Red Bear OS
1b3e94a20d
From release 0.1.0 pre-patched archive. This includes all Red Bear modifications previously maintained as patches in local/patches/relibc/.
77 lines
2.1 KiB
C
77 lines
2.1 KiB
C
//http://www2.cs.uregina.ca/~hamilton/courses/330/notes/unix/pipes/pipes.html
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "test_helpers.h"
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int main(void) {
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int pip[2];
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char instring[20];
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char *outstring = "Hello World!";
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int pipe_status = pipe(pip);
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ERROR_IF(pipe, pipe_status, == -1);
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UNEXP_IF(pipe, pipe_status, != 0);
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int pid = fork();
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ERROR_IF(fork, pid, == -1);
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if (pid == 0) {
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// child: sends message to parent
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// close read end
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int cr = close(pip[0]);
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ERROR_IF(close, cr, == -1);
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UNEXP_IF(close, cr, != 0);
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// send 7 characters in the string, including end-of-string
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ssize_t bytes = write(pip[1], outstring, strlen(outstring));
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ERROR_IF(write, bytes, == -1);
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// check result
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if ((size_t)bytes != strlen(outstring)) {
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fprintf(stderr, "pipe write: %d != %ld\n", bytes, strlen(outstring));
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exit(EXIT_FAILURE);
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}
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// close write end
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int cw = close(pip[1]);
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ERROR_IF(close, cw, == -1);
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UNEXP_IF(close, cw, != 0);
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exit(EXIT_SUCCESS);
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} else {
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// parent: receives message from child
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// close write end
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int cw = close(pip[1]);
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ERROR_IF(close, cw, == -1);
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UNEXP_IF(close, cw, != 0);
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// clear memory
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memset(instring, 0, sizeof(instring));
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// read from the pipe
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ssize_t bytes = read(pip[0], instring, sizeof(instring) - 1);
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ERROR_IF(read, bytes, == -1);
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// check result
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if ((size_t)bytes != strlen(outstring)) {
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fprintf(stderr, "pipe read: %d != %ld\n", bytes, strlen(outstring));
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exit(EXIT_FAILURE);
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} else if (memcmp(instring, outstring, strlen(outstring)) != 0) {
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fprintf(stderr, "pipe read does not match pipe write\n");
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exit(EXIT_FAILURE);
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} else {
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printf("%s\n", instring);
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}
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// close read end
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int cr = close(pip[0]);
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ERROR_IF(close, cr, == -1);
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UNEXP_IF(close, cr, != 0);
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exit(EXIT_SUCCESS);
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}
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}
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