rpm/tools/elfdeps.c

394 lines
9.3 KiB
C

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <error.h>
#include <errno.h>
#include <popt.h>
#include <gelf.h>
#include <rpm/rpmstring.h>
#include <rpm/argv.h>
int filter_private = 0;
int soname_only = 0;
int fake_soname = 1;
int filter_soname = 1;
int require_interp = 0;
typedef struct elfInfo_s {
Elf *elf;
int isDSO;
int isExec; /* requires are only added to executables */
int gotDEBUG;
int gotHASH;
int gotGNUHASH;
char *soname;
char *interp;
const char *marker; /* elf class marker or NULL */
ARGV_t requires;
ARGV_t provides;
} elfInfo;
static int skipPrivate(const char *s)
{
return (filter_private && rstreq(s, "GLIBC_PRIVATE"));
}
/*
* Rough soname sanity filtering: all sane soname's dependencies need to
* contain ".so", and normal linkable libraries start with "lib",
* everything else is an exception of some sort. The most notable
* and common exception is the dynamic linker itself, which we allow
* here, the rest can use --no-filter-soname.
*/
static int skipSoname(const char *soname)
{
int sane = 0;
/* Filter out empty and all-whitespace sonames */
for (const char *s = soname; *s != '\0'; s++) {
if (!risspace(*s)) {
sane = 1;
break;
}
}
if (!sane)
return 1;
if (filter_soname) {
if (!strstr(soname, ".so"))
return 1;
if (rstreqn(soname, "ld.", 3) || rstreqn(soname, "ld-", 3) ||
rstreqn(soname, "ld64.", 3) || rstreqn(soname, "ld64-", 3))
return 0;
if (rstreqn(soname, "lib", 3))
return 0;
else
return 1;
}
return 0;
}
static const char *mkmarker(GElf_Ehdr *ehdr)
{
const char *marker = NULL;
if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) {
switch (ehdr->e_machine) {
case EM_ALPHA:
case EM_FAKE_ALPHA:
/* alpha doesn't traditionally have 64bit markers */
break;
default:
marker = "(64bit)";
break;
}
}
return marker;
}
static void addDep(ARGV_t *deps,
const char *soname, const char *ver, const char *marker)
{
char *dep = NULL;
if (skipSoname(soname))
return;
if (ver || marker) {
rasprintf(&dep,
"%s(%s)%s", soname, ver ? ver : "", marker ? marker : "");
}
argvAdd(deps, dep ? dep : soname);
free(dep);
}
static void processVerDef(Elf_Scn *scn, GElf_Shdr *shdr, elfInfo *ei)
{
Elf_Data *data = NULL;
unsigned int offset, auxoffset;
char *soname = NULL;
while ((data = elf_getdata(scn, data)) != NULL) {
offset = 0;
for (int i = shdr->sh_info; --i >= 0; ) {
GElf_Verdef def_mem, *def;
def = gelf_getverdef (data, offset, &def_mem);
if (def == NULL)
break;
auxoffset = offset + def->vd_aux;
offset += def->vd_next;
for (int j = def->vd_cnt; --j >= 0; ) {
GElf_Verdaux aux_mem, * aux;
const char *s;
aux = gelf_getverdaux (data, auxoffset, &aux_mem);
if (aux == NULL)
break;
s = elf_strptr(ei->elf, shdr->sh_link, aux->vda_name);
if (s == NULL)
break;
if (def->vd_flags & VER_FLG_BASE) {
rfree(soname);
soname = rstrdup(s);
auxoffset += aux->vda_next;
continue;
} else if (soname && !soname_only && !skipPrivate(s)) {
addDep(&ei->provides, soname, s, ei->marker);
}
}
}
}
rfree(soname);
}
static void processVerNeed(Elf_Scn *scn, GElf_Shdr *shdr, elfInfo *ei)
{
Elf_Data *data = NULL;
char *soname = NULL;
while ((data = elf_getdata(scn, data)) != NULL) {
unsigned int offset = 0, auxoffset;
for (int i = shdr->sh_info; --i >= 0; ) {
const char *s = NULL;
GElf_Verneed need_mem, *need;
need = gelf_getverneed (data, offset, &need_mem);
if (need == NULL)
break;
s = elf_strptr(ei->elf, shdr->sh_link, need->vn_file);
if (s == NULL)
break;
rfree(soname);
soname = rstrdup(s);
auxoffset = offset + need->vn_aux;
for (int j = need->vn_cnt; --j >= 0; ) {
GElf_Vernaux aux_mem, * aux;
aux = gelf_getvernaux (data, auxoffset, &aux_mem);
if (aux == NULL)
break;
s = elf_strptr(ei->elf, shdr->sh_link, aux->vna_name);
if (s == NULL)
break;
if (ei->isExec && soname && !soname_only && !skipPrivate(s)) {
addDep(&ei->requires, soname, s, ei->marker);
}
auxoffset += aux->vna_next;
}
offset += need->vn_next;
}
}
rfree(soname);
}
static void processDynamic(Elf_Scn *scn, GElf_Shdr *shdr, elfInfo *ei)
{
Elf_Data *data = NULL;
while ((data = elf_getdata(scn, data)) != NULL) {
for (int i = 0; i < (shdr->sh_size / shdr->sh_entsize); i++) {
const char *s = NULL;
GElf_Dyn dyn_mem, *dyn;
dyn = gelf_getdyn (data, i, &dyn_mem);
if (dyn == NULL)
break;
switch (dyn->d_tag) {
case DT_HASH:
ei->gotHASH = 1;
break;
case DT_GNU_HASH:
ei->gotGNUHASH = 1;
break;
case DT_DEBUG:
ei->gotDEBUG = 1;
break;
case DT_SONAME:
s = elf_strptr(ei->elf, shdr->sh_link, dyn->d_un.d_val);
if (s)
ei->soname = rstrdup(s);
break;
case DT_NEEDED:
if (ei->isExec) {
s = elf_strptr(ei->elf, shdr->sh_link, dyn->d_un.d_val);
if (s)
addDep(&ei->requires, s, NULL, ei->marker);
}
break;
}
}
}
}
static void processSections(elfInfo *ei)
{
Elf_Scn * scn = NULL;
while ((scn = elf_nextscn(ei->elf, scn)) != NULL) {
GElf_Shdr shdr_mem, *shdr;
shdr = gelf_getshdr(scn, &shdr_mem);
if (shdr == NULL)
break;
switch (shdr->sh_type) {
case SHT_GNU_verdef:
processVerDef(scn, shdr, ei);
break;
case SHT_GNU_verneed:
processVerNeed(scn, shdr, ei);
break;
case SHT_DYNAMIC:
processDynamic(scn, shdr, ei);
break;
default:
break;
}
}
}
static void processProgHeaders(elfInfo *ei, GElf_Ehdr *ehdr)
{
for (size_t i = 0; i < ehdr->e_phnum; i++) {
GElf_Phdr mem;
GElf_Phdr *phdr = gelf_getphdr(ei->elf, i, &mem);
if (phdr && phdr->p_type == PT_INTERP) {
size_t maxsize;
char * filedata = elf_rawfile(ei->elf, &maxsize);
if (filedata && phdr->p_offset < maxsize) {
ei->interp = rstrdup(filedata + phdr->p_offset);
break;
}
}
}
}
static int processFile(const char *fn, int dtype)
{
int rc = 1;
int fdno = -1;
struct stat st;
GElf_Ehdr *ehdr, ehdr_mem;
elfInfo *ei = rcalloc(1, sizeof(*ei));
fdno = open(fn, O_RDONLY);
if (fdno < 0 || fstat(fdno, &st) < 0)
goto exit;
(void) elf_version(EV_CURRENT);
ei->elf = elf_begin(fdno, ELF_C_READ, NULL);
if (ei->elf == NULL || elf_kind(ei->elf) != ELF_K_ELF)
goto exit;
ehdr = gelf_getehdr(ei->elf, &ehdr_mem);
if (ehdr == NULL)
goto exit;
if (ehdr->e_type == ET_DYN || ehdr->e_type == ET_EXEC) {
ei->marker = mkmarker(ehdr);
ei->isDSO = (ehdr->e_type == ET_DYN);
ei->isExec = (st.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH));
processProgHeaders(ei, ehdr);
processSections(ei);
}
/*
* For DSOs which use the .gnu_hash section and don't have a .hash
* section, we need to ensure that we have a new enough glibc.
*/
if (ei->isExec && ei->gotGNUHASH && !ei->gotHASH && !soname_only) {
argvAdd(&ei->requires, "rtld(GNU_HASH)");
}
/*
* For DSOs, add DT_SONAME as provide. If its missing, we can fake
* it from the basename if requested. The bizarre looking DT_DEBUG
* check is used to avoid adding basename provides for PIE executables.
*/
if (ei->isDSO && !ei->gotDEBUG) {
if (!ei->soname && fake_soname) {
const char *bn = strrchr(fn, '/');
ei->soname = rstrdup(bn ? bn + 1 : fn);
}
if (ei->soname)
addDep(&ei->provides, ei->soname, NULL, ei->marker);
}
/* If requested and present, add dep for interpreter (ie dynamic linker) */
if (ei->interp && require_interp)
argvAdd(&ei->requires, ei->interp);
rc = 0;
/* dump the requested dependencies for this file */
for (ARGV_t dep = dtype ? ei->requires : ei->provides; dep && *dep; dep++) {
fprintf(stdout, "%s\n", *dep);
}
exit:
if (fdno >= 0) close(fdno);
if (ei) {
argvFree(ei->provides);
argvFree(ei->requires);
free(ei->soname);
free(ei->interp);
if (ei->elf) elf_end(ei->elf);
rfree(ei);
}
return rc;
}
int main(int argc, char *argv[])
{
int provides = 0;
int requires = 0;
poptContext optCon;
struct poptOption opts[] = {
{ "provides", 'P', POPT_ARG_VAL, &provides, -1, NULL, NULL },
{ "requires", 'R', POPT_ARG_VAL, &requires, -1, NULL, NULL },
{ "filter-private", 0, POPT_ARG_VAL, &filter_private, -1, NULL, NULL },
{ "soname-only", 0, POPT_ARG_VAL, &soname_only, -1, NULL, NULL },
{ "no-fake-soname", 0, POPT_ARG_VAL, &fake_soname, 0, NULL, NULL },
{ "no-filter-soname", 0, POPT_ARG_VAL, &filter_soname, 0, NULL, NULL },
{ "require-interp", 0, POPT_ARG_VAL, &require_interp, -1, NULL, NULL },
POPT_AUTOHELP
POPT_TABLEEND
};
optCon = poptGetContext(argv[0], argc, (const char **) argv, opts, 0);
if (argc < 2 || poptGetNextOpt(optCon) == 0) {
poptPrintUsage(optCon, stderr, 0);
exit(EXIT_FAILURE);
}
/* Normally our data comes from stdin, but permit args too */
if (poptPeekArg(optCon)) {
const char *fn;
while ((fn = poptGetArg(optCon)) != NULL) {
(void) processFile(fn, requires);
}
} else {
char fn[BUFSIZ];
while (fgets(fn, sizeof(fn), stdin) != NULL) {
fn[strlen(fn)-1] = '\0';
(void) processFile(fn, requires);
}
}
poptFreeContext(optCon);
return 0;
}