support/scripts/check-host-rpath: document existing functions

As suggested by Arnout Vandecappelle, let's document the
elf_needs_rpath() and check_elf_has_rpath() functions, before we make
them a bit more complicated with per-package directory support.

Suggested-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

support/scripts/check-host-rpath

@@ -39,6 +39,11 @@ is_elf() {
     |grep -E 'Requesting program interpreter:' >/dev/null 2>&1
 }
 
+# This function tells whether a given ELF executable (first argument)
+# needs a RPATH pointing to the host library directory or not. It
+# needs such an RPATH if at least of the libraries used by the ELF
+# executable is available in the host library directory. This function
+# returns 0 when a RPATH is needed, 1 otherwise.
 elf_needs_rpath() {
     local file="${1}"
     local hostdir="${2}"
@@ -54,6 +59,13 @@ elf_needs_rpath() {
     return 1
 }
 
+# This function checks whether at least one of the RPATH of the given
+# ELF executable (first argument) properly points to the host library
+# directory (second argument), either through an absolute RPATH or a
+# relative RPATH. Having such a RPATH will make sure the ELF
+# executable will find at runtime the shared libraries it depends
+# on. This function returns 0 when a proper RPATH was found, or 1
+# otherwise.
 check_elf_has_rpath() {
     local file="${1}"
     local hostdir="${2}"