144 lines
2.9 KiB
C
144 lines
2.9 KiB
C
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/* Check that closing a pipe with a nonempty buffer works.
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#progos: linux
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#output: got: a\ngot: b\nexit: 0\n
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*/
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#include <stddef.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <limits.h>
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#include <unistd.h>
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#include <sched.h>
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#include <signal.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <string.h>
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int pip[2];
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int pipemax;
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int
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process (void *arg)
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{
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char *s = arg;
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int lots = pipemax + 256;
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char *buf = malloc (lots);
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int ret;
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if (buf == NULL)
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abort ();
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*buf = *s;
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/* The first write should go straight through. */
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if (write (pip[1], buf, 1) != 1)
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abort ();
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*buf = s[1];
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/* The second write may or may not be successful for the whole
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write, but should be successful for at least the pipemax part.
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As linux/limits.h clamps PIPE_BUF to 4096, but the page size is
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actually 8k, we can get away with that much. There should be no
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error, though. Doing this on host shows that for
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x86_64-unknown-linux-gnu (2.6.14-1.1656_FC4) pipemax * 10 can be
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successfully written, perhaps for similar reasons. */
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ret = write (pip[1], buf, lots);
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if (ret < pipemax)
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{
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fprintf (stderr, "ret: %d, %s, %d\n", ret, strerror (errno), pipemax);
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fflush (0);
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abort ();
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}
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return 0;
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}
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int
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main (void)
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{
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int retcode;
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int pid;
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int st = 0;
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long stack[16384];
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char buf[1];
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/* We need to turn this off because we don't want (to have to model) a
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SIGPIPE resulting from the close. */
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if (signal (SIGPIPE, SIG_IGN) != SIG_DFL)
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abort ();
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retcode = pipe (pip);
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if (retcode != 0)
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{
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fprintf (stderr, "Bad pipe %d\n", retcode);
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abort ();
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}
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#ifdef PIPE_MAX
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pipemax = PIPE_MAX;
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#else
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pipemax = fpathconf (pip[1], _PC_PIPE_BUF);
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#endif
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if (pipemax <= 0)
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{
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fprintf (stderr, "Bad pipemax %d\n", pipemax);
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abort ();
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}
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pid = clone (process, (char *) stack + sizeof (stack) - 64,
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(CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND)
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| SIGCHLD, "ab");
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if (pid <= 0)
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{
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fprintf (stderr, "Bad clone %d\n", pid);
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abort ();
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}
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while ((retcode = read (pip[0], buf, 1)) == 0)
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;
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if (retcode != 1)
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{
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fprintf (stderr, "Bad read 1: %d\n", retcode);
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abort ();
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}
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printf ("got: %c\n", buf[0]);
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/* Need to read out something from the second write too before
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closing, or the writer can get EPIPE. */
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while ((retcode = read (pip[0], buf, 1)) == 0)
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;
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if (retcode != 1)
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{
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fprintf (stderr, "Bad read 2: %d\n", retcode);
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abort ();
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}
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printf ("got: %c\n", buf[0]);
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if (close (pip[0]) != 0)
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{
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perror ("pip close");
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abort ();
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}
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retcode = waitpid (pid, &st, __WALL);
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if (retcode != pid || !WIFEXITED (st))
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{
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fprintf (stderr, "Bad wait %d:%d %x\n", pid, retcode, st);
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perror ("errno");
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abort ();
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}
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printf ("exit: %d\n", WEXITSTATUS (st));
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return 0;
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}
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