1 /* $OpenBSD: pread.c,v 1.4 2011/11/06 15:00:34 guenther Exp $ */ 2 /* 3 * Written by Artur Grabowski <art@openbsd.org> 2002 Public Domain. 4 */ 5 #include <err.h> 6 #include <errno.h> 7 #include <fcntl.h> 8 #include <limits.h> 9 #include <stdio.h> 10 #include <stdlib.h> 11 #include <unistd.h> 12 13 int 14 main(int argc, char *argv[]) 15 { 16 char temp[] = "/tmp/dup2XXXXXXXXX"; 17 const char magic[10] = "0123456789"; 18 char c; 19 int fd, ret; 20 21 if ((fd = mkstemp(temp)) < 0) 22 err(1, "mkstemp"); 23 remove(temp); 24 25 if (write(fd, magic, sizeof(magic)) != sizeof(magic)) 26 err(1, "write"); 27 28 if (lseek(fd, 0, SEEK_SET) != 0) 29 err(1, "lseek"); 30 31 if (read(fd, &c, 1) != 1) 32 err(1, "read1"); 33 34 if (c != magic[0]) 35 errx(1, "read1 %c != %c", c, magic[0]); 36 37 if (pread(fd, &c, 1, 7) != 1) 38 err(1, "pread"); 39 40 if (c != magic[7]) 41 errx(1, "pread %c != %c", c, magic[7]); 42 43 if (read(fd, &c, 1) != 1) 44 err(1, "read2"); 45 46 if (c != magic[1]) 47 errx(1, "read2 %c != %c", c, magic[1]); 48 49 if ((ret = pread(fd, &c, 1, -1)) != -1) 50 errx(1, "pread with negative offset succeeded,\ 51 returning %d", ret); 52 if (errno != EINVAL) 53 err(1, "pread with negative offset"); 54 55 if ((ret = pread(fd, &c, 3, LLONG_MAX)) != -1) 56 errx(1, "pread with wrapping offset succeeded,\ 57 returning %d", ret); 58 if (errno != EINVAL) 59 err(1, "pread with wrapping offset"); 60 61 if (read(fd, &c, 1) != 1) 62 err(1, "read3"); 63 64 if (c != magic[2]) 65 errx(1, "read3 %c != %c", c, magic[2]); 66 67 close(fd); 68 69 /* also, verify that pread fails on ttys */ 70 fd = open("/dev/tty", O_RDWR); 71 if (fd < 0) 72 printf("skipping tty test\n"); 73 else if ((ret = pread(fd, &c, 1, 7)) != -1) 74 errx(1, "pread succeeded on tty, returning %d", ret); 75 else if (errno != ESPIPE) 76 err(1, "pread"); 77 78 return 0; 79 } 80