From 542bb9be7cd0c05e3fb1beb849b70d79fec42189 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 31 Mar 2022 11:09:48 +0200
Subject: [PATCH] tree-wide: unify some code that looks for --help in the
 command line

---
 src/backlight/backlight.c           |  5 +++--
 src/basic/process-util.c            | 24 ++++++++++++++++++++++++
 src/basic/process-util.h            |  2 ++
 src/cryptsetup/cryptsetup.c         |  3 ++-
 src/integritysetup/integritysetup.c |  8 +++-----
 src/veritysetup/veritysetup.c       |  6 ++----
 6 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/src/backlight/backlight.c b/src/backlight/backlight.c
index 5a3095cbba..a4e5d77f6c 100644
--- a/src/backlight/backlight.c
+++ b/src/backlight/backlight.c
@@ -14,10 +14,11 @@
 #include "mkdir.h"
 #include "parse-util.h"
 #include "pretty-print.h"
-#include "terminal-util.h"
+#include "process-util.h"
 #include "reboot-util.h"
 #include "string-util.h"
 #include "strv.h"
+#include "terminal-util.h"
 #include "util.h"
 
 static int help(void) {
@@ -368,7 +369,7 @@ static int run(int argc, char *argv[]) {
 
         log_setup();
 
-        if (strv_contains(strv_skip(argv, 1), "--help"))
+        if (argv_looks_like_help(argc, argv))
                 return help();
 
         if (argc != 3)
diff --git a/src/basic/process-util.c b/src/basic/process-util.c
index 72807d039c..10aec10bfa 100644
--- a/src/basic/process-util.c
+++ b/src/basic/process-util.c
@@ -1615,6 +1615,30 @@ _noreturn_ void freeze(void) {
                 pause();
 }
 
+bool argv_looks_like_help(int argc, char **argv) {
+        char **l;
+
+        /* Scans the command line for indications the user asks for help. This is supposed to be called by
+         * tools that do not implement getopt() style command line parsing because they are not primarily
+         * user-facing. Detects four ways of asking for help:
+         *
+         * 1. Passing zero arguments
+         * 2. Passing "help" as first argument
+         * 3. Passing --help as any argument
+         * 4. Passing -h as any argument
+         */
+
+        if (argc <= 1)
+                return true;
+
+        if (streq_ptr(argv[1], "help"))
+                return true;
+
+        l = strv_skip(argv, 1);
+
+        return strv_contains(l, "--help") ||
+                strv_contains(l, "-h");
+}
 
 static const char *const sigchld_code_table[] = {
         [CLD_EXITED] = "exited",
diff --git a/src/basic/process-util.h b/src/basic/process-util.h
index f22ff76ee8..c07575e580 100644
--- a/src/basic/process-util.h
+++ b/src/basic/process-util.h
@@ -191,3 +191,5 @@ int setpriority_closest(int priority);
 bool invoked_as(char *argv[], const char *token);
 
 _noreturn_ void freeze(void);
+
+bool argv_looks_like_help(int argc, char **argv);
diff --git a/src/cryptsetup/cryptsetup.c b/src/cryptsetup/cryptsetup.c
index 21430d4256..408d7511bf 100644
--- a/src/cryptsetup/cryptsetup.c
+++ b/src/cryptsetup/cryptsetup.c
@@ -34,6 +34,7 @@
 #include "path-util.h"
 #include "pkcs11-util.h"
 #include "pretty-print.h"
+#include "process-util.h"
 #include "random-util.h"
 #include "string-util.h"
 #include "strv.h"
@@ -1719,7 +1720,7 @@ static int run(int argc, char *argv[]) {
         const char *verb;
         int r;
 
-        if (argc <= 1)
+        if (argv_looks_like_help(argc, argv))
                 return help();
 
         if (argc < 3)
diff --git a/src/integritysetup/integritysetup.c b/src/integritysetup/integritysetup.c
index d8cfd12e95..7eff0ce5dc 100644
--- a/src/integritysetup/integritysetup.c
+++ b/src/integritysetup/integritysetup.c
@@ -12,9 +12,10 @@
 #include "log.h"
 #include "main-func.h"
 #include "memory-util.h"
-#include "path-util.h"
 #include "parse-util.h"
+#include "path-util.h"
 #include "pretty-print.h"
+#include "process-util.h"
 #include "string-util.h"
 #include "terminal-util.h"
 
@@ -90,10 +91,7 @@ static int run(int argc, char *argv[]) {
         int r;
         char *action, *volume;
 
-        if (argc <= 1 ||
-            strv_contains(strv_skip(argv, 1), "--help") ||
-            strv_contains(strv_skip(argv, 1), "-h") ||
-            streq(argv[1], "help"))
+        if (argv_looks_like_help(argc, argv))
                 return help();
 
         if (argc < 3)
diff --git a/src/veritysetup/veritysetup.c b/src/veritysetup/veritysetup.c
index a81e93cb75..1d1baaa59d 100644
--- a/src/veritysetup/veritysetup.c
+++ b/src/veritysetup/veritysetup.c
@@ -12,6 +12,7 @@
 #include "main-func.h"
 #include "path-util.h"
 #include "pretty-print.h"
+#include "process-util.h"
 #include "string-util.h"
 #include "terminal-util.h"
 
@@ -114,10 +115,7 @@ static int run(int argc, char *argv[]) {
         const char *verb;
         int r;
 
-        if (argc <= 1 ||
-            strv_contains(strv_skip(argv, 1), "--help") ||
-            strv_contains(strv_skip(argv, 1), "-h") ||
-            streq(argv[1], "help"))
+        if (argv_looks_like_help(argc, argv))
                 return help();
 
         if (argc < 3)