fallocate: Add truncate (-t) option

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/contrib/fallocate.c b/contrib/fallocate.c
index 23684f3..0e8319f 100644 (file)
--- a/contrib/fallocate.c
+++ b/contrib/fallocate.c
@@ -21,7 +21,6 @@
  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#define _GNU_SOURCE
 #define _LARGEFILE_SOURCE
 #define _LARGEFILE64_SOURCE
 
@@ -39,7 +38,7 @@
 
 void usage(void)
 {
-       printf("Usage: fallocate [-n] [-o offset] -l length filename\n");
+       printf("Usage: fallocate [-nt] [-o offset] -l length filename\n");
        exit(EXIT_FAILURE);
 }
 
@@ -93,8 +92,9 @@ int main(int argc, char **argv)
        loff_t  offset = 0;
        int     falloc_mode = 0;
        int     error;
+       int     tflag = 0;
 
-       while ((opt = getopt(argc, argv, "nl:o:")) != -1) {
+       while ((opt = getopt(argc, argv, "nl:ot")) != -1) {
                switch(opt) {
                case 'n':
                        /* do not change filesize */
@@ -106,6 +106,9 @@ int main(int argc, char **argv)
                case 'o':
                        offset = cvtnum(optarg);
                        break;
+               case 't':
+                       tflag++;
+                       break;
                default:
                        usage();
                }
@@ -126,6 +129,16 @@ int main(int argc, char **argv)
                usage();
        }
 
+       if (tflag && (falloc_mode & FALLOC_FL_KEEP_SIZE)) {
+               printf("-n and -t options incompatible\n");
+               usage();
+       }
+
+       if (tflag && offset) {
+               printf("-n and -o options incompatible\n");
+               usage();
+       }
+
        if (optind == argc) {
                printf("Error: no filename specified\n");
                usage();
@@ -134,13 +147,16 @@ int main(int argc, char **argv)
        fname = argv[optind++];
 
        /* Should we create the file if it doesn't already exist? */
-       fd = open(fname, O_WRONLY|O_DIRECTORY);
+       fd = open(fname, O_WRONLY|O_LARGEFILE);
        if (fd < 0) {
                perror("Error opening file");
                exit(EXIT_FAILURE);
        }
 
-       error = syscall(SYS_fallocate, fd, falloc_mode, offset, length);
+       if (tflag)
+               error = ftruncate(fd, length);
+       else
+               error = syscall(SYS_fallocate, fd, falloc_mode, offset, length);
 
        if (error < 0) {
                perror("fallocate failed");