small stupid changes. no code changes

[oweals/busybox.git] / libbb / loop.c

diff --git a/libbb/loop.c b/libbb/loop.c
index 10217931b7090d5c768b55b50a53cfe52d93fc92..14835ec245989b254a3f3c88d41a391e4f562ea6 100644 (file)
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -3,18 +3,11 @@
  * Utility routines.
  *
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 2005 by Rob Landley <rob@landley.net>
  *
  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */
 
-
-#include <features.h>
-#include <stdio.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/ioctl.h>
 #include "libbb.h"
 
 /* For 2.6, use the cleaned up header to get the 64 bit API. */
@@ -51,15 +44,32 @@ typedef struct {
 } bb_loop_info;
 #endif
 
-extern int del_loop(const char *device)
+char *query_loop(const char *device)
 {
-       int fd,rc=0;
+       int fd;
+       bb_loop_info loopinfo;
+       char *dev = 0;
+
+       fd = open(device, O_RDONLY);
+       if (fd < 0) return 0;
+       if (!ioctl(fd, BB_LOOP_GET_STATUS, &loopinfo))
+               dev = xasprintf("%ld %s", (long) loopinfo.lo_offset,
+                               (char *)loopinfo.lo_file_name);
+       close(fd);
+
+       return dev;
+}
+
+
+int del_loop(const char *device)
+{
+       int fd, rc;
+
+       fd = open(device, O_RDONLY);
+       if (fd < 0) return 1;
+       rc = ioctl(fd, LOOP_CLR_FD, 0);
+       close(fd);
 
-       if ((fd = open(device, O_RDONLY)) < 0) rc=1;
-       else {
-               if (ioctl(fd, LOOP_CLR_FD, 0) < 0) rc=1;
-               close(fd);
-       }
        return rc;
 }
 
@@ -69,63 +79,71 @@ extern int del_loop(const char *device)
    search will re-use an existing loop device already bound to that
    file/offset if it finds one.
  */
-extern int set_loop(char **device, const char *file, int offset)
+int set_loop(char **device, const char *file, unsigned long long offset)
 {
-       char dev[20];
+       char dev[20], *try;
        bb_loop_info loopinfo;
        struct stat statbuf;
-       int i, dfd, ffd, mode, rc=1;
+       int i, dfd, ffd, mode, rc=-1;
 
        /* Open the file.  Barf if this doesn't work.  */
-       if((ffd = open(file, mode=O_RDWR))<0 && (ffd = open(file,mode=O_RDONLY))<0)
-               return errno;
+       mode = O_RDWR;
+       ffd = open(file, mode);
+       if (ffd < 0) {
+               mode = O_RDONLY;
+               ffd = open(file, mode);
+               if (ffd < 0)
+                       return -errno;
+       }
 
        /* Find a loop device.  */
-       for(i=0;rc;i++) {
-               sprintf(dev, LOOP_FORMAT, i++);
+       try = *device ? : dev;
+       for (i=0;rc;i++) {
+               sprintf(dev, LOOP_FORMAT, i);
+
                /* Ran out of block devices, return failure.  */
-               if(stat(*device ? *device : dev, &statbuf) ||
-                               !S_ISBLK(statbuf.st_mode)) {
-                       rc=ENOENT;
+               if (stat(try, &statbuf) || !S_ISBLK(statbuf.st_mode)) {
+                       rc=-ENOENT;
                        break;
                }
                /* Open the sucker and check its loopiness.  */
-               if((dfd=open(dev, mode))<0 && errno==EROFS)
-                       dfd=open(dev,mode=O_RDONLY);
-               if(dfd<0) continue;
+               dfd = open(try, mode);
+               if (dfd < 0 && errno == EROFS) {
+                       mode = O_RDONLY;
+                       dfd = open(try, mode);
+               }
+               if (dfd < 0) goto try_again;
+
+               rc = ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
 
-               rc=ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
                /* If device free, claim it.  */
-               if(rc && errno==ENXIO) {
+               if (rc && errno == ENXIO) {
                        memset(&loopinfo, 0, sizeof(loopinfo));
-                       safe_strncpy(loopinfo.lo_file_name, file, LO_NAME_SIZE);
+                       safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
                        loopinfo.lo_offset = offset;
                        /* Associate free loop device with file.  */
-                       if(!ioctl(dfd, LOOP_SET_FD, ffd) &&
-                          !ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) rc=0;
-                       else ioctl(dfd, LOOP_CLR_FD, 0);
+                       if (!ioctl(dfd, LOOP_SET_FD, ffd)) {
+                               if (!ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) rc = 0;
+                               else ioctl(dfd, LOOP_CLR_FD, 0);
+                       }
+
                /* If this block device already set up right, re-use it.
                   (Yes this is racy, but associating two loop devices with the same
                   file isn't pretty either.  In general, mounting the same file twice
                   without using losetup manually is problematic.)
                 */
-               } else if(strcmp(file,loopinfo.lo_file_name)
-                                       || offset!=loopinfo.lo_offset) rc=1;
+               } else if (strcmp(file,(char *)loopinfo.lo_file_name)
+               || offset != loopinfo.lo_offset) {
+                       rc = -1;
+               }
                close(dfd);
-               if(*device) break;
+try_again:
+               if (*device) break;
        }
        close(ffd);
-       if(!rc) {
-               if(!*device) *device=strdup(dev);
+       if (!rc) {
+               if (!*device) *device = strdup(dev);
                return mode==O_RDONLY ? 1 : 0;
-       } else return rc;
+       }
+       return rc;
 }
-
-/* END CODE */
-/*
-Local Variables:
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/