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Diffstat (limited to 'libbb/loop.c')
-rw-r--r--libbb/loop.c163
1 files changed, 71 insertions, 92 deletions
diff --git a/libbb/loop.c b/libbb/loop.c
index c4c3da4b1..25f66fcea 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -19,10 +19,8 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
+
#include <features.h>
-#if defined (__GLIBC__) && !defined(__UCLIBC__)
-#include <linux/posix_types.h>
-#endif
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
@@ -30,127 +28,108 @@
#include <unistd.h>
#include <sys/ioctl.h>
#include "libbb.h"
-#ifdef CONFIG_FEATURE_MOUNT_LOOP
-/* Grumble... The 2.6.x kernel breaks asm/posix_types.h
- * so we get to try and cope as best we can... */
+/* For 2.6, use the cleaned up header to get the 64 bit API. */
#include <linux/version.h>
-
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
-#define __bb_kernel_dev_t __kernel_old_dev_t
-#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
-#define __bb_kernel_dev_t __kernel_dev_t
-#else
-#define __bb_kernel_dev_t unsigned short
-#endif
+#include <linux/loop.h>
+typedef struct loop_info64 bb_loop_info;
+#define BB_LOOP_SET_STATUS LOOP_SET_STATUS64
+#define BB_LOOP_GET_STATUS LOOP_GET_STATUS64
-/* Stuff stolen from linux/loop.h */
+/* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */
+#else
+/* Stuff stolen from linux/loop.h for 2.4 and earlier kernels*/
+#include <linux/posix_types.h>
#define LO_NAME_SIZE 64
#define LO_KEY_SIZE 32
#define LOOP_SET_FD 0x4C00
#define LOOP_CLR_FD 0x4C01
-#define LOOP_SET_STATUS 0x4C02
-#define LOOP_GET_STATUS 0x4C03
-struct loop_info {
+#define BB_LOOP_SET_STATUS 0x4C02
+#define BB_LOOP_GET_STATUS 0x4C03
+typedef struct {
int lo_number;
- __bb_kernel_dev_t lo_device;
+ __kernel_dev_t lo_device;
unsigned long lo_inode;
- __bb_kernel_dev_t lo_rdevice;
+ __kernel_dev_t lo_rdevice;
int lo_offset;
int lo_encrypt_type;
int lo_encrypt_key_size;
int lo_flags;
- char lo_name[LO_NAME_SIZE];
+ char lo_file_name[LO_NAME_SIZE];
unsigned char lo_encrypt_key[LO_KEY_SIZE];
unsigned long lo_init[2];
char reserved[4];
-};
+} bb_loop_info;
+#endif
extern int del_loop(const char *device)
{
- int fd;
+ int fd,rc=0;
- if ((fd = open(device, O_RDONLY)) < 0) {
- bb_perror_msg("%s", device);
- return (FALSE);
- }
- if (ioctl(fd, LOOP_CLR_FD, 0) < 0) {
+ if ((fd = open(device, O_RDONLY)) < 0) rc=1;
+ else {
+ if (ioctl(fd, LOOP_CLR_FD, 0) < 0) rc=1;
close(fd);
- bb_perror_msg("ioctl: LOOP_CLR_FD");
- return (FALSE);
}
- close(fd);
- return (TRUE);
+ return rc;
}
-extern int set_loop(const char *device, const char *file, int offset,
- int *loopro)
-{
- struct loop_info loopinfo;
- int fd, ffd, mode;
-
- mode = *loopro ? O_RDONLY : O_RDWR;
- if ((ffd = open(file, mode)) < 0 && !*loopro
- && (errno != EROFS || (ffd = open(file, mode = O_RDONLY)) < 0)) {
- bb_perror_msg("%s", file);
- return 1;
- }
- if ((fd = open(device, mode)) < 0) {
- close(ffd);
- bb_perror_msg("%s", device);
- return 1;
- }
- *loopro = (mode == O_RDONLY);
-
- memset(&loopinfo, 0, sizeof(loopinfo));
- safe_strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
-
- loopinfo.lo_offset = offset;
-
- loopinfo.lo_encrypt_key_size = 0;
- if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
- bb_perror_msg("ioctl: LOOP_SET_FD");
- close(fd);
- close(ffd);
- return 1;
- }
- if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
- (void) ioctl(fd, LOOP_CLR_FD, 0);
- bb_perror_msg("ioctl: LOOP_SET_STATUS");
- close(fd);
- close(ffd);
- return 1;
- }
- close(fd);
- close(ffd);
- return 0;
-}
-
-extern char *find_unused_loop_device(void)
+// Returns 0 if mounted RW, 1 if mounted read-only, <0 for error.
+// *device is loop device to use, or if *device==NULL finds a loop device to
+// mount it on and sets *device to a strdup of that loop device name. This
+// 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)
{
char dev[20];
- int i, fd;
+ bb_loop_info loopinfo;
struct stat statbuf;
- struct loop_info loopinfo;
+ int i, dfd, ffd, mode, rc=1;
- for (i = 0; i <= CONFIG_FEATURE_MOUNT_LOOP_MAX; i++) {
- sprintf(dev, LOOP_FORMAT, i);
- if (stat(dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) {
- if ((fd = open(dev, O_RDONLY)) >= 0) {
- if (ioctl(fd, LOOP_GET_STATUS, &loopinfo) != 0) {
- if (errno == ENXIO) { /* probably free */
- close(fd);
- return strdup(dev);
- }
- }
- close(fd);
- }
+ // Open the file. Barf if this doesn't work.
+ if((ffd = open(file, mode=O_RDWR))<0)
+ if(errno!=EROFS || (ffd=open(file,mode=O_RDONLY))<0)
+ return errno;
+
+ // Find a loop device
+ for(i=0;rc;i++) {
+ sprintf(dev, LOOP_FORMAT, i++);
+ // Ran out of block devices, return failure.
+ if(stat(*device ? : dev, &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;
+
+ rc=ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
+ // If device free, claim it.
+ if(rc && errno==ENXIO) {
+ memset(&loopinfo, 0, sizeof(loopinfo));
+ safe_strncpy(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 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;
+ close(dfd);
+ if(*device) break;
}
- return NULL;
+ close(ffd);
+ if(!rc) {
+ if(!*device) *device=strdup(dev);
+ return mode==O_RDONLY ? 1 : 0;
+ } else return rc;
}
-#endif
-
/* END CODE */
/*
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