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/** \ingroup rpmio
* \file rpmio/rpmsq.c
*/
#include "system.h"
#include <signal.h>
#include <sys/signal.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rpm/rpmsq.h>
#include <rpm/rpmlog.h>
#include "debug.h"
static int disableInterruptSafety;
static sigset_t rpmsqCaught;
static sigset_t rpmsqActive;
typedef struct rpmsig_s * rpmsig;
static void rpmsqTerm(int signum, siginfo_t *info, void *context)
{
if (info->si_pid == 0) {
rpmlog(RPMLOG_DEBUG,
"exiting on signal %d (killed by death, eh?)\n", signum);
} else {
rpmlog(RPMLOG_WARNING,
_("exiting on signal %d from pid %d\n"), signum, info->si_pid);
}
exit(EXIT_FAILURE);
}
static struct rpmsig_s {
int signum;
rpmsqAction_t defhandler;
rpmsqAction_t handler;
siginfo_t siginfo;
struct sigaction oact;
} rpmsigTbl[] = {
{ SIGINT, rpmsqTerm, NULL },
{ SIGQUIT, rpmsqTerm, NULL },
{ SIGHUP, rpmsqTerm, NULL },
{ SIGTERM, rpmsqTerm, NULL },
{ SIGPIPE, rpmsqTerm, NULL },
{ -1, NULL, NULL },
};
static int rpmsigGet(int signum, struct rpmsig_s **sig)
{
for (rpmsig tbl = rpmsigTbl; tbl->signum >= 0; tbl++) {
if (tbl->signum == signum) {
*sig = tbl;
return 1;
}
}
return 0;
}
int rpmsqIsCaught(int signum)
{
return sigismember(&rpmsqCaught, signum);
}
static void rpmsqHandler(int signum, siginfo_t * info, void * context)
{
int save = errno;
if (sigismember(&rpmsqActive, signum)) {
rpmsig sig = NULL;
(void) sigaddset(&rpmsqCaught, signum);
if (rpmsigGet(signum, &sig))
memcpy(&sig->siginfo, info, sizeof(*info));
}
errno = save;
}
int rpmsqEnable(int signum, rpmsqAction_t handler)
{
int tblsignum = abs(signum);
struct sigaction sa;
rpmsig tbl;
int ret = -1;
if (disableInterruptSafety)
return 0;
for (tbl = rpmsigTbl; tbl->signum >= 0; tbl++) {
if (tblsignum != tbl->signum)
continue;
if (signum >= 0) { /* Enable. */
if (!sigismember(&rpmsqActive, tblsignum)) {
(void) sigdelset(&rpmsqCaught, tbl->signum);
/* XXX Don't set a signal handler if already SIG_IGN */
(void) sigaction(tbl->signum, NULL, &tbl->oact);
if (tbl->oact.sa_handler == SIG_IGN)
continue;
(void) sigemptyset (&sa.sa_mask);
sa.sa_flags = SA_SIGINFO;
sa.sa_sigaction = rpmsqHandler;
if (sigaction(tbl->signum, &sa, &tbl->oact) < 0)
break;
sigaddset(&rpmsqActive, tblsignum);
tbl->handler = (handler != NULL) ? handler : tbl->defhandler;
}
} else { /* Disable. */
if (sigismember(&rpmsqActive, tblsignum)) {
if (sigaction(tbl->signum, &tbl->oact, NULL) < 0)
break;
sigdelset(&rpmsqActive, tblsignum);
tbl->handler = NULL;
}
}
ret = sigismember(&rpmsqActive, tblsignum);
break;
}
return ret;
}
int rpmsqPoll(void)
{
sigset_t newMask, oldMask;
int n = 0;
/* block all signals while processing the queue */
(void) sigfillset(&newMask);
(void) sigprocmask(SIG_BLOCK, &newMask, &oldMask);
for (rpmsig tbl = rpmsigTbl; tbl->signum >= 0; tbl++) {
if (sigismember(&rpmsqCaught, tbl->signum)) {
n++;
/* delete signal before running handler to prevent recursing */
sigdelset(&rpmsqCaught, tbl->signum);
if (tbl->handler) {
tbl->handler(tbl->signum, &tbl->siginfo, NULL);
memset(&tbl->siginfo, 0, sizeof(tbl->siginfo));
}
}
}
sigprocmask(SIG_SETMASK, &oldMask, NULL);
return n;
}
/** \ingroup rpmio
*
* By default, librpm will trap various unix signals such as SIGINT and SIGTERM,
* in order to avoid process exit while locks are held or a transaction is being
* performed. However, there exist tools that operate on non-running roots (traditionally
* build systems such as mock), as well as deployment tools such as rpm-ostree.
*
* These tools are more robust against interruption - typically they
* will just throw away the partially constructed root. This function
* is designed for use by those tools, so an operator can happily
* press Control-C.
*
* It's recommended to call this once only at process startup if this
* behavior is desired (and to then avoid using librpm against "live"
* databases), because currently signal handlers will not be retroactively
* applied if a database is open.
*/
void rpmsqSetInterruptSafety(int on)
{
disableInterruptSafety = !on;
}
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