1 files changed, 538 insertions, 59 deletions

diff --git a/lib/libc/stdlib/getenv.c b/lib/libc/stdlib/getenv.c
index 306b6a1..5f6f497 100644
--- a/lib/libc/stdlib/getenv.c
+++ b/lib/libc/stdlib/getenv.c
@@ -1,89 +1,568 @@
-/*
- * Copyright (c) 1987, 1993
- *	The Regents of the University of California.  All rights reserved.
+/*-
+ * Copyright (c) 2007 Sean C. Farley <scf@FreeBSD.org>
+ * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
+ *    notice, this list of conditions and the following disclaimer,
+ *    without modification, immediately at the beginning of the file.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 4. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
  *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#if defined(LIBC_SCCS) && !defined(lint)
-static char sccsid[] = "@(#)getenv.c	8.1 (Berkeley) 6/4/93";
-#endif /* LIBC_SCCS and not lint */
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <sys/types.h>
+#include <err.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <stdlib.h>
-#include <stddef.h>
-#include <string.h>
 
-inline char *__findenv(const char *, int *);
+/*
+ * Standard environ.  environ variable is exposed to entire process.
+ *
+ *	origEnviron:	Upon cleanup on unloading of library or failure, this
+ *			allows environ to return to as it was before.
+ *	environSize:	Number of variables environ can hold.  Can only
+ *			increase.
+ */
+extern char **environ;
+static char **origEnviron;
+static int environSize = 0;
+
+/*
+ * Array of environment variables built from environ.  Each element records:
+ *	name:		Pointer to name=value string
+ *	name length:	Length of name not counting '=' character
+ *	value:		Pointer to value within same string as name
+ *	value size:	Size (not length) of space for value not counting the
+ *			nul character
+ *	active state:	true/false value to signify whether variable is active.
+ *			Useful since multiple variables with the same name can
+ *			co-exist.  At most, one variable can be active at any
+ *			one time.
+ *	putenv:		Created from putenv() call.  This memory must not be
+ *			reused.
+ */
+static struct envVars {
+	size_t nameLen;
+	size_t valueSize;
+	char *name;
+	char *value;
+	bool active;
+	bool putenv;
+} *envVars = NULL;
 
 /*
- * __findenv --
- *	Returns pointer to value associated with name, if any, else NULL.
- *	Sets offset to be the offset of the name/value combination in the
- *	environmental array, for use by setenv(3) and unsetenv(3).
- *	Explicitly removes '=' in argument name.
+ * Environment array information.
  *
- *	This routine *should* be a static; don't use it.
+ *	envActive:	Number of active variables in array.
+ *	envVarsSize:	Size of array.
+ *	envVarsTotal:	Number of total variables in array (active or not).
+ */
+static int envActive = 0;
+static int envVarsSize = 0;
+static int envVarsTotal = 0;
+
+
+/* Deinitialization of new environment. */
+static void __attribute__ ((destructor)) __clean_env(void);
+
+
+/*
+ * Inline strlen() for performance.  Also, perform check for an equals sign.
+ * Cheaper here than peforming a strchr() later.
+ */
+static inline size_t
+__strleneq(const char *str)
+{
+	const char *s;
+
+	for (s = str; *s != '\0'; ++s)
+		if (*s == '=')
+			return (0);
+
+	return (s - str);
+}
+
+
+/*
+ * Comparison of an environment name=value to a name.
+ */
+static inline bool
+strncmpeq(const char *nameValue, const char *name, size_t nameLen)
+{
+	if (strncmp(nameValue, name, nameLen) == 0 && nameValue[nameLen] == '=')
+		return (true);
+
+	return (false);
+}
+
+
+/*
+ * Using environment, returns pointer to value associated with name, if any,
+ * else NULL.  If the onlyActive flag is set to true, only variables that are
+ * active are returned else all are.
+ */
+static inline char *
+__findenv(const char *name, size_t nameLen, int *envNdx, bool onlyActive)
+{
+	int ndx;
+
+	/*
+	 * Find environment variable from end of array (more likely to be
+	 * active).  A variable created by putenv is always active or it is not
+	 * tracked in the array.
+	 */
+	for (ndx = *envNdx; ndx >= 0; ndx--)
+		if (envVars[ndx].putenv) {
+			if (strncmpeq(envVars[ndx].name, name, nameLen)) {
+				*envNdx = ndx;
+				return (envVars[ndx].name + nameLen +
+				    sizeof ("=") - 1);
+			}
+		} else if ((!onlyActive || envVars[ndx].active) &&
+		    (envVars[ndx].nameLen == nameLen &&
+		    strncmpeq(envVars[ndx].name, name, nameLen))) {
+			*envNdx = ndx;
+			return (envVars[ndx].value);
+		}
+
+	return (NULL);
+}
+
+
+/*
+ * Using environ, returns pointer to value associated with name, if any, else
+ * NULL.  Used on the original environ passed into the program.
  */
-inline char *
-__findenv(name, offset)
-	const char *name;
-	int *offset;
+static char *
+__findenv_environ(const char *name, size_t nameLen)
 {
-	extern char **environ;
-	int len, i;
-	const char *np;
-	char **p, *cp;
+	int envNdx;
 
-	if (name == NULL || environ == NULL)
+	/* Check for non-existant environment. */
+	if (environ == NULL)
 		return (NULL);
-	for (np = name; *np && *np != '='; ++np)
-		continue;
-	len = np - name;
-	for (p = environ; (cp = *p) != NULL; ++p) {
-		for (np = name, i = len; i && *cp; i--)
-			if (*cp++ != *np++)
-				break;
-		if (i == 0 && *cp++ == '=') {
-			*offset = p - environ;
-			return (cp);
+
+	/* Find variable within environ. */
+	for (envNdx = 0; environ[envNdx] != NULL; envNdx++)
+		if (strncmpeq(environ[envNdx], name, nameLen))
+			return (&(environ[envNdx][nameLen + sizeof("=") - 1]));
+
+	return (NULL);
+}
+
+
+/*
+ * Using the environment, rebuild the environ array for use by other C library
+ * calls that depend upon it.
+ */
+static int
+__rebuild_environ(int newEnvironSize)
+{
+	char **tmpEnviron;
+	int envNdx;
+	int environNdx;
+	int tmpEnvironSize;
+
+	/* Resize environ. */
+	if (newEnvironSize > environSize) {
+		tmpEnvironSize = newEnvironSize * 2;
+		tmpEnviron = realloc(environ, sizeof (*environ) *
+		    (tmpEnvironSize + 1));
+		if (tmpEnviron == NULL)
+			return (-1);
+		environSize = tmpEnvironSize;
+		environ = tmpEnviron;
+	}
+	envActive = newEnvironSize;
+
+	/* Assign active variables to environ. */
+	for (envNdx = envVarsTotal - 1, environNdx = 0; envNdx >= 0; envNdx--)
+		if (envVars[envNdx].active)
+			environ[environNdx++] = envVars[envNdx].name;
+	environ[environNdx] = NULL;
+
+	return (0);
+}
+
+
+/*
+ * Enlarge new environment.
+ */
+static inline bool
+__enlarge_env(void)
+{
+	int newEnvVarsSize;
+	struct envVars *tmpEnvVars;
+
+	envVarsTotal++;
+	if (envVarsTotal > envVarsSize) {
+		newEnvVarsSize = envVarsTotal * 2;
+		tmpEnvVars = realloc(envVars, sizeof (*envVars) *
+		    newEnvVarsSize);
+		if (tmpEnvVars == NULL) {
+			envVarsTotal--;
+			return (false);
 		}
+		envVarsSize = newEnvVarsSize;
+		envVars = tmpEnvVars;
 	}
-	return (NULL);
+
+	return (true);
+}
+
+
+/*
+ * Using environ, build an environment for use by standard C library calls.
+ */
+static int
+__build_env(void)
+{
+	char **env;
+	int activeNdx;
+	int envNdx;
+	int rtrnVal;
+	int savedErrno;
+	size_t nameLen;
+
+	/* Check for non-existant environment. */
+	if (environ == NULL)
+		return (0);
+	if (environ[0] == NULL)
+		goto SaveEnviron;
+
+	/* Count environment variables. */
+	for (env = environ, envVarsTotal = 0; *env != NULL; env++)
+		envVarsTotal++;
+	envVarsSize = envVarsTotal * 2;
+
+	/* Create new environment. */
+	envVars = calloc(1, sizeof (*envVars) * envVarsSize);
+	if (envVars == NULL)
+		goto Failure;
+
+	/* Copy environ values and keep track of them. */
+	for (envNdx = envVarsTotal - 1; envNdx >= 0; envNdx--) {
+		envVars[envNdx].putenv = false;
+		envVars[envNdx].name =
+		    strdup(environ[envVarsTotal - envNdx - 1]);
+		if (envVars[envNdx].name == NULL)
+			goto Failure;
+		envVars[envNdx].value = strchr(envVars[envNdx].name, '=');
+		if (envVars[envNdx].value != NULL) {
+			envVars[envNdx].value++;
+			envVars[envNdx].valueSize =
+			    strlen(envVars[envNdx].value);
+		} else {
+			warnx("environment corrupt; missing value for %s",
+			    envVars[envNdx].name);
+			errno = EFAULT;
+			goto Failure;
+		}
+
+		/*
+		 * Find most current version of variable to make active.  This
+		 * will prevent multiple active variables from being created
+		 * during this initialization phase.
+		 */
+		nameLen = envVars[envNdx].value - envVars[envNdx].name - 1;
+		envVars[envNdx].nameLen = nameLen;
+		activeNdx = envVarsTotal - 1;
+		if (__findenv(envVars[envNdx].name, nameLen, &activeNdx,
+		    false) == NULL) {
+			warnx("environment corrupt; unable to find %.*s",
+			    nameLen, envVars[envNdx].name);
+			errno = EFAULT;
+			goto Failure;
+		}
+		envVars[activeNdx].active = true;
+	}
+
+	/* Create a new environ. */
+SaveEnviron:
+	origEnviron = environ;
+	environ = NULL;
+	if (envVarsTotal > 0) {
+		rtrnVal = __rebuild_environ(envVarsTotal);
+		if (rtrnVal == -1) {
+			savedErrno = errno;
+			__clean_env();
+			errno = savedErrno;
+		}
+	} else
+		rtrnVal = 0;
+
+	return (rtrnVal);
+
+Failure:
+	savedErrno = errno;
+	__clean_env();
+	errno = savedErrno;
+
+	return (-1);
+}
+
+
+/*
+ * Remove variable added by putenv() from variable tracking array.
+ */
+static void
+__remove_putenv(int envNdx)
+{
+	memmove(&(envVars[envNdx]), &(envVars[envNdx + 1]),
+	    (envVarsTotal - envNdx) * sizeof (*envVars));
+	envVarsTotal--;
+
+	return;
+}
+
+
+/*
+ * Deallocate the environment built from environ as well as environ then set
+ * both to NULL.  Eases debugging of memory leaks.
+ */
+static void
+__clean_env(void)
+{
+	int envNdx;
+
+	/* Deallocate environment and environ if created by *env(). */
+	if (envVars != NULL) {
+		for (envNdx = 0; envNdx < envVarsTotal; envNdx++)
+			if (!envVars[envNdx].putenv)
+				free(envVars[envNdx].name);
+		free(envVars);
+		envVars = NULL;
+
+		/* Restore original environ. */
+		if (origEnviron != NULL) {
+			free(environ);
+			environ = origEnviron;
+		}
+	}
+
+	return;
 }
 
+
 /*
- * getenv --
- *	Returns ptr to value associated with name, if any, else NULL.
+ * Returns the value of a variable or NULL if none are found.
  */
 char *
-getenv(name)
-	const char *name;
+getenv(const char *name)
+{
+	int envNdx;
+	size_t nameLen;
+
+	/* Check for malformed name. */
+	if (name == NULL || (nameLen = __strleneq(name)) == 0) {
+		errno = EINVAL;
+		return (NULL);
+	}
+
+	/* Find environment variable via environ or rebuilt environment. */
+	if (envVars == NULL)
+		return (__findenv_environ(name, nameLen));
+	else {
+		envNdx = envVarsTotal - 1;
+		return (__findenv(name, nameLen, &envNdx, true));
+	}
+}
+
+
+/*
+ * Set the value of a variable.  Older settings are labeled as inactive.  If an
+ * older setting has enough room to store the new value, it will be reused.  No
+ * previous variables are ever freed here to avoid causing a segmentation fault
+ * in a user's code.
+ */
+int
+setenv(const char *name, const char *value, int overwrite)
+{
+	bool reuse;
+	char *env;
+	int envNdx;
+	int newEnvActive;
+	size_t nameLen;
+	size_t valueLen;
+
+	/* Check for malformed name. */
+	if (name == NULL || (nameLen = __strleneq(name)) == 0) {
+		errno = EINVAL;
+		return (-1);
+	}
+
+	/* Initialize environment. */
+	if (envVars == NULL && __build_env() == -1)
+		return (-1);
+
+	/* Find existing environment variable large enough to use. */
+	envNdx = envVarsTotal - 1;
+	newEnvActive = envActive;
+	valueLen = strlen(value);
+	reuse = false;
+	if (__findenv(name, nameLen, &envNdx, false) != NULL) {
+		/* Deactivate entry if overwrite is allowed. */
+		if (envVars[envNdx].active) {
+			if (overwrite == 0)
+				return (0);
+			envVars[envNdx].active = false;
+			newEnvActive--;
+		}
+
+		/* putenv() created variable cannot be reused. */
+		if (envVars[envNdx].putenv)
+			__remove_putenv(envNdx);
+
+		/* Entry is large enough to reuse. */
+		else if (envVars[envNdx].valueSize >= valueLen)
+			reuse = true;
+
+	}
+
+	/* Create new variable if none was found of sufficient size. */
+	if (! reuse) {
+		/* Enlarge environment. */
+		envNdx = envVarsTotal;
+		if (!__enlarge_env())
+			return (-1);
+
+		/* Create environment entry. */
+		envVars[envNdx].name = malloc(nameLen + sizeof ("=") +
+		    valueLen);
+		if (envVars[envNdx].name == NULL) {
+			envVarsTotal--;
+			return (-1);
+		}
+		envVars[envNdx].nameLen = nameLen;
+		envVars[envNdx].valueSize = valueLen;
+
+		/* Save name of name/value pair. */
+		env = stpcpy(envVars[envNdx].name, name);
+		if ((envVars[envNdx].name)[nameLen] != '=')
+			env = stpcpy(env, "=");
+	}
+	else
+		env = envVars[envNdx].value;
+
+	/* Save value of name/value pair. */
+	strcpy(env, value);
+	envVars[envNdx].value = env;
+	envVars[envNdx].active = true;
+	newEnvActive++;
+
+	/* No need to rebuild environ if the variable was reused. */
+	if (reuse)
+		return (0);
+	else
+		return (__rebuild_environ(newEnvActive));
+}
+
+
+/*
+ * Insert a "name=value" string into then environment.  Special settings must be
+ * made to keep setenv() from reusing this memory block and unsetenv() from
+ * allowing it to be tracked.
+ */
+int
+putenv(char *string)
 {
-	int offset;
+	char *equals;
+	int envNdx;
+	int newEnvActive;
+	size_t nameLen;
+
+	/* Check for malformed argument. */
+	if (string == NULL || (equals = strchr(string, '=')) == NULL ||
+	    (nameLen = equals - string) == 0) {
+		errno = EINVAL;
+		return (-1);
+	}
+
+	/* Initialize environment. */
+	if (envVars == NULL && __build_env() == -1)
+		return (-1);
+
+	/* Deactivate previous environment variable. */
+	envNdx = envVarsTotal - 1;
+	newEnvActive = envActive;
+	if (__findenv(string, nameLen, &envNdx, true) != NULL) {
+		/* Reuse previous putenv slot. */
+		if (envVars[envNdx].putenv) {
+			envVars[envNdx].name = string;
+			return (__rebuild_environ(envActive));
+		} else {
+			newEnvActive--;
+			envVars[envNdx].active = false;
+		}
+	}
+
+	/* Enlarge environment. */
+	envNdx = envVarsTotal;
+	if (!__enlarge_env())
+		return (-1);
+
+	/* Create environment entry. */
+	envVars[envNdx].name = string;
+	envVars[envNdx].nameLen = -1;
+	envVars[envNdx].value = NULL;
+	envVars[envNdx].valueSize = -1;
+	envVars[envNdx].putenv = true;
+	envVars[envNdx].active = true;
+	newEnvActive++;
+
+	return (__rebuild_environ(newEnvActive));
+}
+
+
+/*
+ * Unset variable with the same name by flagging it as inactive.  No variable is
+ * ever freed.
+ */
+int
+unsetenv(const char *name)
+{
+	int envNdx;
+	size_t nameLen;
+
+	/* Check for malformed name. */
+	if (name == NULL || (nameLen = __strleneq(name)) == 0) {
+		errno = EINVAL;
+		return (-1);
+	}
+
+	/* Initialize environment. */
+	if (envVars == NULL && __build_env() == -1)
+		return (-1);
+
+	/* Deactivate specified variable. */
+	envNdx = envVarsTotal - 1;
+	if (__findenv(name, nameLen, &envNdx, true) != NULL) {
+		envVars[envNdx].active = false;
+		if (envVars[envNdx].putenv)
+			__remove_putenv(envNdx);
+		__rebuild_environ(envActive - 1);
+	}
 
-	return (__findenv(name, &offset));
+	return (0);
 }