[patch] ax25-tools-kissnetd-pty.diff: Add symlinking support to kissnetd

ax25-tools-kissnetd-pty.diff (text/plain), 13.48 KB, created by Stuart Longland on 2014-03-29 12:28:18 UTC

--- kiss/kissnetd.c.orig	2014-01-11 11:33:59.332000000 +1000
+++ kiss/kissnetd.c	2014-01-11 12:47:50.938000000 +1000
@@ -8,12 +8,13 @@
  *
  * F1OAT 960804 - Frederic RIBLE
  */
- 
+
 #include <stdio.h>
 #define __USE_XOPEN
 #include <stdlib.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <sys/stat.h>
 #include <string.h>
 #include <unistd.h>
 #include <assert.h>
@@ -23,11 +24,17 @@
 #include <syslog.h>
 #include <time.h>
 #include <limits.h>
+#include <signal.h>
+
+#include <pwd.h>
+#include <grp.h>
 
 static char *Version = "1.5";
 static int VerboseMode = 0;
 static int MaxFrameSize = 512;
 
+#define PTMX_TTY	"/dev/ptmx"
+
 #define REOPEN_TIMEOUT	30	/* try tio reopen every 10 s */
 
 struct PortDescriptor {
@@ -39,20 +46,34 @@
 	char		namepts[PATH_MAX];  /* name of the unix98 pts slaves, which
 				       * the client has to use */
 	int		is_active;
+	int		is_unix98;
+	int		is_symlinked;
+
+	int		do_chown;
+	uid_t		pty_uid;
+	gid_t		pty_gid;
+
+	mode_t		pty_mode;
 };
 
 static struct PortDescriptor *PortList[FD_SETSIZE];
 
 static int NbPort = 0;
 
+static int SetPtyOwner = 0;
+static uid_t PtyOwnerUid = 0;
+static gid_t PtyOwnerGid = 0;
+
+static mode_t PtyMode = 0;
+
 static void Usage(void)
 {
-	fprintf(stderr, "\nUsage : kissnetd [-v] [-f size] [-p num | /dev/pty?? [/dev/pty??]* ]\n");
+	fprintf(stderr, "\nUsage : kissnetd [-v] [-f size] [-p num | /dev/pty?? [/dev/pty??]* | [owner=USER:GROUP] [mode=MODE] pty:/dev/symlink1 [pty:/dev/symlink2]* ]\n");
 	fprintf(stderr, " -v       : Verbose mode, trace on stdout\n");
 	fprintf(stderr, " -f size  : Set max frame size to size bytes (default 512)\n");
 	fprintf(stderr, " -p num   : Number of /dev/ptmx-master-devices has to open\n");
 	exit(1);
-} 
+}
 
 static void Banner(int Small)
 {
@@ -64,7 +85,7 @@
 		printf("* Network broadcast between kiss ports *\n");
 		printf("*      ATEPRA FPAC/Linux Project       *\n");
 		printf("****************************************\n");
-		printf("*         kissnetd Version %-4s        *\n", Version); 
+		printf("*         kissnetd Version %-4s        *\n", Version);
 		printf("*        by Frederic RIBLE F1OAT       *\n");
 		printf("****************************************\n");
 	}
@@ -73,30 +94,41 @@
 static void NewPort(char *Name)
 {
 	struct PortDescriptor *MyPort;
-	
+
 	if (VerboseMode) {
 		printf("Opening port %s\n", Name);
 	}
-	
+
 	if (NbPort == FD_SETSIZE) {
 		fprintf(stderr, "Cannot handle %s : too many ports\n", Name);
 		exit(1);
 	}
-	
+
 	MyPort = calloc(sizeof(struct PortDescriptor), 1);
 	if (MyPort) MyPort->FrameBuffer = calloc(sizeof (unsigned char), MaxFrameSize);
 	if (!MyPort || !MyPort->FrameBuffer) {
 		perror("cannot allocate port descriptor");
 		exit(1);
 	}
-	
-	strncpy(MyPort->Name, Name, PATH_MAX-1);
+
+	MyPort->is_symlinked = (strstr(Name, "pty:") == Name);
+	MyPort->is_unix98 = MyPort->is_symlinked
+				|| (!strcmp(PTMX_TTY, Name));
+
+	strncpy(MyPort->Name, (MyPort->is_symlinked
+				? index(Name, ':') + 1
+				: Name), PATH_MAX-1);
+
 	MyPort->Name[PATH_MAX-1] = '\0';
 	MyPort->Fd = -1;
 	MyPort->FrameBuffer[0] = 0xC0;
 	MyPort->BufferIndex = 1;
 	MyPort->namepts [0] = '\0';
 	MyPort->is_active = 0;
+	MyPort->do_chown = SetPtyOwner;
+	MyPort->pty_uid = PtyOwnerUid;
+	MyPort->pty_gid = PtyOwnerGid;
+	MyPort->pty_mode= PtyMode;
 	PortList[NbPort++] = MyPort;
 }
 
@@ -104,17 +136,20 @@
 {
 	char MyString[80];
 	PortList[PortNumber]->TimeLastOpen = time(NULL);
-		
+
 	if (VerboseMode) {
 		printf("Reopening port %d\n", PortNumber);
 	}
-	
+
 	if (PortList[PortNumber]->namepts[0] == '\0') {
-		
+
 		syslog(LOG_WARNING, "kissnetd : Opening port %s\n", PortList[PortNumber]->Name);
-		PortList[PortNumber]->Fd = open(PortList[PortNumber]->Name, O_RDWR | O_NONBLOCK);
+		PortList[PortNumber]->Fd = open(
+				(PortList[PortNumber]->is_symlinked
+				 ? PTMX_TTY
+				 : PortList[PortNumber]->Name), O_RDWR | O_NONBLOCK);
 		if (PortList[PortNumber]->Fd < 0) {
-			syslog(LOG_WARNING, "kissnetd : Error opening port %s : %s\n", 
+			syslog(LOG_WARNING, "kissnetd : Error opening port %s : %s\n",
 				PortList[PortNumber]->Name, strerror(errno));
 			if (VerboseMode) {
 				sprintf(MyString, "cannot reopen %s", PortList[PortNumber]->Name);
@@ -123,12 +158,12 @@
 			return;
 		}
 		PortList[PortNumber]->is_active = 1;
-		if (!strcmp(PortList[PortNumber]->Name, "/dev/ptmx")) {
+		if (PortList[PortNumber]->is_unix98) {
 			char *npts;
 			/* get name of pts-device */
 			if ((npts = ptsname(PortList[PortNumber]->Fd)) == NULL) {
 				sprintf(MyString, "Cannot get name of pts-device.\n");
-				syslog(LOG_WARNING, "kissnetd : Cannot get name of pts-device\n"); 
+				syslog(LOG_WARNING, "kissnetd : Cannot get name of pts-device\n");
 				exit(1);
 			}
 			strncpy(PortList[PortNumber]->namepts, npts, PATH_MAX-1);
@@ -140,11 +175,39 @@
 				syslog(LOG_WARNING, "kissnetd : Cannot unlock pts-device %s\n", PortList[PortNumber]->namepts);
 				exit(1);
 			}
-			syslog(LOG_WARNING, "kissnetd : Using /dev/ptmx with slave pty %s\n", PortList[PortNumber]->namepts);
+
+			if (PortList[PortNumber]->do_chown) {
+				if (chown(PortList[PortNumber]->namepts,
+						PortList[PortNumber]->pty_uid,
+						PortList[PortNumber]->pty_gid)) {
+					syslog(LOG_CRIT, "Cannot chown %s\n",
+							PortList[PortNumber]->namepts);
+					exit(1);
+				}
+			}
+			if (PortList[PortNumber]->pty_mode) {
+				if (chmod(PortList[PortNumber]->namepts,
+						PortList[PortNumber]->pty_mode)) {
+					syslog(LOG_CRIT, "Cannot chmod %s\n",
+							PortList[PortNumber]->namepts);
+					exit(1);
+				}
+			}
+
+			if (PortList[PortNumber]->is_symlinked) {
+				/* Create symbolic link */
+				if (symlink(PortList[PortNumber]->namepts, PortList[PortNumber]->Name)) {
+					syslog(LOG_CRIT, "Cannot symlink %s to %s\n", PortList[PortNumber]->namepts,
+							PortList[PortNumber]->Name);
+					exit(1);
+				}
+			} else {
+				syslog(LOG_WARNING, "kissnetd : Using /dev/ptmx with slave pty %s\n", PortList[PortNumber]->namepts);
+			}
 		}
 	} else {
 		if (PortList[PortNumber]->Fd == -1) {
-			syslog(LOG_WARNING, "kissnetd : Cannot reopen port ptmx (slave %s) : not supported by ptmx-device\n", 
+			syslog(LOG_WARNING, "kissnetd : Cannot reopen port ptmx (slave %s) : not supported by ptmx-device\n",
 		       	PortList[PortNumber]->namepts);
 			if (VerboseMode) {
 				sprintf(MyString, "cannot reopen ptmx (slave %s).", PortList[PortNumber]->namepts);
@@ -152,7 +215,7 @@
 			}
 			return;
 		}
-		syslog(LOG_WARNING, "kissnetd : Trying to poll port ptmx (slave %s).\n", 
+		syslog(LOG_WARNING, "kissnetd : Trying to poll port ptmx (slave %s).\n",
 		       	PortList[PortNumber]->namepts);
 		PortList[PortNumber]->is_active = 1;
 	}
@@ -163,12 +226,12 @@
 	int i;
 	static int wrote_info = 0;
 	time_t CurrentTime = time(NULL);
-	
+
 	for (i=0; i<NbPort; i++) {
 		if (PortList[i]->Fd >= 0 &&  PortList[i]->is_active == 1) continue;
 		if ( (CurrentTime - PortList[i]->TimeLastOpen) > REOPEN_TIMEOUT ) ReopenPort(i);
 	}
-	
+
 	if (!wrote_info) {
 		for (i=0; i<NbPort; i++) {
 			if (PortList[i]->namepts[0] != '\0') {
@@ -197,37 +260,37 @@
 {
 	int i;
 	int rc;
-	
+
 	/* Broadcast only info frames */
-	
+
 	if (PortList[InputPort]->FrameBuffer[1] != 0x00 && \
 	    PortList[InputPort]->FrameBuffer[1] != 0x20 && \
 	    PortList[InputPort]->FrameBuffer[1] != 0x80)
 		return;
-	
+
 	for (i=0; i<NbPort; i++) {
 		int offset = 0;
 		if (i == InputPort) continue;
 		if (PortList[i]->Fd < 0 || PortList[i]->is_active == 0) continue;
 again:
-		rc = write(PortList[i]->Fd, 
-			   PortList[InputPort]->FrameBuffer+offset, 
+		rc = write(PortList[i]->Fd,
+			   PortList[InputPort]->FrameBuffer+offset,
 			   PortList[InputPort]->BufferIndex-offset);
 		if (rc < 0) {
 			if (errno == EAGAIN) {
 				if (PortList[i]->namepts[0] == '\0')
-					syslog(LOG_WARNING, "kissnetd : write buffer full on port %s. dropping frame. %s", 
+					syslog(LOG_WARNING, "kissnetd : write buffer full on port %s. dropping frame. %s",
 						PortList[i]->Name, strerror(errno));
 				else
-					syslog(LOG_WARNING, "kissnetd : write buffer full on ptmx port %s. dropping frame. %s", 
+					syslog(LOG_WARNING, "kissnetd : write buffer full on ptmx port %s. dropping frame. %s",
 						PortList[i]->namepts, strerror(errno));
 				continue;
 			}
 			if (PortList[i]->namepts[0] == '\0')
-				syslog(LOG_WARNING, "kissnetd : Error writing to port %s : %s\n", 
+				syslog(LOG_WARNING, "kissnetd : Error writing to port %s : %s\n",
 					PortList[i]->Name, strerror(errno));
 			else
-				syslog(LOG_WARNING, "kissnetd : Error writing to port ptmx (slave %s) : %s\n", 
+				syslog(LOG_WARNING, "kissnetd : Error writing to port ptmx (slave %s) : %s\n",
 					PortList[i]->namepts, strerror(errno));
 			if (VerboseMode) perror("write");
 			PortList[i]->is_active = 0;
@@ -241,7 +304,7 @@
 			printf("Sending %d bytes on port %d : rc=%d\n",
 				PortList[InputPort]->BufferIndex,
 				i, rc);
-		}	   
+		}
 		if (rc < PortList[InputPort]->BufferIndex-offset) {
 			offset += rc;
 			goto again;
@@ -255,7 +318,7 @@
 	int Length;
 	int i;
 	struct PortDescriptor *MyPort = PortList[PortNumber];
-	
+
 	Length = read(MyPort->Fd, MyBuffer, sizeof(MyBuffer));
 	if (VerboseMode) {
 		printf("Read port %d : rc=%d\n", PortNumber, Length);
@@ -265,10 +328,10 @@
 		if (errno == EAGAIN)
 			return;
 		if (MyPort->namepts[0] == '\0')
-			syslog(LOG_WARNING, "kissnetd : Error reading from port %s : %s\n", 
+			syslog(LOG_WARNING, "kissnetd : Error reading from port %s : %s\n",
 				PortList[PortNumber]->Name, strerror(errno));
 		else
-			syslog(LOG_WARNING, "kissnetd : Error reading from port ptmx (slave %s) : %s\n", 
+			syslog(LOG_WARNING, "kissnetd : Error reading from port ptmx (slave %s) : %s\n",
 				PortList[PortNumber]->namepts, strerror(errno));
 		if (VerboseMode) perror("read");
 		MyPort->is_active = 0;
@@ -285,11 +348,11 @@
 				MyPort->BufferIndex = 1;
 			}
 		}
-		else {		
+		else {
 			MyPort->FrameBuffer[MyPort->BufferIndex++] = MyBuffer[i];
 			if (MyBuffer[i] == 0xC0) {
 				Broadcast(PortNumber);
-				MyPort->BufferIndex = 1; 
+				MyPort->BufferIndex = 1;
 			}
 		}
 	}
@@ -300,19 +363,19 @@
 	static fd_set MyFdSet;
 	int i, rc;
 	struct timeval Timeout;
-	
+
 	Timeout.tv_sec = 1;
 	Timeout.tv_usec = 0;
-	
+
 	FD_ZERO(&MyFdSet);
 	for (i=0; i<NbPort; i++) {
 		if (PortList[i]->Fd >= 0 && PortList[i]->is_active) FD_SET(PortList[i]->Fd, &MyFdSet);
 	}
 	rc = select(FD_SETSIZE, &MyFdSet, NULL, NULL, &Timeout);
-	
+
 	if (VerboseMode) printf("select : rc=%d\n", rc);
 	if (!rc ) TickReopen();
-	
+
 	if (rc > 0) {
 		for (i=0; i<NbPort && rc; i++) {
 			if (PortList[i]->Fd < 0) continue;
@@ -321,7 +384,64 @@
 				rc--;
 			}
 		}
-	}	
+	}
+}
+
+/*
+ * Parse the owner string; given as a user:group pair.  Result is stored
+ * in PtyOwnerUid and PtyOwnerGid; and overrides previously set defaults.
+ */
+static int ParseOwner(char* owner)
+{
+	char* colon;
+	char* pty_owner_group;
+
+	if (!strcmp(owner, "default")) {
+		SetPtyOwner = 0;
+		return 0;
+	}
+
+	colon = index(owner, ':');
+	if (!colon) {
+		fprintf(stderr, "Owner must be given in the form user:group\n");
+		return 1;
+	}
+	*colon = 0;
+	pty_owner_group = colon + 1;
+
+	if (owner) {
+		/* Look up the user */
+		struct passwd user;
+		struct passwd* user_ptr = NULL;
+		struct group grp;
+		struct group* grp_ptr = NULL;
+		char buffer[512];
+		int err = getpwnam_r(owner, &user,
+				buffer, sizeof(buffer)-1, &user_ptr);
+		if (err) {
+			fprintf(stderr,
+				"Failed to look up user: %s (%d)\n",
+				strerror(err), err);
+			return 1;
+		}
+
+		err = getgrnam_r(pty_owner_group, &grp,
+				buffer, sizeof(buffer)-1, &grp_ptr);
+		if (err) {
+			fprintf(stderr,
+				"Failed to look up group: %s (%d)\n",
+				strerror(err), err);
+			return 1;
+		}
+
+		if (user_ptr && grp_ptr) {
+			PtyOwnerUid = user_ptr->pw_uid;
+			PtyOwnerGid = grp_ptr->gr_gid;
+			SetPtyOwner = 1;
+			return 0;
+		}
+	}
+	return 1;
 }
 
 static void ProcessArgv(int argc, char *argv[])
@@ -329,7 +449,7 @@
 	int opt;
 	int i=0;
 	int ptmxdevices = 0;
-	
+
 	while ((opt = getopt(argc, argv, "vf:p:")) != -1) {
 		switch (opt) {
 		case 'v':
@@ -345,7 +465,16 @@
 				exit(1);
 			}
 			for (i=0; i < ptmxdevices; i++)
-				NewPort("/dev/ptmx");
+				NewPort(PTMX_TTY);
+			break;
+		case 'o':
+			/* Change the owner of the ptys */
+			if (ParseOwner(optarg))
+				exit(1);
+			break;
+		case 'm':
+			/* Change the mode of the pty */
+			PtyMode = (mode_t)strtoul(optarg, NULL, 8);
 			break;
 		default:
 			fprintf(stderr, "Invalid option %s\n", argv[optind]);
@@ -353,9 +482,19 @@
 			exit(1);
 		}
 	}
-		
-	while (optind < argc)
-		NewPort(argv[optind++]);
+
+	while (optind < argc) {
+		char* arg = argv[optind++];
+		if (strstr(arg, "owner=") == arg) {
+			if (ParseOwner(index(arg,'=')+1))
+				exit(1);
+		} else if (strstr(arg, "mode=") == arg) {
+			PtyMode = (mode_t)strtoul(index(arg,'=')+1,
+				NULL, 8);
+		} else {
+			NewPort(arg);
+		}
+	}
 
 	if (NbPort < 2) {
 		fprintf(stderr, "This multiplexer needs at least two pty's\n");
@@ -363,8 +502,25 @@
 	}
 }
 
+void cleanup(void)
+{
+	/* Clean up symbolic links */
+	int i;
+	for (i=0; i<NbPort; i++) {
+		if (PortList[i]->is_symlinked) {
+			if (unlink(PortList[i]->Name))
+				syslog(LOG_WARNING, "Failed to unlink %s",
+					PortList[i]->Name);
+		}
+	}
+}
+void cleanup_sig(int signal)
+{
+	cleanup();
+	exit(0);
+}
 
-int main(int argc, char *argv[]) 
+int main(int argc, char *argv[])
 {
 	if (argc < 2) {
 		Banner(0);
@@ -373,8 +529,13 @@
 	else {
 		Banner(1);
 	}
-	
+
+	atexit(cleanup);
+	signal(SIGTERM, cleanup_sig);
+	signal(SIGINT, cleanup_sig);
+	signal(SIGQUIT, cleanup_sig);
+
 	ProcessArgv(argc, argv);
 	while (1) ProcessPortList();
-	return 0;	
+	return 0;
 }