Am Mon, 11. May 2009, 09:12:56 +0200 schrieb Jö Fahlke:
> Am Sun, 10. May 2009, 22:18:48 +0200 schrieb Michael Biebl:
> > Thanks a lot for the detailed bug report. Care to write a patch, now that 
> > you
> > already did the analysis? I'm very busy atm.
> 
> I'll have to see whether I find time myself.
> 
> Using getline() would make this stuff much easier -- but getline() is a GNU
> extension.  So is it permissible to use getline() or would I have to provide a
> replacement in case it isn't available?

Applied is a first version of a patch to improve ifparser_init().  I didn't
use getline() after all.  It compiles and I did some rudimentary testing.  I'm
still working on an improvement regarding the handling of continued lines.

Comments?

Bye,
Jö.

-- 
oil -- operation iraqi liberation
http://www.mo.tecsamples.de/mahnwache/index.html
Index: network-manager-0.7.1/system-settings/plugins/ifupdown/interface_parser.c
===================================================================
--- network-manager-0.7.1.orig/system-settings/plugins/ifupdown/interface_parser.c	2009-05-12 00:58:39.000000000 +0200
+++ network-manager-0.7.1/system-settings/plugins/ifupdown/interface_parser.c	2009-05-12 01:08:45.000000000 +0200
@@ -26,6 +26,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 #include "nm-utils.h"
 
 if_block* first;
@@ -74,86 +75,204 @@
 	//printf("added data '%s' with key '%s'\n",data,key);
 }
 
-#define SPACE_OR_TAB(string,ret) {ret = strchr(string,' ');ret=(ret == NULL?strchr(string,'\t'):ret);}
+
+/** Append a line read from a stream to a string
+ *
+ * Read a line from stream and append it at the location *str+*str_len.  If
+ * the line terminated in a newline, it is stripped.  *str_len is then updated
+ * to reflect the new size.  On entrance, *str may be unterminated, but on
+ * exit it is always terminted with a newline (unless an allocation error
+ * occured).
+ *
+ * If the space available for *str is insufficient, new space is allocated
+ * using realloc().  *str_size is updated accordingly.
+ *
+ * On entrance, *str may be NULL.  In this case the initial values of
+ * *str_size and *str_len don't matter and some space is allocated using
+ * malloc().
+ *
+ * On success, the return value is the number of characters read, which is
+ * usually more than the number of characters actually appended because of the
+ * newline-stripping.  On error or EOF -1 is returned.  The return value will
+ * never be 0 size zero characters read is interpreted as EOF.
+ *
+ * \param str      Pointer to the string to be appended to.
+ * \param str_size Allocated space for the string.
+ * \param str_len  Length of string.
+ * \param stream   The stream to read from.
+ */
+static ssize_t append_line(char **str, size_t *str_size, size_t *str_len, FILE *stream)
+{
+
+	size_t chars_read;
+	size_t global_chars_read = 0;
+
+	if(*str == NULL)
+	{
+		char *newstr = (char *)malloc(80);
+		if(newstr == NULL)
+			return -1;
+		*str = newstr;
+		*str_size = 80;
+		*str_len = 0;
+		(*str)[0] = '\0';
+	}
+
+	do {
+		if(*str_size <= *str_len + 1)
+		{
+			char *newstr = (char *)realloc(*str, *str_size * 2);
+			if(newstr == NULL)
+				return -1;
+			*str = newstr;
+			*str_size = *str_size * 2;
+		}
+
+		if(fgets(*str+*str_len, *str_size-*str_len, stream) == NULL)
+			/* restore terminating \0 in case there was an error */
+			(*str)[*str_len] = '\0';
+		chars_read = strlen(*str+*str_len);
+		*str_len += chars_read;
+		global_chars_read += chars_read;
+	} while(chars_read > 0 && (*str)[*str_len-1] != '\n');
+
+	/* trim trailing newline */
+	if(global_chars_read > 0 && (*str)[*str_len-1] == '\n')
+		(*str)[--*str_len] = '\0';
+
+	if(global_chars_read == 0)
+		return -1;
+	return global_chars_read;
+}
 
 void ifparser_init(void)
 {
 	FILE *inp = fopen(ENI_INTERFACES_FILE, "r");
-	int ret = 0;
-	char *line;
-	char *space;
-	char rline[255];
+	ssize_t ret = 0;
+	char *line = NULL;
+	size_t line_space = 0;   /* reserved space for line */
+	size_t line_length; /* actual string length of line */
+	size_t word1, word1_end;
+	size_t word2;
+	size_t line_end;
 
 	if (inp == NULL)
 	{
 		nm_warning ("Error: Can't open %s\n", ENI_INTERFACES_FILE);
 		return;
 	}
-	first = last = NULL;
+
 	while(1)
 	{
-		line = space = NULL;
-		ret = fscanf(inp,"%255[^\n]\n",rline);
-		if (ret == EOF)
-			break;
-		// If the line did not match, skip it
-		if (ret == 0) {
-			char *ignored;
+		line_length = 0;
 
-			ignored = fgets(rline, 255, inp);
+		ret = append_line(&line, &line_space, &line_length, inp);
+		if(ret == -1)
+			break; /* failed to read line; probably EOF */
+
+		/* trim leading whitespace */
+		word1 = 0;
+		while(isspace(line[word1]))
+			++word1;
+
+		/* skip comments and empty lines */
+		if (line[word1] == '#' || line[word1] == '\0')
 			continue;
+
+		/* handle continued lines */
+		while(line[line_length-1] == '\\')
+		{
+			--line_length;
+			ret = append_line(&line, &line_space, &line_length, inp);
+			if(ret == -1)
+				break;
 		}
 
-		line = rline;
-		while(line[0] == ' ')
-			line++;
-		if (line[0]=='#' || line[0]=='\0')
+		/* find end of first word */
+		word1_end = word1;
+		while(line[word1_end] != '\0' && !isspace(line[word1_end]))
+			++word1_end;
+		/* find beginning of second word */
+		word2 = word1_end;
+		while(isspace(line[word2]))
+			++word2;
+		/* skip line if there is no second word */
+		if(line[word2] == '\0')
+		{
+			nm_warning ("Error: Can't parse interface line '%s'\n",line);
 			continue;
+		}
 
-		SPACE_OR_TAB(line,space)
-			if (space == NULL)
-			{
-				nm_warning ("Error: Can't parse interface line '%s'\n",line);
-				continue;
-			}
-		space[0] = '\0';
+		/* trim end of line */
+		line_end = line_length-1;
+		while(isspace(line[line_end]))
+			--line_end;
+		++line_end;
 
 		// There are four different stanzas:
 		// iface, mapping, auto and allow-*. Create a block for each of them.
-		if (strcmp(line,"iface")==0)
+		if (word1_end == word1+5 && strncmp(line+word1,"iface",5)==0)
 		{
-			char *space2 = strchr(space+1,' ');
-			if (space2 == NULL)
+			size_t word2_end;
+			size_t word3, word3_end;
+			size_t word4;
+
+			/* find end of second word */
+			word2_end = word2;
+			while(line[word2_end] != '\0' && !isspace(line[word2_end]))
+				++word2_end;
+
+			/* find beginning of third word */
+			word3 = word2_end;
+			while(isspace(line[word3]))
+				++word3;
+			if (line[word3] == '\0')
 			{
-				nm_warning ("Error: Can't parse iface line '%s'\n",space+1);
+				nm_warning ("Error: Can't parse iface line '%s'\n",line);
 				continue;
 			}
-			space2[0]='\0';
-			add_block(line,space+1);
 
-			if (space2[1]!='\0')
+			/* find end of third word */
+			word3_end = word3;
+			while(line[word3_end] != '\0' && !isspace(line[word3_end]))
+				++word3_end;
+
+			/* find beginning of fourth word */
+			word4 = word3_end;
+			while(isspace(line[word4]))
+				++word4;
+			if (line[word4] == '\0')
 			{
-				space = strchr(space2+1,' ');
-				if (space == NULL)
-				{
-					nm_warning ("Error: Can't parse data '%s'\n",space2+1);
-					continue;
-				}
-				space[0] = '\0';
-				add_data(space2+1,space+1);
+				nm_warning ("Error: Can't parse iface line '%s'\n",line);
+				continue;
 			}
+
+			/* no more error-printing to be done here, we can modify line */
+			/* add block with i.e. "iface" "eth0" */
+			line[word1_end] = '\0';
+			line[word2_end] = '\0';
+			add_block(line+word1, line+word2);
+
+			/* add data with i.e. "inet" "dhcp" */
+			line[word3_end] = '\0';
+			line[line_end] = '\0';
+			add_data(line+word3, line+word4);
 		}
-		else if (strcmp(line,"auto")==0)
-			add_block(line,space+1);
-		else if (strcmp(line,"mapping")==0)
-			add_block(line,space+1);
-		else if (strncmp(line,"allow-",6)==0)
-			add_block(line,space+1);
 		else
-			add_data(line,space+1);
+		{
+			/* no more error-printing to be done here, we can modify line */
+			line[word1_end] = '\0';
+			line[line_end] = '\0';
+			if(strcmp(line+word1,"auto")==0 ||
+			   strcmp(line+word1,"mapping")==0 ||
+			   strncmp(line+word1,"allow-",6)==0)
+				add_block(line+word1, line+word2);
+			else
+				add_data(line+word1, line+word2);
+		}
 
-		//printf("line: '%s' ret=%d\n",rline,ret);
 	}
+	free(line);
 	fclose(inp);
 }
 

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