Revision be0f272bfc83797f70d44faca86954df62e2bbc0 authored by Ard Biesheuvel on 20 November 2017, 17:41:30 UTC, committed by Will Deacon on 01 December 2017, 13:04:59 UTC
When building the arm64 kernel with both CONFIG_ARM64_MODULE_PLTS and
CONFIG_DYNAMIC_FTRACE enabled, the ftrace-mod.o object file is built
with the kernel and contains a trampoline that is linked into each
module, so that modules can be loaded far away from the kernel and
still reach the ftrace entry point in the core kernel with an ordinary
relative branch, as is emitted by the compiler instrumentation code
dynamic ftrace relies on.

In order to be able to build out of tree modules, this object file
needs to be included into the linux-headers or linux-devel packages,
which is undesirable, as it makes arm64 a special case (although a
precedent does exist for 32-bit PPC).

Given that the trampoline essentially consists of a PLT entry, let's
not bother with a source or object file for it, and simply patch it
in whenever the trampoline is being populated, using the existing
PLT support routines.

Cc: <stable@vger.kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
1 parent 7e8b9c1
Raw File
genksyms.c
/* Generate kernel symbol version hashes.
   Copyright 1996, 1997 Linux International.

   New implementation contributed by Richard Henderson <rth@tamu.edu>
   Based on original work by Bjorn Ekwall <bj0rn@blox.se>

   This file was part of the Linux modutils 2.4.22: moved back into the
   kernel sources by Rusty Russell/Kai Germaschewski.

   This program is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 2 of the License, or (at your
   option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <stdarg.h>
#ifdef __GNU_LIBRARY__
#include <getopt.h>
#endif				/* __GNU_LIBRARY__ */

#include "genksyms.h"
/*----------------------------------------------------------------------*/

#define HASH_BUCKETS  4096

static struct symbol *symtab[HASH_BUCKETS];
static FILE *debugfile;

int cur_line = 1;
char *cur_filename, *source_file;
int in_source_file;

static int flag_debug, flag_dump_defs, flag_reference, flag_dump_types,
	   flag_preserve, flag_warnings, flag_rel_crcs;
static const char *mod_prefix = "";

static int errors;
static int nsyms;

static struct symbol *expansion_trail;
static struct symbol *visited_symbols;

static const struct {
	int n;
	const char *name;
} symbol_types[] = {
	[SYM_NORMAL]     = { 0, NULL},
	[SYM_TYPEDEF]    = {'t', "typedef"},
	[SYM_ENUM]       = {'e', "enum"},
	[SYM_STRUCT]     = {'s', "struct"},
	[SYM_UNION]      = {'u', "union"},
	[SYM_ENUM_CONST] = {'E', "enum constant"},
};

static int equal_list(struct string_list *a, struct string_list *b);
static void print_list(FILE * f, struct string_list *list);
static struct string_list *concat_list(struct string_list *start, ...);
static struct string_list *mk_node(const char *string);
static void print_location(void);
static void print_type_name(enum symbol_type type, const char *name);

/*----------------------------------------------------------------------*/

static const unsigned int crctab32[] = {
	0x00000000U, 0x77073096U, 0xee0e612cU, 0x990951baU, 0x076dc419U,
	0x706af48fU, 0xe963a535U, 0x9e6495a3U, 0x0edb8832U, 0x79dcb8a4U,
	0xe0d5e91eU, 0x97d2d988U, 0x09b64c2bU, 0x7eb17cbdU, 0xe7b82d07U,
	0x90bf1d91U, 0x1db71064U, 0x6ab020f2U, 0xf3b97148U, 0x84be41deU,
	0x1adad47dU, 0x6ddde4ebU, 0xf4d4b551U, 0x83d385c7U, 0x136c9856U,
	0x646ba8c0U, 0xfd62f97aU, 0x8a65c9ecU, 0x14015c4fU, 0x63066cd9U,
	0xfa0f3d63U, 0x8d080df5U, 0x3b6e20c8U, 0x4c69105eU, 0xd56041e4U,
	0xa2677172U, 0x3c03e4d1U, 0x4b04d447U, 0xd20d85fdU, 0xa50ab56bU,
	0x35b5a8faU, 0x42b2986cU, 0xdbbbc9d6U, 0xacbcf940U, 0x32d86ce3U,
	0x45df5c75U, 0xdcd60dcfU, 0xabd13d59U, 0x26d930acU, 0x51de003aU,
	0xc8d75180U, 0xbfd06116U, 0x21b4f4b5U, 0x56b3c423U, 0xcfba9599U,
	0xb8bda50fU, 0x2802b89eU, 0x5f058808U, 0xc60cd9b2U, 0xb10be924U,
	0x2f6f7c87U, 0x58684c11U, 0xc1611dabU, 0xb6662d3dU, 0x76dc4190U,
	0x01db7106U, 0x98d220bcU, 0xefd5102aU, 0x71b18589U, 0x06b6b51fU,
	0x9fbfe4a5U, 0xe8b8d433U, 0x7807c9a2U, 0x0f00f934U, 0x9609a88eU,
	0xe10e9818U, 0x7f6a0dbbU, 0x086d3d2dU, 0x91646c97U, 0xe6635c01U,
	0x6b6b51f4U, 0x1c6c6162U, 0x856530d8U, 0xf262004eU, 0x6c0695edU,
	0x1b01a57bU, 0x8208f4c1U, 0xf50fc457U, 0x65b0d9c6U, 0x12b7e950U,
	0x8bbeb8eaU, 0xfcb9887cU, 0x62dd1ddfU, 0x15da2d49U, 0x8cd37cf3U,
	0xfbd44c65U, 0x4db26158U, 0x3ab551ceU, 0xa3bc0074U, 0xd4bb30e2U,
	0x4adfa541U, 0x3dd895d7U, 0xa4d1c46dU, 0xd3d6f4fbU, 0x4369e96aU,
	0x346ed9fcU, 0xad678846U, 0xda60b8d0U, 0x44042d73U, 0x33031de5U,
	0xaa0a4c5fU, 0xdd0d7cc9U, 0x5005713cU, 0x270241aaU, 0xbe0b1010U,
	0xc90c2086U, 0x5768b525U, 0x206f85b3U, 0xb966d409U, 0xce61e49fU,
	0x5edef90eU, 0x29d9c998U, 0xb0d09822U, 0xc7d7a8b4U, 0x59b33d17U,
	0x2eb40d81U, 0xb7bd5c3bU, 0xc0ba6cadU, 0xedb88320U, 0x9abfb3b6U,
	0x03b6e20cU, 0x74b1d29aU, 0xead54739U, 0x9dd277afU, 0x04db2615U,
	0x73dc1683U, 0xe3630b12U, 0x94643b84U, 0x0d6d6a3eU, 0x7a6a5aa8U,
	0xe40ecf0bU, 0x9309ff9dU, 0x0a00ae27U, 0x7d079eb1U, 0xf00f9344U,
	0x8708a3d2U, 0x1e01f268U, 0x6906c2feU, 0xf762575dU, 0x806567cbU,
	0x196c3671U, 0x6e6b06e7U, 0xfed41b76U, 0x89d32be0U, 0x10da7a5aU,
	0x67dd4accU, 0xf9b9df6fU, 0x8ebeeff9U, 0x17b7be43U, 0x60b08ed5U,
	0xd6d6a3e8U, 0xa1d1937eU, 0x38d8c2c4U, 0x4fdff252U, 0xd1bb67f1U,
	0xa6bc5767U, 0x3fb506ddU, 0x48b2364bU, 0xd80d2bdaU, 0xaf0a1b4cU,
	0x36034af6U, 0x41047a60U, 0xdf60efc3U, 0xa867df55U, 0x316e8eefU,
	0x4669be79U, 0xcb61b38cU, 0xbc66831aU, 0x256fd2a0U, 0x5268e236U,
	0xcc0c7795U, 0xbb0b4703U, 0x220216b9U, 0x5505262fU, 0xc5ba3bbeU,
	0xb2bd0b28U, 0x2bb45a92U, 0x5cb36a04U, 0xc2d7ffa7U, 0xb5d0cf31U,
	0x2cd99e8bU, 0x5bdeae1dU, 0x9b64c2b0U, 0xec63f226U, 0x756aa39cU,
	0x026d930aU, 0x9c0906a9U, 0xeb0e363fU, 0x72076785U, 0x05005713U,
	0x95bf4a82U, 0xe2b87a14U, 0x7bb12baeU, 0x0cb61b38U, 0x92d28e9bU,
	0xe5d5be0dU, 0x7cdcefb7U, 0x0bdbdf21U, 0x86d3d2d4U, 0xf1d4e242U,
	0x68ddb3f8U, 0x1fda836eU, 0x81be16cdU, 0xf6b9265bU, 0x6fb077e1U,
	0x18b74777U, 0x88085ae6U, 0xff0f6a70U, 0x66063bcaU, 0x11010b5cU,
	0x8f659effU, 0xf862ae69U, 0x616bffd3U, 0x166ccf45U, 0xa00ae278U,
	0xd70dd2eeU, 0x4e048354U, 0x3903b3c2U, 0xa7672661U, 0xd06016f7U,
	0x4969474dU, 0x3e6e77dbU, 0xaed16a4aU, 0xd9d65adcU, 0x40df0b66U,
	0x37d83bf0U, 0xa9bcae53U, 0xdebb9ec5U, 0x47b2cf7fU, 0x30b5ffe9U,
	0xbdbdf21cU, 0xcabac28aU, 0x53b39330U, 0x24b4a3a6U, 0xbad03605U,
	0xcdd70693U, 0x54de5729U, 0x23d967bfU, 0xb3667a2eU, 0xc4614ab8U,
	0x5d681b02U, 0x2a6f2b94U, 0xb40bbe37U, 0xc30c8ea1U, 0x5a05df1bU,
	0x2d02ef8dU
};

static unsigned long partial_crc32_one(unsigned char c, unsigned long crc)
{
	return crctab32[(crc ^ c) & 0xff] ^ (crc >> 8);
}

static unsigned long partial_crc32(const char *s, unsigned long crc)
{
	while (*s)
		crc = partial_crc32_one(*s++, crc);
	return crc;
}

static unsigned long crc32(const char *s)
{
	return partial_crc32(s, 0xffffffff) ^ 0xffffffff;
}

/*----------------------------------------------------------------------*/

static enum symbol_type map_to_ns(enum symbol_type t)
{
	switch (t) {
	case SYM_ENUM_CONST:
	case SYM_NORMAL:
	case SYM_TYPEDEF:
		return SYM_NORMAL;
	case SYM_ENUM:
	case SYM_STRUCT:
	case SYM_UNION:
		return SYM_STRUCT;
	}
	return t;
}

struct symbol *find_symbol(const char *name, enum symbol_type ns, int exact)
{
	unsigned long h = crc32(name) % HASH_BUCKETS;
	struct symbol *sym;

	for (sym = symtab[h]; sym; sym = sym->hash_next)
		if (map_to_ns(sym->type) == map_to_ns(ns) &&
		    strcmp(name, sym->name) == 0 &&
		    sym->is_declared)
			break;

	if (exact && sym && sym->type != ns)
		return NULL;
	return sym;
}

static int is_unknown_symbol(struct symbol *sym)
{
	struct string_list *defn;

	return ((sym->type == SYM_STRUCT ||
		 sym->type == SYM_UNION ||
		 sym->type == SYM_ENUM) &&
		(defn = sym->defn)  && defn->tag == SYM_NORMAL &&
			strcmp(defn->string, "}") == 0 &&
		(defn = defn->next) && defn->tag == SYM_NORMAL &&
			strcmp(defn->string, "UNKNOWN") == 0 &&
		(defn = defn->next) && defn->tag == SYM_NORMAL &&
			strcmp(defn->string, "{") == 0);
}

static struct symbol *__add_symbol(const char *name, enum symbol_type type,
			    struct string_list *defn, int is_extern,
			    int is_reference)
{
	unsigned long h;
	struct symbol *sym;
	enum symbol_status status = STATUS_UNCHANGED;
	/* The parser adds symbols in the order their declaration completes,
	 * so it is safe to store the value of the previous enum constant in
	 * a static variable.
	 */
	static int enum_counter;
	static struct string_list *last_enum_expr;

	if (type == SYM_ENUM_CONST) {
		if (defn) {
			free_list(last_enum_expr, NULL);
			last_enum_expr = copy_list_range(defn, NULL);
			enum_counter = 1;
		} else {
			struct string_list *expr;
			char buf[20];

			snprintf(buf, sizeof(buf), "%d", enum_counter++);
			if (last_enum_expr) {
				expr = copy_list_range(last_enum_expr, NULL);
				defn = concat_list(mk_node("("),
						   expr,
						   mk_node(")"),
						   mk_node("+"),
						   mk_node(buf), NULL);
			} else {
				defn = mk_node(buf);
			}
		}
	} else if (type == SYM_ENUM) {
		free_list(last_enum_expr, NULL);
		last_enum_expr = NULL;
		enum_counter = 0;
		if (!name)
			/* Anonymous enum definition, nothing more to do */
			return NULL;
	}

	h = crc32(name) % HASH_BUCKETS;
	for (sym = symtab[h]; sym; sym = sym->hash_next) {
		if (map_to_ns(sym->type) == map_to_ns(type) &&
		    strcmp(name, sym->name) == 0) {
			if (is_reference)
				/* fall through */ ;
			else if (sym->type == type &&
				 equal_list(sym->defn, defn)) {
				if (!sym->is_declared && sym->is_override) {
					print_location();
					print_type_name(type, name);
					fprintf(stderr, " modversion is "
						"unchanged\n");
				}
				sym->is_declared = 1;
				return sym;
			} else if (!sym->is_declared) {
				if (sym->is_override && flag_preserve) {
					print_location();
					fprintf(stderr, "ignoring ");
					print_type_name(type, name);
					fprintf(stderr, " modversion change\n");
					sym->is_declared = 1;
					return sym;
				} else {
					status = is_unknown_symbol(sym) ?
						STATUS_DEFINED : STATUS_MODIFIED;
				}
			} else {
				error_with_pos("redefinition of %s", name);
				return sym;
			}
			break;
		}
	}

	if (sym) {
		struct symbol **psym;

		for (psym = &symtab[h]; *psym; psym = &(*psym)->hash_next) {
			if (*psym == sym) {
				*psym = sym->hash_next;
				break;
			}
		}
		--nsyms;
	}

	sym = xmalloc(sizeof(*sym));
	sym->name = name;
	sym->type = type;
	sym->defn = defn;
	sym->expansion_trail = NULL;
	sym->visited = NULL;
	sym->is_extern = is_extern;

	sym->hash_next = symtab[h];
	symtab[h] = sym;

	sym->is_declared = !is_reference;
	sym->status = status;
	sym->is_override = 0;

	if (flag_debug) {
		if (symbol_types[type].name)
			fprintf(debugfile, "Defn for %s %s == <",
				symbol_types[type].name, name);
		else
			fprintf(debugfile, "Defn for type%d %s == <",
				type, name);
		if (is_extern)
			fputs("extern ", debugfile);
		print_list(debugfile, defn);
		fputs(">\n", debugfile);
	}

	++nsyms;
	return sym;
}

struct symbol *add_symbol(const char *name, enum symbol_type type,
			  struct string_list *defn, int is_extern)
{
	return __add_symbol(name, type, defn, is_extern, 0);
}

static struct symbol *add_reference_symbol(const char *name, enum symbol_type type,
				    struct string_list *defn, int is_extern)
{
	return __add_symbol(name, type, defn, is_extern, 1);
}

/*----------------------------------------------------------------------*/

void free_node(struct string_list *node)
{
	free(node->string);
	free(node);
}

void free_list(struct string_list *s, struct string_list *e)
{
	while (s != e) {
		struct string_list *next = s->next;
		free_node(s);
		s = next;
	}
}

static struct string_list *mk_node(const char *string)
{
	struct string_list *newnode;

	newnode = xmalloc(sizeof(*newnode));
	newnode->string = xstrdup(string);
	newnode->tag = SYM_NORMAL;
	newnode->next = NULL;

	return newnode;
}

static struct string_list *concat_list(struct string_list *start, ...)
{
	va_list ap;
	struct string_list *n, *n2;

	if (!start)
		return NULL;
	for (va_start(ap, start); (n = va_arg(ap, struct string_list *));) {
		for (n2 = n; n2->next; n2 = n2->next)
			;
		n2->next = start;
		start = n;
	}
	va_end(ap);
	return start;
}

struct string_list *copy_node(struct string_list *node)
{
	struct string_list *newnode;

	newnode = xmalloc(sizeof(*newnode));
	newnode->string = xstrdup(node->string);
	newnode->tag = node->tag;

	return newnode;
}

struct string_list *copy_list_range(struct string_list *start,
				    struct string_list *end)
{
	struct string_list *res, *n;

	if (start == end)
		return NULL;
	n = res = copy_node(start);
	for (start = start->next; start != end; start = start->next) {
		n->next = copy_node(start);
		n = n->next;
	}
	n->next = NULL;
	return res;
}

static int equal_list(struct string_list *a, struct string_list *b)
{
	while (a && b) {
		if (a->tag != b->tag || strcmp(a->string, b->string))
			return 0;
		a = a->next;
		b = b->next;
	}

	return !a && !b;
}

#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))

static struct string_list *read_node(FILE *f)
{
	char buffer[256];
	struct string_list node = {
		.string = buffer,
		.tag = SYM_NORMAL };
	int c, in_string = 0;

	while ((c = fgetc(f)) != EOF) {
		if (!in_string && c == ' ') {
			if (node.string == buffer)
				continue;
			break;
		} else if (c == '"') {
			in_string = !in_string;
		} else if (c == '\n') {
			if (node.string == buffer)
				return NULL;
			ungetc(c, f);
			break;
		}
		if (node.string >= buffer + sizeof(buffer) - 1) {
			fprintf(stderr, "Token too long\n");
			exit(1);
		}
		*node.string++ = c;
	}
	if (node.string == buffer)
		return NULL;
	*node.string = 0;
	node.string = buffer;

	if (node.string[1] == '#') {
		size_t n;

		for (n = 0; n < ARRAY_SIZE(symbol_types); n++) {
			if (node.string[0] == symbol_types[n].n) {
				node.tag = n;
				node.string += 2;
				return copy_node(&node);
			}
		}
		fprintf(stderr, "Unknown type %c\n", node.string[0]);
		exit(1);
	}
	return copy_node(&node);
}

static void read_reference(FILE *f)
{
	while (!feof(f)) {
		struct string_list *defn = NULL;
		struct string_list *sym, *def;
		int is_extern = 0, is_override = 0;
		struct symbol *subsym;

		sym = read_node(f);
		if (sym && sym->tag == SYM_NORMAL &&
		    !strcmp(sym->string, "override")) {
			is_override = 1;
			free_node(sym);
			sym = read_node(f);
		}
		if (!sym)
			continue;
		def = read_node(f);
		if (def && def->tag == SYM_NORMAL &&
		    !strcmp(def->string, "extern")) {
			is_extern = 1;
			free_node(def);
			def = read_node(f);
		}
		while (def) {
			def->next = defn;
			defn = def;
			def = read_node(f);
		}
		subsym = add_reference_symbol(xstrdup(sym->string), sym->tag,
					      defn, is_extern);
		subsym->is_override = is_override;
		free_node(sym);
	}
}

static void print_node(FILE * f, struct string_list *list)
{
	if (symbol_types[list->tag].n) {
		putc(symbol_types[list->tag].n, f);
		putc('#', f);
	}
	fputs(list->string, f);
}

static void print_list(FILE * f, struct string_list *list)
{
	struct string_list **e, **b;
	struct string_list *tmp, **tmp2;
	int elem = 1;

	if (list == NULL) {
		fputs("(nil)", f);
		return;
	}

	tmp = list;
	while ((tmp = tmp->next) != NULL)
		elem++;

	b = alloca(elem * sizeof(*e));
	e = b + elem;
	tmp2 = e - 1;

	(*tmp2--) = list;
	while ((list = list->next) != NULL)
		*(tmp2--) = list;

	while (b != e) {
		print_node(f, *b++);
		putc(' ', f);
	}
}

static unsigned long expand_and_crc_sym(struct symbol *sym, unsigned long crc)
{
	struct string_list *list = sym->defn;
	struct string_list **e, **b;
	struct string_list *tmp, **tmp2;
	int elem = 1;

	if (!list)
		return crc;

	tmp = list;
	while ((tmp = tmp->next) != NULL)
		elem++;

	b = alloca(elem * sizeof(*e));
	e = b + elem;
	tmp2 = e - 1;

	*(tmp2--) = list;
	while ((list = list->next) != NULL)
		*(tmp2--) = list;

	while (b != e) {
		struct string_list *cur;
		struct symbol *subsym;

		cur = *(b++);
		switch (cur->tag) {
		case SYM_NORMAL:
			if (flag_dump_defs)
				fprintf(debugfile, "%s ", cur->string);
			crc = partial_crc32(cur->string, crc);
			crc = partial_crc32_one(' ', crc);
			break;

		case SYM_ENUM_CONST:
		case SYM_TYPEDEF:
			subsym = find_symbol(cur->string, cur->tag, 0);
			/* FIXME: Bad reference files can segfault here. */
			if (subsym->expansion_trail) {
				if (flag_dump_defs)
					fprintf(debugfile, "%s ", cur->string);
				crc = partial_crc32(cur->string, crc);
				crc = partial_crc32_one(' ', crc);
			} else {
				subsym->expansion_trail = expansion_trail;
				expansion_trail = subsym;
				crc = expand_and_crc_sym(subsym, crc);
			}
			break;

		case SYM_STRUCT:
		case SYM_UNION:
		case SYM_ENUM:
			subsym = find_symbol(cur->string, cur->tag, 0);
			if (!subsym) {
				struct string_list *n;

				error_with_pos("expand undefined %s %s",
					       symbol_types[cur->tag].name,
					       cur->string);
				n = concat_list(mk_node
						(symbol_types[cur->tag].name),
						mk_node(cur->string),
						mk_node("{"),
						mk_node("UNKNOWN"),
						mk_node("}"), NULL);
				subsym =
				    add_symbol(cur->string, cur->tag, n, 0);
			}
			if (subsym->expansion_trail) {
				if (flag_dump_defs) {
					fprintf(debugfile, "%s %s ",
						symbol_types[cur->tag].name,
						cur->string);
				}

				crc = partial_crc32(symbol_types[cur->tag].name,
						    crc);
				crc = partial_crc32_one(' ', crc);
				crc = partial_crc32(cur->string, crc);
				crc = partial_crc32_one(' ', crc);
			} else {
				subsym->expansion_trail = expansion_trail;
				expansion_trail = subsym;
				crc = expand_and_crc_sym(subsym, crc);
			}
			break;
		}
	}

	{
		static struct symbol **end = &visited_symbols;

		if (!sym->visited) {
			*end = sym;
			end = &sym->visited;
			sym->visited = (struct symbol *)-1L;
		}
	}

	return crc;
}

void export_symbol(const char *name)
{
	struct symbol *sym;

	sym = find_symbol(name, SYM_NORMAL, 0);
	if (!sym)
		error_with_pos("export undefined symbol %s", name);
	else {
		unsigned long crc;
		int has_changed = 0;

		if (flag_dump_defs)
			fprintf(debugfile, "Export %s == <", name);

		expansion_trail = (struct symbol *)-1L;

		sym->expansion_trail = expansion_trail;
		expansion_trail = sym;
		crc = expand_and_crc_sym(sym, 0xffffffff) ^ 0xffffffff;

		sym = expansion_trail;
		while (sym != (struct symbol *)-1L) {
			struct symbol *n = sym->expansion_trail;

			if (sym->status != STATUS_UNCHANGED) {
				if (!has_changed) {
					print_location();
					fprintf(stderr, "%s: %s: modversion "
						"changed because of changes "
						"in ", flag_preserve ? "error" :
						       "warning", name);
				} else
					fprintf(stderr, ", ");
				print_type_name(sym->type, sym->name);
				if (sym->status == STATUS_DEFINED)
					fprintf(stderr, " (became defined)");
				has_changed = 1;
				if (flag_preserve)
					errors++;
			}
			sym->expansion_trail = 0;
			sym = n;
		}
		if (has_changed)
			fprintf(stderr, "\n");

		if (flag_dump_defs)
			fputs(">\n", debugfile);

		/* Used as a linker script. */
		printf(!flag_rel_crcs ? "%s__crc_%s = 0x%08lx;\n" :
		       "SECTIONS { .rodata : ALIGN(4) { "
		       "%s__crc_%s = .; LONG(0x%08lx); } }\n",
		       mod_prefix, name, crc);
	}
}

/*----------------------------------------------------------------------*/

static void print_location(void)
{
	fprintf(stderr, "%s:%d: ", cur_filename ? : "<stdin>", cur_line);
}

static void print_type_name(enum symbol_type type, const char *name)
{
	if (symbol_types[type].name)
		fprintf(stderr, "%s %s", symbol_types[type].name, name);
	else
		fprintf(stderr, "%s", name);
}

void error_with_pos(const char *fmt, ...)
{
	va_list args;

	if (flag_warnings) {
		print_location();

		va_start(args, fmt);
		vfprintf(stderr, fmt, args);
		va_end(args);
		putc('\n', stderr);

		errors++;
	}
}

static void genksyms_usage(void)
{
	fputs("Usage:\n" "genksyms [-adDTwqhVR] > /path/to/.tmp_obj.ver\n" "\n"
#ifdef __GNU_LIBRARY__
	      "  -s, --symbol-prefix   Select symbol prefix\n"
	      "  -d, --debug           Increment the debug level (repeatable)\n"
	      "  -D, --dump            Dump expanded symbol defs (for debugging only)\n"
	      "  -r, --reference file  Read reference symbols from a file\n"
	      "  -T, --dump-types file Dump expanded types into file\n"
	      "  -p, --preserve        Preserve reference modversions or fail\n"
	      "  -w, --warnings        Enable warnings\n"
	      "  -q, --quiet           Disable warnings (default)\n"
	      "  -h, --help            Print this message\n"
	      "  -V, --version         Print the release version\n"
	      "  -R, --relative-crc    Emit section relative symbol CRCs\n"
#else				/* __GNU_LIBRARY__ */
	      "  -s                    Select symbol prefix\n"
	      "  -d                    Increment the debug level (repeatable)\n"
	      "  -D                    Dump expanded symbol defs (for debugging only)\n"
	      "  -r file               Read reference symbols from a file\n"
	      "  -T file               Dump expanded types into file\n"
	      "  -p                    Preserve reference modversions or fail\n"
	      "  -w                    Enable warnings\n"
	      "  -q                    Disable warnings (default)\n"
	      "  -h                    Print this message\n"
	      "  -V                    Print the release version\n"
	      "  -R                    Emit section relative symbol CRCs\n"
#endif				/* __GNU_LIBRARY__ */
	      , stderr);
}

int main(int argc, char **argv)
{
	FILE *dumpfile = NULL, *ref_file = NULL;
	int o;

#ifdef __GNU_LIBRARY__
	struct option long_opts[] = {
		{"symbol-prefix", 1, 0, 's'},
		{"debug", 0, 0, 'd'},
		{"warnings", 0, 0, 'w'},
		{"quiet", 0, 0, 'q'},
		{"dump", 0, 0, 'D'},
		{"reference", 1, 0, 'r'},
		{"dump-types", 1, 0, 'T'},
		{"preserve", 0, 0, 'p'},
		{"version", 0, 0, 'V'},
		{"help", 0, 0, 'h'},
		{"relative-crc", 0, 0, 'R'},
		{0, 0, 0, 0}
	};

	while ((o = getopt_long(argc, argv, "s:dwqVDr:T:phR",
				&long_opts[0], NULL)) != EOF)
#else				/* __GNU_LIBRARY__ */
	while ((o = getopt(argc, argv, "s:dwqVDr:T:phR")) != EOF)
#endif				/* __GNU_LIBRARY__ */
		switch (o) {
		case 's':
			mod_prefix = optarg;
			break;
		case 'd':
			flag_debug++;
			break;
		case 'w':
			flag_warnings = 1;
			break;
		case 'q':
			flag_warnings = 0;
			break;
		case 'V':
			fputs("genksyms version 2.5.60\n", stderr);
			break;
		case 'D':
			flag_dump_defs = 1;
			break;
		case 'r':
			flag_reference = 1;
			ref_file = fopen(optarg, "r");
			if (!ref_file) {
				perror(optarg);
				return 1;
			}
			break;
		case 'T':
			flag_dump_types = 1;
			dumpfile = fopen(optarg, "w");
			if (!dumpfile) {
				perror(optarg);
				return 1;
			}
			break;
		case 'p':
			flag_preserve = 1;
			break;
		case 'h':
			genksyms_usage();
			return 0;
		case 'R':
			flag_rel_crcs = 1;
			break;
		default:
			genksyms_usage();
			return 1;
		}
	{
		extern int yydebug;
		extern int yy_flex_debug;

		yydebug = (flag_debug > 1);
		yy_flex_debug = (flag_debug > 2);

		debugfile = stderr;
		/* setlinebuf(debugfile); */
	}

	if (flag_reference) {
		read_reference(ref_file);
		fclose(ref_file);
	}

	yyparse();

	if (flag_dump_types && visited_symbols) {
		while (visited_symbols != (struct symbol *)-1L) {
			struct symbol *sym = visited_symbols;

			if (sym->is_override)
				fputs("override ", dumpfile);
			if (symbol_types[sym->type].n) {
				putc(symbol_types[sym->type].n, dumpfile);
				putc('#', dumpfile);
			}
			fputs(sym->name, dumpfile);
			putc(' ', dumpfile);
			if (sym->is_extern)
				fputs("extern ", dumpfile);
			print_list(dumpfile, sym->defn);
			putc('\n', dumpfile);

			visited_symbols = sym->visited;
			sym->visited = NULL;
		}
	}

	if (flag_debug) {
		fprintf(debugfile, "Hash table occupancy %d/%d = %g\n",
			nsyms, HASH_BUCKETS,
			(double)nsyms / (double)HASH_BUCKETS);
	}

	if (dumpfile)
		fclose(dumpfile);

	return errors != 0;
}
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