Simplify string handling (piecemeal)

[alejandro-colomar]

This is a subset of the patches from #1048 for an easier review.

Cc: @hallyn
Cc: @ikerexxe

[ikerexxe]

Did you test the changes in the last commit? The change raises concerns about its potential to work correctly.

[alejandro-colomar]

Did you test the changes in the last commit?

I haven't tested this.

The change raises concerns about its potential to work correctly.

Do you mean this?

commit 5e0c907a5b72b1f8a506939182f283ed4c088dbb (HEAD -> str, gh/str)
Author: Alejandro Colomar <[email protected]>
Date:   Wed Jul 3 23:49:04 2024 +0200

    src/suauth.c: check_su_auth(): Use pointers to simplify
    
    Signed-off-by: Alejandro Colomar <[email protected]>

diff --git a/src/suauth.c b/src/suauth.c
index 895f1278..cbb33dc8 100644
--- a/src/suauth.c
+++ b/src/suauth.c
@@ -18,6 +18,7 @@
 
 #include "defines.h"
 #include "prototypes.h"
+#include "string/strchr/stpspn.h"
 #include "string/strchr/strrspn.h"
 #include "string/strtok/stpsep.h"
 
@@ -47,7 +48,6 @@ int check_su_auth (const char *actual_id,
                    const char *wanted_id,
                    bool su_to_root)
 {
-       int posn;
        const char field[] = ":";
        FILE *authfile_fd;
        char temp[1024];
@@ -73,6 +73,8 @@ int check_su_auth (const char *actual_id,
        }
 
        while (fgets (temp, sizeof (temp), authfile_fd) != NULL) {
+               char  *p;
+
                lines++;
 
                if (stpsep(temp, "\n") == NULL) {
@@ -84,12 +86,11 @@ int check_su_auth (const char *actual_id,
 
                stpcpy(strrspn(temp, " \t"), "");
 
-               posn = strspn(temp, " \t");
-
-               if (temp[posn] == '#' || temp[posn] == '\0') {
+               p = stpspn(temp, " \t");
+               if (*p == '#' || *p == '\0')
                        continue;
-               }
-               if (!(to_users = strtok (temp + posn, field))
+
+               if (!(to_users = strtok(p, field))
                    || !(from_users = strtok (NULL, field))
                    || !(action = strtok (NULL, field))
                    || strtok (NULL, field)) {

What do you think might be incorrect?

stpcpn() is defined as s_ + strspn(s_, accept);
so p = stpspn(temp, ...) would be equivalent to p = temp + strspn(temp, ...)
so *p would be equivalent to *(temp + posn), so equivalent to temp[posn].

[hallyn]

Let me take a closer look at this tonight. I'm pretty sure I already reviewed it as part of 1048 but I'll make sure :)

[hallyn]

lgtm. Only possible issue would still be replacing isspace() with only checking for ' ' and '\t', but the other chars like \f aren't really valid anyway, i believe.

[ikerexxe]

Do you mean this?

commit 5e0c907a5b72b1f8a506939182f283ed4c088dbb (HEAD -> str, gh/str)

Yes, I meant that one, and there's nothing I can point to that might fail. It was just a feeling more than anything else.