mirror/guile
mirror/guile
1
Fork 0
mirror of https://git.savannah.gnu.org/git/guile.git synced 2025-05-20 11:40:18 +02:00
Code Activity

'readdir' no longer deadlocks upon error.

Browse source 
If 'readdir' returned an error, we'd call SCM_SYSERROR, which would try
to acquire 'scm_i_misc_mutex' and sit there forever because it was
already taken.

Reported at <https://bugs.gnu.org/29335>.

* libguile/filesys.c (scm_opendir): Allocate storage for a mutex and
store it as the third word of the SMOB.
(scm_readdir): Use that mutex instead of 'scm_i_misc_mutex'.  Fixes the
deadlock upon error.
(scm_rewindir): Lock the mutex around the 'rewinddir' call.
This commit is contained in:
Ludovic Courtès 2017-11-17 23:05:53 +01:00
parent 6ad28ae3bc
commit 187655cedb
1 changed files with 19 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

21
libguile/filesys.c
View file

@ -1727,10 +1727,17 @@ SCM_DEFINE (scm_opendir, "opendir", 1, 0, 0,
#define FUNC_NAME s_scm_opendir
{
DIR *ds;
scm_i_pthread_mutex_t *mutex;
mutex = scm_gc_malloc_pointerless (sizeof *mutex, "dirstream-mutex");
scm_i_pthread_mutex_init (mutex, NULL);
STRING_SYSCALL (dirname, c_dirname, ds = opendir (c_dirname));
if (ds == NULL)
SCM_SYSERROR;
SCM_RETURN_NEWSMOB (scm_tc16_dir | (SCM_DIR_FLAG_OPEN<<16), ds);
SCM_RETURN_NEWSMOB2 (scm_tc16_dir | (SCM_DIR_FLAG_OPEN << 16),
ds, SCM_PACK_POINTER (mutex));
}
#undef FUNC_NAME
@ -1743,14 +1750,17 @@ SCM_DEFINE (scm_readdir, "readdir", 1, 0, 0,
#define FUNC_NAME s_scm_readdir
{
SCM ret;
scm_i_pthread_mutex_t *mutex;
struct dirent_or_dirent64 *rdent;
SCM_VALIDATE_DIR (1, port);
if (!SCM_DIR_OPEN_P (port))
SCM_MISC_ERROR ("Directory ~S is not open.", scm_list_1 (port));
mutex = (scm_i_pthread_mutex_t *) SCM_SMOB_DATA_2 (port);
scm_dynwind_begin (0);
scm_i_dynwind_pthread_mutex_lock (&scm_i_misc_mutex);
scm_i_dynwind_pthread_mutex_lock (mutex);
errno = 0;
SCM_SYSCALL (rdent = readdir_or_readdir64 ((DIR *) SCM_SMOB_DATA_1 (port)));
@ -1761,6 +1771,7 @@ SCM_DEFINE (scm_readdir, "readdir", 1, 0, 0,
: SCM_EOF_VAL);
scm_dynwind_end ();
return ret;
}
#undef FUNC_NAME
@ -1772,11 +1783,17 @@ SCM_DEFINE (scm_rewinddir, "rewinddir", 1, 0, 0,
"@code{readdir} will return the first directory entry.")
#define FUNC_NAME s_scm_rewinddir
{
scm_i_pthread_mutex_t *mutex;
SCM_VALIDATE_DIR (1, port);
if (!SCM_DIR_OPEN_P (port))
SCM_MISC_ERROR ("Directory ~S is not open.", scm_list_1 (port));
mutex = (scm_i_pthread_mutex_t *) SCM_SMOB_DATA_2 (port);
scm_i_pthread_mutex_lock (mutex);
rewinddir ((DIR *) SCM_SMOB_DATA_1 (port));
scm_i_pthread_mutex_unlock (mutex);
return SCM_UNSPECIFIED;
}