x86: remove arbitrary ELF section limit in i386 relocatable kernel
Impact: build failure in maximal configurations The 32-bit x86 relocatable kernel requires an auxilliary host program to process the relocations. This program had a hard-coded arbitrary limit of a 100 ELF sections. Instead of a hard-coded limit, allocate the structures dynamically. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
This commit is contained in:
H. Peter Anvin
Родитель
aa60d13fb0
Коммит
908ec7afac
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@ -10,16 +10,20 @@
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#define USE_BSD
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#include <endian.h>
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#define MAX_SHDRS 100
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
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static Elf32_Ehdr ehdr;
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static Elf32_Shdr shdr[MAX_SHDRS];
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static Elf32_Sym *symtab[MAX_SHDRS];
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static Elf32_Rel *reltab[MAX_SHDRS];
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static char *strtab[MAX_SHDRS];
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static unsigned long reloc_count, reloc_idx;
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static unsigned long *relocs;
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struct section {
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Elf32_Shdr shdr;
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struct section *link;
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Elf32_Sym *symtab;
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Elf32_Rel *reltab;
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char *strtab;
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};
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static struct section *secs;
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/*
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* Following symbols have been audited. There values are constant and do
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* not change if bzImage is loaded at a different physical address than
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@ -35,7 +39,7 @@ static int is_safe_abs_reloc(const char* sym_name)
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{
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int i;
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for(i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) {
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for (i = 0; i < ARRAY_SIZE(safe_abs_relocs); i++) {
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if (!strcmp(sym_name, safe_abs_relocs[i]))
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/* Match found */
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return 1;
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@ -137,10 +141,10 @@ static const char *sec_name(unsigned shndx)
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{
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const char *sec_strtab;
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const char *name;
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sec_strtab = strtab[ehdr.e_shstrndx];
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sec_strtab = secs[ehdr.e_shstrndx].strtab;
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name = "<noname>";
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if (shndx < ehdr.e_shnum) {
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name = sec_strtab + shdr[shndx].sh_name;
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name = sec_strtab + secs[shndx].shdr.sh_name;
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}
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else if (shndx == SHN_ABS) {
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name = "ABSOLUTE";
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@ -159,7 +163,7 @@ static const char *sym_name(const char *sym_strtab, Elf32_Sym *sym)
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name = sym_strtab + sym->st_name;
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}
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else {
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name = sec_name(shdr[sym->st_shndx].sh_name);
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name = sec_name(secs[sym->st_shndx].shdr.sh_name);
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}
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return name;
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}
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@ -244,29 +248,34 @@ static void read_ehdr(FILE *fp)
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static void read_shdrs(FILE *fp)
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{
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int i;
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if (ehdr.e_shnum > MAX_SHDRS) {
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die("%d section headers supported: %d\n",
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ehdr.e_shnum, MAX_SHDRS);
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Elf32_Shdr shdr;
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secs = calloc(ehdr.e_shnum, sizeof(struct section));
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if (!secs) {
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die("Unable to allocate %d section headers\n",
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ehdr.e_shnum);
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}
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if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
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die("Seek to %d failed: %s\n",
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ehdr.e_shoff, strerror(errno));
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}
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if (fread(&shdr, sizeof(shdr[0]), ehdr.e_shnum, fp) != ehdr.e_shnum) {
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die("Cannot read ELF section headers: %s\n",
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strerror(errno));
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}
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for(i = 0; i < ehdr.e_shnum; i++) {
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shdr[i].sh_name = elf32_to_cpu(shdr[i].sh_name);
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shdr[i].sh_type = elf32_to_cpu(shdr[i].sh_type);
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shdr[i].sh_flags = elf32_to_cpu(shdr[i].sh_flags);
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shdr[i].sh_addr = elf32_to_cpu(shdr[i].sh_addr);
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shdr[i].sh_offset = elf32_to_cpu(shdr[i].sh_offset);
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shdr[i].sh_size = elf32_to_cpu(shdr[i].sh_size);
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shdr[i].sh_link = elf32_to_cpu(shdr[i].sh_link);
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shdr[i].sh_info = elf32_to_cpu(shdr[i].sh_info);
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shdr[i].sh_addralign = elf32_to_cpu(shdr[i].sh_addralign);
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shdr[i].sh_entsize = elf32_to_cpu(shdr[i].sh_entsize);
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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if (fread(&shdr, sizeof shdr, 1, fp) != 1)
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die("Cannot read ELF section headers %d/%d: %s\n",
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i, ehdr.e_shnum, strerror(errno));
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sec->shdr.sh_name = elf32_to_cpu(shdr.sh_name);
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sec->shdr.sh_type = elf32_to_cpu(shdr.sh_type);
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sec->shdr.sh_flags = elf32_to_cpu(shdr.sh_flags);
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sec->shdr.sh_addr = elf32_to_cpu(shdr.sh_addr);
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sec->shdr.sh_offset = elf32_to_cpu(shdr.sh_offset);
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sec->shdr.sh_size = elf32_to_cpu(shdr.sh_size);
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sec->shdr.sh_link = elf32_to_cpu(shdr.sh_link);
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sec->shdr.sh_info = elf32_to_cpu(shdr.sh_info);
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sec->shdr.sh_addralign = elf32_to_cpu(shdr.sh_addralign);
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sec->shdr.sh_entsize = elf32_to_cpu(shdr.sh_entsize);
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if (sec->shdr.sh_link < ehdr.e_shnum)
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sec->link = &secs[sec->shdr.sh_link];
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}
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}
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@ -274,20 +283,22 @@ static void read_shdrs(FILE *fp)
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static void read_strtabs(FILE *fp)
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{
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int i;
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for(i = 0; i < ehdr.e_shnum; i++) {
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if (shdr[i].sh_type != SHT_STRTAB) {
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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if (sec->shdr.sh_type != SHT_STRTAB) {
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continue;
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}
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strtab[i] = malloc(shdr[i].sh_size);
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if (!strtab[i]) {
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sec->strtab = malloc(sec->shdr.sh_size);
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if (!sec->strtab) {
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die("malloc of %d bytes for strtab failed\n",
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shdr[i].sh_size);
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sec->shdr.sh_size);
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}
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if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
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if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
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die("Seek to %d failed: %s\n",
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shdr[i].sh_offset, strerror(errno));
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sec->shdr.sh_offset, strerror(errno));
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}
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if (fread(strtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
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if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
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!= sec->shdr.sh_size) {
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die("Cannot read symbol table: %s\n",
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strerror(errno));
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}
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@ -297,28 +308,31 @@ static void read_strtabs(FILE *fp)
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static void read_symtabs(FILE *fp)
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{
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int i,j;
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for(i = 0; i < ehdr.e_shnum; i++) {
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if (shdr[i].sh_type != SHT_SYMTAB) {
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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if (sec->shdr.sh_type != SHT_SYMTAB) {
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continue;
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}
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symtab[i] = malloc(shdr[i].sh_size);
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if (!symtab[i]) {
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sec->symtab = malloc(sec->shdr.sh_size);
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if (!sec->symtab) {
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die("malloc of %d bytes for symtab failed\n",
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shdr[i].sh_size);
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sec->shdr.sh_size);
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}
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if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
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if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
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die("Seek to %d failed: %s\n",
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shdr[i].sh_offset, strerror(errno));
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sec->shdr.sh_offset, strerror(errno));
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}
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if (fread(symtab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
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if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
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!= sec->shdr.sh_size) {
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die("Cannot read symbol table: %s\n",
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strerror(errno));
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}
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for(j = 0; j < shdr[i].sh_size/sizeof(symtab[i][0]); j++) {
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symtab[i][j].st_name = elf32_to_cpu(symtab[i][j].st_name);
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symtab[i][j].st_value = elf32_to_cpu(symtab[i][j].st_value);
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symtab[i][j].st_size = elf32_to_cpu(symtab[i][j].st_size);
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symtab[i][j].st_shndx = elf16_to_cpu(symtab[i][j].st_shndx);
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for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
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Elf32_Sym *sym = &sec->symtab[j];
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sym->st_name = elf32_to_cpu(sym->st_name);
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sym->st_value = elf32_to_cpu(sym->st_value);
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sym->st_size = elf32_to_cpu(sym->st_size);
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sym->st_shndx = elf16_to_cpu(sym->st_shndx);
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}
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}
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}
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@ -327,26 +341,29 @@ static void read_symtabs(FILE *fp)
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static void read_relocs(FILE *fp)
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{
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int i,j;
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for(i = 0; i < ehdr.e_shnum; i++) {
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if (shdr[i].sh_type != SHT_REL) {
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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if (sec->shdr.sh_type != SHT_REL) {
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continue;
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}
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reltab[i] = malloc(shdr[i].sh_size);
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if (!reltab[i]) {
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sec->reltab = malloc(sec->shdr.sh_size);
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if (!sec->reltab) {
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die("malloc of %d bytes for relocs failed\n",
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shdr[i].sh_size);
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sec->shdr.sh_size);
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}
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if (fseek(fp, shdr[i].sh_offset, SEEK_SET) < 0) {
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if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
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die("Seek to %d failed: %s\n",
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shdr[i].sh_offset, strerror(errno));
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sec->shdr.sh_offset, strerror(errno));
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}
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if (fread(reltab[i], 1, shdr[i].sh_size, fp) != shdr[i].sh_size) {
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if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
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!= sec->shdr.sh_size) {
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die("Cannot read symbol table: %s\n",
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strerror(errno));
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}
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for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
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reltab[i][j].r_offset = elf32_to_cpu(reltab[i][j].r_offset);
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reltab[i][j].r_info = elf32_to_cpu(reltab[i][j].r_info);
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for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
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Elf32_Rel *rel = &sec->reltab[j];
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rel->r_offset = elf32_to_cpu(rel->r_offset);
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rel->r_info = elf32_to_cpu(rel->r_info);
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}
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}
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}
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@ -357,19 +374,21 @@ static void print_absolute_symbols(void)
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int i;
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printf("Absolute symbols\n");
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printf(" Num: Value Size Type Bind Visibility Name\n");
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for(i = 0; i < ehdr.e_shnum; i++) {
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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char *sym_strtab;
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Elf32_Sym *sh_symtab;
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int j;
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if (shdr[i].sh_type != SHT_SYMTAB) {
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if (sec->shdr.sh_type != SHT_SYMTAB) {
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continue;
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}
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sh_symtab = symtab[i];
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sym_strtab = strtab[shdr[i].sh_link];
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for(j = 0; j < shdr[i].sh_size/sizeof(symtab[0][0]); j++) {
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sh_symtab = sec->symtab;
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sym_strtab = sec->link->strtab;
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for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Sym); j++) {
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Elf32_Sym *sym;
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const char *name;
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sym = &symtab[i][j];
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sym = &sec->symtab[j];
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name = sym_name(sym_strtab, sym);
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if (sym->st_shndx != SHN_ABS) {
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continue;
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@ -389,26 +408,27 @@ static void print_absolute_relocs(void)
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{
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int i, printed = 0;
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for(i = 0; i < ehdr.e_shnum; i++) {
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for (i = 0; i < ehdr.e_shnum; i++) {
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struct section *sec = &secs[i];
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struct section *sec_applies, *sec_symtab;
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char *sym_strtab;
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Elf32_Sym *sh_symtab;
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unsigned sec_applies, sec_symtab;
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int j;
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if (shdr[i].sh_type != SHT_REL) {
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if (sec->shdr.sh_type != SHT_REL) {
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continue;
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}
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sec_symtab = shdr[i].sh_link;
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sec_applies = shdr[i].sh_info;
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if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
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sec_symtab = sec->link;
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sec_applies = &secs[sec->shdr.sh_info];
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if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
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continue;
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}
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sh_symtab = symtab[sec_symtab];
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sym_strtab = strtab[shdr[sec_symtab].sh_link];
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for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
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sh_symtab = sec_symtab->symtab;
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sym_strtab = sec_symtab->link->strtab;
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for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
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Elf32_Rel *rel;
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Elf32_Sym *sym;
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const char *name;
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rel = &reltab[i][j];
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rel = &sec->reltab[j];
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sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
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name = sym_name(sym_strtab, sym);
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if (sym->st_shndx != SHN_ABS) {
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@ -456,26 +476,28 @@ static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym))
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{
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int i;
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/* Walk through the relocations */
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for(i = 0; i < ehdr.e_shnum; i++) {
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for (i = 0; i < ehdr.e_shnum; i++) {
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char *sym_strtab;
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Elf32_Sym *sh_symtab;
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unsigned sec_applies, sec_symtab;
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struct section *sec_applies, *sec_symtab;
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int j;
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if (shdr[i].sh_type != SHT_REL) {
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struct section *sec = &secs[i];
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if (sec->shdr.sh_type != SHT_REL) {
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continue;
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}
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sec_symtab = shdr[i].sh_link;
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sec_applies = shdr[i].sh_info;
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if (!(shdr[sec_applies].sh_flags & SHF_ALLOC)) {
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sec_symtab = sec->link;
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sec_applies = &secs[sec->shdr.sh_info];
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if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
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continue;
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}
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sh_symtab = symtab[sec_symtab];
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sym_strtab = strtab[shdr[sec_symtab].sh_link];
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for(j = 0; j < shdr[i].sh_size/sizeof(reltab[0][0]); j++) {
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sh_symtab = sec_symtab->symtab;
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sym_strtab = sec->link->strtab;
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for (j = 0; j < sec->shdr.sh_size/sizeof(Elf32_Rel); j++) {
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Elf32_Rel *rel;
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Elf32_Sym *sym;
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unsigned r_type;
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rel = &reltab[i][j];
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rel = &sec->reltab[j];
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sym = &sh_symtab[ELF32_R_SYM(rel->r_info)];
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r_type = ELF32_R_TYPE(rel->r_info);
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/* Don't visit relocations to absolute symbols */
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@ -539,7 +561,7 @@ static void emit_relocs(int as_text)
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*/
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printf(".section \".data.reloc\",\"a\"\n");
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printf(".balign 4\n");
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for(i = 0; i < reloc_count; i++) {
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for (i = 0; i < reloc_count; i++) {
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printf("\t .long 0x%08lx\n", relocs[i]);
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}
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printf("\n");
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@ -550,7 +572,7 @@ static void emit_relocs(int as_text)
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/* Print a stop */
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printf("%c%c%c%c", buf[0], buf[1], buf[2], buf[3]);
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/* Now print each relocation */
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for(i = 0; i < reloc_count; i++) {
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for (i = 0; i < reloc_count; i++) {
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buf[0] = (relocs[i] >> 0) & 0xff;
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buf[1] = (relocs[i] >> 8) & 0xff;
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buf[2] = (relocs[i] >> 16) & 0xff;
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@ -577,7 +599,7 @@ int main(int argc, char **argv)
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show_absolute_relocs = 0;
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as_text = 0;
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fname = NULL;
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for(i = 1; i < argc; i++) {
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for (i = 1; i < argc; i++) {
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char *arg = argv[i];
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if (*arg == '-') {
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if (strcmp(argv[1], "--abs-syms") == 0) {
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Загрузка…
Ссылка в новой задаче