[autobackport: sssd-2-9] krb5_child: use ERR_CHECK_NEXT_AUTH_TYPE instead of EAGAIN

[sssd-bot]

This is an automatic backport of PR#8176 krb5_child: use ERR_CHECK_NEXT_AUTH_TYPE instead of EAGAIN to branch sssd-2-9, created by @sumit-bose.

Please make sure this backport is correct.

Note

The commits were cherry-picked without conflicts.

You can push changes to this pull request

git remote add sssd-bot git@github.com:sssd-bot/sssd.git
git fetch sssd-bot refs/heads/SSSD-sssd-backport-pr8176-to-sssd-2-9
git checkout SSSD-sssd-backport-pr8176-to-sssd-2-9
git push sssd-bot SSSD-sssd-backport-pr8176-to-sssd-2-9 --force

---

Original commits
7ddb51f - utils: add new error code ERR_CHECK_NEXT_AUTH_TYPE
0adc2e7 - krb5_child: use ERR_CHECK_NEXT_AUTH_TYPE instead of EAGAIN
da82d1d - krb5_child: clarify EAGAIN returned by krb5_get_init_creds_password()

Backported commits

• 6d68d95 - utils: add new error code ERR_CHECK_NEXT_AUTH_TYPE
• 400f90c - krb5_child: use ERR_CHECK_NEXT_AUTH_TYPE instead of EAGAIN
• 8590f0d - krb5_child: clarify EAGAIN returned by krb5_get_init_creds_password()

---

Original Pull Request Body

This patch used the new error code ERR_CHECK_NEXT_AUTH_TYPE while
processing different authentication types instead of EAGAIN because
EAGAIN might have side effects when returned to the callers.

Resolves: #8108

[gemini-code-assist]

Code Review

This pull request correctly backports a change to introduce a new error code, ERR_CHECK_NEXT_AUTH_TYPE, replacing the more generic EAGAIN for signaling that the next authentication method should be tried. This is a good improvement as it enhances code clarity and prevents potential side effects from the ambiguous use of EAGAIN. The changes are consistently applied across src/providers/krb5/krb5_child.c, and the new error code is properly defined. The addition of a comment to clarify the handling of EAGAIN from krb5_get_init_creds_password() is also a welcome improvement. The changes are sound and I have not found any issues.

[ikerexxe]

LGTM!

[sssd-bot]

The pull request was accepted by @ikerexxe with the following PR CI status:

---

🟢 CodeQL (success)
🟢 rpm-build:centos-stream-9-x86_64:upstream (success)
🟢 Analyze (target) / cppcheck (success)
🟢 Build / make-distcheck (success)
🟢 ci / prepare (success)
🔴 ci / system (centos-9) (failure)
🟢 Static code analysis / codeql (success)
🟢 Static code analysis / pre-commit (success)
🟢 Static code analysis / python-system-tests (success)

---

There are unsuccessful or unfinished checks. Make sure that the failures are not related to this pull request before merging.