Attachment 6904 Details for Bug 8466 – Fix invalid assumption about dirent structure definition

[patch] Fix invalid assumption about dirent structure definition

0004-Fix-invalid-assumption-about-dirent-structure-defini.patch (text/plain), 7.06 KB, created by (account disabled) on 2011-09-17 05:27:44 UTC

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Created: 2011-09-17 05:27:44 UTC

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patch

obsolete

>From 80d40805c3073f97251595d63cea2a1fff1cf2f1 Mon Sep 17 00:00:00 2001
>Date: Tue, 30 Aug 2011 18:10:12 -0700
>Subject: [PATCH 4/5] Fix invalid assumption about dirent structure definition.
>
>The code assumed that dirent.d_name is statically defined as an array
>large enough to hold the name. On Solaris this isn't the case: d_name
>is defined as 'char d_name[1]'. Posix also does not specify that the
>static definition must be a full-sized array.
>
>One implication of this is that dirent's need not all be the same size.
>
>The fix here therefore removes both those assumptions. It allocates a
>buffer that contains a set of pointers to dirent's, followed by the actual
>dirent's. Furthermore it copies the individual dirent's based on their
>actual dynamic size, not the static size of the struct. As an optimization
>it makes use of popular, but non-posix-defined struct members where
>available to efficiently determine the size, but falls back to the always
>correct strlen() if these are not available.
>
>A side effect of this is that this reduces the memory use quite
>significantly in most cases.
>---
> source3/configure.in          |    2 +
> source3/m4/aclocal.m4         |   26 ++++++++++++++++++++++++
> source3/modules/vfs_dirsort.c |   44 +++++++++++++++++++++++++++++++---------
> source3/wscript               |    6 +++++
> 4 files changed, 68 insertions(+), 10 deletions(-)
>
>diff --git a/source3/configure.in b/source3/configure.in
>index 73c80c3..9ca89bd 100644
>--- a/source3/configure.in
>+++ b/source3/configure.in
>@@ -822,6 +822,8 @@ AC_STRUCT_ST_RDEV
> AC_DIRENT_D_OFF
> AC_DIR_D_FD
> AC_DIR_DD_FD
>+AC_DIRENT_D_RECLEN
>+AC_DIRENT_D_NAMLEN
> AC_CHECK_TYPE(ssize_t, int)
> AC_CHECK_TYPE(wchar_t, unsigned short)
> 
>diff --git a/source3/m4/aclocal.m4 b/source3/m4/aclocal.m4
>index 9fb9431..466d19d 100644
>--- a/source3/m4/aclocal.m4
>+++ b/source3/m4/aclocal.m4
>@@ -37,6 +37,32 @@ if test $ac_cv_dir_dd_fd = yes; then
> fi
> ])
> 
>+dnl test whether dirent has a d_reclen member
>+AC_DEFUN(AC_DIRENT_D_RECLEN,
>+[AC_CACHE_CHECK([for d_reclen in dirent], ac_cv_dirent_d_reclen,
>+[AC_TRY_COMPILE([
>+#include <unistd.h>
>+#include <sys/types.h>
>+#include <dirent.h>], [struct dirent d; d.d_reclen;],
>+ac_cv_dirent_d_reclen=yes, ac_cv_dirent_d_reclen=no)])
>+if test $ac_cv_dirent_d_reclen = yes; then
>+  AC_DEFINE(HAVE_DIRENT_D_RECLEN,1,[Whether dirent has a d_reclen member])
>+fi
>+])
>+
>+dnl test whether dirent has a d_namlen member
>+AC_DEFUN(AC_DIRENT_D_NAMLEN,
>+[AC_CACHE_CHECK([for d_namlen in dirent], ac_cv_dirent_d_namlen,
>+[AC_TRY_COMPILE([
>+#include <unistd.h>
>+#include <sys/types.h>
>+#include <dirent.h>], [struct dirent d; d.d_namlen;],
>+ac_cv_dirent_d_namlen=yes, ac_cv_dirent_d_namlen=no)])
>+if test $ac_cv_dirent_d_namlen = yes; then
>+  AC_DEFINE(HAVE_DIRENT_D_NAMLEN,1,[Whether dirent has a d_namlen member])
>+fi
>+])
>+
> dnl Mark specified module as shared
> dnl SMB_MODULE(name,static_files,shared_files,subsystem,whatif-static,whatif-shared)
> AC_DEFUN(SMB_MODULE,
>diff --git a/source3/modules/vfs_dirsort.c b/source3/modules/vfs_dirsort.c
>index c3070de..38154ff 100644
>--- a/source3/modules/vfs_dirsort.c
>+++ b/source3/modules/vfs_dirsort.c
>@@ -32,14 +32,27 @@
> #error "need either dirfd, DIR.d_fd, or DIR.dd_fd"
> #endif
> 
>-static int compare_dirent (const SMB_STRUCT_DIRENT *da, const SMB_STRUCT_DIRENT *db)
>+#ifdef HAVE_DIRENT_D_RECLEN
>+#define DIRENT_RECLEN(rec) (rec->d_reclen)
>+#elif HAVE_DIRENT_D_NAMLEN
>+#define DIRENT_RECLEN(rec) \
>+	((offsetof(SMB_STRUCT_DIRENT, d_name[0]) + \
>+	  (rec->d_namlen) + 1 + 7) & ~7)
>+#else
>+#define DIRENT_RECLEN(rec) \
>+	((offsetof(SMB_STRUCT_DIRENT, d_name[0]) + \
>+	  (strlen(rec->d_name)) + 1 + 7) & ~7)
>+#endif
>+
>+static int compare_dirent(SMB_STRUCT_DIRENT * const *da,
>+			  SMB_STRUCT_DIRENT * const *db)
> {
>-	return StrCaseCmp(da->d_name, db->d_name);
>+	return StrCaseCmp((*da)->d_name, (*db)->d_name);
> }
> 
> struct dirsort_privates {
> 	long pos;
>-	SMB_STRUCT_DIRENT *directory_list;
>+	SMB_STRUCT_DIRENT **directory_list;
> 	long number_of_entries;
> 	time_t mtime;
> 	SMB_STRUCT_DIR *source_directory;
>@@ -60,20 +73,25 @@ static bool open_and_sort_dir (vfs_handle_struct *handle)
> 	SMB_STRUCT_DIRENT *dp;
> 	struct stat dir_stat;
> 	long current_pos;
>+	unsigned dirents_size;
>+	char *next_dirent;
>+	unsigned reclen;
> 	struct dirsort_privates *data = NULL;
> 
> 	SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
> 				return false);
> 
> 	data->number_of_entries = 0;
>+	dirents_size = 0;
> 
> 	if (fstat(data->fd, &dir_stat) == 0) {
> 		data->mtime = dir_stat.st_mtime;
> 	}
> 
>-	while (SMB_VFS_NEXT_READDIR(handle, data->source_directory, NULL)
>-	       != NULL) {
>+	while ((dp = SMB_VFS_NEXT_READDIR(handle, data->source_directory,
>+					  NULL)) != NULL) {
> 		data->number_of_entries++;
>+		dirents_size += sizeof(SMB_STRUCT_DIRENT *) + DIRENT_RECLEN(dp);
> 	}
> 
> 	/* Open the underlying directory and count the number of entries
>@@ -82,18 +100,24 @@ static bool open_and_sort_dir (vfs_handle_struct *handle)
> 
> 	/* Set up an array and read the directory entries into it */
> 	SAFE_FREE(data->directory_list); /* destroy previous cache if needed */
>-	data->directory_list = (SMB_STRUCT_DIRENT *)SMB_MALLOC(
>-		data->number_of_entries * sizeof(SMB_STRUCT_DIRENT));
>+	data->directory_list = (SMB_STRUCT_DIRENT **)SMB_MALLOC(dirents_size);
> 	if (!data->directory_list) {
> 		return false;
> 	}
> 	current_pos = data->pos;
> 	data->pos = 0;
>+	next_dirent = (char *) &data->directory_list[data->number_of_entries];
> 	while ((dp = SMB_VFS_NEXT_READDIR(handle, data->source_directory,
> 					  NULL)) != NULL) {
>-		if (data->pos >= data->number_of_entries)
>+		reclen = DIRENT_RECLEN(dp);
>+		if (data->pos >= data->number_of_entries ||
>+		    next_dirent + reclen >
>+			    ((char *) data->directory_list) + dirents_size)
> 			break;		/* directory changed since opendir */
>-		data->directory_list[data->pos++] = *dp;
>+		data->directory_list[data->pos++] =
>+			(SMB_STRUCT_DIRENT *) next_dirent;
>+		memcpy(next_dirent, dp, reclen);
>+		next_dirent += reclen;
> 	}
> 
> 	/* Sort the directory entries by name */
>@@ -209,7 +233,7 @@ static SMB_STRUCT_DIRENT *dirsort_readdir(vfs_handle_struct *handle,
> 		return NULL;
> 	}
> 
>-	return &data->directory_list[data->pos++];
>+	return data->directory_list[data->pos++];
> }
> 
> static void dirsort_seekdir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp,
>diff --git a/source3/wscript b/source3/wscript
>index ecbc58a..264889c 100644
>--- a/source3/wscript
>+++ b/source3/wscript
>@@ -529,6 +529,12 @@ msg.msg_acctrightslen = sizeof(fd);
>     conf.CHECK_STRUCTURE_MEMBER('struct dirent', 'd_off',
>                                 headers='unistd.h sys/types.h dirent.h',
>                                 define='HAVE_DIRENT_D_OFF')
>+    conf.CHECK_STRUCTURE_MEMBER('struct dirent', 'd_reclen',
>+                                headers='unistd.h sys/types.h dirent.h',
>+                                define='HAVE_DIRENT_D_RECLEN')
>+    conf.CHECK_STRUCTURE_MEMBER('struct dirent', 'd_namlen',
>+                                headers='unistd.h sys/types.h dirent.h',
>+                                define='HAVE_DIRENT_D_NAMLEN')
> 
>     conf.CHECK_FUNCS('setnetgrent getnetgrent endnetgrent')
>     if conf.CHECK_CFLAGS('-Werror-implicit-function-declaration'):
>-- 
>1.7.3.4
>

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Attachments on bug 8466: 6904