source: bootcd/isolinux/syslinux-6.03/gpxe/src/util/iccfix.c

#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <elf.h>
#include <gpxe/tables.h>

#define DEBUG 0

#define eprintf(...) fprintf ( stderr, __VA_ARGS__ )

#define dprintf(...) do {                                               \
        if ( DEBUG )                                                    \
                fprintf ( stderr, __VA_ARGS__ );                        \
        } while ( 0 )

#ifdef SELF_INCLUDED

/**
 * Fix up ICC alignments
 *
 * @v elf               ELF header
 * @ret rc              Return status code
 *
 * See comments in tables.h for an explanation of why this monstrosity
 * is necessary.
 */
static int ICCFIX ( void *elf ) {
        ELF_EHDR *ehdr = elf;
        ELF_SHDR *shdr = ( elf + ehdr->e_shoff );
        size_t shentsize = ehdr->e_shentsize;
        unsigned int shnum = ehdr->e_shnum;
        ELF_SHDR *strtab = ( ( ( void * ) shdr ) +
                             ( ehdr->e_shstrndx * shentsize ) );
        char *strings = ( elf + strtab->sh_offset );

        for ( ; shnum-- ; shdr = ( ( ( void * ) shdr ) + shentsize ) ) {
                char *name = ( strings + shdr->sh_name );
                unsigned long align = shdr->sh_addralign;
                unsigned long new_align;

                if ( ( strncmp ( name, ".tbl.", 5 ) == 0 ) &&
                     ( align >= ICC_ALIGN_HACK_FACTOR ) ) {
                        new_align = ( align / ICC_ALIGN_HACK_FACTOR );
                        shdr->sh_addralign = new_align;
                        dprintf ( "Section \"%s\": alignment %d->%d\n",
                                  name, align, new_align );
                }
        }
        return 0;
}

#else /* SELF_INCLUDED */

#define SELF_INCLUDED

/* Include iccfix32() function */
#define ELF_EHDR Elf32_Ehdr
#define ELF_SHDR Elf32_Shdr
#define ICCFIX iccfix32
#include "iccfix.c"
#undef ELF_EHDR
#undef ELF_SHDR
#undef ICCFIX

/* Include iccfix64() function */
#define ELF_EHDR Elf64_Ehdr
#define ELF_SHDR Elf64_Shdr
#define ICCFIX iccfix64
#include "iccfix.c"
#undef ELF_EHDR
#undef ELF_SHDR
#undef ICCFIX

static int iccfix ( const char *filename ) {
        int fd;
        struct stat stat;
        void *elf;
        unsigned char *eident;
        int rc;

        /* Open and mmap file */
        fd = open ( filename, O_RDWR );
        if ( fd < 0 ) {
                eprintf ( "Could not open %s: %s\n",
                          filename, strerror ( errno ) );
                rc = -1;
                goto err_open;
        }
        if ( fstat ( fd, &stat ) < 0 ) {
                eprintf ( "Could not determine size of %s: %s\n",
                          filename, strerror ( errno ) );
                rc = -1;
                goto err_fstat;
        }
        elf = mmap ( NULL, stat.st_size, ( PROT_READ | PROT_WRITE ),
                     MAP_SHARED, fd, 0 );
        if ( elf == MAP_FAILED ) {
                eprintf ( "Could not map %s: %s\n",
                          filename, strerror ( errno ) );
                rc = -1;
                goto err_mmap;
        }

        /* Perform fixups */
        eident = elf;
        switch ( eident[EI_CLASS] ) {
        case ELFCLASS32:
                rc = iccfix32 ( elf );
                break;
        case ELFCLASS64:
                rc = iccfix64 ( elf );
                break;
        default:
                eprintf ( "Unknown ELF class %d in %s\n",
                          eident[EI_CLASS], filename );
                rc = -1;
                break;
        }

        munmap ( elf, stat.st_size );
 err_mmap:
 err_fstat:
        close ( fd );
 err_open:
        return rc;
}

int main ( int argc, char **argv ) {
        int i;
        int rc;

        /* Parse command line */
        if ( argc < 2 ) {
                eprintf ( "Syntax: %s <object_file>...\n", argv[0] );
                exit ( 1 );
        }

        /* Process each object in turn */
        for ( i = 1 ; i < argc ; i++ ) {
                if ( ( rc = iccfix ( argv[i] ) ) != 0 ) {
                        eprintf ( "Could not fix up %s\n", argv[i] );
                        exit ( 1 );
                }
        }

        return 0;
}

#endif /* SELF_INCLUDED */