1#include <dirent.h>
2#include <fcntl.h>
3#include <stdio.h>
4#include <stdlib.h>
5#include <string.h>
6#include <unistd.h>
7#include <sys/stat.h>
8
9
10static void prepare (void);
11#define PREPARE(argc, argv) prepare ()
12
13static int do_test (void);
14#define TEST_FUNCTION do_test ()
15
16#include "../test-skeleton.c"
17
18static int dir_fd;
19
20static void
21prepare (void)
22{
23 size_t test_dir_len = strlen (test_dir);
24 static const char dir_name[] = "/tst-symlinkat.XXXXXX";
25
26 size_t dirbuflen = test_dir_len + sizeof (dir_name);
27 char *dirbuf = malloc (size: dirbuflen);
28 if (dirbuf == NULL)
29 {
30 puts (s: "out of memory");
31 exit (1);
32 }
33
34 snprintf (s: dirbuf, maxlen: dirbuflen, format: "%s%s", test_dir, dir_name);
35 if (mkdtemp (template: dirbuf) == NULL)
36 {
37 puts (s: "cannot create temporary directory");
38 exit (1);
39 }
40
41 add_temp_file (name: dirbuf);
42
43 dir_fd = open (file: dirbuf, O_RDONLY | O_DIRECTORY);
44 if (dir_fd == -1)
45 {
46 puts (s: "cannot open directory");
47 exit (1);
48 }
49}
50
51
52static int
53do_test (void)
54{
55 /* fdopendir takes over the descriptor, make a copy. */
56 int dupfd = dup (fd: dir_fd);
57 if (dupfd == -1)
58 {
59 puts (s: "dup failed");
60 return 1;
61 }
62 if (lseek (fd: dupfd, offset: 0, SEEK_SET) != 0)
63 {
64 puts (s: "1st lseek failed");
65 return 1;
66 }
67
68 /* The directory should be empty safe the . and .. files. */
69 DIR *dir = fdopendir (fd: dupfd);
70 if (dir == NULL)
71 {
72 puts (s: "fdopendir failed");
73 return 1;
74 }
75 struct dirent64 *d;
76 while ((d = readdir64 (dirp: dir)) != NULL)
77 if (strcmp (d->d_name, ".") != 0 && strcmp (d->d_name, "..") != 0)
78 {
79 printf (format: "temp directory contains file \"%s\"\n", d->d_name);
80 return 1;
81 }
82 closedir (dirp: dir);
83
84 static const char symlinkcontent[] = "some-file";
85 if (symlinkat (from: symlinkcontent, tofd: dir_fd, to: "another-file") != 0)
86 {
87 puts (s: "symlinkat failed");
88 return 1;
89 }
90
91 struct stat64 st2;
92 if (fstatat64 (fd: dir_fd, file: "another-file", buf: &st2, AT_SYMLINK_NOFOLLOW) != 0)
93 {
94 puts (s: "fstatat64 failed");
95 return 1;
96 }
97 if (!S_ISLNK (st2.st_mode))
98 {
99 puts (s: "2nd fstatat64 does not show file is a symlink");
100 return 1;
101 }
102
103 if (fstatat64 (fd: dir_fd, file: symlinkcontent, buf: &st2, AT_SYMLINK_NOFOLLOW) == 0)
104 {
105 puts (s: "2nd fstatat64 succeeded");
106 return 1;
107 }
108
109 char buf[100];
110 int n = readlinkat (dir_fd, "another-file", buf, sizeof (buf));
111 if (n == -1)
112 {
113 puts (s: "readlinkat failed");
114 return 1;
115 }
116 if (n != sizeof (symlinkcontent) - 1)
117 {
118 printf (format: "readlinkat returned %d, expected %zu\n",
119 n, sizeof (symlinkcontent) - 1);
120 return 1;
121 }
122 if (strncmp (buf, symlinkcontent, n) != 0)
123 {
124 puts (s: "readlinkat retrieved wrong link content");
125 return 1;
126 }
127
128 if (unlinkat (fd: dir_fd, name: "another-file", flag: 0) != 0)
129 {
130 puts (s: "unlinkat failed");
131 return 1;
132 }
133
134 close (fd: dir_fd);
135
136 return 0;
137}
138

source code of glibc/io/tst-readlinkat.c