fix include

[877509395]

Fix lex "include [ \t]filename" handle. To support more spaces/tabs after include key word. Before this change, code supports only one space after include. but lex support more.

[martinhsv]

I like the simplification of leaving out regex.h.

But I don't think you need to make a copy. For example, for the first of the two sections, wouldn't this suffice?:

char *tmpStr = yytext + strlen("include");
const char *file = strtok ( tmpStr, " \t");

[877509395]

strtok(str) will set the next byte of last byte of token to '\0' if token found, so it may change the str. If str contains multiple [ \t], and we need enumerate all possible tokens(call strtok multiple times), multiple bytes would be set to 0. below is a example.

#include <string.h>
int main () {
  char str[80] = "This is - www.runoob.com - website";
  const char s[2] = "-";
  int i=0;
  char *token;
  int length;
  length = strlen(str);
  token = strtok(str, s);
  while( token != NULL ) {
    i++;
    printf( "token%d =%s\n", i,token );
    printf( "token%d address=%p\n", i, token );
    token = strtok(NULL, s);
    printf("\n");
  }
  printf( "str =%s\n",str);
  printf( "str =%p\n", str );
  return(0);
}

the output is:
token1 =This is
token1 address=0x7ffe0e856810

token2 = www.runoob.com
token2 address=0x7ffe0e856819

token3 = website
token3 address=0x7ffe0e85682a

str =This is
str =0x7ffe0e856810
~
From the output, str is changed to "This is", the next byte of "This is" changed to 0. every token address is between str and str+length;

For our case, strtok only is called only once, and based on the below grammar, it is NOT possible there is a [ \t]+ in "CONFIG_VALUE_PATH", so strtok will not change CONFIG_VALUE_PATH LUCKILY;
"CONFIG_VALUE_PATH [0-9A-Za-z_/.-*:]+"
{CONFIG_INCLUDE}[ \t]+{CONFIG_VALUE_PATH}
{CONFIG_INCLUDE}[ \t]+["]{CONFIG_VALUE_PATH}["]

so below change can suffice.
char *tmpStr = yytext + strlen("include");
const char *file = strtok ( tmpStr, " \t");

But I think it is a good practice to first strdup and then free for strtok：

1. strtok may do harm to input.
2. In case for some reason in the future, CONFIG_VALUE_PATH can contain space/tab.
3. hidden logic(can not contain space/tab in CONFIG_VALUE_PATH) of the code need to dig out

[martinhsv]

Ok, good point. I agree that it's unwise to use strtok here without a copy.

Is it worth considering using strspn instead? It's a little more narrowly focussed on what is needed here.

char *tmpStr = yytext + strlen("include");
const char file = tmpStr + strspn ( tmpStr, " \t");

[877509395]

Perfect, strspn exactly matches this context. I think I should go through libc.pdf to know every function.


remove tmpStr, merge two lines into one line:

const char *file = yytext + strlen("include")+ strspn ( yytext + strlen("include"), " \t");

Is it OK to remove tmpStr?

[877509395]

#include <stdio.h>

#include <string.h>
int main(int argc, char**argv)
{
  const char *yytext = "include lj lj ljsdfj";
  const char *file = yytext + strlen("include")+ strspn ( yytext + strlen("include"), " \t");
  printf("%s", file);
}
the output is:
[root@localhost strcspn]# ./a.out
lj lj ljsdfj

[877509395]

BTW,
Same issue also seems exists in many other line. for example,
{CONFIG_DIR_AUDIT_LOG2}[ \t]+{CONFIG_VALUE_PATH} { return p::make_CONFIG_DIR_AUDIT_LOG2(strchr(yytext, ' ') + 1, *driver.loc.back());
I have not check it carefully now.

[877509395]

misoperation close this PR and delete lexhandle

[martinhsv]

Regarding collapsing the code change to a single line, I might lean towards leaving it as two lines, because:

• allocating an extra pointer on the stack doesn't really create extra cost or risk and
• it may make the code a little bit easier to read and
• it avoids duplicating code strlen("include") ... including having a hard-coded string specified twice; it's generally a good coding practice to avoid such duplication

My preference on that isn't particularly strong, however,

[877509395]

reasonable

[877509395]

will submit PR tomorrow