// SPDX-License-Identifier: GPL-2.0-only
/*
 * sorttable.c: Sort the kernel's table
 *
 * Added ORC unwind tables sort support and other updates:
 * Copyright (C) 1999-2019 Alibaba Group Holding Limited. by:
 * Shile Zhang <shile.zhang@linux.alibaba.com>
 *
 * Copyright 2011 - 2012 Cavium, Inc.
 *
 * Based on code taken from recortmcount.c which is:
 *
 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>.  All rights reserved.
 *
 * Restructured to fit Linux format, as well as other updates:
 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
 */

/*
 * Strategy: alter the vmlinux file in-place.
 */

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <getopt.h>
#include <elf.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>

#include <tools/be_byteshift.h>
#include <tools/le_byteshift.h>

#ifndef EM_ARCOMPACT
#define EM_ARCOMPACT    93
#endif

#ifndef EM_XTENSA
#define EM_XTENSA       94
#endif

#ifndef EM_AARCH64
#define EM_AARCH64      183
#endif

#ifndef EM_MICROBLAZE
#define EM_MICROBLAZE   189
#endif

#ifndef EM_ARCV2
#define EM_ARCV2        195
#endif

#ifndef EM_RISCV
#define EM_RISCV        243
#endif

static uint32_t (*r)(const uint32_t *);
static uint16_t (*r2)(const uint16_t *);
static uint64_t (*r8)(const uint64_t *);
static void (*w)(uint32_t, uint32_t *);
static void (*w2)(uint16_t, uint16_t *);
static void (*w8)(uint64_t, uint64_t *);
typedef void (*table_sort_t)(char *, int);

/*
 * Get the whole file as a programming convenience in order to avoid
 * malloc+lseek+read+free of many pieces.  If successful, then mmap
 * avoids copying unused pieces; else just read the whole file.
 * Open for both read and write.
 */
static void *mmap_file(char const *fname, size_t *size)
{
        int fd;
        struct stat sb;
        void *addr = NULL;

        fd = open(fname, O_RDWR);
        if (fd < 0) {
                perror(fname);
                return NULL;
        }
        if (fstat(fd, &sb) < 0) {
                perror(fname);
                goto out;
        }
        if (!S_ISREG(sb.st_mode)) {
                fprintf(stderr, "not a regular file: %s\n", fname);
                goto out;
        }

        addr = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
        if (addr == MAP_FAILED) {
                fprintf(stderr, "Could not mmap file: %s\n", fname);
                goto out;
        }

        *size = sb.st_size;

out:
        close(fd);
        return addr;
}

static uint32_t rbe(const uint32_t *x)
{
        return get_unaligned_be32(x);
}

static uint16_t r2be(const uint16_t *x)
{
        return get_unaligned_be16(x);
}

static uint64_t r8be(const uint64_t *x)
{
        return get_unaligned_be64(x);
}

static uint32_t rle(const uint32_t *x)
{
        return get_unaligned_le32(x);
}

static uint16_t r2le(const uint16_t *x)
{
        return get_unaligned_le16(x);
}

static uint64_t r8le(const uint64_t *x)
{
        return get_unaligned_le64(x);
}

static void wbe(uint32_t val, uint32_t *x)
{
        put_unaligned_be32(val, x);
}

static void w2be(uint16_t val, uint16_t *x)
{
        put_unaligned_be16(val, x);
}

static void w8be(uint64_t val, uint64_t *x)
{
        put_unaligned_be64(val, x);
}

static void wle(uint32_t val, uint32_t *x)
{
        put_unaligned_le32(val, x);
}

static void w2le(uint16_t val, uint16_t *x)
{
        put_unaligned_le16(val, x);
}

static void w8le(uint64_t val, uint64_t *x)
{
        put_unaligned_le64(val, x);
}

/*
 * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
 * the way to -256..-1, to avoid conflicting with real section
 * indices.
 */
#define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1))

static inline int is_shndx_special(unsigned int i)
{
        return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE;
}

/* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
static inline unsigned int get_secindex(unsigned int shndx,
                                        unsigned int sym_offs,
                                        const Elf32_Word *symtab_shndx_start)
{
        if (is_shndx_special(shndx))
                return SPECIAL(shndx);
        if (shndx != SHN_XINDEX)
                return shndx;
        return r(&symtab_shndx_start[sym_offs]);
}

/* 32 bit and 64 bit are very similar */
#include "sorttable.h"
#define SORTTABLE_64
#include "sorttable.h"

static int compare_relative_table(const void *a, const void *b)
{
        int32_t av = (int32_t)r(a);
        int32_t bv = (int32_t)r(b);

        if (av < bv)
                return -1;
        if (av > bv)
                return 1;
        return 0;
}

static void sort_relative_table(char *extab_image, int image_size)
{
        int i = 0;

        /*
         * Do the same thing the runtime sort does, first normalize to
         * being relative to the start of the section.
         */
        while (i < image_size) {
                uint32_t *loc = (uint32_t *)(extab_image + i);
                w(r(loc) + i, loc);
                i += 4;
        }

        qsort(extab_image, image_size / 8, 8, compare_relative_table);

        /* Now denormalize. */
        i = 0;
        while (i < image_size) {
                uint32_t *loc = (uint32_t *)(extab_image + i);
                w(r(loc) - i, loc);
                i += 4;
        }
}

static void sort_relative_table_with_data(char *extab_image, int image_size)
{
        int i = 0;

        while (i < image_size) {
                uint32_t *loc = (uint32_t *)(extab_image + i);

                w(r(loc) + i, loc);
                w(r(loc + 1) + i + 4, loc + 1);
                /* Don't touch the fixup type or data */

                i += sizeof(uint32_t) * 3;
        }

        qsort(extab_image, image_size / 12, 12, compare_relative_table);

        i = 0;
        while (i < image_size) {
                uint32_t *loc = (uint32_t *)(extab_image + i);

                w(r(loc) - i, loc);
                w(r(loc + 1) - (i + 4), loc + 1);
                /* Don't touch the fixup type or data */

                i += sizeof(uint32_t) * 3;
        }
}

static void s390_sort_relative_table(char *extab_image, int image_size)
{
        int i;

        for (i = 0; i < image_size; i += 16) {
                char *loc = extab_image + i;
                uint64_t handler;

                w(r((uint32_t *)loc) + i, (uint32_t *)loc);
                w(r((uint32_t *)(loc + 4)) + (i + 4), (uint32_t *)(loc + 4));
                /*
                 * 0 is a special self-relative handler value, which means that
                 * handler should be ignored. It is safe, because it means that
                 * handler field points to itself, which should never happen.
                 * When creating extable-relative values, keep it as 0, since
                 * this should never occur either: it would mean that handler
                 * field points to the first extable entry.
                 */
                handler = r8((uint64_t *)(loc + 8));
                if (handler)
                        handler += i + 8;
                w8(handler, (uint64_t *)(loc + 8));
        }

        qsort(extab_image, image_size / 16, 16, compare_relative_table);

        for (i = 0; i < image_size; i += 16) {
                char *loc = extab_image + i;
                uint64_t handler;

                w(r((uint32_t *)loc) - i, (uint32_t *)loc);
                w(r((uint32_t *)(loc + 4)) - (i + 4), (uint32_t *)(loc + 4));
                handler = r8((uint64_t *)(loc + 8));
                if (handler)
                        handler -= i + 8;
                w8(handler, (uint64_t *)(loc + 8));
        }
}

static int do_file(char const *const fname, void *addr)
{
        int rc = -1;
        Elf32_Ehdr *ehdr = addr;
        table_sort_t custom_sort = NULL;

        switch (ehdr->e_ident[EI_DATA]) {
        case ELFDATA2LSB:
                r       = rle;
                r2      = r2le;
                r8      = r8le;
                w       = wle;
                w2      = w2le;
                w8      = w8le;
                break;
        case ELFDATA2MSB:
                r       = rbe;
                r2      = r2be;
                r8      = r8be;
                w       = wbe;
                w2      = w2be;
                w8      = w8be;
                break;
        default:
                fprintf(stderr, "unrecognized ELF data encoding %d: %s\n",
                        ehdr->e_ident[EI_DATA], fname);
                return -1;
        }

        if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0 ||
            (r2(&ehdr->e_type) != ET_EXEC && r2(&ehdr->e_type) != ET_DYN) ||
            ehdr->e_ident[EI_VERSION] != EV_CURRENT) {
                fprintf(stderr, "unrecognized ET_EXEC/ET_DYN file %s\n", fname);
                return -1;
        }

        switch (r2(&ehdr->e_machine)) {
        case EM_386:
        case EM_AARCH64:
        case EM_RISCV:
        case EM_X86_64:
                custom_sort = sort_relative_table_with_data;
                break;
        case EM_S390:
                custom_sort = s390_sort_relative_table;
                break;
        case EM_PARISC:
        case EM_PPC:
        case EM_PPC64:
                custom_sort = sort_relative_table;
                break;
        case EM_ARCOMPACT:
        case EM_ARCV2:
        case EM_ARM:
        case EM_MICROBLAZE:
        case EM_MIPS:
        case EM_XTENSA:
                break;
        default:
                fprintf(stderr, "unrecognized e_machine %d %s\n",
                        r2(&ehdr->e_machine), fname);
                return -1;
        }

        switch (ehdr->e_ident[EI_CLASS]) {
        case ELFCLASS32:
                if (r2(&ehdr->e_ehsize) != sizeof(Elf32_Ehdr) ||
                    r2(&ehdr->e_shentsize) != sizeof(Elf32_Shdr)) {
                        fprintf(stderr,
                                "unrecognized ET_EXEC/ET_DYN file: %s\n", fname);
                        break;
                }
                rc = do_sort_32(ehdr, fname, custom_sort);
                break;
        case ELFCLASS64:
                {
                Elf64_Ehdr *const ghdr = (Elf64_Ehdr *)ehdr;
                if (r2(&ghdr->e_ehsize) != sizeof(Elf64_Ehdr) ||
                    r2(&ghdr->e_shentsize) != sizeof(Elf64_Shdr)) {
                        fprintf(stderr,
                                "unrecognized ET_EXEC/ET_DYN file: %s\n",
                                fname);
                        break;
                }
                rc = do_sort_64(ghdr, fname, custom_sort);
                }
                break;
        default:
                fprintf(stderr, "unrecognized ELF class %d %s\n",
                        ehdr->e_ident[EI_CLASS], fname);
                break;
        }

        return rc;
}

int main(int argc, char *argv[])
{
        int i, n_error = 0;  /* gcc-4.3.0 false positive complaint */
        size_t size = 0;
        void *addr = NULL;

        if (argc < 2) {
                fprintf(stderr, "usage: sorttable vmlinux...\n");
                return 0;
        }

        /* Process each file in turn, allowing deep failure. */
        for (i = 1; i < argc; i++) {
                addr = mmap_file(argv[i], &size);
                if (!addr) {
                        ++n_error;
                        continue;
                }

                if (do_file(argv[i], addr))
                        ++n_error;

                munmap(addr, size);
        }

        return !!n_error;
}