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authorLudovic Courtès <ludo@gnu.org>2017-11-17 23:05:53 +0100
committerLudovic Courtès <ludo@gnu.org>2017-11-17 23:05:53 +0100
commit187655cedb42cc4b01088179649b02295cd35260 (patch)
tree102b56348466a44ecb61c68e842d8173731e49b2 /libguile/filesys.c
parent6ad28ae3bc6a6d9e95ab7d70510d12c97673a143 (diff)
downloadguile-187655cedb42cc4b01088179649b02295cd35260.tar.gz
'readdir' no longer deadlocks upon error.
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.
Diffstat (limited to 'libguile/filesys.c')
-rw-r--r--libguile/filesys.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/libguile/filesys.c b/libguile/filesys.c
index af283dd5e..d146f50ef 100644
--- a/libguile/filesys.c
+++ b/libguile/filesys.c
@@ -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;
}