it can be called from the Linux
function. On non-Linux systems, the macro for os_find_running_interfaces just
calls the common function; on Linux it calls the Linux function.
This function finds the addresses of all the running interfaces on the machine.
A chain of blocks containing the textual form of the addresses is returned.
Problems:
(1) Solaris 2 has the SIOGIFNUM call to get the number of interfaces, but
other OS (including Solaris 1) appear not to. So just screw in a largeish
fixed number, defined by MAX_INTERFACES. This is in the config.h file and
can be changed in Local/Makefile. Unfortunately, the www addressing scheme
means that some hosts have a very large number of virtual interfaces. Such
hosts are recommended to set local_interfaces to avoid problems with this.
(2) If the standard code is run on IRIX, it does not return any alias
interfaces. There is special purpose code for that operating system, which
uses the sysctl() function. The code is in OS/os.c-IRIX, and this code isn't
used on that OS.
(3) Some experimental/developing OS (e.g. GNU/Hurd) do not have any means
of finding the interfaces. If NO_FIND_INTERFACES is set, a fudge-up is used
instead.
(4) Some operating systems set the IP address in what SIOCGIFCONF returns;
others do not, and require SIOCGIFADDR to be called to get it. For most of
the former, calling the latter does no harm, but it causes grief on Linux and
BSD systems in the case of IP aliasing, so a means of cutting it out is
provided.
Arguments: none
Returns: a chain of ip_address_items, each pointing to a textual
version of an IP address, with the port field set to zero
*/
#ifndef NO_FIND_INTERFACES
/* If there is IPv6 support, and SIOCGLIFCONF is defined, define macros to
use these new, longer versions of the old IPv4 interfaces. Otherwise, define
the macros to use the historical versions. */
#if HAVE_IPV6 && defined SIOCGLIFCONF
#define V_ifconf lifconf
#define V_ifreq lifreq
#define V_GIFADDR SIOCGLIFADDR
#define V_GIFCONF SIOCGLIFCONF
#define V_GIFFLAGS SIOCGLIFFLAGS
#define V_ifc_buf lifc_buf
#define V_ifc_family lifc_family
#define V_ifc_flags lifc_flags
#define V_ifc_len lifc_len
#define V_ifr_addr lifr_addr
#define V_ifr_flags lifr_flags
#define V_ifr_name lifr_name
#define V_FAMILY_QUERY AF_UNSPEC
#define V_family ss_family
#else
#define V_ifconf ifconf
#define V_ifreq ifreq
#define V_GIFADDR SIOCGIFADDR
#define V_GIFCONF SIOCGIFCONF
#define V_GIFFLAGS SIOCGIFFLAGS
#define V_ifc_buf ifc_buf
#define V_ifc_family ifc_family
#define V_ifc_flags ifc_flags
#define V_ifc_len ifc_len
#define V_ifr_addr ifr_addr
#define V_ifr_flags ifr_flags
#define V_ifr_name ifr_name
#define V_family sa_family
#endif
/* In all cases of IPv6 support, use an IPv6 socket. Otherwise (at least on
Solaris 8) the call to read the flags doesn't work for IPv6 interfaces. If
we find we can't actually make an IPv6 socket, the code will revert to trying
an IPv4 socket. */
#if HAVE_IPV6
#define FAMILY AF_INET6
#else
#define FAMILY AF_INET
#endif
/* OK, after all that preliminary stuff, here's the code. */
ip_address_item *
os_common_find_running_interfaces(void)
{
struct V_ifconf ifc;
struct V_ifreq ifreq;
int vs;
ip_address_item *yield = NULL;
ip_address_item *last = NULL;
ip_address_item *next;
char *cp;
char buf[MAX_INTERFACES*sizeof(struct V_ifreq)];
struct sockaddr *addrp;
size_t len = 0;
char addrbuf[256];
/* We have to create a socket in order to do ioctls on it to find out
what we want to know. */
if ((vs = socket(FAMILY, SOCK_DGRAM, 0)) < 0)
{
#if HAVE_IPV6
DEBUG(D_interface)
debug_printf("Unable to create IPv6 socket to find interface addresses:\n "
"error %d %s\nTrying for an IPv4 socket\n", errno, strerror(errno));
vs = socket(AF_INET, SOCK_DGRAM, 0);
if (vs < 0)
#endif
log_write(0, LOG_PANIC_DIE, "Unable to create IPv4 socket to find interface "
"addresses: %d %s", errno, strerror(errno));
}
/* Get the interface configuration. Some additional data is required when the
new structures are in use. */
ifc.V_ifc_len = sizeof(buf);
ifc.V_ifc_buf = buf;
#ifdef V_FAMILY_QUERY
ifc.V_ifc_family = V_FAMILY_QUERY;
ifc.V_ifc_flags = 0;
#endif
if (ioctl(vs, V_GIFCONF, (char *)&ifc) < 0)
log_write(0, LOG_PANIC_DIE, "Unable to get interface configuration: %d %s",
errno, strerror(errno));
/* If the buffer is big enough, the ioctl sets the value of ifc.V_ifc_len to
the amount actually used. If the buffer isn't big enough, at least on some
operating systems, ifc.V_ifc_len still gets set to correspond to the total
number of interfaces, even though they don't all fit in the buffer. */
if (ifc.V_ifc_len > sizeof(buf))
{
ifc.V_ifc_len = sizeof(buf);
DEBUG(D_interface)
debug_printf("more than %d interfaces found: remainder not used\n"
"(set MAX_INTERFACES in Local/Makefile and rebuild if you want more)\n",
MAX_INTERFACES);
}
/* For each interface, check it is an IP interface, get its flags, and see if
it is up; if not, skip.
BSD systems differ from others in what SIOCGIFCONF returns. Other systems
return a vector of ifreq structures whose size is as defined by the structure.
BSD systems allow sockaddrs to be longer than their sizeof, which in turn makes
the ifreq structures longer than their sizeof. The code below has its origins
in amd and ifconfig; it uses the sa_len field of each sockaddr to determine
each item's length.
This is complicated by the fact that, at least on BSD systems, the data in the
buffer is not guaranteed to be aligned. Thus, we must first copy the basic
struct to some aligned memory before looking at the field in the fixed part to
find its length, and then recopy the correct length. */
for (cp = buf; cp < buf + ifc.V_ifc_len; cp += len)
{
memcpy((char *)&ifreq, cp, sizeof(ifreq));
#ifndef HAVE_SA_LEN
len = sizeof(struct V_ifreq);
#else
len = ((ifreq.ifr_addr.sa_len > sizeof(ifreq.ifr_addr))?
ifreq.ifr_addr.sa_len : sizeof(ifreq.ifr_addr)) +
sizeof(ifreq.V_ifr_name);
if (len > sizeof(addrbuf))
log_write(0, LOG_PANIC_DIE, "Address for %s interface is absurdly long",
ifreq.V_ifr_name);
#endif
/* If not an IP interface, skip */
if (ifreq.V_ifr_addr.V_family != AF_INET
#if HAVE_IPV6
&& ifreq.V_ifr_addr.V_family != AF_INET6
#endif
) continue;
/* Get the interface flags, and if the interface is down, continue. Formerly,
we treated the inability to get the flags as a panic-die error. However, it
seems that on some OS (Solaris 9 being the case noted), it is possible to
have an interface in this list for which this call fails because the
interface hasn't been "plumbed" to any protocol (IPv4 or IPv6). Therefore,
we now just treat this case as "down" as well. */
if (ioctl(vs, V_GIFFLAGS, (char *)&ifreq) < 0)
{
continue;
/*************
log_write(0, LOG_PANIC_DIE, "Unable to get flags for %s interface: %d %s",
ifreq.V_ifr_name, errno, strerror(errno));
*************/
}
if ((ifreq.V_ifr_flags & IFF_UP) == 0) continue;
/* On some operating systems we have to get the IP address of the interface
by another call. On others, it's already there, but we must copy the full
length because we only copied the basic length above, and anyway,
GIFFLAGS may have wrecked the data. */
#ifndef SIOCGIFCONF_GIVES_ADDR
if (ioctl(vs, V_GIFADDR, (char *)&ifreq) < 0)
log_write(0, LOG_PANIC_DIE, "Unable to get IP address for %s interface: "
"%d %s", ifreq.V_ifr_name, errno, strerror(errno));
addrp = &ifreq.V_ifr_addr;
#else
memcpy(addrbuf, cp + offsetof(struct V_ifreq, V_ifr_addr),
len - sizeof(ifreq.V_ifr_name));
addrp = (struct sockaddr *)addrbuf;
#endif
/* Create a data block for the address, fill in the data, and put it on the
chain. */
next = store_get(sizeof(ip_address_item));
next->next = NULL;
next->port = 0;
(void)host_ntoa(-1, addrp, next->address, NULL);
if (yield == NULL) yield = last = next; else
{
last->next = next;
last = next;
}
DEBUG(D_interface) debug_printf("Actual local interface address is %s (%s)\n",
last->address, ifreq.V_ifr_name);
}
/* Close the socket, and return the chain of data blocks. */
(void)close(vs);
return yield;
}
#else /* NO_FIND_INTERFACES */
/* Some experimental or developing OS (e.g. GNU/Hurd) do not have the ioctls,
and there is no other way to get a list of the (IP addresses of) local
interfaces. We just return the loopback address(es). */
ip_address_item *
os_common_find_running_interfaces(void)
{
ip_address_item *yield = store_get(sizeof(address_item));
yield->address = US"127.0.0.1";
yield->port = 0;
yield->next = NULL;
#if HAVE_IPV6
yield->next = store_get(sizeof(address_item));
yield->next->address = US"::1";
yield->next->port = 0;
yield->next->next = NULL;
#endif
DEBUG(D_interface) debug_printf("Unable to find local interface addresses "
"on this OS: returning loopback address(es)\n");
return yield;
}
#endif /* NO_FIND_INTERFACES */
#endif /* FIND_RUNNING_INTERFACES */
/*************************************************
**************************************************
* Stand-alone test program *
**************************************************
*************************************************/
#ifdef STAND_ALONE
#ifdef CLOCKS_PER_SEC
#define REAL_CLOCK_TICK CLOCKS_PER_SEC
#else
#ifdef CLK_TCK
#define REAL_CLOCK_TICK CLK_TCK
#else
#define REAL_CLOCK_TICK 1000000 /* SunOS4 */
#endif
#endif
int main(int argc, char **argv)
{
char buffer[128];
int fd = fileno(stdin);
int rc;
printf("Testing restarting signal; wait for handler message, then type a line\n");
strcpy(buffer, "*** default ***\n");
os_restarting_signal(SIGALRM, sigalrm_handler);
alarm(2);
if ((rc = read(fd, buffer, sizeof(buffer))) < 0)
printf("No data read\n");
else
{
buffer[rc] = 0;
printf("Read: %s", buffer);
}
alarm(0);
printf("Testing non-restarting signal; should read no data after handler message\n");
strcpy(buffer, "*** default ***\n");
os_non_restarting_signal(SIGALRM, sigalrm_handler);
alarm(2);
if ((rc = read(fd, buffer, sizeof(buffer))) < 0)
printf("No data read\n");
else
{
buffer[rc] = 0;
printf("Read: %s", buffer);
}
alarm(0);
printf("Testing load averages (last test - ^C to kill)\n");
for (;;)
{
int avg;
clock_t used;
clock_t before = clock();
avg = os_getloadavg();
used = clock() - before;
printf("cpu time = %.2f ", (double)used/REAL_CLOCK_TICK);
if (avg < 0)
{
printf("load average not available\n");
break;
}
printf("load average = %.2f\n", (double)avg/1000.0);
sleep(2);
}
return 0;
}
#endif
/* End of os.c */
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