| /* | |
| #progos: linux | |
| #output: got: a\nthen: bc\nexit: 0\n | |
| */ | |
| /* This is a very limited subset of what ex1.c does; we just check that | |
| thread creation (clone syscall) and pipe writes and reads work. */ | |
| #include <stddef.h> | |
| #include <stdio.h> | |
| #include <stdlib.h> | |
| #include <unistd.h> | |
| #include <sched.h> | |
| #include <signal.h> | |
| #include <sys/types.h> | |
| #include <sys/wait.h> | |
| int pip[2]; | |
| int | |
| process (void *arg) | |
| { | |
| char *s = arg; | |
| if (write (pip[1], s+2, 1) != 1) abort (); | |
| if (write (pip[1], s+1, 1) != 1) abort (); | |
| if (write (pip[1], s, 1) != 1) abort (); | |
| return 0; | |
| } | |
| int | |
| main (void) | |
| { | |
| int retcode; | |
| int pid; | |
| int st; | |
| long stack[16384]; | |
| char buf[10] = {0}; | |
| retcode = pipe (pip); | |
| if (retcode != 0) | |
| { | |
| fprintf (stderr, "Bad pipe %d\n", retcode); | |
| abort (); | |
| } | |
| pid = clone (process, (char *) stack + sizeof (stack) - 64, | |
| (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND) | |
| | SIGCHLD, "cba"); | |
| if (pid <= 0) | |
| { | |
| fprintf (stderr, "Bad clone %d\n", pid); | |
| abort (); | |
| } | |
| if ((retcode = read (pip[0], buf, 1)) != 1) | |
| { | |
| fprintf (stderr, "Bad read 1: %d\n", retcode); | |
| abort (); | |
| } | |
| printf ("got: %c\n", buf[0]); | |
| retcode = read (pip[0], buf, 2); | |
| if (retcode == 1) | |
| { | |
| retcode = read (pip[0], buf+1, 1); | |
| if (retcode != 1) | |
| { | |
| fprintf (stderr, "Bad read 1.5: %d\n", retcode); | |
| abort (); | |
| } | |
| retcode = 2; | |
| } | |
| if (retcode != 2) | |
| { | |
| fprintf (stderr, "Bad read 2: %d\n", retcode); | |
| abort (); | |
| } | |
| printf ("then: %s\n", buf); | |
| retcode = wait4 (-1, &st, WNOHANG | __WCLONE, NULL); | |
| if (retcode != pid || !WIFEXITED (st)) | |
| { | |
| fprintf (stderr, "Bad wait %d %x\n", retcode, st); | |
| abort (); | |
| } | |
| printf ("exit: %d\n", WEXITSTATUS (st)); | |
| return 0; | |
| } |