From: Karel Zak Date: Mon, 26 Oct 2009 12:33:03 +0000 (+0100) Subject: mount: and libblkid: covert /dev/dm-N to /dev/mapper/ X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a992137b7b8720600c99917af87f0e4cddad8682;p=util-linux mount: and libblkid: covert /dev/dm-N to /dev/mapper/ * mount(8) uses private device-mapper names in mtab * libblkid returns private device-mapper names when evaluate udev /dev/disk-by symlinks. * on systems where DM is fully integrated with udev the /dev/mapper/ files are symlinks to /dev/dm-N. It means we need a special care to hide private device-mapper names. Signed-off-by: Karel Zak --- diff --git a/include/canonicalize.h b/include/canonicalize.h index b04510c7..f26df18c 100644 --- a/include/canonicalize.h +++ b/include/canonicalize.h @@ -4,5 +4,6 @@ #include "c.h" /* for PATH_MAX */ extern char *canonicalize_path(const char *path); +extern char *canonicalize_dm_name(const char *ptname); #endif /* CANONICALIZE_H */ diff --git a/lib/canonicalize.c b/lib/canonicalize.c index b888fbb8..e54cf0c0 100644 --- a/lib/canonicalize.c +++ b/lib/canonicalize.c @@ -20,6 +20,9 @@ * * TODO: use canonicalize_file_name() when exist in glibc */ +#include +#include +#include #include #include #include @@ -136,17 +139,54 @@ myrealpath(const char *path, char *resolved_path, int maxreslth) { return NULL; } +/* + * Converts private "dm-N" names to "/dev/mapper/" + * + * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs + * provides the real DM device names in /sys/block//dm/name + */ char * -canonicalize_path(const char *path) { +canonicalize_dm_name(const char *ptname) +{ + FILE *f; + size_t sz; + char path[256], name[256], *res = NULL; + + snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname); + if (!(f = fopen(path, "r"))) + return NULL; + + /* read "\n" from sysfs */ + if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) { + name[sz - 1] = '\0'; + snprintf(path, sizeof(path), "/dev/mapper/%s", name); + res = strdup(path); + } + fclose(f); + return res; +} + +char * +canonicalize_path(const char *path) +{ char canonical[PATH_MAX+2]; + char *p; if (path == NULL) return NULL; - if (myrealpath (path, canonical, PATH_MAX+1)) - return strdup(canonical); + if (!myrealpath(path, canonical, PATH_MAX+1)) + return strdup(path); + + + p = strrchr(canonical, '/'); + if (p && strncmp(p, "/dm-", 4) == 0 && isdigit(*(p + 4))) { + p = canonicalize_dm_name(p+1); + if (p) + return p; + } - return strdup(path); + return strdup(canonical); } diff --git a/shlibs/blkid/src/devname.c b/shlibs/blkid/src/devname.c index fe0d1b33..d048c722 100644 --- a/shlibs/blkid/src/devname.c +++ b/shlibs/blkid/src/devname.c @@ -38,6 +38,7 @@ #include #include "blkidP.h" +#include "canonicalize.h" /* $(top_srcdir)/include */ /* * Find a dev struct in the cache by device name, if available. @@ -152,30 +153,6 @@ static int is_dm_leaf(const char *devname) return ret; } -/* - * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs - * provides the real DM device names in /sys/block//dm/name - */ -static char *get_dm_name(const char *ptname) -{ - FILE *f; - size_t sz; - char path[256], name[256], *res = NULL; - - snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname); - if ((f = fopen(path, "r")) == NULL) - return NULL; - - /* read "\n" from sysfs */ - if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) { - name[sz - 1] = '\0'; - snprintf(path, sizeof(path), "/dev/mapper/%s", name); - res = blkid_strdup(path); - } - fclose(f); - return res; -} - /* * Probe a single block device to add to the device cache. */ @@ -207,7 +184,7 @@ static void probe_one(blkid_cache cache, const char *ptname, * to standard /dev/mapper/. */ if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) { - devname = get_dm_name(ptname); + devname = canonicalize_dm_name(ptname); if (!devname) blkid__scan_dir("/dev/mapper", devno, 0, &devname); if (devname)