/* vi: set sw=4 ts=4: */ /* * Utility routines. * * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ #include "libbb.h" /* Find block device /dev/XXX which contains specified file * We handle /dev/dir/dir/dir too, at a cost of ~80 more bytes code */ /* Do not reallocate all this stuff on each recursion */ enum { DEVNAME_MAX = 256 }; struct arena { struct stat st; dev_t dev; /* Was PATH_MAX, but we recurse _/dev_. We can assume * people are not crazy enough to have mega-deep tree there */ char devpath[DEVNAME_MAX]; }; static char *find_block_device_in_dir(struct arena *ap) { DIR *dir; struct dirent *entry; char *retpath = NULL; int len, rem; len = strlen(ap->devpath); rem = DEVNAME_MAX-2 - len; if (rem <= 0) return NULL; dir = opendir(ap->devpath); if (!dir) return NULL; ap->devpath[len++] = '/'; while ((entry = readdir(dir)) != NULL) { safe_strncpy(ap->devpath + len, entry->d_name, rem); /* lstat: do not follow links */ if (lstat(ap->devpath, &ap->st) != 0) continue; if (S_ISBLK(ap->st.st_mode) && ap->st.st_rdev == ap->dev) { retpath = xstrdup(ap->devpath); break; } if (S_ISDIR(ap->st.st_mode)) { /* Do not recurse for '.' and '..' */ if (DOT_OR_DOTDOT(entry->d_name)) continue; retpath = find_block_device_in_dir(ap); if (retpath) break; } } closedir(dir); return retpath; } char* FAST_FUNC find_block_device(const char *path) { struct arena a; if (stat(path, &a.st) != 0) return NULL; a.dev = S_ISBLK(a.st.st_mode) ? a.st.st_rdev : a.st.st_dev; strcpy(a.devpath, "/dev"); return find_block_device_in_dir(&a); }