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/* ISC license. */
#include <skalibs/nonposix.h> /* for SKALIBS_NSIG to work */
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <skalibs/sgetopt.h>
#include <skalibs/types.h>
#include <skalibs/nsig.h>
#include <skalibs/sig.h>
#include <skalibs/strerr2.h>
#include <skalibs/iopause.h>
#include <skalibs/selfpipe.h>
#include <skalibs/env.h>
#include <skalibs/djbunix.h>
#include <execline/execline.h>
#define USAGE "trap [ -x ] { signal { cmdline } ... } prog..."
#define dieusage() strerr_dieusage(100, USAGE) ;
static pid_t pids[SKALIBS_NSIG + 1] ;
static char const *const *argvs[SKALIBS_NSIG] ; /* initted with 0s */
static inline void action (unsigned int i, char const *const *envp, size_t envlen)
{
if (argvs[i])
{
if (!pids[i])
{
char const *newenvp[envlen + 3] ;
char modif[9 + PID_FMT + UINT_FMT] = "!=" ;
size_t m = 2 ;
m += pid_fmt(modif + m, pids[SKALIBS_NSIG]) ;
modif[m++] = 0 ;
memcpy(modif + m, "SIGNAL=", 7) ; m += 7 ;
m += uint_fmt(modif + m, i) ;
modif[m++] = 0 ;
if (!env_merge(newenvp, envlen + 3, envp, envlen, modif, m))
strerr_diefu1sys(111, "adjust environment for child") ;
pids[i] = child_spawn0(argvs[i][0], argvs[i], newenvp) ;
if (!pids[i]) strerr_diefu2sys(111, "spawn ", argvs[i][0]) ;
}
}
else kill(pids[SKALIBS_NSIG], i) ;
}
int main (int argc, char const **argv, char const *const *envp)
{
size_t envlen = env_len(envp) ;
iopause_fd x = { .events = IOPAUSE_READ } ;
sigset_t set ;
int xfersigs = 0 ;
unsigned int argc1 ;
unsigned int i = 0 ;
PROG = "trap" ;
{
subgetopt_t l = SUBGETOPT_ZERO ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "xt:", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'x' : xfersigs = 1 ; break ;
default : dieusage() ;
}
}
argc -= l.ind ; argv += l.ind ;
}
if (!argc) dieusage() ;
argc1 = el_semicolon(argv) ;
if (!argc1) strerr_dief1x(100, "empty block") ;
if (argc1 >= argc) strerr_dief1x(100, "unterminated block") ;
if (argc1 + 1 == argc) dieusage() ;
argv[argc1] = 0 ;
while (i < argc1)
{
unsigned int argc2 ;
int sig = 0 ;
if (!sig0_scan(argv[i], &sig) && strcasecmp(argv[i], "default"))
strerr_dief3x(100, "unrecognized", " directive: ", argv[i]) ;
argc2 = el_semicolon(argv + ++i) ;
if (i + argc2 >= argc1)
strerr_dief3x(100, "unterminated", " internal block for directive ", argv[i-1]) ;
if (argvs[sig])
strerr_dief3x(100, "duplicate", " directive: ", argv[i-1]) ;
switch (sig)
{
case SIGCHLD : strerr_dief2x(100, "SIGCHLD", " cannot be trapped") ;
case SIGKILL : strerr_dief2x(100, "SIGKILL", " cannot be trapped") ;
case SIGSTOP : strerr_dief2x(100, "SIGSTOP", " cannot be trapped") ;
default :
argvs[sig] = argv + i ;
break ;
}
argv[i + argc2] = 0 ;
i += argc2 + 1 ;
}
if (argvs[0])
for (i = 1 ; i < SKALIBS_NSIG ; i++)
if (!argvs[i])
argvs[i] = argvs[0] ;
if (xfersigs)
{
sigfillset(&set) ;
sigdelset(&set, SIGCHLD) ;
sigdelset(&set, SIGKILL) ;
sigdelset(&set, SIGSTOP) ;
}
else
{
sigemptyset(&set) ;
for (i = 1 ; i < SKALIBS_NSIG ; i++)
if (argvs[i])
sigaddset(&set, i) ;
}
x.fd = selfpipe_init() ;
if (x.fd < 0) strerr_diefu1sys(111, "selfpipe_init") ;
if (selfpipe_trapset(&set) < 0) strerr_diefu1sys(111, "trap signals") ;
pids[SKALIBS_NSIG] = child_spawn0(argv[argc1 + 1], argv + argc1 + 1, envp) ;
if (!pids[SKALIBS_NSIG]) strerr_diefu2sys(111, "spawn ", argv[argc1 + 1]) ;
loop:
if (iopause_g(&x, 1, 0) < 0) strerr_diefu1sys(111, "iopause") ;
for (;;)
{
int r = selfpipe_read() ;
switch (r)
{
case -1 : strerr_diefu1sys(111, "selfpipe_read") ;
case 0 : goto loop ;
case SIGCHLD :
for (;;)
{
int wstat ;
ssize_t id = wait_pids_nohang(pids, SKALIBS_NSIG + 1, &wstat) ;
if (id < 0 && errno != ECHILD)
strerr_diefu1sys(111, "wait") ;
if (id <= 0) break ;
pids[id - 1] = 0 ;
if (id == SKALIBS_NSIG + 1) return wait_estatus(wstat) ;
}
break ;
default :
action(r, envp, envlen) ;
}
}
}
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