PERFORCE change 100686 for review
Scott Long
scottl at FreeBSD.org
Thu Jul 6 03:48:33 UTC 2006
http://perforce.freebsd.org/chv.cgi?CH=100686
Change 100686 by scottl at scottl-wv1u on 2006/07/06 03:47:59
Use a sleep mutex to protect kernel environment handling instead of
an sx lock. The sx lock seemed to only be used to get around the
copyout case in kenv(KENV_DUMP) path. Fix that path to safely use a
sleep lock instead.
Affected files ...
.. //depot/projects/scottl-camlock/src/sys/kern/kern_environment.c#7 edit
.. //depot/projects/scottl-camlock/src/sys/kern/subr_hints.c#3 edit
.. //depot/projects/scottl-camlock/src/sys/sys/systm.h#7 edit
Differences ...
==== //depot/projects/scottl-camlock/src/sys/kern/kern_environment.c#7 (text+ko) ====
@@ -48,7 +48,6 @@
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/kernel.h>
-#include <sys/sx.h>
#include <sys/systm.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
@@ -65,7 +64,7 @@
/* dynamic environment variables */
char **kenvp;
-struct sx kenv_lock;
+struct mtx kenv_lock;
/*
* No need to protect this with a mutex
@@ -86,7 +85,7 @@
int len;
} */ *uap;
{
- char *name, *value;
+ char *name, *value, *buffer;
size_t len, done, needed;
int error, i;
@@ -100,7 +99,8 @@
return (error);
#endif
done = needed = 0;
- sx_slock(&kenv_lock);
+ buffer = malloc(uap->len, M_TEMP, M_WAITOK|M_ZERO);
+ mtx_lock(&kenv_lock);
for (i = 0; kenvp[i] != NULL; i++) {
len = strlen(kenvp[i]) + 1;
needed += len;
@@ -110,14 +110,15 @@
* buffer, just keep computing the required size.
*/
if (uap->value != NULL && len > 0) {
- error = copyout(kenvp[i], uap->value + done,
- len);
- if (error)
+ if (done + len > uap->len)
break;
+ bcopy(kenvp[i], buffer + done, len);
done += len;
}
}
- sx_sunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
+ error = copyout(buffer, uap->value, done);
+ free(buffer, M_TEMP);
td->td_retval[0] = ((done == needed) ? 0 : needed);
return (error);
}
@@ -220,7 +221,7 @@
}
kenvp[i] = NULL;
- sx_init(&kenv_lock, "kernel environment");
+ mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
dynamic_kenv = 1;
}
SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
@@ -242,7 +243,7 @@
char *cp;
int len, i;
- sx_assert(&kenv_lock, SX_LOCKED);
+ mtx_assert(&kenv_lock, MA_OWNED);
len = strlen(name);
for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
if ((strncmp(cp, name, len) == 0) &&
@@ -288,16 +289,16 @@
int len;
if (dynamic_kenv) {
- sx_slock(&kenv_lock);
+ mtx_lock(&kenv_lock);
cp = _getenv_dynamic(name, NULL);
if (cp != NULL) {
strcpy(buf, cp);
- sx_sunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
len = strlen(buf) + 1;
ret = malloc(len, M_KENV, M_WAITOK);
strcpy(ret, buf);
} else {
- sx_sunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
ret = NULL;
}
} else
@@ -314,9 +315,9 @@
char *cp;
if (dynamic_kenv) {
- sx_slock(&kenv_lock);
+ mtx_lock(&kenv_lock);
cp = _getenv_dynamic(name, NULL);
- sx_sunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
} else
cp = _getenv_static(name);
if (cp != NULL)
@@ -344,12 +345,12 @@
buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
sprintf(buf, "%s=%s", name, value);
- sx_xlock(&kenv_lock);
+ mtx_lock(&kenv_lock);
cp = _getenv_dynamic(name, &i);
if (cp != NULL) {
oldenv = kenvp[i];
kenvp[i] = buf;
- sx_xunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
free(oldenv, M_KENV);
} else {
/* We add the option if it wasn't found */
@@ -359,13 +360,13 @@
/* Bounds checking */
if (i < 0 || i >= KENV_SIZE) {
free(buf, M_KENV);
- sx_xunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
return (-1);
}
kenvp[i] = buf;
kenvp[i + 1] = NULL;
- sx_xunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
}
return (0);
}
@@ -381,18 +382,18 @@
KENV_CHECK;
- sx_xlock(&kenv_lock);
+ mtx_lock(&kenv_lock);
cp = _getenv_dynamic(name, &i);
if (cp != NULL) {
oldenv = kenvp[i];
for (j = i + 1; kenvp[j] != NULL; j++)
kenvp[i++] = kenvp[j];
kenvp[i] = NULL;
- sx_xunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
free(oldenv, M_KENV);
return (0);
}
- sx_xunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
return (-1);
}
==== //depot/projects/scottl-camlock/src/sys/kern/subr_hints.c#3 (text+ko) ====
@@ -29,7 +29,7 @@
#include <sys/param.h>
#include <sys/lock.h>
-#include <sys/sx.h>
+#include <sys/mutex.h>
#include <sys/systm.h>
#include <sys/bus.h>
@@ -72,7 +72,7 @@
break;
case 2: /* fallback mode */
if (dynamic_kenv) {
- sx_slock(&kenv_lock);
+ mtx_lock(&kenv_lock);
cp = kenvp[0];
for (i = 0; cp != NULL; cp = kenvp[++i]) {
if (!strncmp(cp, "hint.", 5)) {
@@ -81,7 +81,7 @@
break;
}
}
- sx_sunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
} else {
cp = kern_envp;
while (cp) {
@@ -114,11 +114,11 @@
}
if (use_kenv) {
- sx_slock(&kenv_lock);
+ mtx_lock(&kenv_lock);
i = 0;
cp = kenvp[0];
if (cp == NULL) {
- sx_sunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
return (ENOENT);
}
} else
@@ -165,7 +165,7 @@
}
}
if (use_kenv)
- sx_sunlock(&kenv_lock);
+ mtx_unlock(&kenv_lock);
if (cp == NULL)
return ENOENT;
==== //depot/projects/scottl-camlock/src/sys/sys/systm.h#7 (text+ko) ====
@@ -102,7 +102,7 @@
extern int envmode;
extern int hintmode; /* 0 = off. 1 = config, 2 = fallback */
extern int dynamic_kenv;
-extern struct sx kenv_lock;
+extern struct mtx kenv_lock;
extern char *kern_envp;
extern char static_env[];
extern char static_hints[]; /* by config for now */
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