BUG/MAJOR: map: fix segfault during 'show map/acl' on cli.
The reference of the current map/acl element to dump could
be destroyed if map is updated from an 'http-request del-map'
configuration rule or throught a 'del map/acl' on CLI.
We use a 'back_refs' chaining element to fix this. As it
is done to dump sessions.
This patch needs also fix:
'BUG/MAJOR: cli: fix custom io_release was crushed by NULL.'
To clean the back_ref and avoid a crash on a further
del/clear map operation.
Those fixes should be backported on mainline branches 1.7 and 1.6.
This patch wont directly apply on 1.6.
diff --git a/include/types/applet.h b/include/types/applet.h
index 71976d8..5c1b074 100644
--- a/include/types/applet.h
+++ b/include/types/applet.h
@@ -141,7 +141,7 @@
struct {
unsigned int display_flags;
struct pat_ref *ref;
- struct pat_ref_elt *elt;
+ struct bref bref; /* back-reference from the pat_ref_elt being dumped */
struct pattern_expr *expr;
struct chunk chunk;
} map;
diff --git a/include/types/pattern.h b/include/types/pattern.h
index 912e086..d7ce613 100644
--- a/include/types/pattern.h
+++ b/include/types/pattern.h
@@ -114,6 +114,7 @@
*/
struct pat_ref_elt {
struct list list; /* Used to chain elements. */
+ struct list back_refs; /* list of users tracking this pat ref */
char *pattern;
char *sample;
int line;
diff --git a/src/map.c b/src/map.c
index e8c6a2a..0c48683 100644
--- a/src/map.c
+++ b/src/map.c
@@ -299,44 +299,67 @@
static int cli_io_handler_pat_list(struct appctx *appctx)
{
struct stream_interface *si = appctx->owner;
+ struct pat_ref_elt *elt;
+
+ if (unlikely(si_ic(si)->flags & (CF_WRITE_ERROR|CF_SHUTW))) {
+ /* If we're forced to shut down, we might have to remove our
+ * reference to the last ref_elt being dumped.
+ */
+ if (appctx->st2 == STAT_ST_LIST) {
+ if (!LIST_ISEMPTY(&appctx->ctx.sess.bref.users)) {
+ LIST_DEL(&appctx->ctx.sess.bref.users);
+ LIST_INIT(&appctx->ctx.sess.bref.users);
+ }
+ }
+ return 1;
+ }
switch (appctx->st2) {
case STAT_ST_INIT:
- /* Init to the first entry. The list cannot be change */
- appctx->ctx.map.elt = LIST_NEXT(&appctx->ctx.map.ref->head,
- struct pat_ref_elt *, list);
- if (&appctx->ctx.map.elt->list == &appctx->ctx.map.ref->head)
- appctx->ctx.map.elt = NULL;
+ /* the function had not been called yet, let's prepare the
+ * buffer for a response. We initialize the current stream
+ * pointer to the first in the global list. When a target
+ * stream is being destroyed, it is responsible for updating
+ * this pointer. We know we have reached the end when this
+ * pointer points back to the head of the streams list.
+ */
+ LIST_INIT(&appctx->ctx.map.bref.users);
+ appctx->ctx.map.bref.ref = appctx->ctx.map.ref->head.n;
appctx->st2 = STAT_ST_LIST;
/* fall through */
case STAT_ST_LIST:
- while (appctx->ctx.map.elt) {
+ if (!LIST_ISEMPTY(&appctx->ctx.map.bref.users)) {
+ LIST_DEL(&appctx->ctx.map.bref.users);
+ LIST_INIT(&appctx->ctx.map.bref.users);
+ }
+
+ while (appctx->ctx.map.bref.ref != &appctx->ctx.map.ref->head) {
chunk_reset(&trash);
+ elt = LIST_ELEM(appctx->ctx.map.bref.ref, struct pat_ref_elt *, list);
+
/* build messages */
- if (appctx->ctx.map.elt->sample)
+ if (elt->sample)
chunk_appendf(&trash, "%p %s %s\n",
- appctx->ctx.map.elt, appctx->ctx.map.elt->pattern,
- appctx->ctx.map.elt->sample);
+ elt, elt->pattern,
+ elt->sample);
else
chunk_appendf(&trash, "%p %s\n",
- appctx->ctx.map.elt, appctx->ctx.map.elt->pattern);
+ elt, elt->pattern);
if (bi_putchk(si_ic(si), &trash) == -1) {
/* let's try again later from this stream. We add ourselves into
* this stream's users so that it can remove us upon termination.
*/
si_applet_cant_put(si);
+ LIST_ADDQ(&elt->back_refs, &appctx->ctx.map.bref.users);
return 0;
}
/* get next list entry and check the end of the list */
- appctx->ctx.map.elt = LIST_NEXT(&appctx->ctx.map.elt->list,
- struct pat_ref_elt *, list);
- if (&appctx->ctx.map.elt->list == &appctx->ctx.map.ref->head)
- break;
+ appctx->ctx.map.bref.ref = elt->list.n;
}
appctx->st2 = STAT_ST_FIN;
@@ -583,6 +606,14 @@
return 1;
}
+static void cli_release_show_map(struct appctx *appctx)
+{
+ if (appctx->st2 == STAT_ST_LIST) {
+ if (!LIST_ISEMPTY(&appctx->ctx.map.bref.users))
+ LIST_DEL(&appctx->ctx.map.bref.users);
+ }
+}
+
static int cli_parse_show_map(char **args, struct appctx *appctx, void *private)
{
if (strcmp(args[1], "map") == 0 ||
@@ -612,6 +643,7 @@
return 1;
}
appctx->io_handler = cli_io_handler_pat_list;
+ appctx->io_release = cli_release_show_map;
return 0;
}
diff --git a/src/pattern.c b/src/pattern.c
index 60fe462..2059309 100644
--- a/src/pattern.c
+++ b/src/pattern.c
@@ -1581,10 +1581,22 @@
{
struct pattern_expr *expr;
struct pat_ref_elt *elt, *safe;
+ struct bref *bref, *back;
/* delete pattern from reference */
list_for_each_entry_safe(elt, safe, &ref->head, list) {
if (elt == refelt) {
+ list_for_each_entry_safe(bref, back, &elt->back_refs, users) {
+ /*
+ * we have to unlink all watchers. We must not relink them if
+ * this elt was the last one in the list.
+ */
+ LIST_DEL(&bref->users);
+ LIST_INIT(&bref->users);
+ if (elt->list.n != &ref->head)
+ LIST_ADDQ(&LIST_ELEM(elt->list.n, struct stream *, list)->back_refs, &bref->users);
+ bref->ref = elt->list.n;
+ }
list_for_each_entry(expr, &ref->pat, list)
pattern_delete(expr, elt);
@@ -1606,11 +1618,23 @@
{
struct pattern_expr *expr;
struct pat_ref_elt *elt, *safe;
+ struct bref *bref, *back;
int found = 0;
/* delete pattern from reference */
list_for_each_entry_safe(elt, safe, &ref->head, list) {
if (strcmp(key, elt->pattern) == 0) {
+ list_for_each_entry_safe(bref, back, &elt->back_refs, users) {
+ /*
+ * we have to unlink all watchers. We must not relink them if
+ * this elt was the last one in the list.
+ */
+ LIST_DEL(&bref->users);
+ LIST_INIT(&bref->users);
+ if (elt->list.n != &ref->head)
+ LIST_ADDQ(&LIST_ELEM(elt->list.n, struct stream *, list)->back_refs, &bref->users);
+ bref->ref = elt->list.n;
+ }
list_for_each_entry(expr, &ref->pat, list)
pattern_delete(expr, elt);
@@ -1853,6 +1877,7 @@
else
elt->sample = NULL;
+ LIST_INIT(&elt->back_refs);
LIST_ADDQ(&ref->head, &elt->list);
return 1;
@@ -1948,6 +1973,7 @@
else
elt->sample = NULL;
+ LIST_INIT(&elt->back_refs);
LIST_ADDQ(&ref->head, &elt->list);
list_for_each_entry(expr, &ref->pat, list) {
@@ -1995,8 +2021,20 @@
{
struct pat_ref_elt *elt, *safe;
struct pattern_expr *expr;
+ struct bref *bref, *back;
list_for_each_entry_safe(elt, safe, &ref->head, list) {
+ list_for_each_entry_safe(bref, back, &elt->back_refs, users) {
+ /*
+ * we have to unlink all watchers. We must not relink them if
+ * this elt was the last one in the list.
+ */
+ LIST_DEL(&bref->users);
+ LIST_INIT(&bref->users);
+ if (elt->list.n != &ref->head)
+ LIST_ADDQ(&LIST_ELEM(elt->list.n, struct stream *, list)->back_refs, &bref->users);
+ bref->ref = elt->list.n;
+ }
LIST_DEL(&elt->list);
free(elt->pattern);
free(elt->sample);