2 * Copyright (c) 1995 - 2000 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
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7 * modification, are permitted provided that the following conditions
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11 * notice, this list of conditions and the following disclaimer.
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14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
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41 #include <sys/types.h>
50 child(const char *filename)
55 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
57 err(1, "open %s", filename);
58 ret = write(fd, "hej", 3);
60 err(1, "write %s", filename);
65 parent(const char *filename, pid_t child_pid)
73 ret = waitpid(child_pid, &stat, 0);
75 err(1, "waitpid %u", (unsigned)child_pid);
76 if (!WIFEXITED(stat) || WEXITSTATUS(stat) != 0)
77 errx(1, "weird child %u", (unsigned)child_pid);
78 fd = open(filename, O_RDONLY, 0);
80 err(1, "open %s", filename);
83 err(1, "fstat %s", filename);
85 errx(1, "size of %s = %u != 3", filename, (unsigned)sb.st_size);
86 ret = read(fd, buf, sizeof(buf));
88 err(1, "read %s", filename);
90 errx(1, "short read from %s", filename);
91 if (memcmp(buf, "hej", 3) != 0)
92 errx(1, "bad contents of %s = `%.3s'\n", filename, buf);
98 doit(const char *filename)
107 return child(filename);
109 return parent(filename, pid);
113 main(int argc, char **argv)
115 const char *file = "foo";
118 if (argc != 2 && argc != 1)
119 errx(1, "usage: %s [file]", argv[0]);