From: Karel Zak Date: Fri, 25 Sep 2009 12:40:23 +0000 (+0200) Subject: libblkid: use fstatat(), improve readdir() usage X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f38fd19d2b0367f5f4517ba30a8964802c7ce1ab;p=util-linux libblkid: use fstatat(), improve readdir() usage * fix possible memory leak in ubi_probe_all() * use dirent->d_type if available (this is tricky, because d_type is not supported on all systems and some filesystems returns DT_UNKNOWN). The dirent->d_type allows to avoid unnecessary stat() calls. * use fstatat() if available -- allows to avoid malloc() and sprintf("%s/%s", dirname, dirent->d_name) Signed-off-by: Karel Zak --- diff --git a/TODO b/TODO index 44fb2f85..bf2c5f9a 100644 --- a/TODO +++ b/TODO @@ -26,8 +26,6 @@ libblkid [ -- Christoph Hellwig, 16 Feb 2009 ] (1) http://git.kernel.org/?p=fs/xfs/xfsprogs-dev.git;a=tree;f=libdisk; - - use fstatat() in blkid__scan_dir() - - add values: FSSIZE -- filesystem size (klibc requirement) diff --git a/shlibs/blkid/src/blkidP.h b/shlibs/blkid/src/blkidP.h index 68116c0c..d09529ef 100644 --- a/shlibs/blkid/src/blkidP.h +++ b/shlibs/blkid/src/blkidP.h @@ -17,6 +17,8 @@ #define CONFIG_BLKID_DEBUG 1 #include +#include +#include #include #include @@ -279,6 +281,9 @@ struct blkid_struct_cache extern char *blkid_strdup(const char *s); extern char *blkid_strndup(const char *s, const int length); +extern char *blkid_strconcat(const char *a, const char *b, const char *c); +extern int blkid_fstatat(DIR *dir, const char *dirname, const char *filename, + struct stat *st, int nofollow); #define BLKID_CACHE_FILE "/etc/blkid.tab" #define BLKID_CONFIG_FILE "/etc/blkid.conf" diff --git a/shlibs/blkid/src/devname.c b/shlibs/blkid/src/devname.c index 1acb9d5a..fe0d1b33 100644 --- a/shlibs/blkid/src/devname.c +++ b/shlibs/blkid/src/devname.c @@ -407,35 +407,31 @@ ubi_probe_all(blkid_cache cache, int only_if_new) continue ; while ((iter = readdir(dir)) != NULL) { - char *name, *device; + char *name; struct stat st; dev_t dev; name = iter->d_name; - +#ifdef _DIRENT_HAVE_D_TYPE + if (iter->d_type != DT_UNKNOWN && + iter->d_type != DT_CHR && iter->d_type != DT_LNK) + continue; +#endif if (!strcmp(name, ".") || !strcmp(name, "..") || !strstr(name, "ubi")) continue; if (!strcmp(name, "ubi_ctrl")) continue; - device = malloc(strlen(*dirname) + strlen(name) + 2); - if (!device) - break ; - sprintf(device, "%s/%s", *dirname, name); - if (stat(device, &st)) - break ; - - if (!(st.st_rdev & 0xFF)) { // It's an UBI Device - free(device); - continue ; - } + if (blkid_fstatat(dir, *dirname, name, &st, 0)) + continue; + dev = st.st_rdev; - DBG(DEBUG_DEVNAME, printf("UBI vol %s: devno 0x%04X\n", - device, - (int) dev)); - probe_one(cache, name, dev, BLKID_PRI_UBI, - only_if_new); - free(device); + + if (!S_ISCHR(st.st_mode) || !minor(dev)) + continue; + DBG(DEBUG_DEVNAME, printf("UBI vol %s/%s: devno 0x%04X\n", + *dirname, name, (int) dev)); + probe_one(cache, name, dev, BLKID_PRI_UBI, only_if_new); } closedir(dir); } diff --git a/shlibs/blkid/src/devno.c b/shlibs/blkid/src/devno.c index 8518f9fd..11f212ef 100644 --- a/shlibs/blkid/src/devno.c +++ b/shlibs/blkid/src/devno.c @@ -30,6 +30,7 @@ #if HAVE_SYS_MKDEV_H #include #endif +#include #include "blkidP.h" #include "pathnames.h" @@ -57,17 +58,68 @@ char *blkid_strdup(const char *s) return blkid_strndup(s, 0); } +char *blkid_strconcat(const char *a, const char *b, const char *c) +{ + char *res, *p; + size_t len, al, bl, cl; + + al = a ? strlen(a) : 0; + bl = b ? strlen(b) : 0; + cl = c ? strlen(c) : 0; + + len = al + bl + cl; + if (!len) + return NULL; + p = res = malloc(len + 1); + if (!res) + return NULL; + if (al) { + memcpy(p, a, al); + p += al; + } + if (bl) { + memcpy(p, b, bl); + p += bl; + } + if (cl) { + memcpy(p, c, cl); + p += cl; + } + *p = '\0'; + return res; +} + +int blkid_fstatat(DIR *dir, const char *dirname, const char *filename, + struct stat *st, int nofollow) +{ +#ifdef HAVE_FSTATAT + return fstatat(dirfd(dir), filename, st, + nofollow ? AT_SYMLINK_NOFOLLOW : 0); +#else + char device[PATH_MAX]; + int len; + + len = snprintf(device, sizeof(device), "%s/%s", *dirname, name); + if (len < 0 || len + 1 > sizeof(path)) + return -1; + + return nofollow ? lstat(device, st) : stat(device, st); +#endif +} + /* * This function adds an entry to the directory list */ -static void add_to_dirlist(const char *name, struct dir_list **list) +static void add_to_dirlist(const char *dir, const char *subdir, + struct dir_list **list) { struct dir_list *dp; dp = malloc(sizeof(struct dir_list)); if (!dp) return; - dp->name = blkid_strdup(name); + dp->name = subdir ? blkid_strconcat(dir, "/", subdir) : + blkid_strdup(dir); if (!dp->name) { free(dp); return; @@ -96,36 +148,48 @@ void blkid__scan_dir(char *dirname, dev_t devno, struct dir_list **list, { DIR *dir; struct dirent *dp; - char path[1024]; - int dirlen; struct stat st; if ((dir = opendir(dirname)) == NULL) return; - dirlen = strlen(dirname) + 2; + while ((dp = readdir(dir)) != 0) { - if (dirlen + strlen(dp->d_name) >= sizeof(path)) +#ifdef _DIRENT_HAVE_D_TYPE + if (dp->d_type != DT_UNKNOWN && dp->d_type != DT_BLK && + dp->d_type != DT_LNK && dp->d_type != DT_DIR) continue; - +#endif if (dp->d_name[0] == '.' && ((dp->d_name[1] == 0) || ((dp->d_name[1] == '.') && (dp->d_name[2] == 0)))) continue; - sprintf(path, "%s/%s", dirname, dp->d_name); - if (stat(path, &st) < 0) + if (blkid_fstatat(dir, dirname, dp->d_name, &st, 0)) continue; if (S_ISBLK(st.st_mode) && st.st_rdev == devno) { - *devname = blkid_strdup(path); + *devname = blkid_strconcat(dirname, "/", dp->d_name); DBG(DEBUG_DEVNO, - printf("found 0x%llx at %s (%p)\n", (long long)devno, - path, *devname)); + printf("found 0x%llx at %s\n", (long long)devno, + *devname)); break; } - if (list && S_ISDIR(st.st_mode) && !lstat(path, &st) && - S_ISDIR(st.st_mode)) - add_to_dirlist(path, list); + + if (!list || !S_ISDIR(st.st_mode)) + continue; + + /* add subdirectory (but not symlink) to the list */ +#ifdef _DIRENT_HAVE_D_TYPE + if (dp->d_type == DT_LNK) + continue; + if (dp->d_type == DT_UNKNOWN) +#endif + { + if (blkid_fstatat(dir, dirname, dp->d_name, &st, 1) || + !S_ISDIR(st.st_mode)) + continue; /* symlink or lstat() failed */ + } + add_to_dirlist(dirname, dp->d_name, list); } closedir(dir); return; @@ -161,7 +225,7 @@ char *blkid_devno_to_devname(dev_t devno) * importance, since we are using a stack... */ for (dir = devdirs; *dir; dir++) - add_to_dirlist(*dir, &list); + add_to_dirlist(*dir, NULL, &list); while (list) { struct dir_list *current = list;