1 /* 2 * Copyright (c) 2006 Darren Tucker 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15 */ 16 17 #include <sys/types.h> 18 #include <sys/stat.h> 19 20 #include <fcntl.h> 21 #include <stdio.h> 22 #include <stdlib.h> 23 #include <unistd.h> 24 25 #define NUM_OPENS 10 26 27 int closefrom(int); 28 29 void 30 fail(char *msg) 31 { 32 fprintf(stderr, "closefrom: %s\n", msg); 33 exit(1); 34 } 35 36 int 37 main(void) 38 { 39 int i, max, fds[NUM_OPENS]; 40 char buf[512]; 41 42 for (i = 0; i < NUM_OPENS; i++) 43 if ((fds[i] = open("/dev/null", O_RDONLY)) == -1) 44 exit(0); /* can't test */ 45 max = i - 1; 46 47 /* should close last fd only */ 48 closefrom(fds[max]); 49 if (close(fds[max]) != -1) 50 fail("failed to close highest fd"); 51 52 /* make sure we can still use remaining descriptors */ 53 for (i = 0; i < max; i++) 54 if (read(fds[i], buf, sizeof(buf)) == -1) 55 fail("closed descriptors it should not have"); 56 57 /* should close all fds */ 58 closefrom(fds[0]); 59 for (i = 0; i < NUM_OPENS; i++) 60 if (close(fds[i]) != -1) 61 fail("failed to close from lowest fd"); 62 return 0; 63 } 64