In making LVM tests more reproducible and insulating them from
any existing LVM set-up, I've been using LVM_SYSTEM_DIR to specify
a different /dev directory. However, that broke down for tests
that ran dmsetup, since dmsetup hard-codes /dev.
Here's a patch to make dmsetup honor a new DM_DEVDIR envvar,
in using that value in place of "/dev":
Allow $DM_DEVDIR envvar to override default of "/dev".
* dmsetup/dmsetup.c (DEV_PATH): Remove definition.
(parse_loop_device_name): Add parameter: dev_dir.
Declare the "dev" parameter to be "const".
Use dev_dir, not DEV_PATH. Handle the case in which dev_dir
does not end in a "/".
(_get_abspath): Declare "path" parameter "const", to match.
(_process_losetup_switches): Add parameter: dev_dir.
Pass dev_dir to parse_loop_device_name.
(_process_switches): Add parameter: dev_dir.
Pass dev_dir to _process_losetup_switches.
(main): Set dev_dir from the DM_DEVDIR envvar, else to "/dev".
Call dm_set_dev_dir.
* lib/libdm-common.c (dm_set_dev_dir): Rewrite to be careful
about boundary conditions, now that dev_dir may be tainted.
As for the way I call dm_set_dev_dir in main, note that I call
it only when using a value from DM_DEVDIR, and not when using
the default of "/dev". That's sort of ugly, but using "/dev"
is the default that is hard-coded into libdevmapper, via this:
lib/libdm-common.c:
#define DEV_DIR "/dev/"
static char _dm_dir[PATH_MAX] = DEV_DIR DM_DIR;
Ideally, libdevmapper wouldn't rely on any such static variable,
of course, but there may well be existing callers, so I won't
try to change that.
Signed-off-by: Jim Meyering <meyering@xxxxxxxxxx>
---
dmsetup/dmsetup.c | 35 ++++++++++++++++++++++++++---------
lib/libdm-common.c | 15 +++++++++++++--
2 files changed, 39 insertions(+), 11 deletions(-)
diff --git a/dmsetup/dmsetup.c b/dmsetup/dmsetup.c
index 562f628..ca864b8 100644
--- a/dmsetup/dmsetup.c
+++ b/dmsetup/dmsetup.c
@@ -97,7 +97,6 @@ extern char *optarg;
/* FIXME Should be elsewhere */
#define SECTOR_SHIFT 9L
-#define DEV_PATH "/dev/"
#define err(msg, x...) fprintf(stderr, msg "\n", ##x)
@@ -2129,7 +2128,7 @@ static int _process_tree_options(const char *options)
* Returns the full absolute path, or NULL if the path could
* not be resolved.
*/
-static char *_get_abspath(char *path)
+static char *_get_abspath(const char *path)
{
char *_path;
@@ -2141,7 +2140,7 @@ static char *_get_abspath(char *path)
return _path;
}
-static char *parse_loop_device_name(char *dev)
+static char *parse_loop_device_name(const char *dev, const char *dev_dir)
{
char *buf;
char *device;
@@ -2153,7 +2152,13 @@ static char *parse_loop_device_name(char *dev)
if (!(device = _get_abspath(dev)))
goto error;
- if (strncmp(device, DEV_PATH, strlen(DEV_PATH)))
+ if (strncmp(device, dev_dir, strlen(dev_dir)))
+ goto error;
+
+ /* If dev_dir does not end in a slash, ensure that the
+ following byte in the device string is "/". */
+ if (dev_dir[strlen(dev_dir) - 1] != '/'
+ && device[strlen(dev_dir)] != '/')
goto error;
strncpy(buf, strrchr(device, '/') + 1, (size_t) PATH_MAX);
@@ -2234,7 +2239,8 @@ error:
return 0;
}
-static int _process_losetup_switches(const char *base, int *argc, char ***argv)
+static int _process_losetup_switches(const char *base, int *argc, char ***argv,
+ const char *dev_dir)
{
static int ind;
int c;
@@ -2297,7 +2303,7 @@ static int _process_losetup_switches(const char *base, int *argc, char ***argv)
return 0;
}
- if (!(device_name = parse_loop_device_name((*argv)[0]))) {
+ if (!(device_name = parse_loop_device_name((*argv)[0], dev_dir))) {
fprintf(stderr, "%s: Could not parse loop_device %s\n",
base, (*argv)[0]);
_losetup_usage(stderr);
@@ -2344,7 +2350,7 @@ static int _process_losetup_switches(const char *base, int *argc, char ***argv)
return 1;
}
-static int _process_switches(int *argc, char ***argv)
+static int _process_switches(int *argc, char ***argv, const char *dev_dir)
{
char *base, *namebase;
static int ind;
@@ -2422,7 +2428,7 @@ static int _process_switches(int *argc, char ***argv)
}
if (!strcmp(base, "losetup") || !strcmp(base, "dmlosetup")){
- r = _process_losetup_switches(base, argc, argv);
+ r = _process_losetup_switches(base, argc, argv, dev_dir);
free(namebase);
return r;
}
@@ -2539,10 +2545,21 @@ int main(int argc, char **argv)
{
struct command *c;
int r = 1;
+ const char *dev_dir;
(void) setlocale(LC_ALL, "");
- if (!_process_switches(&argc, &argv)) {
+ dev_dir = getenv ("DM_DEVDIR");
+ if (dev_dir && *dev_dir) {
+ if (!dm_set_dev_dir(dev_dir)) {
+ fprintf(stderr, "Invalid DM_DEVDIR envvar value.\n");
+ goto out;
+ }
+ } else {
+ dev_dir = "/dev";
+ }
+
+ if (!_process_switches(&argc, &argv, dev_dir)) {
fprintf(stderr, "Couldn't process command line.\n");
goto out;
}
diff --git a/lib/libdm-common.c b/lib/libdm-common.c
index c8c3500..c87903a 100644
--- a/lib/libdm-common.c
+++ b/lib/libdm-common.c
@@ -463,9 +463,20 @@ void update_devs(void)
_pop_node_ops();
}
-int dm_set_dev_dir(const char *dir)
+int dm_set_dev_dir(const char *dev_dir)
{
- snprintf(_dm_dir, sizeof(_dm_dir), "%s%s", dir, DM_DIR);
+ size_t len;
+ const char *slash;
+ if (*dev_dir != '/')
+ return 0;
+
+ len = strlen(dev_dir);
+ slash = dev_dir[len-1] == '/' ? "" : "/";
+
+ if (snprintf(_dm_dir, sizeof _dm_dir, "%s%s%s", dev_dir, slash, DM_DIR)
+ >= sizeof _dm_dir)
+ return 0;
+
return 1;
}
--
1.5.3.4.206.g58ba4
--
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