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      1 /*
      2  * Copyright (c) International Business Machines  Corp., 2001
      3  *   07/2001 Ported by Wayne Boyer
      4  *
      5  * This program is free software;  you can redistribute it and/or modify
      6  * it under the terms of the GNU General Public License as published by
      7  * the Free Software Foundation; either version 2 of the License, or
      8  * (at your option) any later version.
      9  *
     10  * This program is distributed in the hope that it will be useful,
     11  * but WITHOUT ANY WARRANTY;  without even the implied warranty of
     12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
     13  * the GNU General Public License for more details.
     14  */
     15 
     16 /*
     17  * Test Description :
     18  *   Testcase to check the basic functionality of the readlink(2),
     19  *   readlink() will succeed to read the contents of the symbolic link.
     20  */
     21 
     22 #include <pwd.h>
     23 #include <errno.h>
     24 #include <string.h>
     25 
     26 #include "tst_test.h"
     27 
     28 #define TESTFILE "test_file"
     29 #define SYMFILE	"slink_file"
     30 
     31 static uid_t nobody_uid;
     32 
     33 static void test_readlink(void)
     34 {
     35 	char buffer[256];
     36 	int exp_val = strlen(TESTFILE);
     37 
     38 	TEST(readlink(SYMFILE, buffer, sizeof(buffer)));
     39 	if (TST_RET == -1) {
     40 		tst_res(TFAIL | TTERRNO, "readlink() on %s failed", SYMFILE);
     41 		return;
     42 	}
     43 
     44 	if (TST_RET != exp_val) {
     45 		tst_res(TFAIL, "readlink() returned value %ld "
     46 			"did't match, Expected %d", TST_RET, exp_val);
     47 		return;
     48 	}
     49 
     50 	if (memcmp(buffer, TESTFILE, exp_val) != 0) {
     51 		tst_res(TFAIL, "Pathname %s and buffer contents %s differ",
     52 			TESTFILE, buffer);
     53 	} else {
     54 		tst_res(TPASS, "readlink() functionality on '%s' was correct",
     55 			SYMFILE);
     56 	}
     57 }
     58 
     59 static void verify_readlink(unsigned int n)
     60 {
     61 	pid_t pid;
     62 
     63 	if (n) {
     64 		tst_res(TINFO, "Running test as nobody");
     65 		pid = SAFE_FORK();
     66 
     67 		if (!pid) {
     68 			SAFE_SETUID(nobody_uid);
     69 			test_readlink();
     70 			return;
     71 		}
     72 	} else {
     73 		tst_res(TINFO, "Running test as root");
     74 		test_readlink();
     75 	}
     76 }
     77 
     78 static void setup(void)
     79 {
     80 	int fd;
     81 	struct passwd *pw;
     82 
     83 	pw = SAFE_GETPWNAM("nobody");
     84 
     85 	nobody_uid = pw->pw_uid;
     86 
     87 	fd = SAFE_OPEN(TESTFILE, O_RDWR | O_CREAT, 0444);
     88 	SAFE_CLOSE(fd);
     89 	SAFE_SYMLINK(TESTFILE, SYMFILE);
     90 }
     91 
     92 static struct tst_test test = {
     93 	.test = verify_readlink,\
     94 	.tcnt = 2,
     95 	.setup = setup,
     96 	.forks_child = 1,
     97 	.needs_root = 1,
     98 	.needs_tmpdir = 1,
     99 };
    100