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70 lines
1.5 KiB
70 lines
1.5 KiB
#include <common.h>
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int main(int argc, char **argv)
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{
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int pfds[2];
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int ret = pipe(pfds);
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char *msg1 = "hello, sonny!";
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char *msg2 = "hello, laddy!";
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const int msglen = strlen(msg1) + 1;
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if (ret < 0)
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err(ret, "pipe");
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printf("pipe fds: %d %d\n", pfds[0], pfds[1]);
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int child = 0;
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int status;
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int pid1 = fork();
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int pid2 = fork();
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if (pid1 == 0)
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child = 1;
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if (child) {
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close(pfds[1]);
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char buf[msglen];
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ret = read(pfds[0], buf, sizeof(buf));
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if (ret < 0)
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err(ret, "read");
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printf("got: %s\n", buf);
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if (ret != msglen)
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errx(-1, "only read %d of %d bytes\n", ret, msglen);
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if (pid2 != 0) {
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if ((ret = wait(&status)) < 0)
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err(ret, "wait1");
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if (WEXITSTATUS(status) != 0)
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errx(status, "child child failed %d", status);
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}
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return 0;
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}
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close(pfds[0]);
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char *msg = (pid2 == 0) ? msg1 : msg2;
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printf("sending: %s\n", msg);
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ret = write(pfds[1], msg, msglen);
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printf("sent\n");
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if (ret < 0)
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err(ret, "write");
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if (ret != msglen)
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errx(-1, "only wrote %d of %d bytes\n", ret, msglen);
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if (pid2 == 0)
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return 0;
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if ((ret = wait(&status)) < 0)
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err(ret, "wait2");
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if (WEXITSTATUS(status) != 0)
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err(status, "parent child failed %d", status);
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if ((ret = wait(&status)) < 0)
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err(ret, "wait3");
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if (WEXITSTATUS(status) != 0)
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err(status, "parent child2 failed %d", status);
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// try write on pipe with no readers
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if ((ret = write(pfds[1], "fail", 4) >= 0))
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errx(-1, "write should have failed %d", ret);
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printf("success\n");
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return 0;
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}
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