10 #define T1 "write data before unlink\n"
11 #define T2 "write data after unlink\n"
14 int main(int argc, char **argv)
20 if (argc < 2 || argc > 3) {
21 fprintf(stderr, "usage: %s filename [filename2]\n", argv[0]);
31 fprintf(stderr, "opening\n");
32 fd = open(fname, O_RDWR | O_TRUNC | O_CREAT, 0644);
34 fprintf(stderr, "open (normal) %s\n", strerror(errno));
38 fprintf(stderr, "writing\n");
39 rc = write(fd, T1, strlen(T1) + 1);
40 if (rc != strlen(T1) + 1) {
41 fprintf(stderr, "write (normal) %s (rc %d)\n",
47 fprintf(stderr, "closing %s\n", fname);
50 fprintf(stderr, "close (normal) %s\n", strerror(errno));
54 fprintf(stderr, "opening %s\n", fname2);
55 fd = open(fname2, O_RDWR);
57 fprintf(stderr, "open (unlink) %s\n", strerror(errno));
61 fprintf (stderr, "unlinking %s\n", fname2);
64 fprintf(stderr, "unlink %s\n", strerror(errno));
68 if (access(fname2, F_OK) == 0) {
69 fprintf(stderr, "%s still exists\n", fname2);
73 fprintf(stderr, "resetting fd offset\n");
74 rc = lseek(fd, 0, SEEK_SET);
76 fprintf(stderr, "seek %s\n", strerror(errno));
80 printf("unlink %s and press enter\n", fname);
84 if (access(fname, F_OK) == 0) {
85 fprintf(stderr, "%s still exists\n", fname);
89 fprintf(stderr, "fstating\n");
92 fprintf(stderr, "fstat (unlink) %s\n", strerror(errno));
96 fprintf(stderr, "st_nlink = %d\n", (int)st.st_nlink);
98 fprintf(stderr, "reading\n");
99 rc = read(fd, buf, strlen(T1) + 1);
100 if (rc != strlen(T1) + 1) {
101 fprintf(stderr, "read (unlink) %s (rc %d)\n",
102 strerror(errno), rc);
106 fprintf(stderr, "comparing data\n");
107 if (memcmp(buf, T1, strlen(T1) + 1) ) {
108 fprintf(stderr, "FAILURE: read wrong data after unlink\n");
112 fprintf(stderr, "truncating\n");
113 rc = ftruncate(fd, 0);
115 fprintf(stderr, "truncate (unlink) %s\n", strerror(errno));
119 fprintf(stderr, "seeking\n");
120 rc = lseek(fd, 0, SEEK_SET);
122 fprintf(stderr, "seek (after unlink trunc) %s\n",
127 fprintf(stderr, "writing again\n");
128 rc = write(fd, T2, strlen(T2) + 1);
129 if (rc != strlen(T2) + 1) {
130 fprintf(stderr, "write (after unlink trunc) %s (rc %d)\n",
131 strerror(errno), rc);
135 fprintf(stderr, "seeking\n");
136 rc = lseek(fd, 0, SEEK_SET);
138 fprintf(stderr, "seek (before unlink read) %s\n",
143 fprintf(stderr, "reading again\n");
144 rc = read(fd, buf, strlen(T2) + 1);
145 if (rc != strlen(T2) + 1) {
146 fprintf(stderr, "read (after unlink rewrite) %s (rc %d)\n",
147 strerror(errno), rc);
151 fprintf(stderr, "comparing data again\n");
152 if (memcmp(buf, T2, strlen(T2) + 1)) {
153 fprintf(stderr, "FAILURE: read wrong data after rewrite\n");
157 fprintf(stderr, "closing\n");
160 fprintf(stderr, "close (unlink) %s\n", strerror(errno));
164 fprintf(stderr, "SUCCESS - goto beer\n");