Trattazione di linkat e openat con O_TMPFILE, con programmi di test ed

[gapil.git] / sources / test_linkat.c

diff --git a/sources/test_linkat.c b/sources/test_linkat.c
index 6931cd7c3ef2d40265e69e24e6ba0a178d6563fc..fbc06dc0881963d11835ddc10bbf1e560eaa2795 100644 (file)
--- a/sources/test_linkat.c
+++ b/sources/test_linkat.c
@@ -19,7 +19,9 @@
 /****************************************************************
  *
  * Program test_linkat.c: 
- * Program to test use of linkat and O_TMPFILE and other combinations 
+ * Program to test use of linkat with an O_TMPFILE or linking another file 
+ * using AT_EMPTY_PATH or AT_SYMLINK_FOLLOW on /proc/self/fd/N
+ * giving the option to wait to remove source file
  *
  * Author: Simone Piccardi
  * Oct. 2018
@@ -42,6 +44,7 @@
 #include <sys/types.h>
 #include <fcntl.h>
 
+
 /* Help printing routine */
 void usage(void);
 
@@ -95,13 +98,15 @@ int main(int argc, char *argv[])
     }
     char *path, *dir, *file;
     char pattern[] = "prova prova prova\n";
+    char outbuff[2048];
     path = strdup(argv[optind]);
     file = basename(argv[optind]);
     dir = dirname(argv[optind]);
-    printf("Working on dir %s file: %s\nwith path: %s\n",
+    printf("Destination on dir %s file: %s\n            with path: %s\n",
           dir, file, path);
     int fd, newfd;
     if ( ! srcfile ) {
+       // temp file with O_TMPFILE
        fd = open(dir, O_TMPFILE|O_RDWR,S_IRUSR|S_IWUSR);
        if ( fd <= 0 )
            perror("cannot open TMPFILE");
@@ -110,28 +115,32 @@ int main(int argc, char *argv[])
        else
            printf("saved %d chars on fd %d\n", i, fd);
     } else {
-       printf("source is %s\n", srcfile);
+       // user provided source
+       printf("source file is %s\n", srcfile);
        if ( (fd = open(srcfile, O_RDONLY)) < 0 ) {
            perror("cannot open source");
            exit(1);
        }
+       printf("waiting %d second to remove the file\n", wait);
+       sleep(wait);
     }
     newfd = open(dir, O_PATH|O_RDWR);
     int err;
     err = linkat(fd, "", newfd, file, AT_EMPTY_PATH);
     if ( err < 0  ) {
-       perror("error on creating TMPFILE");
-       printf("cannot link fd %d on fd %d, %s with AT_EMPTY_PATH\n",
+       perror("error on creating TMPFILE with AT_EMPTY_PATH");
+       printf("cannot link fd %d on fd %d/%s with AT_EMPTY_PATH\n",
               fd, newfd, file);
        char fdpath[PATH_MAX];
        snprintf(fdpath, PATH_MAX, "/proc/self/fd/%d", fd);
-       printf("fd path %s\n", fdpath);
+       printf("Attempt to use AT_SYMLINK_FOLLOW with path %s\n", fdpath);
        err = linkat(AT_FDCWD, fdpath, newfd, file, AT_SYMLINK_FOLLOW);
        if ( err < 0  ) {
             perror("still error creating TMPFILE");
-           sleep(wait);
            exit(1);
-        }
+        } else {
+           printf("Success, fd %d on fd %d/%s created\n", fd, newfd, file);
+       }
        if ( fchmodat(newfd, file,S_IRUSR|S_IWUSR,0) < 0 )
            perror("Cannot change permission to new file");
     }
@@ -143,8 +152,9 @@ int main(int argc, char *argv[])
  */
 void usage(void) {
     printf("Program testlinkat : test linkat for a file  \n");
+    printf("Create a link to a tempfile or a link to -f indicated file");
     printf("Usage:\n");
-    printf("  testlinkat [-h] file mode \n");
+    printf("  testlinkat [-h] destfilepathname \n");
     printf("  -h          print this help\n");
     printf("  -w [N]      wait N seconds\n");
     printf("  -f [file]           use file as source\n");