Re: Patch for util-linux (in particular, losetup) to allow passing "sizelimit" | |
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Karel Zak wrote:
We need to support the option in mount(8) too.
My suggestion is to use the long options only:
* mark '-s' in util-linux-ng as deprecated and suggest to use the long
option '--show' only.
* use (only) the long option '--sizelimit' for the loop sizelimit. It means
without '-S'.
Attached is a patch with both changes, against the git repository. Shachar
diff --git a/AUTHORS b/AUTHORS
index 2c25a0e..334a5e4 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -102,6 +102,7 @@ CONTRIBUTORS:
Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
Santiago Vila Doncel <sanvila@xxxxxxx>
Sascha Sommer <ssommer@xxxxxxx>
+ Shachar Shemesh <shachar@xxxxxxxxxx>
Simon Mihevc <simonmihevc@xxxxxxxx>
Stefan Krah <stefan@xxxxxxxxxxxx>
Stepan Kasal <skasal@xxxxxxxxxx>
diff --git a/mount/lomount.c b/mount/lomount.c
index ac379c0..81a6ac3 100644
--- a/mount/lomount.c
+++ b/mount/lomount.c
@@ -609,7 +609,7 @@ digits_only(const char *s) {
int
set_loop(const char *device, const char *file, unsigned long long offset,
- const char *encryption, int pfd, int *options) {
+ unsigned long long sizelimit, const char *encryption, int pfd, int *options) {
struct loop_info64 loopinfo64;
int fd, ffd, mode, i;
char *pass;
@@ -657,6 +657,7 @@ set_loop(const char *device, const char *file, unsigned long long offset,
}
loopinfo64.lo_offset = offset;
+ loopinfo64.lo_sizelimit = sizelimit;
#ifdef MCL_FUTURE
/*
@@ -758,8 +759,8 @@ set_loop(const char *device, const char *file, unsigned long long offset,
close (fd);
if (verbose > 1)
- printf(_("set_loop(%s,%s,%llu): success\n"),
- device, filename, offset);
+ printf(_("set_loop(%s,%s,%llu,%llu): success\n"),
+ device, filename, offset, sizelimit);
if (file != filename)
free(filename);
return 0;
@@ -795,8 +796,9 @@ mutter(void) {
}
int
-set_loop (const char *device, const char *file, unsigned long long offset,
- const char *encryption, int *loopro) {
+set_loop(const char *device, const char *file, unsigned long long offset,
+ unsigned long long sizelimit, const char *encryption, int pfd, int *loopro,
+ int keysz, int hash_pass) {
mutter();
return 1;
}
@@ -835,6 +837,7 @@ usage(void) {
" -e | --encryption <type> enable data encryption with specified <name/num>\n"
" -h | --help this help\n"
" -o | --offset <num> start at offset <num> into file\n"
+ " --sizelimit <num> loop limited to only <num> bytes of the file\n"
" -p | --pass-fd <num> read passphrase from file descriptor <num>\n"
" -r | --read-only setup read-only loop device\n"
" -s | --show print device name (with -f <file>)\n"
@@ -845,13 +848,14 @@ usage(void) {
int
main(int argc, char **argv) {
- char *p, *offset, *encryption, *passfd, *device, *file, *assoc;
+ char *p, *offset, *sizelimit, *encryption, *passfd, *device, *file, *assoc;
int delete, find, c, all;
int res = 0;
int showdev = 0;
int ro = 0;
int pfd = -1;
- unsigned long long off;
+ unsigned long long off, slimit;
+#define SIZELIMIT_OPT 1
struct option longopts[] = {
{ "all", 0, 0, 'a' },
{ "detach", 0, 0, 'd' },
@@ -860,6 +864,7 @@ main(int argc, char **argv) {
{ "help", 0, 0, 'h' },
{ "associated", 1, 0, 'j' },
{ "offset", 1, 0, 'o' },
+ { "sizelimit", 1, 0, SIZELIMIT_OPT },
{ "pass-fd", 1, 0, 'p' },
{ "read-only", 0, 0, 'r' },
{ "show", 0, 0, 's' },
@@ -873,7 +878,8 @@ main(int argc, char **argv) {
delete = find = all = 0;
off = 0;
- assoc = offset = encryption = passfd = NULL;
+ slimit = 0;
+ assoc = offset = sizelimit = encryption = passfd = NULL;
progname = argv[0];
if ((p = strrchr(progname, '/')) != NULL)
@@ -904,6 +910,9 @@ main(int argc, char **argv) {
case 'o':
offset = optarg;
break;
+ case SIZELIMIT_OPT:
+ sizelimit = optarg;
+ break;
case 'p':
passfd = optarg;
break;
@@ -921,7 +930,7 @@ main(int argc, char **argv) {
if (argc == 1) {
usage();
} else if (delete) {
- if (argc != optind+1 || encryption || offset ||
+ if (argc != optind+1 || encryption || offset || sizelimit ||
find || all || showdev || assoc || ro)
usage();
} else if (find) {
@@ -941,6 +950,9 @@ main(int argc, char **argv) {
if (offset && sscanf(offset, "%llu", &off) != 1)
usage();
+ if (sizelimit && sscanf(sizelimit, "%llu", &slimit) != 1)
+ usage();
+
if (all)
return show_used_loop_devices();
else if (assoc)
@@ -972,7 +984,7 @@ main(int argc, char **argv) {
if (passfd && sscanf(passfd, "%d", &pfd) != 1)
usage();
do {
- res = set_loop(device, file, off, encryption, pfd, &ro);
+ res = set_loop(device, file, off, slimit, encryption, pfd, &ro);
if (res == 2 && find) {
if (verbose)
printf("stolen loop=%s...trying again\n",
diff --git a/mount/lomount.h b/mount/lomount.h
index a5c1ae8..f332a70 100644
--- a/mount/lomount.h
+++ b/mount/lomount.h
@@ -1,4 +1,4 @@
-extern int set_loop(const char *, const char *, unsigned long long,
+extern int set_loop(const char *, const char *, unsigned long long, unsigned long long,
const char *, int, int *);
extern int del_loop(const char *);
extern int is_loop_device(const char *);
diff --git a/mount/losetup.8 b/mount/losetup.8
index 400ec2c..69bd867 100644
--- a/mount/losetup.8
+++ b/mount/losetup.8
@@ -35,6 +35,7 @@ Setup loop device:
.IR encryption ]
.RB [ \-o
.IR offset ]
+.RB [ \-\-sizelimit=\fIlimit\fP ]
.RB [ \-p
.IR pfd ]
.RB [ \-r ]
@@ -84,6 +85,8 @@ show status of all loop devices associated with given
.IP "\fB\-o, \-\-offset \fIoffset\fP"
the data start is moved \fIoffset\fP bytes into the specified file or
device
+.IP "\fB\-\-sizelimit \fIlimit\fP"
+The data end is set to no more than \fIsizelimit\fP bytes after the data start.
.IP "\fB\-p, \-\-pass-fd \fInum\fP"
read the passphrase from file descriptor with number
.I num
@@ -97,7 +100,7 @@ option and a
.I file
argument are present
.IP "\fB\-v, \-\-verbose\fP"
-verbose mode
+verbose mode. The short form of this option (\fB\-s\fP) is deprecated.
.SH RETURN VALUE
.B losetup
diff --git a/mount/mount.c b/mount/mount.c
index fcc5531..bed792d 100644
--- a/mount/mount.c
+++ b/mount/mount.c
@@ -182,8 +182,8 @@ static const struct opt_map opt_map[] = {
static int opt_nofail = 0;
-static const char *opt_loopdev, *opt_vfstype, *opt_offset, *opt_encryption,
- *opt_speed, *opt_comment, *opt_uhelper;
+static const char *opt_loopdev, *opt_vfstype, *opt_offset, *opt_sizelimit,
+ *opt_encryption, *opt_speed, *opt_comment, *opt_uhelper;
static int mounted (const char *spec0, const char *node0);
static int check_special_mountprog(const char *spec, const char *node,
@@ -197,6 +197,7 @@ static struct string_opt_map {
{ "loop=", 0, &opt_loopdev },
{ "vfs=", 1, &opt_vfstype },
{ "offset=", 0, &opt_offset },
+ { "sizelimit=", 0, &opt_sizelimit },
{ "encryption=", 0, &opt_encryption },
{ "speed=", 0, &opt_speed },
{ "comment=", 1, &opt_comment },
@@ -872,7 +873,7 @@ loop_check(const char **spec, const char **type, int *flags,
int *loop, const char **loopdev, const char **loopfile,
const char *node) {
int looptype;
- unsigned long long offset;
+ unsigned long long offset, sizelimit;
/*
* In the case of a loop mount, either type is of the form lo@/dev/loop5
@@ -897,7 +898,7 @@ loop_check(const char **spec, const char **type, int *flags,
*type = opt_vfstype;
}
- *loop = ((*flags & MS_LOOP) || *loopdev || opt_offset || opt_encryption);
+ *loop = ((*flags & MS_LOOP) || *loopdev || opt_offset || opt_sizelimit || opt_encryption);
*loopfile = *spec;
if (*loop) {
@@ -913,6 +914,7 @@ loop_check(const char **spec, const char **type, int *flags,
loop_opts |= SETLOOP_RDONLY;
offset = opt_offset ? strtoull(opt_offset, NULL, 0) : 0;
+ sizelimit = opt_sizelimit ? strtoull(opt_sizelimit, NULL, 0) : 0;
if (is_mounted_same_loopfile(node, *loopfile, offset)) {
error(_("mount: according to mtab %s is already mounted on %s as loop"), *loopfile, node);
@@ -927,7 +929,7 @@ loop_check(const char **spec, const char **type, int *flags,
if (verbose)
printf(_("mount: going to use the loop device %s\n"), *loopdev);
- if ((res = set_loop(*loopdev, *loopfile, offset,
+ if ((res = set_loop(*loopdev, *loopfile, offset, sizelimit,
opt_encryption, pfd, &loop_opts))) {
if (res == 2) {
/* loop dev has been grabbed by some other process,
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