From: Lucas De Marchi <lucas.de.marchi@gmail.com>
Date: Thu, 14 Nov 2024 16:33:14 +0000 (-0600)
Subject: depmod: Fix handling relative moduledir
X-Git-Tag: v34~70
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a9e69c02d6c26edc9a8bae5ca2b7c4d9d21da9dc;p=thirdparty%2Fkmod.git

depmod: Fix handling relative moduledir

Make sure moduledir is always relative to the basedir and document it as
such.

Note: scdoc 1.11.3 produces a strange result when trying to render the
man page for the 2 examples. Workaround that by ending with an explicit
newline, which produces another stranger behavior (but visually correct)
of indenting the next line.

Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/243
---

diff --git a/man/depmod.8.scd b/man/depmod.8.scd
index c3d44279..a64ee97e 100644
--- a/man/depmod.8.scd
+++ b/man/depmod.8.scd
@@ -56,6 +56,9 @@ rather than the current kernel version (as returned by *uname -r*).
 	distribution vendor who needs to pre-generate the meta-data files rather
 	than running *depmod* again later.
 
+	If a relative path is given, it's relative to the current working
+	directory.
+
 	Example:
 		depmod -b /my/build/staging/dir/
 
@@ -69,13 +72,27 @@ rather than the current kernel version (as returned by *uname -r*).
 	building *modules.dep* file in _basedir_ for a system that uses a
 	different prefix, e.g. _/usr/lib/modules_ vs _/lib/modules_.
 
-	Example:
-		depmod -b /tmp/build -m /kernel-modules
+	Relative and absolute paths are accepted, but they are always relative
+	to the _basedir_.
+
+	Examples:
+		depmod -b /tmp/build -m /kernel-modules++
+depmod -b /tmp/build -m kernel-modules
 
 	This expects all input files under
 	_/tmp/build/kernel-modules/$(uname -r)_ and generates index files under
 	that same directory.
 
+	Without an accompanying *-b* argument, the moduledir is relative to _/_.
+	Example:
+
+		depmod -m foo/bar
+
+	This expects all input files under _/foo/bar/$(uname -r)_ and generates
+	index files under the same directory. Unless libkmod is prepared to
+	handle that arbitrary location, it won't work in runtime.
+
+
 *-o* _outdir_, *--outdir* _outdir_
 	Set the output directory where *depmod* will store any generated file.
 	_outdir_ serves as a root to that location, similar to how _basedir_ is
@@ -83,6 +100,9 @@ rather than the current kernel version (as returned by *uname -r*).
 	_basedir_ it will result in the input being that directory, but the output
 	being the one set by _outdir_.
 
+	If a relative path is given, it's relative to the current working
+	directory.
+
 	Example:
 		depmod -o /my/build/staging/dir/
 
diff --git a/tools/depmod.c b/tools/depmod.c
index d85fa542..2238e5cd 100644
--- a/tools/depmod.c
+++ b/tools/depmod.c
@@ -36,7 +36,6 @@
 #define DEFAULT_VERBOSE LOG_WARNING
 static int verbose = DEFAULT_VERBOSE;
 
-static const char *module_directory = MODULE_DIRECTORY;
 static const char CFG_BUILTIN_KEY[] = "built-in";
 static const char CFG_EXTERNAL_KEY[] = "external";
 static const char *const default_cfg_paths[] = {
@@ -2924,6 +2923,7 @@ static int do_depmod(int argc, char *argv[])
 	const char *module_symvers = NULL;
 	const char *null_kmod_config = NULL;
 	const char *root = "";
+	const char *module_directory = MODULE_DIRECTORY;
 	struct utsname un;
 	struct kmod_ctx *ctx = NULL;
 	struct cfg cfg;
@@ -3033,19 +3033,22 @@ static int do_depmod(int argc, char *argv[])
 		cfg.kversion = un.release;
 	}
 
-	cfg.dirnamelen = snprintf(cfg.dirname, PATH_MAX, "%s%s/%s", root,
+	/* module directory is always relative to basedir/outdir */
+	while (module_directory[0] == '/')
+		module_directory++;
+
+	cfg.dirnamelen = snprintf(cfg.dirname, PATH_MAX, "%s/%s/%s", root,
 				  module_directory, cfg.kversion);
 	if (cfg.dirnamelen >= PATH_MAX) {
-		ERR("Bad directory %s%s/%s: path too long\n", root,
-		    module_directory, cfg.kversion);
+		ERR("Bad directory %s/%s/%s: path too long\n", root, module_directory,
+		    cfg.kversion);
 		goto cmdline_failed;
 	}
 
-	cfg.outdirnamelen = snprintf(cfg.outdirname, PATH_MAX, "%s%s/%s",
-				     out_root ?: root, module_directory,
-				     cfg.kversion);
+	cfg.outdirnamelen = snprintf(cfg.outdirname, PATH_MAX, "%s/%s/%s",
+				     out_root ?: root, module_directory, cfg.kversion);
 	if (cfg.outdirnamelen >= PATH_MAX) {
-		ERR("Bad directory %s%s/%s: path too long\n", out_root ?: root,
+		ERR("Bad directory %s/%s/%s: path too long\n", out_root ?: root,
 		    module_directory, cfg.kversion);
 		goto cmdline_failed;
 	}