Page MenuHomeFreeBSD
Files F165050309

D2123.id.diff
No OneTemporary
Actions

D2123.id.diff
View Options

Index: sys/kern/imgact_binmisc.c
===================================================================
--- sys/kern/imgact_binmisc.c
+++ sys/kern/imgact_binmisc.c
@@ -1,5 +1,5 @@
/*-
- * Copyright (c) 2013, Stacey D. Son
+ * Copyright (c) 2013-15, Stacey D. Son
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -41,6 +41,9 @@
#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.
@@ -95,11 +98,68 @@
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.
@@ -111,7 +171,7 @@
char t[IBE_INTERP_LEN_MAX];
char *sp, *tp;
- bzero(t, sizeof(t));
+ memset(t, 0, sizeof(t));
/*
* Normalize interpreter string. Replace white space between args with
@@ -152,8 +212,6 @@
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);
@@ -203,7 +261,7 @@
{
imgact_binmisc_entry_t *ibe;
- mtx_assert(&interp_list_mtx, MA_OWNED);
+ interp_list_assert_locked();
SLIST_FOREACH(ibe, &interpreter_list, link) {
if (strncmp(name, ibe->ibe_name, IBE_NAME_MAX) == 0)
@@ -260,21 +318,21 @@
}
}
- mtx_lock(&interp_list_mtx);
- if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
- mtx_unlock(&interp_list_mtx);
- return (EEXIST);
- }
- mtx_unlock(&interp_list_mtx);
-
+ /* Preallocate a new entry. */
ibe = imgact_binmisc_new_entry(xbe);
if (!ibe)
return (ENOMEM);
- mtx_lock(&interp_list_mtx);
+ interp_list_wlock();
+ if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
+ interp_list_wunlock();
+ imgact_binmisc_destroy_entry(ibe);
+ return (EEXIST);
+ }
+
SLIST_INSERT_HEAD(&interpreter_list, ibe, link);
interp_list_entry_count++;
- mtx_unlock(&interp_list_mtx);
+ interp_list_wunlock();
return (0);
}
@@ -288,14 +346,14 @@
{
imgact_binmisc_entry_t *ibe;
- mtx_lock(&interp_list_mtx);
+ interp_list_wlock();
if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
- mtx_unlock(&interp_list_mtx);
+ interp_list_wunlock();
return (ENOENT);
}
SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link);
interp_list_entry_count--;
- mtx_unlock(&interp_list_mtx);
+ interp_list_wunlock();
imgact_binmisc_destroy_entry(ibe);
@@ -311,14 +369,14 @@
{
imgact_binmisc_entry_t *ibe;
- mtx_lock(&interp_list_mtx);
+ interp_list_rlock();
if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
return (ENOENT);
}
- ibe->ibe_flags &= ~IBF_ENABLED;
- mtx_unlock(&interp_list_mtx);
+ atomic_clear_32(&ibe->ibe_flags, IBF_ENABLED);
+ interp_list_runlock();
return (0);
}
@@ -332,14 +390,14 @@
{
imgact_binmisc_entry_t *ibe;
- mtx_lock(&interp_list_mtx);
+ interp_list_rlock();
if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
return (ENOENT);
}
- ibe->ibe_flags |= IBF_ENABLED;
- mtx_unlock(&interp_list_mtx);
+ atomic_set_32(&ibe->ibe_flags, IBF_ENABLED);
+ interp_list_runlock();
return (0);
}
@@ -350,9 +408,9 @@
{
uint32_t i;
- mtx_assert(&interp_list_mtx, MA_OWNED);
+ interp_list_assert_rlocked();
- bzero(xbe, sizeof(*xbe));
+ memset(xbe, 0, sizeof(*xbe));
strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX);
/* Copy interpreter string. Replace NULL breaks with space. */
@@ -382,14 +440,14 @@
imgact_binmisc_entry_t *ibe;
int error = 0;
- mtx_lock(&interp_list_mtx);
+ interp_list_rlock();
if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
return (ENOENT);
}
error = imgact_binmisc_populate_xbe(xbe, ibe);
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
return (error);
}
@@ -404,12 +462,12 @@
imgact_binmisc_entry_t *ibe;
int error = 0, count;
- mtx_lock(&interp_list_mtx);
+ interp_list_rlock();
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) {
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
return (ENOMEM);
}
@@ -419,7 +477,7 @@
if (error)
break;
}
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
if (!error)
error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count);
@@ -556,7 +614,7 @@
int i;
size_t sz;
- mtx_assert(&interp_list_mtx, MA_OWNED);
+ interp_list_assert_rlocked();
SLIST_FOREACH(ibe, &interpreter_list, link) {
if (!(IBF_ENABLED & ibe->ibe_flags))
@@ -593,15 +651,15 @@
char *s, *d;
/* Do we have an interpreter for the given image header? */
- mtx_lock(&interp_list_mtx);
+ interp_list_rlock();
if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) {
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
return (-1);
}
/* No interpreter nesting allowed. */
if (imgp->interpreted & IMGACT_BINMISC) {
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
return (ENOEXEC);
}
@@ -649,7 +707,7 @@
default:
/* Hmm... This shouldn't happen. */
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
printf("%s: Unknown macro #%c sequence in "
"interpreter string\n", KMOD_NAME, *(s + 1));
error = EINVAL;
@@ -660,12 +718,15 @@
/* Check to make sure we won't overrun the stringspace. */
if (offset > imgp->args->stringspace) {
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
error = E2BIG;
goto done;
}
- /* Make room for the interpreter */
+ /*
+ * Make room for the interpreter. Doing an overlapping copy so
+ * bcopy() must be used.
+ */
bcopy(imgp->args->begin_argv, imgp->args->begin_argv + offset,
imgp->args->endp - imgp->args->begin_argv);
@@ -720,7 +781,7 @@
s++;
}
*d = '\0';
- mtx_unlock(&interp_list_mtx);
+ interp_list_runlock();
if (!error)
imgp->interpreter_name = imgp->args->begin_argv;
@@ -745,13 +806,13 @@
imgact_binmisc_entry_t *ibe, *ibe_tmp;
/* Free all the interpreters. */
- mtx_lock(&interp_list_mtx);
+ interp_list_wlock();
SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) {
SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry,
link);
imgact_binmisc_destroy_entry(ibe);
}
- mtx_unlock(&interp_list_mtx);
+ interp_list_wunlock();
mtx_destroy(&interp_list_mtx);
}

File Metadata

Mime Type
text/plain
Expires
Thu, Aug 6, 1:58 PM (13 h, 19 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
36121153
Default Alt Text
D2123.id.diff (8 KB)

Event Timeline