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
This commit is contained in:
Peter Marschall
committed by
Dan Williams
Dan Williams
parent
4397f4463a
commit
a5b77939fb
@@ -73,15 +73,30 @@ void add_data(const char *key,const char *data)
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//printf("added data '%s' with key '%s'\n",data,key);
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}
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#define SPACE_OR_TAB(string,ret) {ret = strchr(string,' ');ret=(ret == NULL?strchr(string,'\t'):ret);}
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// join values in src with spaces into dst; dst needs to be large enough
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static char *join_values_with_spaces(char *dst, char **src)
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{
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if (dst != NULL) {
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*dst = '\0';
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if (src != NULL && *src != NULL) {
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strcat(dst, *src);
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for (src++; *src != NULL; src++) {
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strcat(dst, " ");
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strcat(dst, *src);
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}
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}
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}
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return(dst);
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}
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void ifparser_init (const char *eni_file)
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{
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FILE *inp = fopen (eni_file, "r");
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int ret = 0;
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char *line;
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char *space;
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char rline[255];
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char line[255];
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int skip_to_block = 1;
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int skip_long_line = 0;
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int offs = 0;
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if (inp == NULL) {
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nm_warning ("Error: Can't open %s\n", eni_file);
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@@ -89,69 +104,107 @@ void ifparser_init (const char *eni_file)
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}
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first = last = NULL;
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while(1)
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while (!feof(inp))
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{
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line = space = NULL;
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ret = fscanf(inp,"%255[^\n]\n",rline);
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if (ret == EOF)
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break;
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// If the line did not match, skip it
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if (ret == 0) {
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char *ignored;
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char *token[128]; // 255 chars can only be split into 127 tokens
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char value[255]; // large enough to join previously split tokens
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char *safeptr;
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int toknum;
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int len = 0;
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ignored = fgets(rline, 255, inp);
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char *ptr = fgets(line+offs, 255-offs, inp);
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if (ptr == NULL)
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break;
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len = strlen(line);
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// skip over-long lines
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if (!feof(inp) && len > 0 && line[len-1] != '\n') {
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if (!skip_long_line)
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g_message ("Error: Skipping over-long-line '%s...'\n", line);
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skip_long_line = 1;
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continue;
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}
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line = rline;
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while(line[0] == ' ')
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line++;
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if (line[0]=='#' || line[0]=='\0')
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// trailing '\n' found: remove it & reset offset to 0
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if (len > 0 && line[len-1] == '\n') {
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line[--len] = '\0';
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offs = 0;
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}
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// if we're in long_line_skip mode, terminate it for real next line
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if (skip_long_line) {
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if (len == 0 || line[len-1] != '\\')
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skip_long_line = 0;
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continue;
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}
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// unwrap wrapped lines
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if (len > 0 && line[len-1] == '\\') {
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offs = len - 1;
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continue;
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}
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//printf(">>%s<<\n", line);
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#define SPACES " \t"
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// tokenize input;
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for (toknum = 0, token[toknum] = strtok_r(line, SPACES, &safeptr);
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token[toknum] != NULL;
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toknum++, token[toknum] = strtok_r(NULL, SPACES, &safeptr))
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;
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// ignore comments and empty lines
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if (toknum == 0 || *token[0]=='#')
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continue;
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SPACE_OR_TAB(line,space)
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if (space == NULL)
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{
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nm_warning ("Error: Can't parse interface line '%s'\n",line);
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continue;
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}
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space[0] = '\0';
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if (toknum < 2) {
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g_message ("Error: Can't parse interface line '%s'\n",
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join_values_with_spaces(value, token));
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skip_to_block = 1;
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continue;
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}
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// There are four different stanzas:
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// iface, mapping, auto and allow-*. Create a block for each of them.
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if (strcmp(line,"iface")==0)
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{
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char *space2 = strchr(space+1,' ');
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if (space2 == NULL)
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{
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nm_warning ("Error: Can't parse iface line '%s'\n",space+1);
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// iface stanza takes at least 3 parameters
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if (strcmp(token[0], "iface") == 0) {
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if (toknum < 4) {
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g_message ("Error: Can't parse iface line '%s'\n",
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join_values_with_spaces(value, token));
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continue;
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}
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space2[0]='\0';
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add_block(line,space+1);
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if (space2[1]!='\0')
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{
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space = strchr(space2+1,' ');
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if (space == NULL)
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{
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nm_warning ("Error: Can't parse data '%s'\n",space2+1);
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continue;
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}
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space[0] = '\0';
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add_data(space2+1,space+1);
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}
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add_block(token[0], token[1]);
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skip_to_block = 0;
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add_data(token[2], join_values_with_spaces(value, token + 3));
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}
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// auto and allow-auto stanzas are equivalent,
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// both can take multiple interfaces as parameters: add one block for each
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else if (strcmp(token[0], "auto") == 0 ||
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strcmp(token[0], "allow-auto") == 0) {
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int i;
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for (i = 1; i < toknum; i++)
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add_block("auto", token[i]);
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skip_to_block = 0;
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}
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else if (strcmp(token[0], "mapping") == 0) {
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add_block(token[0], join_values_with_spaces(value, token + 1));
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skip_to_block = 0;
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}
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// allow-* can take multiple interfaces as parameters: add one block for each
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else if (strncmp(token[0],"allow-",6) == 0) {
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int i;
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for (i = 1; i < toknum; i++)
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add_block(token[0], token[i]);
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skip_to_block = 0;
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}
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else {
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if (skip_to_block)
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g_message ("Error: ignoring out-of-block data '%s'\n",
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join_values_with_spaces(value, token));
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else
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add_data(token[0], join_values_with_spaces(value, token + 1));
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}
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else if (strcmp(line,"auto")==0)
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add_block(line,space+1);
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else if (strcmp(line,"mapping")==0)
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add_block(line,space+1);
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else if (strncmp(line,"allow-",6)==0)
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add_block(line,space+1);
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else
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add_data(line,space+1);
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//printf("line: '%s' ret=%d\n",rline,ret);
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}
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fclose(inp);
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}
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