| Message ID | 1464972610-24115-1-git-send-email-cjp256@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Chris Patterson writes ("[PATCH v3 1/2] libxl: replace deprecated readdir_r() with readdir()"):
> From: Chris Patterson <pattersonc@ainfosec.com>
>
> Replace the usage of readdir_r() with readdir() to address a
> compilation error under glibc due to the deprecation of readdir_r
> for their next release (2.24) [1, 2].
>
> Remove code specific to usage of readdir_r which is no longer required,
> such as zalloc_dirent().
Great, thanks.
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Ian.
On Fri, Jun 03, 2016 at 05:59:42PM +0100, Ian Jackson wrote: > Chris Patterson writes ("[PATCH v3 1/2] libxl: replace deprecated readdir_r() with readdir()"): > > From: Chris Patterson <pattersonc@ainfosec.com> > > > > Replace the usage of readdir_r() with readdir() to address a > > compilation error under glibc due to the deprecation of readdir_r > > for their next release (2.24) [1, 2]. > > > > Remove code specific to usage of readdir_r which is no longer required, > > such as zalloc_dirent(). > > Great, thanks. > > Acked-by: Ian Jackson <ian.jackson@eu.citrix.com> > Thanks both. I think we can take this series for 4.7. I've queued it up. Wei. > Ian.
On Fri, Jun 3, 2016 at 5:50 PM, Chris Patterson <cjp256@gmail.com> wrote: > From: Chris Patterson <pattersonc@ainfosec.com> > > Replace the usage of readdir_r() with readdir() to address a > compilation error under glibc due to the deprecation of readdir_r > for their next release (2.24) [1, 2]. > > Remove code specific to usage of readdir_r which is no longer required, > such as zalloc_dirent(). > > -- > > From the GNU libc manual [3]: > " > It is expected that future versions of POSIX will obsolete readdir_r and > mandate the level of thread safety for readdir which is provided by the > GNU C Library and other implementations today. > " > > There is a filed bug in the Austin Group Defect Tracker [4] in which 'dalias' > proposes (in comment 0001632) that: > " > I would like to propose an alternate solution. For readdir, replace the text: > "The readdir() function need not be thread-safe." > with: > "If multiple threads call the readdir() function with the same directory > stream argument and without synchronization to preclude simultaneous > access, then the behavior is undefined." > > With this change, the clunky readdir_r function is no longer needed or > useful, and should probably be deprecated. As the only reasonable way > to meet the implementation requirements for readdir is to have the dirent > buffer in the DIR structure, this change should not require any change to > existing implementations. > " > > [1] https://sourceware.org/ml/libc-alpha/2016-02/msg00093.html > [2] https://sourceware.org/bugzilla/show_bug.cgi?id=19056 > [3] https://www.gnu.org/software/libc/manual/html_node/Reading_002fClosing-Directory.html > [4] http://austingroupbugs.net/view.php?id=696 > > Signed-off-by: Chris Patterson <pattersonc@ainfosec.com> Jan, These patches should be backported to the 4.6 branch (and earlier?) as well. The commits are b9daff9 and c2a1786 if you want to cherry-pick them. (b9daff9 doesn't apply quite cleanly because libxl_pvusb.c doesn't exist). -George
diff --git a/tools/libxl/libxl_pvusb.c b/tools/libxl/libxl_pvusb.c index 9f1e842..ec97ff8 100644 --- a/tools/libxl/libxl_pvusb.c +++ b/tools/libxl/libxl_pvusb.c @@ -508,19 +508,10 @@ int libxl_devid_to_device_usbctrl(libxl_ctx *ctx, return rc; } -static void *zalloc_dirent(libxl__gc *gc, const char *dirpath) -{ - size_t need = offsetof(struct dirent, d_name) + - pathconf(dirpath, _PC_NAME_MAX) + 1; - - return libxl__zalloc(gc, need); -} - static char *usbdev_busaddr_to_busid(libxl__gc *gc, int bus, int addr) { DIR *dir; char *busid = NULL; - struct dirent *de_buf; struct dirent *de; /* invalid hostbus or hostaddr */ @@ -533,16 +524,15 @@ static char *usbdev_busaddr_to_busid(libxl__gc *gc, int bus, int addr) return NULL; } - de_buf = zalloc_dirent(gc, SYSFS_USB_DEV); - for (;;) { char *filename; void *buf; int busnum = -1; int devnum = -1; - int r = readdir_r(dir, de_buf, &de); - if (r) { + errno = 0; + de = readdir(dir); + if (!de && errno) { LOGE(ERROR, "failed to readdir %s", SYSFS_USB_DEV); break; } @@ -1157,7 +1147,6 @@ static int usbdev_get_all_interfaces(libxl__gc *gc, const char *busid, { DIR *dir; char *buf; - struct dirent *de_buf; struct dirent *de; int rc; @@ -1172,12 +1161,11 @@ static int usbdev_get_all_interfaces(libxl__gc *gc, const char *busid, return ERROR_FAIL; } - de_buf = zalloc_dirent(gc, SYSFS_USB_DEV); - for (;;) { - int r = readdir_r(dir, de_buf, &de); + errno = 0; + de = readdir(dir); - if (r) { + if (!de && errno) { LOGE(ERROR, "failed to readdir %s", SYSFS_USB_DEV); rc = ERROR_FAIL; goto out; diff --git a/tools/libxl/libxl_utils.c b/tools/libxl/libxl_utils.c index ceb8825..4ca6bcb 100644 --- a/tools/libxl/libxl_utils.c +++ b/tools/libxl/libxl_utils.c @@ -548,14 +548,12 @@ int libxl__remove_directory(libxl__gc *gc, const char *dirpath) goto out; } - size_t need = offsetof(struct dirent, d_name) + - pathconf(dirpath, _PC_NAME_MAX) + 1; - struct dirent *de_buf = libxl__zalloc(gc, need); struct dirent *de; for (;;) { - int r = readdir_r(d, de_buf, &de); - if (r) { + errno = 0; + de = readdir(d); + if (!de && errno) { LOGE(ERROR, "failed to readdir %s for removal", dirpath); rc = ERROR_FAIL; break;