Attachment 217107 Details for Bug 248250 – proposed final patch

[patch] proposed final patch

patch_kenv (text/plain), 4.51 KB, created by Jason A. Harmening on 2020-08-09 08:34:22 UTC

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Creator: Jason A. Harmening

Created: 2020-08-09 08:34:22 UTC

Size: 4.51 KB

patch

obsolete

>Index: sys/kern/kern_environment.c
>===================================================================
>--- sys/kern/kern_environment.c	(revision 363749)
>+++ sys/kern/kern_environment.c	(working copy)
>@@ -59,6 +59,9 @@
> static char *_getenv_dynamic_locked(const char *name, int *idx);
> static char *_getenv_dynamic(const char *name, int *idx);
> 
>+static char *kenv_acquire(const char *name);
>+static void kenv_release(const char *buf);
>+
> static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
> 
> #define KENV_SIZE	512	/* Maximum number of environment strings */
>@@ -88,8 +91,6 @@
> #define KENV_CHECK	if (!dynamic_kenv) \
> 			    panic("%s: called before SI_SUB_KMEM", __func__)
> 
>-static char	*getenv_string_buffer(const char *);
>-
> int
> sys_kenv(td, uap)
> 	struct thread *td;
>@@ -482,16 +483,24 @@
> char *
> kern_getenv(const char *name)
> {
>-	char *ret;
>+	char *cp, *ret;
>+	int len;
> 
> 	if (dynamic_kenv) {
>-		ret = getenv_string_buffer(name);
>-		if (ret == NULL) {
>-			WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
>-			    "getenv");
>+		len = KENV_MNAMELEN + 1 + kenv_mvallen + 1;
>+		ret = uma_zalloc(kenv_zone, M_WAITOK | M_ZERO);
>+		mtx_lock(&kenv_lock);
>+		cp = _getenv_dynamic(name, NULL);
>+		if (cp != NULL)
>+			strlcpy(ret, cp, len);
>+		mtx_unlock(&kenv_lock);
>+		if (cp == NULL) {
>+			uma_zfree(kenv_zone, ret);
>+			ret = NULL;
> 		}
> 	} else
> 		ret = _getenv_static(name);
>+
> 	return (ret);
> }
> 
>@@ -503,12 +512,9 @@
> {
> 	char *cp;
> 
>-	if (dynamic_kenv) {
>-		mtx_lock(&kenv_lock);
>-		cp = _getenv_dynamic(name, NULL);
>-		mtx_unlock(&kenv_lock);
>-	} else
>-		cp = _getenv_static(name);
>+	cp = kenv_acquire(name);
>+	kenv_release(cp);
>+
> 	if (cp != NULL)
> 		return (1);
> 	return (0);
>@@ -615,30 +621,33 @@
> }
> 
> /*
>- * Return a buffer containing the string value from an environment variable
>+ * Return the internal kenv buffer for the variable name, if it exists.
>+ * If the dynamic kenv is initialized and the name is present, return
>+ * with kenv_lock held.
>  */
> static char *
>-getenv_string_buffer(const char *name)
>+kenv_acquire(const char *name)
> {
>-	char *cp, *ret;
>-	int len;
>+	char *value;
> 
> 	if (dynamic_kenv) {
>-		len = KENV_MNAMELEN + 1 + kenv_mvallen + 1;
>-		ret = uma_zalloc(kenv_zone, M_WAITOK | M_ZERO);
> 		mtx_lock(&kenv_lock);
>-		cp = _getenv_dynamic(name, NULL);
>-		if (cp != NULL)
>-			strlcpy(ret, cp, len);
>-		mtx_unlock(&kenv_lock);
>-		if (cp == NULL) {
>-			uma_zfree(kenv_zone, ret);
>-			ret = NULL;
>-		}
>+		value = _getenv_dynamic(name, NULL);
>+		if (value == NULL)
>+			mtx_unlock(&kenv_lock);
>+		return (value);
> 	} else
>-		ret = _getenv_static(name);
>+		return (_getenv_static(name));
>+}
> 
>-	return (ret);
>+/*
>+ * Undo a previous kenv_acquire() operation
>+ */
>+static void
>+kenv_release(const char *buf)
>+{
>+	if ((buf != NULL) && dynamic_kenv)
>+		mtx_unlock(&kenv_lock);
> }
> 
> /*
>@@ -649,17 +658,13 @@
> {
> 	char *cp;
> 
>-	if (dynamic_kenv) {
>-		mtx_lock(&kenv_lock);
>-		cp = _getenv_dynamic(name, NULL);
>-		if (cp != NULL)
>-			strlcpy(data, cp, size);
>-		mtx_unlock(&kenv_lock);
>-	} else {
>-		cp = _getenv_static(name);
>-		if (cp != NULL)
>-			strlcpy(data, cp, size);
>-	}
>+	cp = kenv_acquire(name);
>+
>+	if (cp != NULL)
>+		strlcpy(data, cp, size);
>+
>+	kenv_release(cp);
>+
> 	return (cp != NULL);
> }
> 
>@@ -673,16 +678,18 @@
> 	uint8_t shift;
> 	int64_t value;
> 	int64_t old;
>-	char *buf;
>+	const char *buf;
> 	char *end;
>-	char *ptr;
>+	const char *ptr;
> 	int n;
> 	int rc;
> 
>-	if ((buf = getenv_string_buffer(name)) == NULL)
>-		return (0);
>+	rc = 0;			  /* assume failure */
> 
>-	rc = 0;			  /* assume failure */
>+	buf = kenv_acquire(name);
>+	if (buf == NULL)
>+		goto error;
>+
> 	/* get maximum number of elements */
> 	size /= type_size;
> 
>@@ -797,8 +804,7 @@
> 	if (n != 0)
> 		rc = 1;	/* success */
> error:
>-	if (dynamic_kenv)
>-		uma_zfree(kenv_zone, buf);
>+	kenv_release(buf);
> 	return (rc);
> }
> 
>@@ -898,18 +904,21 @@
> int
> getenv_quad(const char *name, quad_t *data)
> {
>-	char	*value, *vtp;
>-	quad_t	iv;
>+	const char	*value;
>+	char		suffix, *vtp;
>+	quad_t		iv;
> 
>-	value = getenv_string_buffer(name);
>-	if (value == NULL)
>-		return (0);
>+	value = kenv_acquire(name);
>+	if (value == NULL) {
>+		goto error;
>+	}
> 	iv = strtoq(value, &vtp, 0);
> 	if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
>-		freeenv(value);
>-		return (0);
>+		goto error;
> 	}
>-	switch (vtp[0]) {
>+	suffix = vtp[0];
>+	kenv_release(value);
>+	switch (suffix) {
> 	case 't': case 'T':
> 		iv *= 1024;
> 		/* FALLTHROUGH */
>@@ -924,12 +933,13 @@
> 	case '\0':
> 		break;
> 	default:
>-		freeenv(value);
> 		return (0);
> 	}
>-	freeenv(value);
> 	*data = iv;
> 	return (1);
>+error:
>+	kenv_release(value);
>+	return (0);
> }
> 
> /*

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Attachments on bug 248250: 217019 | 217023 | 217024 | 217035 | 217107