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Diffstat (limited to 'ldso')
-rw-r--r--ldso/dlstart.c17
-rw-r--r--ldso/dynlink.c195
2 files changed, 176 insertions, 36 deletions
diff --git a/ldso/dlstart.c b/ldso/dlstart.c
index 20d50f2c..4aac42bc 100644
--- a/ldso/dlstart.c
+++ b/ldso/dlstart.c
@@ -45,7 +45,7 @@ hidden void _dlstart_c(size_t *sp, size_t *dynv)
/* If dynv is null, the entry point was started from loader
* that is not fdpic-aware. We can assume normal fixed-
* displacement ELF loading was performed, but when ldso was
- * run as a command, finding the Ehdr is a heursitic: we
+ * run as a command, finding the Ehdr is a heuristic: we
* have to assume Phdrs start in the first 4k of the file. */
base = aux[AT_BASE];
if (!base) base = aux[AT_PHDR] & -4096;
@@ -140,6 +140,21 @@ hidden void _dlstart_c(size_t *sp, size_t *dynv)
size_t *rel_addr = (void *)(base + rel[0]);
*rel_addr = base + rel[2];
}
+
+ rel = (void *)(base+dyn[DT_RELR]);
+ rel_size = dyn[DT_RELRSZ];
+ size_t *relr_addr = 0;
+ for (; rel_size; rel++, rel_size-=sizeof(size_t)) {
+ if ((rel[0]&1) == 0) {
+ relr_addr = (void *)(base + rel[0]);
+ *relr_addr++ += base;
+ } else {
+ for (size_t i=0, bitmap=rel[0]; bitmap>>=1; i++)
+ if (bitmap&1)
+ relr_addr[i] += base;
+ relr_addr += 8*sizeof(size_t)-1;
+ }
+ }
#endif
stage2_func dls2;
diff --git a/ldso/dynlink.c b/ldso/dynlink.c
index afec985a..715948f4 100644
--- a/ldso/dynlink.c
+++ b/ldso/dynlink.c
@@ -1,6 +1,5 @@
#define _GNU_SOURCE
#define SYSCALL_NO_TLS 1
-#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stddef.h>
@@ -21,11 +20,26 @@
#include <semaphore.h>
#include <sys/membarrier.h>
#include "pthread_impl.h"
+#include "fork_impl.h"
#include "libc.h"
#include "dynlink.h"
-#include "malloc_impl.h"
-static void error(const char *, ...);
+static size_t ldso_page_size;
+/* libc.h may have defined a macro for dynamic PAGE_SIZE already, but
+ * PAGESIZE is only defined if it's constant for the arch. */
+#ifndef PAGESIZE
+#undef PAGE_SIZE
+#define PAGE_SIZE ldso_page_size
+#endif
+
+#define malloc __libc_malloc
+#define calloc __libc_calloc
+#define realloc __libc_realloc
+#define free __libc_free
+
+static void error_impl(const char *, ...);
+static void error_noop(const char *, ...);
+static void (*error)(const char *, ...) = error_noop;
#define MAXP2(a,b) (-(-(a)&-(b)))
#define ALIGN(x,y) ((x)+(y)-1 & -(y))
@@ -79,7 +93,7 @@ struct dso {
struct dso **deps, *needed_by;
size_t ndeps_direct;
size_t next_dep;
- int ctor_visitor;
+ pthread_t ctor_visitor;
char *rpath_orig, *rpath;
struct tls_module tls;
size_t tls_id;
@@ -145,6 +159,8 @@ static struct fdpic_dummy_loadmap app_dummy_loadmap;
struct debug *_dl_debug_addr = &debug;
+extern weak hidden char __ehdr_start[];
+
extern hidden int __malloc_replaced;
hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
@@ -204,7 +220,8 @@ static void decode_vec(size_t *v, size_t *a, size_t cnt)
size_t i;
for (i=0; i<cnt; i++) a[i] = 0;
for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
- a[0] |= 1UL<<v[0];
+ if (v[0] < 8*sizeof(long))
+ a[0] |= 1UL<<v[0];
a[v[0]] = v[1];
}
}
@@ -330,6 +347,35 @@ static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
return find_sym2(dso, s, need_def, 0);
}
+static struct symdef get_lfs64(const char *name)
+{
+ const char *p;
+ static const char lfs64_list[] =
+ "aio_cancel\0aio_error\0aio_fsync\0aio_read\0aio_return\0"
+ "aio_suspend\0aio_write\0alphasort\0creat\0fallocate\0"
+ "fgetpos\0fopen\0freopen\0fseeko\0fsetpos\0fstat\0"
+ "fstatat\0fstatfs\0fstatvfs\0ftello\0ftruncate\0ftw\0"
+ "getdents\0getrlimit\0glob\0globfree\0lio_listio\0"
+ "lockf\0lseek\0lstat\0mkostemp\0mkostemps\0mkstemp\0"
+ "mkstemps\0mmap\0nftw\0open\0openat\0posix_fadvise\0"
+ "posix_fallocate\0pread\0preadv\0prlimit\0pwrite\0"
+ "pwritev\0readdir\0scandir\0sendfile\0setrlimit\0"
+ "stat\0statfs\0statvfs\0tmpfile\0truncate\0versionsort\0"
+ "__fxstat\0__fxstatat\0__lxstat\0__xstat\0";
+ if (!strcmp(name, "readdir64_r"))
+ return find_sym(&ldso, "readdir_r", 1);
+ size_t l = strnlen(name, 18);
+ if (l<2 || name[l-2]!='6' || name[l-1]!='4' || name[l])
+ goto nomatch;
+ for (p=lfs64_list; *p; p++) {
+ if (!strncmp(name, p, l-2) && !p[l-2])
+ return find_sym(&ldso, p, 1);
+ while (*p) p++;
+ }
+nomatch:
+ return (struct symdef){ 0 };
+}
+
static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
{
unsigned char *base = dso->base;
@@ -383,6 +429,7 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
def = (sym->st_info>>4) == STB_LOCAL
? (struct symdef){ .dso = dso, .sym = sym }
: find_sym(ctx, name, type==REL_PLT);
+ if (!def.sym) def = get_lfs64(name);
if (!def.sym && (sym->st_shndx != SHN_UNDEF
|| sym->st_info>>4 != STB_WEAK)) {
if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
@@ -415,8 +462,6 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
}
switch(type) {
- case REL_NONE:
- break;
case REL_OFFSET:
addend -= (size_t)reloc_addr;
case REL_SYMBOLIC:
@@ -469,7 +514,7 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
break;
#endif
case REL_TLSDESC:
- if (stride<3) addend = reloc_addr[1];
+ if (stride<3) addend = reloc_addr[!TLSDESC_BACKWARDS];
if (def.dso->tls_id > static_tls_cnt) {
struct td_index *new = malloc(sizeof *new);
if (!new) {
@@ -494,13 +539,13 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
+ addend;
#endif
}
-#ifdef TLSDESC_BACKWARDS
/* Some archs (32-bit ARM at least) invert the order of
* the descriptor members. Fix them up here. */
- size_t tmp = reloc_addr[0];
- reloc_addr[0] = reloc_addr[1];
- reloc_addr[1] = tmp;
-#endif
+ if (TLSDESC_BACKWARDS) {
+ size_t tmp = reloc_addr[0];
+ reloc_addr[0] = reloc_addr[1];
+ reloc_addr[1] = tmp;
+ }
break;
default:
error("Error relocating %s: unsupported relocation type %d",
@@ -511,6 +556,24 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
}
}
+static void do_relr_relocs(struct dso *dso, size_t *relr, size_t relr_size)
+{
+ if (dso == &ldso) return; /* self-relocation was done in _dlstart */
+ unsigned char *base = dso->base;
+ size_t *reloc_addr;
+ for (; relr_size; relr++, relr_size-=sizeof(size_t))
+ if ((relr[0]&1) == 0) {
+ reloc_addr = laddr(dso, relr[0]);
+ *reloc_addr++ += (size_t)base;
+ } else {
+ int i = 0;
+ for (size_t bitmap=relr[0]; (bitmap>>=1); i++)
+ if (bitmap&1)
+ reloc_addr[i] += (size_t)base;
+ reloc_addr += 8*sizeof(size_t)-1;
+ }
+}
+
static void redo_lazy_relocs()
{
struct dso *p = lazy_head, *next;
@@ -553,16 +616,32 @@ static void reclaim_gaps(struct dso *dso)
for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
if (ph->p_type!=PT_LOAD) continue;
if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
+ if (ph->p_memsz == 0) continue;
reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
reclaim(dso, ph->p_vaddr+ph->p_memsz,
ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
}
}
+static ssize_t read_loop(int fd, void *p, size_t n)
+{
+ for (size_t i=0; i<n; ) {
+ ssize_t l = read(fd, (char *)p+i, n-i);
+ if (l<0) {
+ if (errno==EINTR) continue;
+ else return -1;
+ }
+ if (l==0) return i;
+ i += l;
+ }
+ return n;
+}
+
static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
{
static int no_map_fixed;
char *q;
+ if (!n) return p;
if (!no_map_fixed) {
q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
@@ -849,7 +928,7 @@ static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
case ENOENT:
case ENOTDIR:
case EACCES:
- break;
+ return 0;
default:
return -1;
}
@@ -1063,13 +1142,17 @@ static struct dso *load_library(const char *name, struct dso *needed_by)
snprintf(etc_ldso_path, sizeof etc_ldso_path,
"%.*s/etc/ld-musl-" LDSO_ARCH ".path",
(int)prefix_len, prefix);
- FILE *f = fopen(etc_ldso_path, "rbe");
- if (f) {
- if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
+ fd = open(etc_ldso_path, O_RDONLY|O_CLOEXEC);
+ if (fd>=0) {
+ size_t n = 0;
+ if (!fstat(fd, &st)) n = st.st_size;
+ if ((sys_path = malloc(n+1)))
+ sys_path[n] = 0;
+ if (!sys_path || read_loop(fd, sys_path, n)<0) {
free(sys_path);
sys_path = "";
}
- fclose(f);
+ close(fd);
} else if (errno != ENOENT) {
sys_path = "";
}
@@ -1334,13 +1417,17 @@ static void reloc_all(struct dso *p)
2+(dyn[DT_PLTREL]==DT_RELA));
do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
-
- if (head != &ldso && p->relro_start != p->relro_end &&
- mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
- && errno != ENOSYS) {
- error("Error relocating %s: RELRO protection failed: %m",
- p->name);
- if (runtime) longjmp(*rtld_fail, 1);
+ if (!DL_FDPIC)
+ do_relr_relocs(p, laddr(p, dyn[DT_RELR]), dyn[DT_RELRSZ]);
+
+ if (head != &ldso && p->relro_start != p->relro_end) {
+ long ret = __syscall(SYS_mprotect, laddr(p, p->relro_start),
+ p->relro_end-p->relro_start, PROT_READ);
+ if (ret != 0 && ret != -ENOSYS) {
+ error("Error relocating %s: RELRO protection failed: %m",
+ p->name);
+ if (runtime) longjmp(*rtld_fail, 1);
+ }
}
p->relocated = 1;
@@ -1381,7 +1468,7 @@ void __libc_exit_fini()
{
struct dso *p;
size_t dyn[DYN_CNT];
- int self = __pthread_self()->tid;
+ pthread_t self = __pthread_self();
/* Take both locks before setting shutting_down, so that
* either lock is sufficient to read its value. The lock
@@ -1407,6 +1494,17 @@ void __libc_exit_fini()
}
}
+void __ldso_atfork(int who)
+{
+ if (who<0) {
+ pthread_rwlock_wrlock(&lock);
+ pthread_mutex_lock(&init_fini_lock);
+ } else {
+ pthread_mutex_unlock(&init_fini_lock);
+ pthread_rwlock_unlock(&lock);
+ }
+}
+
static struct dso **queue_ctors(struct dso *dso)
{
size_t cnt, qpos, spos, i;
@@ -1465,6 +1563,13 @@ static struct dso **queue_ctors(struct dso *dso)
}
queue[qpos] = 0;
for (i=0; i<qpos; i++) queue[i]->mark = 0;
+ for (i=0; i<qpos; i++)
+ if (queue[i]->ctor_visitor && queue[i]->ctor_visitor->tid < 0) {
+ error("State of %s is inconsistent due to multithreaded fork\n",
+ queue[i]->name);
+ free(queue);
+ if (runtime) longjmp(*rtld_fail, 1);
+ }
return queue;
}
@@ -1473,7 +1578,7 @@ static void do_init_fini(struct dso **queue)
{
struct dso *p;
size_t dyn[DYN_CNT], i;
- int self = __pthread_self()->tid;
+ pthread_t self = __pthread_self();
pthread_mutex_lock(&init_fini_lock);
for (i=0; (p=queue[i]); i++) {
@@ -1582,7 +1687,7 @@ static void install_new_tls(void)
/* Install new dtv for each thread. */
for (j=0, td=self; !j || td!=self; j++, td=td->next) {
- td->dtv = td->dtv_copy = newdtv[j];
+ td->dtv = newdtv[j];
}
__tl_unlock();
@@ -1620,11 +1725,12 @@ hidden void __dls2(unsigned char *base, size_t *sp)
} else {
ldso.base = base;
}
- Ehdr *ehdr = (void *)ldso.base;
+ Ehdr *ehdr = __ehdr_start ? (void *)__ehdr_start : (void *)ldso.base;
ldso.name = ldso.shortname = "libc.so";
ldso.phnum = ehdr->e_phnum;
ldso.phdr = laddr(&ldso, ehdr->e_phoff);
ldso.phentsize = ehdr->e_phentsize;
+ search_vec(auxv, &ldso_page_size, AT_PAGESZ);
kernel_mapped_dso(&ldso);
decode_dyn(&ldso);
@@ -1717,6 +1823,9 @@ void __dls3(size_t *sp, size_t *auxv)
env_preload = getenv("LD_PRELOAD");
}
+ /* Activate error handler function */
+ error = error_impl;
+
/* If the main program was already loaded by the kernel,
* AT_PHDR will point to some location other than the dynamic
* linker's program headers. */
@@ -1792,7 +1901,7 @@ void __dls3(size_t *sp, size_t *auxv)
dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
_exit(1);
}
- Ehdr *ehdr = (void *)map_library(fd, &app);
+ Ehdr *ehdr = map_library(fd, &app);
if (!ehdr) {
dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
_exit(1);
@@ -1884,6 +1993,10 @@ void __dls3(size_t *sp, size_t *auxv)
size_t *ptr = (size_t *) app.dynv[i+1];
*ptr = (size_t)&debug;
}
+ if (app.dynv[i]==DT_DEBUG_INDIRECT_REL) {
+ size_t *ptr = (size_t *)((size_t)&app.dynv[i] + app.dynv[i+1]);
+ *ptr = (size_t)&debug;
+ }
}
/* This must be done before final relocations, since it calls
@@ -1938,6 +2051,8 @@ void __dls3(size_t *sp, size_t *auxv)
* possibility of incomplete replacement. */
if (find_sym(head, "malloc", 1).dso != &ldso)
__malloc_replaced = 1;
+ if (find_sym(head, "aligned_alloc", 1).dso != &ldso)
+ __aligned_alloc_replaced = 1;
/* Switch to runtime mode: any further failures in the dynamic
* linker are a reportable failure rather than a fatal startup
@@ -1948,7 +2063,7 @@ void __dls3(size_t *sp, size_t *auxv)
debug.bp = dl_debug_state;
debug.head = head;
debug.base = ldso.base;
- debug.state = 0;
+ debug.state = RT_CONSISTENT;
_dl_debug_state();
if (replace_argv0) argv[0] = replace_argv0;
@@ -1997,6 +2112,9 @@ void *dlopen(const char *file, int mode)
pthread_rwlock_wrlock(&lock);
__inhibit_ptc();
+ debug.state = RT_ADD;
+ _dl_debug_state();
+
p = 0;
if (shutting_down) {
error("Cannot dlopen while program is exiting.");
@@ -2056,8 +2174,9 @@ void *dlopen(const char *file, int mode)
load_deps(p);
extend_bfs_deps(p);
pthread_mutex_lock(&init_fini_lock);
- if (!p->constructed) ctor_queue = queue_ctors(p);
+ int constructed = p->constructed;
pthread_mutex_unlock(&init_fini_lock);
+ if (!constructed) ctor_queue = queue_ctors(p);
if (!p->relocated && (mode & RTLD_LAZY)) {
prepare_lazy(p);
for (i=0; p->deps[i]; i++)
@@ -2089,9 +2208,10 @@ void *dlopen(const char *file, int mode)
update_tls_size();
if (tls_cnt != orig_tls_cnt)
install_new_tls();
- _dl_debug_state();
orig_tail = tail;
end:
+ debug.state = RT_CONSISTENT;
+ _dl_debug_state();
__release_ptc();
if (p) gencnt++;
pthread_rwlock_unlock(&lock);
@@ -2285,7 +2405,8 @@ int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void
info.dlpi_adds = gencnt;
info.dlpi_subs = 0;
info.dlpi_tls_modid = current->tls_id;
- info.dlpi_tls_data = current->tls.image;
+ info.dlpi_tls_data = !current->tls_id ? 0 :
+ __tls_get_addr((tls_mod_off_t[]){current->tls_id,0});
ret = (callback)(&info, sizeof (info), data);
@@ -2298,7 +2419,7 @@ int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void
return ret;
}
-static void error(const char *fmt, ...)
+static void error_impl(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
@@ -2312,3 +2433,7 @@ static void error(const char *fmt, ...)
__dl_vseterr(fmt, ap);
va_end(ap);
}
+
+static void error_noop(const char *fmt, ...)
+{
+}
generated by cgit v1.2.1 (git 2.18.0) at 2025-10-31 13:09:13 +0000