From 46f1d17c743145d3ffa045557a6a792eb99f478a Mon Sep 17 00:00:00 2001 From: Zdenek Kabelac Date: Sat, 6 Jul 2019 01:21:39 +0200 Subject: [PATCH] libdm: implement search for device names for older kernels Kernels <2.6.27 don't have /sys/dev dir - add code for looking out device name via longre seach in /sys/block This makes commands like 'dmsetup dep -o blkdevname' working. --- device_mapper/libdm-common.c | 118 +++++++++++++++++++++++++++++++++- libdm/libdm-common.c | 119 ++++++++++++++++++++++++++++++++++- 2 files changed, 235 insertions(+), 2 deletions(-) diff --git a/device_mapper/libdm-common.c b/device_mapper/libdm-common.c index 45dcb4c0d..1cb29f1e8 100644 --- a/device_mapper/libdm-common.c +++ b/device_mapper/libdm-common.c @@ -1874,6 +1874,120 @@ bad: return r; } +static int _sysfs_get_dev_major_minor(const char *path, uint32_t major, uint32_t minor) +{ + FILE *fp; + uint32_t ma, mi; + int r; + + if (!(fp = fopen(path, "r"))) + return 0; + + r = (fscanf(fp, "%" PRIu32 ":%" PRIu32 , &ma, &mi) == 2) && + (ma == major) && (mi == minor); + // log_debug("Checking %s %u:%u -> %d", path, ma, mi, r); + + if (fclose(fp)) + log_sys_error("fclose", path); + + return r; +} + +static int _sysfs_find_kernel_name(uint32_t major, uint32_t minor, char *buf, size_t buf_size) +{ + const char *name, *name_dev; + char path[PATH_MAX]; + struct dirent *dirent, *dirent_dev; + DIR *d, *d_dev; + struct stat st; + int r = 0, sz; + + if (!*_sysfs_dir || + dm_snprintf(path, sizeof(path), "%s/block/", _sysfs_dir) < 0) { + log_error("Failed to build sysfs_path."); + return 0; + } + + if (!(d = opendir(path))) { + log_sys_error("opendir", path); + return 0; + } + + while (!r && (dirent = readdir(d))) { + name = dirent->d_name; + + if (!strcmp(name, ".") || !strcmp(name, "..")) + continue; + + if ((sz = dm_snprintf(path, sizeof(path), "%sblock/%s/dev", + _sysfs_dir, name)) == -1) { + log_warn("Couldn't create path for %s.", name); + continue; + } + + if (_sysfs_get_dev_major_minor(path, major, minor)) { + r = dm_strncpy(buf, name, buf_size); + break; /* found */ + } + + path[sz - 4] = 0; /* strip /dev from end of path string */ + if (stat(path, &st)) + continue; + + if (S_ISDIR(st.st_mode)) { + + /* let's assume there is no tree-complex device in past systems */ + if (!(d_dev = opendir(path))) { + log_sys_debug("opendir", path); + continue; + } + + while ((dirent_dev = readdir(d_dev))) { + name_dev = dirent_dev->d_name; + + /* skip known ignorable paths */ + if (!strcmp(name_dev, ".") || !strcmp(name_dev, "..") || + !strcmp(name_dev, "bdi") || + !strcmp(name_dev, "dev") || + !strcmp(name_dev, "device") || + !strcmp(name_dev, "holders") || + !strcmp(name_dev, "integrity") || + !strcmp(name_dev, "loop") || + !strcmp(name_dev, "queueu") || + !strcmp(name_dev, "md") || + !strcmp(name_dev, "mq") || + !strcmp(name_dev, "power") || + !strcmp(name_dev, "removable") || + !strcmp(name_dev, "slave") || + !strcmp(name_dev, "slaves") || + !strcmp(name_dev, "subsystem") || + !strcmp(name_dev, "trace") || + !strcmp(name_dev, "uevent")) + continue; + + if (dm_snprintf(path, sizeof(path), "%sblock/%s/%s/dev", + _sysfs_dir, name, name_dev) == -1) { + log_warn("Couldn't create path for %s/%s.", name, name_dev); + continue; + } + + if (_sysfs_get_dev_major_minor(path, major, minor)) { + r = dm_strncpy(buf, name_dev, buf_size); + break; /* found */ + } + } + + if (closedir(d_dev)) + log_sys_debug("closedir", name); + } + } + + if (closedir(d)) + log_sys_debug("closedir", path); + + return r; +} + static int _sysfs_get_kernel_name(uint32_t major, uint32_t minor, char *buf, size_t buf_size) { char *name, *sysfs_path, *temp_buf = NULL; @@ -1896,8 +2010,10 @@ static int _sysfs_get_kernel_name(uint32_t major, uint32_t minor, char *buf, siz if ((size = readlink(sysfs_path, temp_buf, PATH_MAX - 1)) < 0) { if (errno != ENOENT) log_sys_error("readlink", sysfs_path); - else + else { log_sys_debug("readlink", sysfs_path); + return _sysfs_find_kernel_name(major, minor, buf, buf_size); + } goto bad; } temp_buf[size] = '\0'; diff --git a/libdm/libdm-common.c b/libdm/libdm-common.c index 7d19f751a..d17c284f2 100644 --- a/libdm/libdm-common.c +++ b/libdm/libdm-common.c @@ -1872,6 +1872,121 @@ bad: return r; } +static int _sysfs_get_dev_major_minor(const char *path, uint32_t major, uint32_t minor) +{ + FILE *fp; + uint32_t ma, mi; + int r; + + if (!(fp = fopen(path, "r"))) + return 0; + + r = (fscanf(fp, "%" PRIu32 ":%" PRIu32 , &ma, &mi) == 2) && + (ma == major) && (mi == minor); + // log_debug("Checking %s %u:%u -> %d", path, ma, mi, r); + + if (fclose(fp)) + log_sys_error("fclose", path); + + return r; +} + + +static int _sysfs_find_kernel_name(uint32_t major, uint32_t minor, char *buf, size_t buf_size) +{ + const char *name, *name_dev; + char path[PATH_MAX]; + struct dirent *dirent, *dirent_dev; + DIR *d, *d_dev; + struct stat st; + int r = 0, sz; + + if (!*_sysfs_dir || + dm_snprintf(path, sizeof(path), "%s/block/", _sysfs_dir) < 0) { + log_error("Failed to build sysfs_path."); + return 0; + } + + if (!(d = opendir(path))) { + log_sys_error("opendir", path); + return 0; + } + + while (!r && (dirent = readdir(d))) { + name = dirent->d_name; + + if (!strcmp(name, ".") || !strcmp(name, "..")) + continue; + + if ((sz = dm_snprintf(path, sizeof(path), "%sblock/%s/dev", + _sysfs_dir, name)) == -1) { + log_warn("Couldn't create path for %s.", name); + continue; + } + + if (_sysfs_get_dev_major_minor(path, major, minor)) { + r = dm_strncpy(buf, name, buf_size); + break; /* found */ + } + + path[sz - 4] = 0; /* strip /dev from end of path string */ + if (stat(path, &st)) + continue; + + if (S_ISDIR(st.st_mode)) { + + /* let's assume there is no tree-complex device in past systems */ + if (!(d_dev = opendir(path))) { + log_sys_debug("opendir", path); + continue; + } + + while ((dirent_dev = readdir(d_dev))) { + name_dev = dirent_dev->d_name; + + /* skip known ignorable paths */ + if (!strcmp(name_dev, ".") || !strcmp(name_dev, "..") || + !strcmp(name_dev, "bdi") || + !strcmp(name_dev, "dev") || + !strcmp(name_dev, "device") || + !strcmp(name_dev, "holders") || + !strcmp(name_dev, "integrity") || + !strcmp(name_dev, "loop") || + !strcmp(name_dev, "queueu") || + !strcmp(name_dev, "md") || + !strcmp(name_dev, "mq") || + !strcmp(name_dev, "power") || + !strcmp(name_dev, "removable") || + !strcmp(name_dev, "slave") || + !strcmp(name_dev, "slaves") || + !strcmp(name_dev, "subsystem") || + !strcmp(name_dev, "trace") || + !strcmp(name_dev, "uevent")) + continue; + + if (dm_snprintf(path, sizeof(path), "%sblock/%s/%s/dev", + _sysfs_dir, name, name_dev) == -1) { + log_warn("Couldn't create path for %s/%s.", name, name_dev); + continue; + } + + if (_sysfs_get_dev_major_minor(path, major, minor)) { + r = dm_strncpy(buf, name_dev, buf_size); + break; /* found */ + } + } + + if (closedir(d_dev)) + log_sys_debug("closedir", name); + } + } + + if (closedir(d)) + log_sys_debug("closedir", path); + + return r; +} + static int _sysfs_get_kernel_name(uint32_t major, uint32_t minor, char *buf, size_t buf_size) { char *name, *sysfs_path, *temp_buf = NULL; @@ -1894,8 +2009,10 @@ static int _sysfs_get_kernel_name(uint32_t major, uint32_t minor, char *buf, siz if ((size = readlink(sysfs_path, temp_buf, PATH_MAX - 1)) < 0) { if (errno != ENOENT) log_sys_error("readlink", sysfs_path); - else + else { log_sys_debug("readlink", sysfs_path); + return _sysfs_find_kernel_name(major, minor, buf, buf_size); + } goto bad; } temp_buf[size] = '\0';