From cda663ab96252d0208078c0c61d3a71c1d3945da Mon Sep 17 00:00:00 2001
From: Andreas Baumann <mail@andreasbaumann.cc>
Date: Sun, 12 Apr 2015 13:57:36 +0200
Subject: ..

---
 src/worker.c | 100 ++++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 68 insertions(+), 32 deletions(-)

(limited to 'src')

diff --git a/src/worker.c b/src/worker.c
index 7807697..c73eb7e 100644
--- a/src/worker.c
+++ b/src/worker.c
@@ -13,6 +13,7 @@
 #include <string.h>
 #include <strings.h>
 #include <stdlib.h>
+#include <ctype.h>
 
 #include <signal.h>
 
@@ -259,78 +260,113 @@ static gboolean watch_output( GIOChannel *channel, GIOCondition condition, gpoin
 
 static char *expand_system_variables( const char *s )
 {
-	char *r = (char *)malloc( strlen( s ) * 2 );
+	size_t r_size = strlen( s ) * 2;
+	char *r = (char *)malloc( r_size );
 	char *d = r;
-	bool var_begin = false;
-	bool in_var = false;
+	enum { COPYING, DOLLAR, OPEN_BRACE, VARIABLE, CLOSE_BRACE, ERROR } state = COPYING;
 	const char *var = NULL;
 	const char *p = s;
 	
-	while( *p != '\0' && d - r < strlen( s ) * 2 - 1 ) {
-		switch( *p ) {
-			case '$':
-				var_begin = true;
+	while( state != ERROR && *p != '\0' && d - r < r_size - 1 ) {
+		switch( state ) {
+			case COPYING:
+				if( *p == '$' ) {
+					state = DOLLAR;
+					p++;
+				} else {
+					*d = *p;
+					d++;
+					p++;
+				}
 				break;
 			
-			case '{':
-				if( var_begin ) {
-					in_var = true;
-					var = p + 1;
+			case DOLLAR:
+				if( *p == '{' ) {
+					state = OPEN_BRACE;
+					p++;
 				} else {
-					fprintf( stderr, "ERROR: Unexpected '{' at position %d in '%s'\n", p-s, s );
-					free( r );
-					return NULL;
+					fprintf( stderr, "ERROR: Unexpected '{' at position %d in '%s'\n", (int)( p - s ), s );
+					state = ERROR;
 				}
 				break;
-			
-			case '}':
-				if( var_begin ) {
-					fprintf( stderr, "ERROR: Empty variable declaration '${}' at position %d in '%s'\n", p-s, s );
-					free( r );
-					return NULL;
+						
+			case OPEN_BRACE:
+				if( *p == '}' ) {
+					fprintf( stderr, "ERROR: Empty variable declaration '${}' at position %d in '%s'\n", (int)( p - s ), s );
+					state = ERROR;
+					p++;
+				} else if( isalpha( *p ) ) {
+					// ok, part of variable name
+					state = VARIABLE;
+					var = p;
+					p++;
+				} else {
+					fprintf( stderr, "ERROR: Illegal character '%c' at position %d in variable in '%s'\n", *p, (int)( p - s ), s );
+					state = ERROR;
 				}
-				in_var = false;
-				var_begin = false;
+				break;
+
+			case VARIABLE:
+				if( *p == '}' ) {
+					state = CLOSE_BRACE;
+				} else if( isalpha( *p ) ) {
+					// ok, part of variable name
+					p++;
+				} else {
+					fprintf( stderr, "ERROR: Illegal character '%c' at position %d in variable in '%s'\n", *p, (int)( p - s ), s );
+					state = ERROR;
+				}
+				break;
+			
+			case CLOSE_BRACE:
 				if( strncmp( var, "ARCH", 4 ) == 0 ) {
 					char machine_arch[100];
 					system_arch( machine_arch, sizeof( machine_arch ) );
 					strncpy( d, machine_arch, strlen( machine_arch ) );
 					d += strlen( machine_arch );
+					state = COPYING;
 				} else if( strncmp( var, "OS", 2 ) == 0 ) {
 					char os_name[100];
 					system_os( os_name, sizeof( os_name ) );
 					strncpy( d, os_name, strlen( os_name ) );
 					d += strlen( os_name );
+					state = COPYING;
 				} else if( strncmp( var, "HOST", 4 ) == 0 ) {
 					char hostname[100];
 					gethostname( hostname, sizeof( hostname ) );
 					strncpy( d, hostname, strlen( hostname ) );
 					d += strlen( hostname );
+					state = COPYING;
 				} else if( strncmp( var, "CPUS", 4 ) == 0 ) {
 					unsigned int nofCpus = system_available_cpus( );
 					char buf[10];
 					snprintf( buf, sizeof( buf ), "%d", nofCpus );
 					strncpy( d, buf, strlen( buf ) );
 					d += strlen( buf );
+					state = COPYING;
 				} else {
-					fprintf( stderr, "ERROR: Unknown variable '${%*s}' at position %d in '%s'\n", p-var, var, p-s, s );
-					free( r );
-					return NULL;
+					fprintf( stderr, "ERROR: Unknown variable '${%*s}' at position %d in '%s'\n", (int)( p-var ), var, (int)( p - s ), s );
+					state = ERROR;
 				}
+				p++;
 				break;
 			
+			case ERROR:
 			default:
-				if( in_var ) {
-					var_begin = false;
-				} else {
-					*d = *p;
-					d++;
-				}					
+				break;
 		}
-		p++;
 	}
 	*d = '\0';
 	
+	if( d - r >= r_size - 1 ) {
+		fprintf( stderr, "ERROR: out of memory while substituting variables in '%s'\n", s );
+		state = ERROR;
+	}
+	
+	if( state == ERROR ) {
+		return NULL;
+	}
+	
 	return r;
 }
 
-- 
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