From: jy910.yun <jy910.yun@samsung.com>
Date: Fri, 7 Nov 2014 09:11:10 +0000 (+0900)
Subject: device-node: Replace system() with the combination of fork/exec
X-Git-Tag: submit/tizen/20141112.104554~2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3c3a64225c9c0d8f218bf1976eff5f22cbb22e17;p=platform%2Fcore%2Fsystem%2Flibdevice-node.git

device-node: Replace system() with the combination of fork/exec

As per man page, it cautions against using system() in a program.
It can make a problem like a ruin of system intergrity
by strange values for some environment variables.

Change-Id: I5d77931c3fbb5fd1851219aaf8e8578d8ed9d255
Signed-off-by: jy910.yun <jy910.yun@samsung.com>
---

diff --git a/devices/extcon.c b/devices/extcon.c
index 42a41d1..dc79e2e 100644
--- a/devices/extcon.c
+++ b/devices/extcon.c
@@ -17,8 +17,83 @@
 
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/wait.h>
 #include "device-internal.h"
 
+static int parent(pid_t pid)
+{
+	int status;
+
+	/* wait for child */
+	if (waitpid(pid, &status, 0) != -1) {
+		/* terminated normally */
+		if (WIFEXITED(status)) {
+			_I("%d terminated by exit(%d)", pid, WEXITSTATUS(status));
+			return WEXITSTATUS(status);
+		} else if (WIFSIGNALED(status)) {
+			_I("%d terminated by signal %d", pid, WTERMSIG(status));
+		} else if (WIFSTOPPED(status)) {
+			_I("%d stopped by signal %d", pid, WSTOPSIG(status));
+		}
+	} else {
+		_I("%d waitpid() failed : %s", pid, strerror(errno));
+	}
+
+	return -EAGAIN;
+}
+
+static void child(const char *argv[])
+{
+	int i, r;
+
+	for (i = 0; i < _NSIG; ++i)
+		signal(i, SIG_DFL);
+
+	r = execv(argv[0], (char **)argv);
+	if (r < 0)
+		exit(EXIT_FAILURE);
+}
+
+int run_save_blenv(const char *extcon_path, const char *val)
+{
+	pid_t pid;
+	struct sigaction act, oldact;
+	int r = -1;
+	const char *extcon_argv[4] = {"/usr/bin/save_blenv", NULL, NULL, NULL};
+
+	if (!extcon_path || !val)
+		return -EINVAL;
+
+	extcon_argv[1] = extcon_path;
+	extcon_argv[2] = val;
+
+	/* Use default signal handler */
+	act.sa_handler = SIG_DFL;
+	act.sa_sigaction = NULL;
+	act.sa_flags = 0;
+	sigemptyset(&act.sa_mask);
+
+	if (sigaction(SIGCHLD, &act, &oldact) < 0)
+		return -errno;
+
+	pid = fork();
+	if (pid < 0) {
+		_E("failed to fork");
+		r = -errno;
+	} else if (pid == 0) {
+		child(extcon_argv);
+	} else
+		r = parent(pid);
+
+	if (sigaction(SIGCHLD, &oldact, NULL) < 0)
+		_E("failed to restore sigaction");
+
+	return r;
+}
+
 static int extcon_get_prop(int prop, int *val)
 {
 	switch (prop) {
@@ -58,18 +133,18 @@ static int extcon_set_prop(int prop, int val)
 		r = PLUGIN_SET(uart_path)(val);
 		if (r == 0) {
 			if (val == PATH_CP)
-				system("/usr/bin/save_blenv uartpath CP");
+				r = run_save_blenv("uartpath", "CP");
 			else
-				system("/usr/bin/save_blenv uartpath AP");
+				r = run_save_blenv("uartpath", "AP");
 		}
 		return r;
 	case PROP_EXTCON_USB_PATH:
 		r = PLUGIN_SET(usb_path)(val);
 		if (r == 0) {
 			if (val == PATH_CP)
-				system("/usr/bin/save_blenv usbpath CP");
+				r = run_save_blenv("usbpath", "CP");
 			else
-				system("/usr/bin/save_blenv usbpath AP");
+				r = run_save_blenv("usbpath", "AP");
 		}
 		return r;
 	}