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1 /*
2  * This file is licensed under the GPL license. For the full content
3  * of this license, see the COPYING file at the top level of this
4  * source tree.
5  */
6 
7 /*
8  * assertion:
9  *  If the array pointed to by s1 is a string that is shorter than n bytes,
10  *  NUL characters will be appended to the copy in the array pointed to
11  *  by s2, until n bytes in all are written
12  *
13  * method:
14  *  -Generate sample string s1 of variable lengths in a loop.
15  *  -Define number of bytes you want to copy,
16  *  which is more than the length of s1.
17  *  -Use strncpy to copy string from s1 to s2.
18  *  -Check whether s2 is appeneded by '\0' after
19  *  writing string s1, till number of bytes given.
20  *  -Repeat the above steps for given number of iterations.
21 */
22 
23 #include <stdio.h>
24 #include <string.h>
25 #include <stdlib.h>
26 #include <unistd.h>
27 #include "posixtest.h"
28 
29 #define STRING_MAX_LEN 50000
30 #define STEP_COUNT 2000
31 #define TNAME "strncpy/2-1.c"
32 #define EXTRA_BYTES 10
33 
random_string(int len)34 char *random_string(int len)
35 {
36     int i;
37     char *output_string;
38     output_string = malloc(len + 1);
39     if (output_string == NULL) {
40         printf(TNAME " Failed to allocate memory\n");
41         exit(PTS_UNRESOLVED);
42     }
43     for (i = 0; i < len; i++)
44         /* Limiting characters from 1-255 */
45         output_string[i] = rand() % 254 + 1;
46     output_string[len] = '\0';
47     return output_string;
48 }
main(void)49 int main(void)
50 {
51     int i, j, c;
52     char *ret_str;
53 
54     for (i = 1; i < STRING_MAX_LEN; i += STEP_COUNT) {
55         c = 0;
56         char *sample_str_1;
57         char *sample_str_2 = malloc(i + EXTRA_BYTES);
58         if (sample_str_2 == NULL) {
59             printf(TNAME " Failed to allocate memory\n");
60             exit(PTS_UNRESOLVED);
61         }
62         sample_str_1 = random_string(i);
63         ret_str = strncpy(sample_str_2, sample_str_1, i + EXTRA_BYTES);
64         sample_str_2[i + EXTRA_BYTES] = '\0';
65 
66         if (strcmp(sample_str_1, sample_str_2) != 0) {
67             printf(TNAME " Test failed, string copy failed. "
68                         "Expected string: %s, But got: %s\n"
69                         , sample_str_1, sample_str_2);
70             exit(PTS_UNRESOLVED);
71         } else if (ret_str != sample_str_2) {
72             printf(TNAME " Test Failed, return is not as expected. "
73                         "Expected return: %p, But obtained: %p\n"
74                         , sample_str_2, ret_str);
75             exit(PTS_FAIL);
76         }
77 
78         for (j = strlen(sample_str_1); j < i + EXTRA_BYTES; j++) {
79             if (sample_str_2[j] == '\0') {
80                 c++;
81             }
82         }
83 
84         if (c != EXTRA_BYTES) {
85             printf(TNAME " Test Failed, The difference in the number of bytes"
86                         " for two strings (s1 and s2) have not been appended"
87                         " with NULL bytes\n");
88             exit(PTS_FAIL);
89         }
90         free(sample_str_1);
91         free(sample_str_2);
92     }
93     printf(TNAME "  Test Passed, The difference in the number of bytes for two "
94                     "strings (s1 and s2) have been appended with NULL bytes in s2\n");
95     exit(PTS_PASS);
96 }
97