From: John Hodge <tpg@mutabah.net>
Date: Sat, 19 Feb 2011 08:48:44 +0000 (+0800)
Subject: Less crashy in door handler
X-Git-Url: https://git.ucc.asn.au/?p=tpg%2Fopendispense2.git;a=commitdiff_plain;h=35305619c1f2e5b1a708b47a90b99439664495c8

Less crashy in door handler
---

diff --git a/src/server/handler_door.c b/src/server/handler_door.c
index 9942526..d903bf9 100644
--- a/src/server/handler_door.c
+++ b/src/server/handler_door.c
@@ -7,14 +7,19 @@
  * This file is licenced under the 3-clause BSD Licence. See the file
  * COPYING for full details.
  */
+#define	DEBUG	1
+#define	USE_POPEN	0
+
 #include "common.h"
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/stat.h>
 #include <fcntl.h>
-
-#define	DEBUG	1
+#include <signal.h>
+#if !USE_POPEN
+# include <unistd.h>
+#endif
 
 #define DOOR_UNLOCKED_DELAY	10	// 10 seconds before it re-locks
 
@@ -24,6 +29,7 @@
  int	Door_InitHandler();
  int	Door_CanDispense(int User, int Item);
  int	Door_DoDispense(int User, int Item);
+void	Door_int_SIGCHLDHandler(int signum);
 
 // === GLOBALS ===
 tHandler	gDoor_Handler = {
@@ -33,11 +39,12 @@ tHandler	gDoor_Handler = {
 	Door_DoDispense
 };
 char	*gsDoor_Password = "";
-// int	giDoor_SerialFD;
+volatile int	giDoor_ChildTerminated;
 
 // == CODE ===
 int Door_InitHandler(void)
 {	
+	signal(SIGCHLD, Door_int_SIGCHLDHandler);
 	return 0;
 }
 
@@ -71,8 +78,14 @@ int Door_CanDispense(int User, int Item)
  */
 int Door_DoDispense(int User, int Item)
 {
-	FILE	*pipe;
-	char	buf[512];	// Buffer flush location - the sewer :)
+	FILE	*child_stdin;
+	char	buf[512];
+	#if !USE_POPEN
+	 int	stdin_pair[2];
+	 int	stdout_pair[2];
+	pid_t	childPid;
+	pid_t	parent_pid;
+	#endif
 	
 	#if DEBUG
 	printf("Door_DoDispense: (User=%i,Item=%i)\n", User, Item);
@@ -90,33 +103,84 @@ int Door_DoDispense(int User, int Item)
 		return 1;
 	}
 	
+	#if !USE_POPEN
+	// Create stdin/stdout
+	if( pipe(stdin_pair) || pipe(stdout_pair) )
+	{
+		perror("pipe");
+		return -1;
+	}
+	
+	parent_pid = getpid();
+	childPid = fork();
+	
+	if( childPid < 0 )
+	{
+		perror("fork");
+		return -1;
+	}
+	
+	// Child process
+	if( childPid == 0 )
+	{
+		// Close write end of stdin, and set it to #0
+		close(stdin_pair[1]);	dup2(stdin_pair[0], 0);
+		// Close read end of stdout, and set it to #1
+		close(stdout_pair[0]);	dup2(stdout_pair[1], 1);
+		
+		execl("llogin", "door", "-w-", NULL);
+		kill(parent_pid, SIGCHLD);
+		perror("execl");
+		exit(-1);
+	}
+	
+	child_stdin = fdopen(stdin_pair[1], "w");
+	close(stdin_pair[0]);	// child stdin read
+	close(stdout_pair[1]);	// child stdout write
+	
+	#else
 	// llogin or other
-	pipe = popen("llogin door -w -", "w");
-	if( !pipe || pipe == (void*)-1 ) {
+	child_stdin = popen("llogin door -w -", "w");
+	if( !child_stdin || child_stdin == (void*)-1 ) {
 		#if DEBUG
 		printf("Door_DoDispense: llogin failure\n");
 		#endif
 		return -1;
 	}
-	if( fread(buf, 512, 1, pipe) == 0 )	return -1;	// Flush!
+	#endif
+	
+	if(fread(buf, 1, 512, child_stdin) == 0)	return -1;
 	
 	// Send password
-	fputs(gsDoor_Password, pipe);
-	fputs("\n", pipe);
-	if( fread(buf, 512, 1, pipe) == 0 )	return -1;	// Flush!
+	if( fputs(gsDoor_Password, child_stdin) <= 0 )	return -1;
+	fputs("\n", child_stdin);
+	
+	
+	#if DEBUG
+	printf("Door_DoDispense: Door unlock\n");
+	#endif
 	
 	// ATH1 - Unlock door
-	fputs("ATH1\n", pipe);
-	if( fread(buf, 512, 1, pipe) == 0 )	return -1;	// Flush!
+	if( fputs("ATH1\n", child_stdin) <= 0)	return -1;
 	
 	// Wait before re-locking
 	sleep(DOOR_UNLOCKED_DELAY);
 
+
+	#if DEBUG
+	printf("Door_DoDispense: Door re-lock\n");
+	#endif
+
 	// Re-lock the door
-	fputs("ATH0\n", pipe);
-	if( fread(buf, 512, 1, pipe) == 0 )	return -1;	// Flush!
+	if( fputs("ATH0\n", child_stdin) <= 0 )	return -1;
 	
-	pclose(pipe);
+	#if !USE_POPEN
+	fclose(child_stdin);
+	close(stdin_pair[1]);	// child stdin write
+	close(stdout_pair[0]);	// child stdout read
+	#else
+	pclose(child_stdin);
+	#endif
 	
 	#if DEBUG
 	printf("Door_DoDispense: User %i opened door\n", User);
@@ -125,4 +189,9 @@ int Door_DoDispense(int User, int Item)
 	return 0;
 }
 
+void Door_int_SIGCHLDHandler(int signum)
+{
+	signum = 0;	// Snut up
+	giDoor_ChildTerminated = 1;
+}