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/* ISC license. */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <sys/socket.h>
#include <linux/netlink.h>
#include <skalibs/types.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/siovec.h>
#include <skalibs/buffer.h>
#include <skalibs/sgetopt.h>
#include <skalibs/error.h>
#include <skalibs/strerr2.h>
#include <skalibs/iopause.h>
#include <skalibs/djbunix.h>
#include <skalibs/sig.h>
#include <skalibs/selfpipe.h>
#define USAGE "s6-uevent-listener [ -v verbosity ] [ -b kbufsz ]"
#define dieusage() strerr_dieusage(100, USAGE)
#define dienomem() strerr_diefu1sys(111, "build string") ;
#define MAXNLSIZE 4096
static unsigned int cont = 1, verbosity = 1 ;
static inline ssize_t fd_recvmsg (int fd, struct msghdr *hdr)
{
ssize_t r ;
do r = recvmsg(fd, hdr, MSG_DONTWAIT) ;
while ((r == -1) && (errno == EINTR)) ;
return r ;
}
static inline int netlink_init_stdin (unsigned int kbufsz)
{
struct sockaddr_nl nl = { .nl_family = AF_NETLINK, .nl_pad = 0, .nl_groups = 1, .nl_pid = 0 } ;
close(0) ;
return socket_internal(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT, DJBUNIX_FLAG_NB|DJBUNIX_FLAG_COE) == 0
&& bind(0, (struct sockaddr *)&nl, sizeof(struct sockaddr_nl)) == 0
&& setsockopt(0, SOL_SOCKET, SO_RCVBUFFORCE, &kbufsz, sizeof(unsigned int)) == 0 ;
}
static inline void handle_signals (void)
{
for (;;)
{
int c = selfpipe_read() ;
switch (c)
{
case -1 : strerr_diefu1sys(111, "selfpipe_read") ;
case 0 : return ;
case SIGTERM :
cont = 0 ;
fd_close(0) ;
break ;
default :
strerr_dief1x(101, "internal error: inconsistent signal state. Please submit a bug-report.") ;
}
}
}
static inline void handle_stdout (void)
{
if (!buffer_flush(buffer_1) && !error_isagain(errno))
strerr_diefu1sys(111, "flush stdout") ;
}
static inline void handle_netlink (void)
{
struct sockaddr_nl nl;
struct iovec v[2] ;
struct msghdr msg =
{
.msg_name = &nl,
.msg_namelen = sizeof(struct sockaddr_nl),
.msg_iov = v,
.msg_iovlen = 2,
.msg_control = 0,
.msg_controllen = 0,
.msg_flags = 0
} ;
ssize_t r ;
buffer_wpeek(buffer_1, v) ;
siovec_trunc(v, 2, siovec_len(v, 2) - 1) ;
r = sanitize_read(fd_recvmsg(0, &msg)) ;
if (r < 0)
{
if (errno == EPIPE)
{
if (verbosity >= 2) strerr_warnw1x("received EOF on netlink") ;
cont = 0 ;
fd_close(0) ;
return ;
}
else strerr_diefu1sys(111, "receive netlink message") ;
}
if (!r) return ;
if (msg.msg_flags & MSG_TRUNC)
strerr_diefu2x(111, "buffer too small for ", "netlink message") ;
if (nl.nl_pid)
{
if (verbosity >= 3)
{
char fmt[PID_FMT] ;
fmt[pid_fmt(fmt, nl.nl_pid)] = 0 ;
strerr_warnw3x("netlink message", " from userspace process ", fmt) ;
}
return ;
}
buffer_wseek(buffer_1, r) ;
buffer_putnoflush(buffer_1, "", 1) ;
}
int main (int argc, char const *const *argv, char const *const *envp)
{
iopause_fd x[3] = { { .events = IOPAUSE_READ }, { .fd = 1 }, { .fd = 0 } } ;
PROG = "s6-uevent-listener" ;
strerr_warnw1x("this program is deprecated, see https://skarnet.org/software/mdevd/") ;
{
unsigned int kbufsz = 65536 ;
subgetopt_t l = SUBGETOPT_ZERO ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "v:b:", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
case 'b' : if (!uint0_scan(l.arg, &kbufsz)) dieusage() ; break ;
default : dieusage() ;
}
}
argc -= l.ind ; argv += l.ind ;
if (!netlink_init_stdin(kbufsz)) strerr_diefu1sys(111, "init netlink") ;
}
x[0].fd = selfpipe_init() ;
if (x[0].fd < 0) strerr_diefu1sys(111, "init selfpipe") ;
if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
if (selfpipe_trap(SIGTERM) < 0) strerr_diefu1sys(111, "trap SIGTERM") ;
if (verbosity >= 2) strerr_warni1x("starting") ;
while (cont || buffer_len(buffer_1))
{
int r ;
x[1].events = buffer_len(buffer_1) ? IOPAUSE_WRITE : 0 ;
x[2].events = buffer_available(buffer_1) >= MAXNLSIZE + 1 ? IOPAUSE_READ : 0 ;
r = iopause(x, 2 + cont, 0, 0) ;
if (r < 0) strerr_diefu1sys(111, "iopause") ;
if (!r) continue ;
if (x[1].revents & IOPAUSE_EXCEPT) break ;
if (x[1].revents & IOPAUSE_WRITE) handle_stdout() ;
if (x[0].revents & (IOPAUSE_READ | IOPAUSE_EXCEPT)) handle_signals() ;
if (cont && x[2].events & IOPAUSE_READ && x[2].revents & (IOPAUSE_READ | IOPAUSE_EXCEPT))
handle_netlink() ;
}
if (verbosity >= 2) strerr_warni1x("exiting") ;
return 0 ;
}
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