Author: sbruno
Date: Fri Jun 5 18:16:10 2015
New Revision: 284043
URL: https://svnweb.freebsd.org/changeset/base/284043
Log:
Revert 284029, update imgact_binmisctl.c change mtx to reader count, at the
request of the submitter.
Will attempt to use an sx_lock for this fix to WITNESS crashes in a later
revision.
Submitted by: sson
Modified:
head/sys/kern/imgact_binmisc.c
Modified: head/sys/kern/imgact_binmisc.c
==============================================================================
--- head/sys/kern/imgact_binmisc.c Fri Jun 5 17:26:07 2015
(r284042)
+++ head/sys/kern/imgact_binmisc.c Fri Jun 5 18:16:10 2015
(r284043)
@@ -1,5 +1,5 @@
/*-
- * Copyright (c) 2013-15, Stacey D. Son
+ * Copyright (c) 2013, Stacey D. Son
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -41,9 +41,6 @@ __FBSDID("$FreeBSD$");
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/sysctl.h>
-#include <sys/sx.h>
-
-#include <machine/atomic.h>
/**
* Miscellaneous binary interpreter image activator.
@@ -98,68 +95,11 @@ static SLIST_HEAD(, imgact_binmisc_entry
SLIST_HEAD_INITIALIZER(interpreter_list);
static int interp_list_entry_count = 0;
-static int interp_list_rcount = 0;
+
static struct mtx interp_list_mtx;
int imgact_binmisc_exec(struct image_params *imgp);
-static inline void
-interp_list_rlock()
-{
-
- /* Don't use atomic_add() here. We must block if the mutex is held. */
- mtx_lock(&interp_list_mtx);
- interp_list_rcount++;
- mtx_unlock(&interp_list_mtx);
-}
-
-static inline void
-interp_list_runlock()
-{
-
- /* Decrement the reader count and wake up one writer, if any. */
- atomic_subtract_int(&interp_list_rcount, 1);
- if (interp_list_rcount == 0)
- wakeup_one(&interp_list_rcount);
-}
-
-static inline void
-interp_list_wlock()
-{
-
- /* Wait until there are no readers. */
- mtx_lock(&interp_list_mtx);
- while (interp_list_rcount)
- mtx_sleep(&interp_list_rcount, &interp_list_mtx, 0, "IABM", 0);
-}
-
-static inline void
-interp_list_wunlock()
-{
-
- mtx_unlock(&interp_list_mtx);
-}
-
-#define interp_list_assert_rlocked() \
- KASSERT(interp_list_rcount > 0, ("%s: interp_list lock not held " \
- "for read", __func__))
-
-#define interp_list_assert_wlocked() mtx_assert(&interp_list_mtx,
MA_OWNED)
-
-#ifdef INVARIANTS
-#define interp_list_assert_locked() do {
\
- if (interp_list_rcount == 0) \
- mtx_assert(&interp_list_mtx, MA_OWNED); \
- else \
- KASSERT(interp_list_rcount > 0, \
- ("%s: interp_list lock not held", __func__)); \
-} while(0)
-
-#else /* ! INVARIANTS */
-
-#define interp_list_assert_locked() do {
\
-} while(0)
-#endif /* ! INVARIANTS */
/*
* Populate the entry with the information about the interpreter.
@@ -171,7 +111,7 @@ imgact_binmisc_populate_interp(char *str
char t[IBE_INTERP_LEN_MAX];
char *sp, *tp;
- memset(t, 0, sizeof(t));
+ bzero(t, sizeof(t));
/*
* Normalize interpreter string. Replace white space between args with
@@ -212,6 +152,8 @@ imgact_binmisc_new_entry(ximgact_binmisc
imgact_binmisc_entry_t *ibe = NULL;
size_t namesz = min(strlen(xbe->xbe_name) + 1, IBE_NAME_MAX);
+ mtx_assert(&interp_list_mtx, MA_NOTOWNED);
+
ibe = malloc(sizeof(*ibe), M_BINMISC, M_WAITOK|M_ZERO);
ibe->ibe_name = malloc(namesz, M_BINMISC, M_WAITOK|M_ZERO);
@@ -261,7 +203,7 @@ imgact_binmisc_find_entry(char *name)
{
imgact_binmisc_entry_t *ibe;
- interp_list_assert_locked();
+ mtx_assert(&interp_list_mtx, MA_OWNED);
SLIST_FOREACH(ibe, &interpreter_list, link) {
if (strncmp(name, ibe->ibe_name, IBE_NAME_MAX) == 0)
@@ -318,21 +260,21 @@ imgact_binmisc_add_entry(ximgact_binmisc
}
}
- /* Preallocate a new entry. */
- ibe = imgact_binmisc_new_entry(xbe);
- if (!ibe)
- return (ENOMEM);
-
- interp_list_wlock();
+ mtx_lock(&interp_list_mtx);
if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
- interp_list_wunlock();
- imgact_binmisc_destroy_entry(ibe);
+ mtx_unlock(&interp_list_mtx);
return (EEXIST);
}
+ mtx_unlock(&interp_list_mtx);
+
+ ibe = imgact_binmisc_new_entry(xbe);
+ if (!ibe)
+ return (ENOMEM);
+ mtx_lock(&interp_list_mtx);
SLIST_INSERT_HEAD(&interpreter_list, ibe, link);
interp_list_entry_count++;
- interp_list_wunlock();
+ mtx_unlock(&interp_list_mtx);
return (0);
}
@@ -346,14 +288,14 @@ imgact_binmisc_remove_entry(char *name)
{
imgact_binmisc_entry_t *ibe;
- interp_list_wlock();
+ mtx_lock(&interp_list_mtx);
if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
- interp_list_wunlock();
+ mtx_unlock(&interp_list_mtx);
return (ENOENT);
}
SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link);
interp_list_entry_count--;
- interp_list_wunlock();
+ mtx_unlock(&interp_list_mtx);
imgact_binmisc_destroy_entry(ibe);
@@ -369,14 +311,14 @@ imgact_binmisc_disable_entry(char *name)
{
imgact_binmisc_entry_t *ibe;
- interp_list_rlock();
+ mtx_lock(&interp_list_mtx);
if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
return (ENOENT);
}
- atomic_clear_32(&ibe->ibe_flags, IBF_ENABLED);
- interp_list_runlock();
+ ibe->ibe_flags &= ~IBF_ENABLED;
+ mtx_unlock(&interp_list_mtx);
return (0);
}
@@ -390,14 +332,14 @@ imgact_binmisc_enable_entry(char *name)
{
imgact_binmisc_entry_t *ibe;
- interp_list_rlock();
+ mtx_lock(&interp_list_mtx);
if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
return (ENOENT);
}
- atomic_set_32(&ibe->ibe_flags, IBF_ENABLED);
- interp_list_runlock();
+ ibe->ibe_flags |= IBF_ENABLED;
+ mtx_unlock(&interp_list_mtx);
return (0);
}
@@ -408,9 +350,9 @@ imgact_binmisc_populate_xbe(ximgact_binm
{
uint32_t i;
- interp_list_assert_rlocked();
+ mtx_assert(&interp_list_mtx, MA_OWNED);
- memset(xbe, 0, sizeof(*xbe));
+ bzero(xbe, sizeof(*xbe));
strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX);
/* Copy interpreter string. Replace NULL breaks with space. */
@@ -440,14 +382,14 @@ imgact_binmisc_lookup_entry(char *name,
imgact_binmisc_entry_t *ibe;
int error = 0;
- interp_list_rlock();
+ mtx_lock(&interp_list_mtx);
if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
return (ENOENT);
}
error = imgact_binmisc_populate_xbe(xbe, ibe);
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
return (error);
}
@@ -462,12 +404,12 @@ imgact_binmisc_get_all_entries(struct sy
imgact_binmisc_entry_t *ibe;
int error = 0, count;
- interp_list_rlock();
+ mtx_lock(&interp_list_mtx);
count = interp_list_entry_count;
/* Don't block in malloc() while holding lock. */
xbe = malloc(sizeof(*xbe) * count, M_BINMISC, M_NOWAIT|M_ZERO);
if (!xbe) {
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
return (ENOMEM);
}
@@ -477,7 +419,7 @@ imgact_binmisc_get_all_entries(struct sy
if (error)
break;
}
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
if (!error)
error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count);
@@ -614,7 +556,7 @@ imgact_binmisc_find_interpreter(const ch
int i;
size_t sz;
- interp_list_assert_rlocked();
+ mtx_assert(&interp_list_mtx, MA_OWNED);
SLIST_FOREACH(ibe, &interpreter_list, link) {
if (!(IBF_ENABLED & ibe->ibe_flags))
@@ -651,15 +593,15 @@ imgact_binmisc_exec(struct image_params
char *s, *d;
/* Do we have an interpreter for the given image header? */
- interp_list_rlock();
+ mtx_lock(&interp_list_mtx);
if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) {
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
return (-1);
}
/* No interpreter nesting allowed. */
if (imgp->interpreted & IMGACT_BINMISC) {
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
return (ENOEXEC);
}
@@ -707,7 +649,7 @@ imgact_binmisc_exec(struct image_params
default:
/* Hmm... This shouldn't happen. */
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
printf("%s: Unknown macro #%c sequence in "
"interpreter string\n", KMOD_NAME, *(s + 1));
error = EINVAL;
@@ -718,15 +660,12 @@ imgact_binmisc_exec(struct image_params
/* Check to make sure we won't overrun the stringspace. */
if (offset > imgp->args->stringspace) {
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
error = E2BIG;
goto done;
}
- /*
- * Make room for the interpreter. Doing an overlapping copy so
- * bcopy() must be used.
- */
+ /* Make room for the interpreter */
bcopy(imgp->args->begin_argv, imgp->args->begin_argv + offset,
imgp->args->endp - imgp->args->begin_argv);
@@ -781,7 +720,7 @@ imgact_binmisc_exec(struct image_params
s++;
}
*d = '\0';
- interp_list_runlock();
+ mtx_unlock(&interp_list_mtx);
if (!error)
imgp->interpreter_name = imgp->args->begin_argv;
@@ -806,13 +745,13 @@ imgact_binmisc_fini(void *arg)
imgact_binmisc_entry_t *ibe, *ibe_tmp;
/* Free all the interpreters. */
- interp_list_wlock();
+ mtx_lock(&interp_list_mtx);
SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) {
SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry,
link);
imgact_binmisc_destroy_entry(ibe);
}
- interp_list_wunlock();
+ mtx_unlock(&interp_list_mtx);
mtx_destroy(&interp_list_mtx);
}
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