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Code Issues Releases Activity

Use a sleep mutex instead of an sx lock for the kernel environment. This

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allows greater flexibility for drivers that want to query the environment.

Reviewed by: jhb, mux
This commit is contained in:
Scott Long 2006-07-09 21:42:58 +00:00
parent 5d0c7501b6
commit e3546a7549
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=160217
3 changed files with 33 additions and 31 deletions
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50
sys/kern/kern_environment.c
View File

@ -48,7 +48,6 @@ __FBSDID("$FreeBSD$");
#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 @@ static char *kernenv_next(char *);
/* 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 @@ kenv(td, uap)
int len;
} */ *uap;
{
char *name, *value;
char *name, *value, *buffer = NULL;
size_t len, done, needed;
int error, i;
@ -100,7 +99,9 @@ kenv(td, uap)
return (error);
#endif
done = needed = 0;
sx_slock(&kenv_lock);
if (uap->len > 0 && uap->value != NULL)
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;
@ -109,15 +110,16 @@ kenv(td, uap)
* If called with a NULL or insufficiently large
* buffer, just keep computing the required size.
*/
if (uap->value != NULL && len > 0) {
error = copyout(kenvp[i], uap->value + done,
len);
if (error)
break;
if (uap->value != NULL && buffer != NULL && len > 0) {
bcopy(kenvp[i], buffer + done, len);
done += len;
}
}
sx_sunlock(&kenv_lock);
mtx_unlock(&kenv_lock);
if (buffer != NULL) {
error = copyout(buffer, uap->value, done);
free(buffer, M_TEMP);
}
td->td_retval[0] = ((done == needed) ? 0 : needed);
return (error);
}
@ -220,7 +222,7 @@ init_dynamic_kenv(void *data __unused)
}
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 +244,7 @@ _getenv_dynamic(const char *name, int *idx)
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 +290,16 @@ getenv(const char *name)
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 +316,9 @@ testenv(const char *name)
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 +346,12 @@ setenv(const char *name, const char *value)
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 +361,13 @@ setenv(const char *name, const char *value)
/* 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 +383,18 @@ unsetenv(const char *name)
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);
}

12
sys/kern/subr_hints.c
View File

@ -29,7 +29,7 @@ __FBSDID("$FreeBSD$");
#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 @@ res_find(int *line, int *startln,
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 @@ res_find(int *line, int *startln,
break;
}
}
sx_sunlock(&kenv_lock);
mtx_unlock(&kenv_lock);
} else {
cp = kern_envp;
while (cp) {
@ -114,11 +114,11 @@ res_find(int *line, int *startln,
}
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 @@ res_find(int *line, int *startln,
}
}
if (use_kenv)
sx_sunlock(&kenv_lock);
mtx_unlock(&kenv_lock);
if (cp == NULL)
return ENOENT;

2
sys/sys/systm.h
View File

@ -102,7 +102,7 @@ extern int maxusers; /* system tune hint */
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 */