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-rw-r--r--losetup.c190
1 files changed, 190 insertions, 0 deletions
diff --git a/losetup.c b/losetup.c
new file mode 100644
index 0000000..2908dbc
--- /dev/null
+++ b/losetup.c
@@ -0,0 +1,190 @@
+/*
+ * losetup.c - setup and control loop devices
+ */
+
+
+#include "internal.h"
+
+const char losetup_usage[] = "losetup\n"
+"\n"
+"\tlosetup loop_device give info\n"
+"\tlosetup -d loop_device delete\n"
+"\tlosetup [ -o offset ] loop_device file setup\n";
+
+/* from mount-2.6d */
+
+/*
+ * losetup.c - setup and control loop devices
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <linux/fs.h>
+/* #include "loop.h" */
+
+/*
+ * include/linux/loop.h
+ *
+ * Written by Theodore Ts'o, 3/29/93.
+ *
+ * Copyright 1993 by Theodore Ts'o. Redistribution of this file is
+ * permitted under the GNU Public License.
+ */
+
+#define LO_NAME_SIZE 64
+#define LO_KEY_SIZE 32
+
+struct loop_info {
+ int lo_number; /* ioctl r/o */
+ dev_t lo_device; /* ioctl r/o */
+ unsigned long lo_inode; /* ioctl r/o */
+ dev_t lo_rdevice; /* ioctl r/o */
+ int lo_offset;
+ int lo_encrypt_type;
+ int lo_encrypt_key_size; /* ioctl w/o */
+ int lo_flags; /* ioctl r/o */
+ char lo_name[LO_NAME_SIZE];
+ unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
+ unsigned long lo_init[2];
+ char reserved[4];
+};
+
+/*
+ * IOCTL commands --- we will commandeer 0x4C ('L')
+ */
+
+#define LOOP_SET_FD 0x4C00
+#define LOOP_CLR_FD 0x4C01
+#define LOOP_SET_STATUS 0x4C02
+#define LOOP_GET_STATUS 0x4C03
+
+/* #include "lomount.h" */
+
+extern int set_loop (const char *, const char *, int, int *);
+extern int del_loop (const char *);
+
+static void show_loop(const char *device)
+{
+ struct loop_info loopinfo;
+ int fd;
+
+ if ((fd = open(device, O_RDWR)) < 0) {
+ perror(device);
+ return;
+ }
+ if (ioctl(fd, LOOP_GET_STATUS, &loopinfo) < 0) {
+ perror("Cannot get loop info");
+ close(fd);
+ return;
+ }
+ printf("%s: [%04x]:%ld (%s) offset %d\n",
+ device, (unsigned int)loopinfo.lo_device, loopinfo.lo_inode,
+ loopinfo.lo_name, loopinfo.lo_offset);
+ close(fd);
+}
+
+
+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)) {
+ perror (file);
+ return 1;
+ }
+ if ((fd = open (device, mode)) < 0) {
+ close(ffd);
+ perror (device);
+ return 1;
+ }
+ *loopro = (mode == O_RDONLY);
+
+ memset(&loopinfo, 0, sizeof(loopinfo));
+ strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
+ loopinfo.lo_name[LO_NAME_SIZE-1] = 0;
+
+ loopinfo.lo_offset = offset;
+
+ loopinfo.lo_encrypt_key_size = 0;
+ if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
+ perror("ioctl: LOOP_SET_FD");
+ exit(1);
+ }
+ if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
+ (void) ioctl(fd, LOOP_CLR_FD, 0);
+ perror("ioctl: LOOP_SET_STATUS");
+ exit(1);
+ }
+ close(fd);
+ close(ffd);
+ return 0;
+}
+
+int del_loop(const char *device)
+{
+ int fd;
+
+ if ((fd = open(device, O_RDONLY)) < 0) {
+ perror(device);
+ exit(1);
+ }
+ if (ioctl(fd, LOOP_CLR_FD, 0) < 0) {
+ perror("ioctl: LOOP_CLR_FD");
+ exit(1);
+ }
+ close(fd);
+ return(0);
+}
+
+
+static int losetup_usage_fn(void)
+{
+ fprintf(stderr, losetup_usage);
+ exit(1);
+}
+
+int losetup_main(struct FileInfo * i, int argc, char * * argv)
+{
+ char *offset;
+ int delete,off,c;
+ int ro = 0;
+
+ delete = off = 0;
+ offset = NULL;
+ while ((c = getopt(argc,argv,"do:")) != EOF) {
+ switch (c) {
+ case 'd':
+ delete = 1;
+ break;
+ case 'o':
+ offset = optarg;
+ break;
+ default:
+ losetup_usage_fn();
+ }
+ }
+ if (argc == 1) losetup_usage_fn();
+ if ((delete && (argc != optind+1 || offset)) ||
+ (!delete && (argc < optind+1 || argc > optind+2)))
+ losetup_usage_fn();
+ if (argc == optind+1)
+ if (delete)
+ del_loop(argv[optind]);
+ else
+ show_loop(argv[optind]);
+ else {
+ if (offset && sscanf(offset,"%d",&off) != 1)
+ losetup_usage_fn();
+ set_loop(argv[optind],argv[optind+1],off,&ro);
+ }
+ return 0;
+}