Hi,
the previous implementation of the parser for /etc/network/interfaces had
quite a few drawbacks:
- it expected the lines to be terminated with "\n", even the last line
- it ignored line wraps with "\\" followed by "\n"
- it expected over-long lines to be shorter than 510 characters
- it ignored line wraps on over-long lines
- it treated spaces and tabs differently
- it did not make sure to really tokenize on word boundaries
- it treated the equivalent stanzas "auto" and "allow-auto" differently
- it ignored the fact that the "allow-*" stanzas can take multiple arguments
that need to be separated to be recognized NetworkManager's processing later
- it allowed "non-block" stanzas to appear before a block
The attached patch is a rewrite of the parser to fix the issues mentioned:
- it accepts the last line even if it is not terminated by "\n"
- it skips over-long lines, emits a warning and even takes int account
that over-long lines may be wrapped to next lines
- it un-wraps wrapped lines
- it uses spaces and tabs equivalently to tokenize the input
- it treats "allow-auto" as a synonym to "auto"
- it splits multi-argument "auto"/"allow-*" stanza into multiple
single-argument stanzas of the same type
- it warns on data stanzas before the first block stanza
Signed-off-by: Peter Marschall <pe...@adpm.de>
Please consider integrating this patch into the next release of NetworkManager
Best
Peter
--
Peter Marschall
pe...@adpm.de
From 464c030738ffca9cf85101d4b34e01e996f368e6 Mon Sep 17 00:00:00 2001
From: Peter Marschall <pe...@adpm.de>
Date: Sun, 8 Aug 2010 14:41:54 +0200
Subject: [PATCH] ifupdown: make parser for /etc/network/interfaces more robust
The previous implementation of the parser for /etc/network/interfaces had
quite a few drawbacks:
- it expected the lines to be terminated with "\n", even the last line
- it ignored line wraps with "\\" followed by "\n"
- it expected over-long lines to be shorter than 510 characters
- it ignored line wraps on over-long lines
- it treated spaces and tabs differently
- it did not make sure to really tokenize on word boundaries
- it treated the equivalent stanzas "auto" and "allow-auto" differently
- it ignored the fact that the "allow-*" stanzas can take multiple arguments
that need to be separated to be recognized NetworkManager's processing later
- it allowed "non-block" stanzas to appear before a block
This patch is a rewrite of the parser to fix the issues mentioned:
- it accepts the last line even if it is not terminated by "\n"
- it skips over-long lines, emits a warning and even takes into account
that over-long lines may be wrapped to next lines
- it un-wraps wrapped lines
- it uses spaces and tabs equivalently to tokenize the input
- it treats "allow-auto" as a synonym to "auto"
- it splits multi-argument "auto"/"allow-*" into multiple
single-argument stanzas of the same type
- it warns on data stanzas before the first block stanza
Signed-off-by: Peter Marschall <pe...@adpm.de>
---
.../plugins/ifupdown/interface_parser.c | 161 +++++++++++++-------
1 files changed, 107 insertions(+), 54 deletions(-)
diff --git a/system-settings/plugins/ifupdown/interface_parser.c b/system-settings/plugins/ifupdown/interface_parser.c
index f28cf7c..b55e31c 100644
--- a/system-settings/plugins/ifupdown/interface_parser.c
+++ b/system-settings/plugins/ifupdown/interface_parser.c
@@ -73,15 +73,30 @@ void add_data(const char *key,const char *data)
//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);}
+// join values in src with spaces into dst; dst needs to be large enough
+static char *join_values_with_spaces(char *dst, char **src)
+{
+ if (dst != NULL) {
+ *dst = '\0';
+ if (src != NULL && *src != NULL) {
+ strcat(dst, *src);
+
+ for (src++; *src != NULL; src++) {
+ strcat(dst, " ");
+ strcat(dst, *src);
+ }
+ }
+ }
+ return(dst);
+}
void ifparser_init(void)
{
FILE *inp = fopen(ENI_INTERFACES_FILE, "r");
- int ret = 0;
- char *line;
- char *space;
- char rline[255];
+ char line[255];
+ int skip_to_block = 1;
+ int skip_long_line = 0;
+ int offs = 0;
if (inp == NULL)
{
@@ -89,69 +104,107 @@ void ifparser_init(void)
return;
}
first = last = NULL;
- while(1)
+ while (!feof(inp))
{
- line = space = NULL;
- ret = fscanf(inp,"%255[^\n]\n",rline);
- if (ret == EOF)
+ char *token[128]; // 255 chars can only be split into 127 tokens
+ char value[255]; // large enough to join previously split tokens
+ char *safeptr;
+ int toknum;
+ int len = 0;
+
+ char *ptr = fgets(line+offs, 255-offs, inp);
+ if (ptr == NULL)
break;
- // If the line did not match, skip it
- if (ret == 0) {
- char *ignored;
- ignored = fgets(rline, 255, inp);
+ len = strlen(line);
+ // skip over-long lines
+ if (!feof(inp) && len > 0 && line[len-1] != '\n') {
+ if (!skip_long_line)
+ nm_warning ("Error: Skipping over-long-line '%s...'\n", line);
+ skip_long_line = 1;
continue;
}
- line = rline;
- while(line[0] == ' ')
- line++;
- if (line[0]=='#' || line[0]=='\0')
+ // trailing '\n' found: remove it & reset offset to 0
+ if (len > 0 && line[len-1] == '\n') {
+ line[--len] = '\0';
+ offs = 0;
+ }
+
+ // if we're in long_line_skip mode, terminate it for real next line
+ if (skip_long_line) {
+ if (len == 0 || line[len-1] != '\\')
+ skip_long_line = 0;
continue;
+ }
- SPACE_OR_TAB(line,space)
- if (space == NULL)
- {
- nm_warning ("Error: Can't parse interface line '%s'\n",line);
- continue;
- }
- space[0] = '\0';
+ // unwrap wrapped lines
+ if (len > 0 && line[len-1] == '\\') {
+ offs = len - 1;
+ continue;
+ }
+
+ //printf(">>%s<<\n", line);
+
+#define SPACES " \t"
+ // tokenize input;
+ for (toknum = 0, token[toknum] = strtok_r(line, SPACES, &safeptr);
+ token[toknum] != NULL;
+ toknum++, token[toknum] = strtok_r(NULL, SPACES, &safeptr))
+ ;
+
+ // ignore comments and empty lines
+ if (toknum == 0 || *token[0]=='#')
+ continue;
+
+ if (toknum < 2) {
+ nm_warning ("Error: Can't parse interface line '%s'\n",
+ join_values_with_spaces(value, token));
+ skip_to_block = 1;
+ continue;
+ }
// There are four different stanzas:
// iface, mapping, auto and allow-*. Create a block for each of them.
- if (strcmp(line,"iface")==0)
- {
- char *space2 = strchr(space+1,' ');
- if (space2 == NULL)
- {
- nm_warning ("Error: Can't parse iface line '%s'\n",space+1);
+
+ // iface stanza takes at least 3 parameters
+ if (strcmp(token[0], "iface") == 0) {
+ if (toknum < 4) {
+ nm_warning ("Error: Can't parse iface line '%s'\n",
+ join_values_with_spaces(value, token));
continue;
}
- space2[0]='\0';
- add_block(line,space+1);
-
- if (space2[1]!='\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);
- }
+ add_block(token[0], token[1]);
+ skip_to_block = 0;
+ add_data(token[2], join_values_with_spaces(value, token + 3));
+ }
+ // auto and allow-auto stanzas are equivalent,
+ // both can take multiple interfaces as parameters: add one block for each
+ else if (strcmp(token[0], "auto") == 0 ||
+ strcmp(token[0], "allow-auto") == 0) {
+ int i;
+ for (i = 1; i < toknum; i++)
+ add_block("auto", token[i]);
+ skip_to_block = 0;
+ }
+ else if (strcmp(token[0], "mapping") == 0) {
+ add_block(token[0], join_values_with_spaces(value, token + 1));
+ skip_to_block = 0;
+ }
+ // allow-* can take multiple interfaces as parameters: add one block for each
+ else if (strncmp(token[0],"allow-",6) == 0) {
+ int i;
+ for (i = 1; i < toknum; i++)
+ add_block(token[0], token[i]);
+ skip_to_block = 0;
+ }
+ else {
+ if (skip_to_block)
+ nm_warning ("Error: ignoring out-of-block data '%s'\n",
+ join_values_with_spaces(value, token));
+ else
+ add_data(token[0], join_values_with_spaces(value, token + 1));
}
- 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);
-
- //printf("line: '%s' ret=%d\n",rline,ret);
}
fclose(inp);
}
--
1.7.1
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