feat(PAM service configuration) (#62)

* docs(typo): fix typo in Contributing.md

* add optional PAM service name

* feat(PAM service name): Add ENV variable configuration for the PAM service name

* feat(PAM service name): Implement suggested changes + update README instructions

* docs(remove segment)

README.md

@@ -23,20 +23,20 @@ LiDM is like any [Display Manager](https://en.wikipedia.org/wiki/X_display_manag
 
 # Index
 
-* [LiDM](#lidm)
-  * [Features](#features)
-  * [WIP](#wip)
-* [Index](#index)
-* [Ideology](#ideology)
-* [Usage](#usage)
-  * [Arguments](#arguments)
-  * [Program](#program)
-* [Requirements](#requirements)
-* [Installation](#installation)
-* [Configuring](#configuring)
-* [Contributing](#contributing)
-* [Inspiration](#inspiration)
-* [Contributors](#contributors)
+- [LiDM](#lidm)
+  - [Features](#features)
+- [Index](#index)
+- [Ideology](#ideology)
+- [Usage](#usage)
+    - [Arguments](#arguments)
+    - [Program](#program)
+- [Requirements](#requirements)
+- [Installation](#installation)
+- [Configuring](#configuring)
+- [PAM](#pam)
+- [Contributing](#contributing)
+- [Inspiration](#inspiration)
+- [Contributors](#contributors)
 
 # Ideology
 
@@ -90,6 +90,12 @@ Colors are gonna be put inside `\x1b[...m`, if you don't know what this is check
 > [!TIP]
 > If you don't like seeing an element, you can change the fg color of it to be the same as the bg, making it invisible.
 
+# PAM
+
+If your distribution does not use the standard PAM service name `login` (`/etc/pam.d/login`) for its PAM services or if you want to use another PAM file, simply set the `LIDM_PAM_SERVICE` env variable to your PAM service name. 
+
+When the env variable is empty it defaults to the `login` PAM service or whatever fallback your distribution packager has defined during compilation.
+
 # Contributing
 
 If you want to contribute check the [contribution guide](docs/CONTRIBUTING.md).

docs/CONTRIBUTING.md

@@ -2,9 +2,10 @@
 
 Contributions are welcome! Here's how you can help:
 
-* [Contributing code](#code)
-* [Reporting issues](#issues)
-* [Other](#other)
+- [Contributing](#contributing)
+  - [Code](#code)
+  - [Issues](#issues)
+  - [Other](#other)
 
 ## Code
 
@@ -18,7 +19,7 @@ For small fixes or incremental improvements simply fork the repo and follow the
    * Check your code works as expected.
    * Run the code formatter: `clang-format -i $(git ls-files "*.c" "*.h")`
    * Run the code linter: `clang-tidy -p . $(git ls-files "*.c" "*.h")`. Some checks are pretty pedantic, feel free to ignore or debate some of the rules.
-   * If you prefer, you can run `make pre-commit` to run several code style checks like the avobe along a few extra stuff.
+   * If you prefer, you can run `make pre-commit` to run several code style checks like the above along a few extra stuff.
 
 3. Commit your changes to a new branch (not `master`, one change per branch) and push it:
    * Commit messages should:

src/auth.c

@@ -35,6 +35,10 @@ int pam_conversation(int num_msg, const struct pam_message** msg,
   return PAM_SUCCESS;
 }
 
+#ifndef PAM_SERVICE_FALLBACK
+#define PAM_SERVICE_FALLBACK "login"
+#endif
+
 #define CHECK_PAM_RET(call) \
   ret = (call);             \
   if (ret != PAM_SUCCESS) { \
@@ -51,7 +55,11 @@ pam_handle_t* get_pamh(char* user, char* passwd) {
   struct pam_conv pamc = {pam_conversation, (void*)passwd};
   int ret;
 
-  CHECK_PAM_RET(pam_start("login", user, &pamc, &pamh))
+  char* pam_service_override = getenv("LIDM_PAM_SERVICE");
+  char* pam_service_name =
+      pam_service_override ? pam_service_override : PAM_SERVICE_FALLBACK;
+
+  CHECK_PAM_RET(pam_start(pam_service_name, user, &pamc, &pamh))
   CHECK_PAM_RET(pam_authenticate(pamh, 0))
   CHECK_PAM_RET(pam_acct_mgmt(pamh, 0))
   CHECK_PAM_RET(pam_setcred(pamh, PAM_ESTABLISH_CRED))

src/desktop.c

@@ -66,8 +66,7 @@ int read_desktop(FILE* fd, void* ctx,
       buf_start[eq_idx] = '\0'; // the equal
       key = trim_str(key);
       char* value = &buf_start[eq_idx + 1];
-      if(buf_start[read_size - 1] == '\n')
-        buf_start[read_size - 1] = '\0';
+      if (buf_start[read_size - 1] == '\n') buf_start[read_size - 1] = '\0';
       value = trim_str(value);
 
       // Callback