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-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 @@
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */ 20 */
21 21
22
22#include <features.h> 23#include <features.h>
23#if defined (__GLIBC__) && !defined(__UCLIBC__)
24#include <linux/posix_types.h>
25#endif
26#include <stdio.h> 24#include <stdio.h>
27#include <errno.h> 25#include <errno.h>
28#include <fcntl.h> 26#include <fcntl.h>
@@ -30,127 +28,108 @@
30#include <unistd.h> 28#include <unistd.h>
31#include <sys/ioctl.h> 29#include <sys/ioctl.h>
32#include "libbb.h" 30#include "libbb.h"
33#ifdef CONFIG_FEATURE_MOUNT_LOOP
34 31
35/* Grumble... The 2.6.x kernel breaks asm/posix_types.h 32/* For 2.6, use the cleaned up header to get the 64 bit API. */
36 * so we get to try and cope as best we can... */
37#include <linux/version.h> 33#include <linux/version.h>
38
39#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0) 34#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
40#define __bb_kernel_dev_t __kernel_old_dev_t 35#include <linux/loop.h>
41#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) 36typedef struct loop_info64 bb_loop_info;
42#define __bb_kernel_dev_t __kernel_dev_t 37#define BB_LOOP_SET_STATUS LOOP_SET_STATUS64
43#else 38#define BB_LOOP_GET_STATUS LOOP_GET_STATUS64
44#define __bb_kernel_dev_t unsigned short
45#endif
46 39
47/* Stuff stolen from linux/loop.h */ 40/* For 2.4 and earlier, use the 32 bit API (and don't trust the headers) */
41#else
42/* Stuff stolen from linux/loop.h for 2.4 and earlier kernels*/
43#include <linux/posix_types.h>
48#define LO_NAME_SIZE 64 44#define LO_NAME_SIZE 64
49#define LO_KEY_SIZE 32 45#define LO_KEY_SIZE 32
50#define LOOP_SET_FD 0x4C00 46#define LOOP_SET_FD 0x4C00
51#define LOOP_CLR_FD 0x4C01 47#define LOOP_CLR_FD 0x4C01
52#define LOOP_SET_STATUS 0x4C02 48#define BB_LOOP_SET_STATUS 0x4C02
53#define LOOP_GET_STATUS 0x4C03 49#define BB_LOOP_GET_STATUS 0x4C03
54struct loop_info { 50typedef struct {
55 int lo_number; 51 int lo_number;
56 __bb_kernel_dev_t lo_device; 52 __kernel_dev_t lo_device;
57 unsigned long lo_inode; 53 unsigned long lo_inode;
58 __bb_kernel_dev_t lo_rdevice; 54 __kernel_dev_t lo_rdevice;
59 int lo_offset; 55 int lo_offset;
60 int lo_encrypt_type; 56 int lo_encrypt_type;
61 int lo_encrypt_key_size; 57 int lo_encrypt_key_size;
62 int lo_flags; 58 int lo_flags;
63 char lo_name[LO_NAME_SIZE]; 59 char lo_file_name[LO_NAME_SIZE];
64 unsigned char lo_encrypt_key[LO_KEY_SIZE]; 60 unsigned char lo_encrypt_key[LO_KEY_SIZE];
65 unsigned long lo_init[2]; 61 unsigned long lo_init[2];
66 char reserved[4]; 62 char reserved[4];
67}; 63} bb_loop_info;
64#endif
68 65
69extern int del_loop(const char *device) 66extern int del_loop(const char *device)
70{ 67{
71 int fd; 68 int fd,rc=0;
72 69
73 if ((fd = open(device, O_RDONLY)) < 0) { 70 if ((fd = open(device, O_RDONLY)) < 0) rc=1;
74 bb_perror_msg("%s", device); 71 else {
75 return (FALSE); 72 if (ioctl(fd, LOOP_CLR_FD, 0) < 0) rc=1;
76 }
77 if (ioctl(fd, LOOP_CLR_FD, 0) < 0) {
78 close(fd); 73 close(fd);
79 bb_perror_msg("ioctl: LOOP_CLR_FD");
80 return (FALSE);
81 } 74 }
82 close(fd); 75 return rc;
83 return (TRUE);
84} 76}
85 77
86extern int set_loop(const char *device, const char *file, int offset, 78// Returns 0 if mounted RW, 1 if mounted read-only, <0 for error.
87 int *loopro) 79// *device is loop device to use, or if *device==NULL finds a loop device to
88{ 80// mount it on and sets *device to a strdup of that loop device name. This
89 struct loop_info loopinfo; 81// search will re-use an existing loop device already bound to that
90 int fd, ffd, mode; 82// file/offset if it finds one.
91 83extern int set_loop(char **device, const char *file, int offset)
92 mode = *loopro ? O_RDONLY : O_RDWR;
93 if ((ffd = open(file, mode)) < 0 && !*loopro
94 && (errno != EROFS || (ffd = open(file, mode = O_RDONLY)) < 0)) {
95 bb_perror_msg("%s", file);
96 return 1;
97 }
98 if ((fd = open(device, mode)) < 0) {
99 close(ffd);
100 bb_perror_msg("%s", device);
101 return 1;
102 }
103 *loopro = (mode == O_RDONLY);
104
105 memset(&loopinfo, 0, sizeof(loopinfo));
106 safe_strncpy(loopinfo.lo_name, file, LO_NAME_SIZE);
107
108 loopinfo.lo_offset = offset;
109
110 loopinfo.lo_encrypt_key_size = 0;
111 if (ioctl(fd, LOOP_SET_FD, ffd) < 0) {
112 bb_perror_msg("ioctl: LOOP_SET_FD");
113 close(fd);
114 close(ffd);
115 return 1;
116 }
117 if (ioctl(fd, LOOP_SET_STATUS, &loopinfo) < 0) {
118 (void) ioctl(fd, LOOP_CLR_FD, 0);
119 bb_perror_msg("ioctl: LOOP_SET_STATUS");
120 close(fd);
121 close(ffd);
122 return 1;
123 }
124 close(fd);
125 close(ffd);
126 return 0;
127}
128
129extern char *find_unused_loop_device(void)
130{ 84{
131 char dev[20]; 85 char dev[20];
132 int i, fd; 86 bb_loop_info loopinfo;
133 struct stat statbuf; 87 struct stat statbuf;
134 struct loop_info loopinfo; 88 int i, dfd, ffd, mode, rc=1;
135 89
136 for (i = 0; i <= CONFIG_FEATURE_MOUNT_LOOP_MAX; i++) { 90 // Open the file. Barf if this doesn't work.
137 sprintf(dev, LOOP_FORMAT, i); 91 if((ffd = open(file, mode=O_RDWR))<0)
138 if (stat(dev, &statbuf) == 0 && S_ISBLK(statbuf.st_mode)) { 92 if(errno!=EROFS || (ffd=open(file,mode=O_RDONLY))<0)
139 if ((fd = open(dev, O_RDONLY)) >= 0) { 93 return errno;
140 if (ioctl(fd, LOOP_GET_STATUS, &loopinfo) != 0) { 94
141 if (errno == ENXIO) { /* probably free */ 95 // Find a loop device
142 close(fd); 96 for(i=0;rc;i++) {
143 return strdup(dev); 97 sprintf(dev, LOOP_FORMAT, i++);
144 } 98 // Ran out of block devices, return failure.
145 } 99 if(stat(*device ? : dev, &statbuf) || !S_ISBLK(statbuf.st_mode)) {
146 close(fd); 100 rc=ENOENT;
147 } 101 break;
148 } 102 }
103 // Open the sucker and check its loopiness.
104 if((dfd=open(dev, mode))<0 && errno==EROFS)
105 dfd=open(dev,mode=O_RDONLY);
106 if(dfd<0) continue;
107
108 rc=ioctl(dfd, BB_LOOP_GET_STATUS, &loopinfo);
109 // If device free, claim it.
110 if(rc && errno==ENXIO) {
111 memset(&loopinfo, 0, sizeof(loopinfo));
112 safe_strncpy(loopinfo.lo_file_name, file, LO_NAME_SIZE);
113 loopinfo.lo_offset = offset;
114 // Associate free loop device with file
115 if(!ioctl(dfd, LOOP_SET_FD, ffd) &&
116 !ioctl(dfd, BB_LOOP_SET_STATUS, &loopinfo)) rc=0;
117 else ioctl(dfd, LOOP_CLR_FD, 0);
118 // If this block device already set up right, re-use it.
119 // (Yes this is racy, but associating two loop devices with the same
120 // file isn't pretty either. In general, mounting the same file twice
121 // without using losetup manually is problematic.)
122 } else if(strcmp(file,loopinfo.lo_file_name)
123 || offset!=loopinfo.lo_offset) rc=1;
124 close(dfd);
125 if(*device) break;
149 } 126 }
150 return NULL; 127 close(ffd);
128 if(!rc) {
129 if(!*device) *device=strdup(dev);
130 return mode==O_RDONLY ? 1 : 0;
131 } else return rc;
151} 132}
152#endif
153
154 133
155/* END CODE */ 134/* END CODE */
156/* 135/*
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