diff options
Diffstat (limited to 'ext2fs')
| -rw-r--r-- | ext2fs/dir.c | 43 |
1 files changed, 39 insertions, 4 deletions
diff --git a/ext2fs/dir.c b/ext2fs/dir.c index 06125d70..1467f70d 100644 --- a/ext2fs/dir.c +++ b/ext2fs/dir.c @@ -1,6 +1,6 @@ /* Directory management routines - Copyright (C) 1994, 1995 Free Software Foundation, Inc. + Copyright (C) 1994, 1995, 1996 Free Software Foundation, Inc. Converted for ext2fs by Miles Bader <miles@gnu.ai.mit.edu> @@ -23,6 +23,7 @@ #include <string.h> #include <stdio.h> #include <dirent.h> +#include <stddef.h> /* This isn't quite right because a file system block may straddle several device blocks, and so a write failure between writing two device blocks @@ -349,7 +350,7 @@ dirscanblock (vm_address_t blockaddr, struct node *dp, int idx, char *name, entry = (struct ext2_dir_entry *)currentoff; if (!entry->rec_len - || entry->rec_len % 4 + || entry->rec_len % EXT2_DIR_PAD || entry->name_len > EXT2_NAME_LEN || currentoff + entry->rec_len > blockaddr + DIRBLKSIZ || EXT2_DIR_REC_LEN (entry->name_len) > entry->rec_len @@ -769,6 +770,10 @@ count_dirents (struct node *dp, int nb, char *buf) return 0; } +/* Returned directory entries are aligned to blocks this many bytes long. + Must be a power of two. */ +#define DIRENT_ALIGN 4 + /* Implement the disikfs_get_directs callback as described in <hurd/diskfs.h>. */ error_t @@ -805,7 +810,25 @@ diskfs_get_directs (struct node *dp, /* Allocate enough space to hold the maximum we might return */ if (!bufsiz || bufsiz > dp->dn_stat.st_size) - allocsize = round_page (dp->dn_stat.st_size); + /* Allocate enough to return the entire directory. Since ext2's + directory format is different than the format used to return the + entries, we allocate enough to hold the on disk directory plus + whatever extra would be necessary in the worst-case. */ + { + /* The minimum size of an ext2fs directory entry. */ + size_t min_entry_size = EXT2_DIR_REC_LEN (0); + /* The minimum size of a returned dirent entry. The +1 is for '\0'. */ + size_t min_dirent_size = offsetof (struct dirent, d_name) + 1; + /* The maximum possible number of ext2fs dir entries in this dir. */ + size_t max_entries = dp->dn_stat.st_size / min_entry_size; + /* The maximum difference in size per directory entry. */ + size_t entry_extra = + DIRENT_ALIGN + + (min_dirent_size > min_entry_size + ? min_dirent_size - min_entry_size : 0); + + allocsize = round_page (dp->dn_stat.st_size + max_entries * entry_extra); + } else allocsize = round_page (bufsiz); @@ -897,7 +920,19 @@ diskfs_get_directs (struct node *dp, /* Length is structure before the name + the name + '\0', all padded to a four-byte alignment. */ rec_len = - (((char *)&userp->d_name - (char *)userp) + name_len + 1 + 3) & ~3; + ((offsetof (struct dirent, d_name) + + name_len + 1 + + (DIRENT_ALIGN - 1)) + & ~(DIRENT_ALIGN - 1)); + + /* See if this record would run over the end of the return buffer. */ + if (bufsiz == 0) + /* It shouldn't ever, as we calculated the worst case size. */ + assert (datap + rec_len <= *data + allocsize); + else + /* It's ok if it does, just leave off returning this entry. */ + if (datap + rec_len > *data + allocsize) + break; userp->d_fileno = entryp->inode; userp->d_reclen = rec_len; |