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nlplug-findfs: maintain environment for exec's in array

Using clearenv and setenv is slow, non-thread safe and problematic.
This makes PATH inherited from parent environment, and explicitly
constructs the rest of the environment for mdev.

--- a/nlplug-findfs.c

+++ b/nlplug-findfs.c

@@ -45,6 +45,7 @@

 #define FOUND_APKOVL	0x4

 static int dodebug;

+static char *default_envp[2];

 char *argv0;

 #if defined(DEBUG)

@@ -65,6 +66,8 @@

 #define dbg(...)

 #endif

+#define envcmp(env, key) (strncmp(env, key "=", strlen(key "=")) == 0)

+

 struct uevent {

 	char *buf;

 	size_t bufsize;

@@ -77,6 +80,7 @@

 	char *minor;

 	char *driver;

 	char devnode[256];

+	char *envp[64];

 };

 struct ueventconf {

@@ -152,13 +156,13 @@

 	return fd;

 }

-void run_child(char **argv)

+void run_child(char **argv, char **envp)

 {

 	pid_t pid;

 	if (!(pid = fork())) {

 		dbg("running %s", argv[0]);

-		if (execv(argv[0], argv) < 0)

+		if (execve(argv[0], argv, envp) < 0)

 			err(1, argv[0]);

 		exit(0);

 	}

@@ -221,7 +225,7 @@

 		devnode,

 		NULL

 	};

-	run_child(mdadm_argv);

+	run_child(mdadm_argv, default_envp);

 }

 void start_lvm2(char *devnode)

@@ -231,7 +235,7 @@

 		"--activate" , "ay", "--noudevsync", "--sysinit",

 		NULL

 	};

-	run_child(lvm2_argv);

+	run_child(lvm2_argv, default_envp);

 }

 void start_cryptsetup(char *devnode, char *cryptdm)

@@ -241,7 +245,7 @@

 		devnode, cryptdm ? cryptdm : "crypdm", NULL

 	};

 	load_kmod("dm-crypt");

-	run_child(cryptsetup_argv);

+	run_child(cryptsetup_argv, default_envp);

 }

 static int is_mounted(const char *devnode) {

@@ -507,7 +511,7 @@

 	} else if (ev->devname != NULL) {

 		if (conf->program_argv[0] != NULL) {

-			run_child(conf->program_argv);

+			run_child(conf->program_argv, ev->envp);

 			conf->fork_count++;

 		}

@@ -534,17 +538,17 @@

 {

 	struct uevent ev;

-	int i, slen = 0;

+	int i, nenvp, slen = 0;

 	char *key, *value;

 	memset(&ev, 0, sizeof(ev));

 	ev.buf = buf;

 	ev.bufsize = len;

-	clearenv();

-	setenv("PATH", "/sbin:/bin", 1);

-	for (i = 0; i < len; i += slen + 1) {

+	nenvp = sizeof(default_envp) / sizeof(default_envp[0]) - 1;

+	memcpy(&ev.envp, default_envp, nenvp * sizeof(default_envp[0]));

+	for (i = 0; i < len; i += slen + 1) {

 		key = buf + i;

 		value = strchr(key, '=');

 		slen = strlen(buf+i);

@@ -558,29 +562,28 @@

 		if (!slen)

 			continue;

-		value[0] = '\0';

 		value++;

-

-		if (strcmp(key, "MODALIAS") == 0) {

+		if (envcmp(key, "MODALIAS")) {

 			ev.modalias = value;

-		} else if (strcmp(key, "ACTION") == 0) {

+		} else if (envcmp(key, "ACTION")) {

 			ev.action = value;

-		} else if (strcmp(key, "SUBSYSTEM") == 0) {

+		} else if (envcmp(key, "SUBSYSTEM")) {

 			ev.subsystem = value;

-		} else if (strcmp(key, "DEVNAME") == 0) {

+		} else if (envcmp(key, "DEVNAME")) {

 			ev.devname = value;

-		} else if (strcmp(key, "MAJOR") == 0) {

+		} else if (envcmp(key, "MAJOR")) {

 			ev.major = value;

-		} else if (strcmp(key, "MINOR") == 0) {

+		} else if (envcmp(key, "MINOR")) {

 			ev.minor = value;

-		} else if (strcmp(key, "DRIVER") == 0) {

+		} else if (envcmp(key, "DRIVER")) {

 			ev.driver = value;

 		}

-		if (strcmp(key, "PATH")) {

-			setenv(key, value, 1);

-		}

+		if (!envcmp(key, "PATH"))

+			ev.envp[nenvp++]= key;

 	}

+	ev.envp[nenvp++] = 0;

+

 	return dispatch_uevent(&ev, conf);

 }

@@ -640,6 +643,11 @@

 	int found = 0, trigger_running = 0;

 	char *program_argv[2] = {0,0};

 	pthread_t tid;

+

+	for (r = 0; environ[r]; r++) {

+		if (envcmp(environ[r], "PATH"))

+			default_envp[0] = environ[r];

+	}

 	memset(&conf, 0, sizeof(conf));

 	conf.program_argv = program_argv;