modutils: optional modutils-small by Vladimir Dronnikov.

 15kb smaller than standard one.
libbb/recursive_action.c: commented-out code for aborting the scan.

3 files changed, 711 insertions, 9 deletions

diff --git a/modutils/Config.in b/modutils/Config.in
index 2b0bcdd..25841b8 100644
--- a/modutils/Config.in
+++ b/modutils/Config.in
@@ -5,14 +5,63 @@
 
 menu "Linux Module Utilities"
 
+config MODPROBE_SMALL
+	bool "Simplified modutils"
+	default n
+	help
+	  Simplified modutils.
+
+	  With this option modprobe does not use or require
+	  modules.dep or /etc/modules.conf files.
+	  It scans module files in /lib/modules/`uname -r` and
+	  determines dependencies and module alias names on the fly.
+	  This may make module loading slower, most notably
+	  when one needs to load module by alias (this requires
+	  scanning through module _bodies_).
+
+	  Additional module parameters can be stored in
+	  /etc/modules/$module_name files.
+
+	  Apart from modprobe, other utilities are also provided:
+	  - insmod is an alias to modprobe
+	  - rmmod is an alias to modprobe -r
+	  - depmod is provided but does nothing
+
+	  As of 2008-07, this code is experimental. It it 15kb smaller
+	  than "non-small" modutils.
+
+config FEATURE_MODPROBE_SMALL_OPTIONS_ON_CMDLINE
+	bool "module options on cmdline"
+	default n
+	depends on MODPROBE_SMALL
+	help
+	  Allow insmod and modprobe take module options from command line.
+	  N.B. Very bloaty.
+
+config FEATURE_MODPROBE_SMALL_CHECK_ALREADY_LOADED
+	bool "Skip loading of already loaded modules"
+	default n
+	depends on MODPROBE_SMALL
+	help
+	  Check if the module is already loaded.
+	  N.B. It's racy.
+
+config FEATURE_MODPROBE_SMALL_ZIPPED
+	bool "Handle gzipped or bzipped modules"
+	default n
+	depends on MODPROBE_SMALL
+	help
+	  Handle compressed modules. Bloaty. Sloooow.
+
 config DEPMOD
 	bool "depmod"
 	default n
+	depends on !MODPROBE_SMALL
 	help
 	  depmod generates modules.dep (FIXME: elaborate)
 
 config FEATURE_DEPMOD_PRUNE_FANCY
-	bool "fancy dependency pruning"
+	bool "Fancy dependency pruning"
 	default n
 	depends on DEPMOD
 	help
@@ -26,7 +75,7 @@ config FEATURE_DEPMOD_PRUNE_FANCY
 	  If unsure, say N.
 
 config FEATURE_DEPMOD_ALIAS
-	bool "alias support"
+	bool "Alias support"
 	default n
 	depends on DEPMOD
 	help
@@ -38,6 +87,7 @@ config FEATURE_DEPMOD_ALIAS
 config INSMOD
 	bool "insmod"
 	default n
+	depends on !MODPROBE_SMALL
 	help
 	  insmod is used to load specified modules in the running kernel.
 
@@ -93,12 +143,14 @@ config FEATURE_INSMOD_LOAD_MAP_FULL
 config RMMOD
 	bool "rmmod"
 	default n
+	depends on !MODPROBE_SMALL
 	help
 	  rmmod is used to unload specified modules from the kernel.
 
 config LSMOD
 	bool "lsmod"
 	default n
+	depends on !MODPROBE_SMALL
 	help
 	  lsmod is used to display a list of loaded modules.
 
@@ -113,6 +165,7 @@ config FEATURE_LSMOD_PRETTY_2_6_OUTPUT
 config MODPROBE
 	bool "modprobe"
 	default n
+	depends on !MODPROBE_SMALL
 	help
 	  Handle the loading of modules, and their dependencies on a high
 	  level.
@@ -196,7 +249,7 @@ config DEFAULT_MODULES_DIR
 	# Simulate indentation
 	string "Default directory containing modules"
 	default "/lib/modules"
-	depends on INSMOD || RMMOD || MODPROBE || DEPMOD
+	depends on INSMOD || RMMOD || MODPROBE || MODPROBE_SMALL || DEPMOD
 	help
 	  Directory that contains kernel modules.
 	  Defaults to "/lib/modules"
@@ -205,7 +258,7 @@ config DEFAULT_DEPMOD_FILE
 	# Simulate indentation
 	string "Default name of modules.dep"
 	default "modules.dep"
-	depends on INSMOD || RMMOD || MODPROBE || DEPMOD
+	depends on INSMOD || RMMOD || MODPROBE || MODPROBE_SMALL || DEPMOD
 	help
 	  Filename that contains kernel modules dependencies.
 	  Defaults to "modules.dep"
diff --git a/modutils/Kbuild b/modutils/Kbuild
index 40ea0ef..8280701 100644
--- a/modutils/Kbuild
+++ b/modutils/Kbuild
@@ -5,8 +5,9 @@
 # Licensed under the GPL v2, see the file LICENSE in this tarball.
 
 lib-y:=
-lib-$(CONFIG_DEPMOD)		+= depmod.o
-lib-$(CONFIG_INSMOD)		+= insmod.o
-lib-$(CONFIG_LSMOD)		+= lsmod.o
-lib-$(CONFIG_MODPROBE)		+= modprobe.o
-lib-$(CONFIG_RMMOD)		+= rmmod.o
+lib-$(CONFIG_DEPMOD)            += depmod.o
+lib-$(CONFIG_INSMOD)            += insmod.o
+lib-$(CONFIG_LSMOD)             += lsmod.o
+lib-$(CONFIG_MODPROBE)          += modprobe.o
+lib-$(CONFIG_MODPROBE_SMALL)    += modprobe-small.o
+lib-$(CONFIG_RMMOD)             += rmmod.o
diff --git a/modutils/modprobe-small.c b/modutils/modprobe-small.c
new file mode 100644
index 0000000..bbcd989
--- /dev/null
+++ b/modutils/modprobe-small.c
@@ -0,0 +1,648 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * simplified modprobe
+ *
+ * Copyright (c) 2008 Vladimir Dronnikov
+ * Copyright (c) 2008 Bernhard Fischer (initial depmod code)
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ */
+
+#include "libbb.h"
+#include "unarchive.h"
+
+#include <sys/utsname.h> /* uname() */
+#include <fnmatch.h>
+
+/* libbb candidate */
+static void *xmalloc_read(int fd, size_t *sizep)
+{
+	char *buf;
+	size_t size, rd_size, total;
+	off_t to_read;
+	struct stat st;
+
+	to_read = sizep ? *sizep : INT_MAX; /* max to read */
+
+	/* Estimate file size */
+	st.st_size = 0; /* in case fstat fails, assume 0 */
+	fstat(fd, &st);
+	/* /proc/N/stat files report st_size 0 */
+	/* In order to make such files readable, we add small const */
+	size = (st.st_size | 0x3ff) + 1;
+
+	total = 0;
+	buf = NULL;
+	while (1) {
+		if (to_read < size)
+			size = to_read;
+		buf = xrealloc(buf, total + size + 1);
+		rd_size = full_read(fd, buf + total, size);
+		if ((ssize_t)rd_size < 0) { /* error */
+			free(buf);
+			return NULL;
+		}
+		total += rd_size;
+		if (rd_size < size) /* EOF */
+			break;
+		to_read -= rd_size;
+		if (to_read <= 0)
+			break;
+		/* grow by 1/8, but in [1k..64k] bounds */
+		size = ((total / 8) | 0x3ff) + 1;
+		if (size > 64*1024)
+			size = 64*1024;
+	}
+	xrealloc(buf, total + 1);
+	buf[total] = '\0';
+
+	if (sizep)
+		*sizep = total;
+	return buf;
+}
+
+
+//#define dbg1_error_msg(...) ((void)0)
+//#define dbg2_error_msg(...) ((void)0)
+#define dbg1_error_msg(...) bb_error_msg(__VA_ARGS__)
+#define dbg2_error_msg(...) bb_error_msg(__VA_ARGS__)
+
+extern int init_module(void *module, unsigned long len, const char *options);
+extern int delete_module(const char *module, unsigned flags);
+extern int query_module(const char *name, int which, void *buf, size_t bufsize, size_t *ret);
+
+enum {
+	OPT_q = (1 << 0), /* be quiet */
+	OPT_r = (1 << 1), /* module removal instead of loading */
+};
+
+typedef struct module_info {
+	char *pathname;
+	char *desc;
+} module_info;
+
+/*
+ * GLOBALS
+ */
+struct globals {
+	module_info *modinfo;
+	char *module_load_options;
+	int module_count;
+	int module_found_idx;
+	int stringbuf_idx;
+	char stringbuf[32 * 1024]; /* some modules have lots of stuff */
+	/* for example, drivers/media/video/saa7134/saa7134.ko */
+};
+#define G (*ptr_to_globals)
+#define modinfo             (G.modinfo            )
+#define module_count        (G.module_count       )
+#define module_found_idx    (G.module_found_idx   )
+#define module_load_options (G.module_load_options)
+#define stringbuf_idx       (G.stringbuf_idx      )
+#define stringbuf           (G.stringbuf          )
+#define INIT_G() do { \
+	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
+} while (0)
+
+
+static void appendc(char c)
+{
+	if (stringbuf_idx < sizeof(stringbuf))
+		stringbuf[stringbuf_idx++] = c;
+}
+
+static void append(const char *s)
+{
+	size_t len = strlen(s);
+	if (stringbuf_idx + len < sizeof(stringbuf)) {
+		memcpy(stringbuf + stringbuf_idx, s, len);
+		stringbuf_idx += len;
+	}
+}
+
+static void reset_stringbuf(void)
+{
+	stringbuf_idx = 0;
+}
+
+static char* copy_stringbuf(void)
+{
+	char *copy = xmalloc(stringbuf_idx);
+	return memcpy(copy, stringbuf, stringbuf_idx);
+}
+
+static char* find_keyword(char *ptr, size_t len, const char *word)
+{
+	int wlen;
+
+	if (!ptr) /* happens if read_module cannot read it */
+		return NULL;
+
+	wlen = strlen(word);
+	len -= wlen - 1;
+	while ((ssize_t)len > 0) {
+		char *old = ptr;
+		/* search for the first char in word */
+		ptr = memchr(ptr, *word, len);
+		if (ptr == NULL) /* no occurance left, done */
+			break;
+		if (strncmp(ptr, word, wlen) == 0)
+			return ptr + wlen; /* found, return ptr past it */
+		++ptr;
+		len -= (ptr - old);
+	}
+	return NULL;
+}
+
+static void replace(char *s, char what, char with)
+{
+	while (*s) {
+		if (what == *s)
+			*s = with;
+		++s;
+	}
+}
+
+#if ENABLE_FEATURE_MODPROBE_SMALL_ZIPPED
+static char *xmalloc_open_zipped_read_close(const char *fname, size_t *sizep)
+{
+	size_t len;
+	char *image;
+	char *suffix;
+
+	int fd = open_or_warn(fname, O_RDONLY);
+	if (fd < 0)
+		return NULL;
+
+	suffix = strrchr(fname, '.');
+	if (suffix) {
+		if (strcmp(suffix, ".gz") == 0)
+			fd = open_transformer(fd, unpack_gz_stream, "gunzip");
+		else if (strcmp(suffix, ".bz2") == 0)
+			fd = open_transformer(fd, unpack_bz2_stream, "bunzip2");
+	}
+
+	len = (sizep) ? *sizep : 64 * 1024 * 1024;
+	image = xmalloc_read(fd, &len);
+	if (!image)
+		bb_perror_msg("read error from '%s'", fname);
+	close(fd);
+
+	if (sizep)
+		*sizep = len;
+	return image;
+}
+# define read_module xmalloc_open_zipped_read_close
+#else
+# define read_module xmalloc_open_read_close
+#endif
+
+/* We use error numbers in a loose translation... */
+static const char *moderror(int err)
+{
+	switch (err) {
+	case ENOEXEC:
+		return "invalid module format";
+	case ENOENT:
+		return "unknown symbol in module or invalid parameter";
+	case ESRCH:
+		return "module has wrong symbol version";
+	case EINVAL: /* "invalid parameter" */
+		return "unknown symbol in module or invalid parameter"
+		+ sizeof("unknown symbol in module or");
+	default:
+		return strerror(err);
+	}
+}
+
+static int load_module(const char *fname, const char *options)
+{
+#if 1
+	int r;
+	size_t len = MAXINT(ssize_t);
+	char *module_image;
+	dbg1_error_msg("load_module('%s','%s')", fname, options);
+
+	module_image = read_module(fname, &len);
+	r = (!module_image || init_module(module_image, len, options ? options : "") != 0);
+	free(module_image);
+	dbg1_error_msg("load_module:%d", r);
+	return r; /* 0 = success */
+#else
+	/* For testing */
+	dbg1_error_msg("load_module('%s','%s')", fname, options);
+	return 1;
+#endif
+}
+
+static char* parse_module(const char *pathname, const char *name)
+{
+	char *module_image;
+	char *ptr;
+	size_t len;
+	size_t pos;
+	dbg1_error_msg("parse_module('%s','%s')", pathname, name);
+
+	/* Read (possibly compressed) module */
+	len = 64 * 1024 * 1024; /* 64 Mb at most */
+	module_image = read_module(pathname, &len);
+
+	reset_stringbuf();
+
+	/* First desc line's format is
+	 * "modname alias1 symbol:sym1 alias2 symbol:sym2 " (note trailing ' ')
+	 */
+	append(name);
+	appendc(' ');
+	/* Aliases */
+	pos = 0;
+	while (1) {
+		ptr = find_keyword(module_image + pos, len - pos, "alias=");
+		if (!ptr) {
+			ptr = find_keyword(module_image + pos, len - pos, "__ksymtab_");
+			if (!ptr)
+				break;
+			/* DOCME: __ksymtab_gpl and __ksymtab_strings occur
+			 * in many modules. What do they mean? */
+			if (strcmp(ptr, "gpl") != 0 && strcmp(ptr, "strings") != 0) {
+				dbg2_error_msg("alias: 'symbol:%s'", ptr);
+				append("symbol:");
+			}
+		} else {
+			dbg2_error_msg("alias: '%s'", ptr);
+		}
+		append(ptr);
+		appendc(' ');
+		pos = (ptr - module_image);
+	}
+	appendc('\0');
+
+	/* Second line: "dependency1 depandency2 " (note trailing ' ') */
+	ptr = find_keyword(module_image, len, "depends=");
+	if (ptr && *ptr) {
+		replace(ptr, ',', ' ');
+		replace(ptr, '-', '_');
+		dbg2_error_msg("dep:'%s'", ptr);
+		append(ptr);
+	}
+	appendc(' '); appendc('\0');
+
+	free(module_image);
+	return copy_stringbuf();
+}
+
+static char* pathname_2_modname(const char *pathname)
+{
+	const char *fname = bb_get_last_path_component_nostrip(pathname);
+	const char *suffix = strrstr(fname, ".ko");
+	char *name = xstrndup(fname, suffix - fname);
+	replace(name, '-', '_');
+	return name;
+}
+
+static FAST_FUNC int fileAction(const char *pathname,
+		struct stat *sb ATTRIBUTE_UNUSED,
+		void *data,
+		int depth ATTRIBUTE_UNUSED)
+{
+	int cur;
+	char *name;
+	const char *fname;
+
+	pathname += 2; /* skip "./" */
+	fname = bb_get_last_path_component_nostrip(pathname);
+	if (!strrstr(fname, ".ko")) {
+		dbg1_error_msg("'%s' is not a module", pathname);
+		return TRUE; /* not a module, continue search */
+	}
+
+	cur = module_count++;
+	if (!(cur & 0xfff)) {
+		modinfo = xrealloc(modinfo, sizeof(modinfo[0]) * (cur + 0x1001));
+	}
+	modinfo[cur].pathname = xstrdup(pathname);
+	modinfo[cur].desc = NULL;
+	modinfo[cur+1].pathname = NULL;
+	modinfo[cur+1].desc = NULL;
+
+	name = pathname_2_modname(fname);
+	if (strcmp(name, data) != 0) {
+		free(name);
+		dbg1_error_msg("'%s' module name doesn't match", pathname);
+		return TRUE; /* module name doesn't match, continue search */
+	}
+
+	dbg1_error_msg("'%s' module name matches", pathname);
+	module_found_idx = cur;
+	modinfo[cur].desc = parse_module(pathname, name);
+
+	if (!(option_mask32 & OPT_r)) {
+		if (load_module(pathname, module_load_options) == 0) {
+			/* Load was successful, there is nothing else to do.
+			 * This can happen ONLY for "top-level" module load,
+			 * not a dep, because deps dont do dirscan. */
+			exit(EXIT_SUCCESS);
+			/*free(name);return RECURSE_RESULT_ABORT;*/
+		}
+	}
+
+	free(name);
+	return TRUE;
+}
+
+static module_info* find_alias(const char *alias)
+{
+	int i;
+	dbg1_error_msg("find_alias('%s')", alias);
+
+	/* First try to find by name (cheaper) */
+	i = 0;
+	while (modinfo[i].pathname) {
+		char *name = pathname_2_modname(modinfo[i].pathname);
+		if (strcmp(name, alias) == 0) {
+			dbg1_error_msg("found '%s' in module '%s'",
+					alias, modinfo[i].pathname);
+			if (!modinfo[i].desc)
+				modinfo[i].desc = parse_module(modinfo[i].pathname, name);
+			free(name);
+			return &modinfo[i];
+		}
+		free(name);
+		i++;
+	}
+
+	/* Scan all module bodies, extract modinfo (it contains aliases) */
+	i = 0;
+	while (modinfo[i].pathname) {
+		char *desc, *s;
+		if (!modinfo[i].desc) {
+			char *name = pathname_2_modname(modinfo[i].pathname);
+			modinfo[i].desc = parse_module(modinfo[i].pathname, name);
+			free(name);
+		}
+		/* "modname alias1 symbol:sym1 alias2 symbol:sym2 " */
+		desc = xstrdup(modinfo[i].desc);
+		/* Does matching substring exist? */
+		replace(desc, ' ', '\0');
+		for (s = desc; *s; s += strlen(s) + 1) {
+			if (strcmp(s, alias) == 0) {
+				free(desc);
+				dbg1_error_msg("found alias '%s' in module '%s'",
+						alias, modinfo[i].pathname);
+				return &modinfo[i];
+			}
+		}
+		free(desc);
+		i++;
+	}
+	dbg1_error_msg("find_alias '%s' returns NULL", alias);
+	return NULL;
+}
+
+#if ENABLE_FEATURE_MODPROBE_SMALL_CHECK_ALREADY_LOADED
+static int already_loaded(const char *name)
+{
+	int ret = 0;
+	int len = strlen(name);
+	char *line;
+	FILE* modules;
+
+	modules = xfopen("/proc/modules", "r");
+	while ((line = xmalloc_fgets(modules)) != NULL) {
+		if (strncmp(line, name, len) == 0 && line[len] == ' ') {
+			free(line);
+			ret = 1;
+			break;
+		}
+		free(line);
+	}
+	fclose(modules);
+	return ret;
+}
+#else
+#define already_loaded(name) is_rmmod
+#endif
+
+/*
+ Given modules definition and module name (or alias, or symbol)
+ load/remove the module respecting dependencies
+*/
+#if !ENABLE_FEATURE_MODPROBE_SMALL_OPTIONS_ON_CMDLINE
+#define process_module(a,b) process_module(a)
+#define cmdline_options ""
+#endif
+static void process_module(char *name, const char *cmdline_options)
+{
+	char *s, *deps, *options;
+	module_info *info;
+	int is_rmmod = (option_mask32 & OPT_r) != 0;
+	dbg1_error_msg("process_module('%s','%s')", name, cmdline_options);
+
+	replace(name, '-', '_');
+
+	dbg1_error_msg("already_loaded:%d is_rmmod:%d", already_loaded(name), is_rmmod);
+	if (already_loaded(name) != is_rmmod) {
+		dbg1_error_msg("nothing to do for '%s'", name);
+		return;
+	}
+
+	options = NULL;
+	if (!is_rmmod) {
+		char *opt_filename = xasprintf("/etc/modules/%s", name);
+		options = xmalloc_open_read_close(opt_filename, NULL);
+		if (options)
+			replace(options, '\n', ' ');
+#if ENABLE_FEATURE_MODPROBE_SMALL_OPTIONS_ON_CMDLINE
+		if (cmdline_options) {
+			/* NB: cmdline_options always have one leading ' '
+			 * (see main()), we remove it here */
+			char *op = xasprintf(options ? "%s %s" : "%s %s" + 3,
+						cmdline_options + 1, options);
+			free(options);
+			options = op;
+		}
+#endif
+		free(opt_filename);
+		module_load_options = options;
+		dbg1_error_msg("process_module('%s'): options:'%s'", name, options);
+	}
+
+	if (!module_count) {
+		/* Scan module directory. This is done only once.
+		 * It will attempt module load, and will exit(EXIT_SUCCESS)
+		 * on success. */
+		module_found_idx = -1;
+		recursive_action(".",
+			ACTION_RECURSE, /* flags */
+			fileAction, /* file action */
+			NULL, /* dir action */
+			name, /* user data */
+			0); /* depth */
+		dbg1_error_msg("dirscan complete");
+		/* Module was not found, or load failed, or is_rmmod */
+		if (module_found_idx >= 0) { /* module was found */
+			info = &modinfo[module_found_idx];
+		} else { /* search for alias, not a plain module name */
+			info = find_alias(name);
+		}
+	} else {
+		info = find_alias(name);
+	}
+
+	/* rmmod? unload it by name */
+	if (is_rmmod) {
+		if (delete_module(name, O_NONBLOCK|O_EXCL) != 0
+		 && !(option_mask32 & OPT_q)
+		) {
+			bb_perror_msg("remove '%s'", name);
+			goto ret;
+		}
+		/* N.B. we do not stop here -
+		 * continue to unload modules on which the module depends:
+		 * "-r --remove: option causes modprobe to remove a module.
+		 * If the modules it depends on are also unused, modprobe
+		 * will try to remove them, too." */
+	}
+
+	if (!info) { /* both dirscan and find_alias found nothing */
+		goto ret;
+	}
+
+	/* Second line of desc contains dependencies */
+	deps = xstrdup(info->desc + strlen(info->desc) + 1);
+
+	/* Transform deps to string list */
+	replace(deps, ' ', '\0');
+	/* Iterate thru dependencies, trying to (un)load them */
+	for (s = deps; *s; s += strlen(s) + 1) {
+		//if (strcmp(name, s) != 0) // N.B. do loops exist?
+		dbg1_error_msg("recurse on dep '%s'", s);
+		process_module(s, NULL);
+		dbg1_error_msg("recurse on dep '%s' done", s);
+	}
+	free(deps);
+
+	/* insmod -> load it */
+	if (!is_rmmod) {
+		errno = 0;
+		if (load_module(info->pathname, options) != 0) {
+			if (EEXIST != errno) {
+				bb_error_msg("insert '%s' %s: %s",
+						info->pathname, options,
+						moderror(errno));
+			} else {
+				dbg1_error_msg("insert '%s' %s: %s",
+						info->pathname, options,
+						moderror(errno));
+			}
+		}
+	}
+ ret:
+	free(options);
+//TODO: return load attempt result from process_module.
+//If dep didn't load ok, continuing makes little sense.
+}
+#undef cmdline_options
+
+
+/* For reference, module-init-tools-0.9.15-pre2 options:
+
+# insmod
+Usage: insmod filename [args]
+
+# rmmod --help
+Usage: rmmod [-fhswvV] modulename ...
+ -f (or --force) forces a module unload, and may crash your machine.
+ -s (or --syslog) says use syslog, not stderr
+ -v (or --verbose) enables more messages
+ -w (or --wait) begins a module removal even if it is used
+    and will stop new users from accessing the module (so it
+    should eventually fall to zero).
+
+# modprobe
+Usage: modprobe [--verbose|--version|--config|--remove] filename [options]
+
+# depmod --help
+depmod 0.9.15-pre2 -- part of module-init-tools
+depmod -[aA] [-n -e -v -q -V -r -u] [-b basedirectory] [forced_version]
+depmod [-n -e -v -q -r -u] [-F kernelsyms] module1.o module2.o ...
+If no arguments (except options) are given, "depmod -a" is assumed
+
+depmod will output a dependancy list suitable for the modprobe utility.
+
+Options:
+        -a, --all               Probe all modules
+        -n, --show              Write the dependency file on stdout only
+        -b basedirectory
+        --basedir basedirectory Use an image of a module tree.
+        -F kernelsyms
+        --filesyms kernelsyms   Use the file instead of the
+                                current kernel symbols.
+*/
+
+int modprobe_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int modprobe_main(int ATTRIBUTE_UNUSED argc, char **argv)
+{
+	struct utsname uts;
+	char applet0 = applet_name[0];
+	USE_FEATURE_MODPROBE_SMALL_OPTIONS_ON_CMDLINE(char *options;)
+
+	/* depmod is a stub */
+	if ('d' == applet0)
+		return EXIT_SUCCESS;
+
+	/* are we lsmod? -> just dump /proc/modules */
+	if ('l' == applet0) {
+		xprint_and_close_file(xfopen("/proc/modules", "r"));
+		return EXIT_SUCCESS;
+	}
+
+	INIT_G();
+
+	/* insmod, modprobe, rmmod require at least one argument */
+	opt_complementary = "-1";
+	/* only -q (quiet) and -r (rmmod),
+	 * the rest are accepted and ignored (compat) */
+	getopt32(argv, "qrfsvw");
+	argv += optind;
+
+	/* are we rmmod? -> simulate modprobe -r */
+	if ('r' == applet0) {
+		option_mask32 |= OPT_r;
+	}
+
+	/* goto modules directory */
+	xchdir(CONFIG_DEFAULT_MODULES_DIR);
+	uname(&uts); /* never fails */
+	xchdir(uts.release);
+
+#if ENABLE_FEATURE_MODPROBE_SMALL_OPTIONS_ON_CMDLINE
+	/* If not rmmod, parse possible module options given on command line.
+	 * insmod/modprobe takes one module name, the rest are parameters. */
+	options = NULL;
+	if ('r' != applet0) {
+		char **arg = argv;
+		while (*++arg) {
+			/* Enclose options in quotes */
+			char *s = options;
+			options = xasprintf("%s \"%s\"", s ? s : "", *arg);
+			free(s);
+			*arg = NULL;
+		}
+	}
+#else
+	if ('r' != applet0)
+		argv[1] = NULL;
+#endif
+
+	/* Load/remove modules.
+	 * Only rmmod loops here, insmod/modprobe has only argv[0] */
+	do {
+		process_module(*argv++, options);
+	} while (*argv);
+
+	if (ENABLE_FEATURE_CLEAN_UP) {
+		USE_FEATURE_MODPROBE_SMALL_OPTIONS_ON_CMDLINE(free(options);)
+	}
+	return EXIT_SUCCESS;
+}