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-rw-r--r--src/ldso/dynlink.c133
1 files changed, 125 insertions, 8 deletions
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 03f09208..35ff9626 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -13,6 +13,8 @@
#include <limits.h>
#include <elf.h>
#include <setjmp.h>
+#include <pthread.h>
+#include <dlfcn.h>
#include "reloc.h"
@@ -45,14 +47,17 @@ struct dso
ino_t ino;
int global;
int relocated;
+ struct dso **deps;
char *name;
char buf[];
};
static struct dso *head, *tail, *libc;
static char *env_path, *sys_path;
+static int rtld_used;
static int runtime;
static jmp_buf rtld_fail;
+static pthread_rwlock_t lock;
#define AUX_CNT 15
#define DYN_CNT 34
@@ -91,8 +96,12 @@ static Sym *lookup(const char *s, uint32_t h, Sym *syms, uint32_t *hashtab, char
static void *find_sym(struct dso *dso, const char *s, int need_def)
{
uint32_t h = hash(s);
+ if (h==0x6b366be && !strcmp(s, "dlopen")) rtld_used = 1;
+ if (h==0x6b3afd && !strcmp(s, "dlsym")) rtld_used = 1;
for (; dso; dso=dso->next) {
- Sym *sym = lookup(s, h, dso->syms, dso->hashtab, dso->strings);
+ Sym *sym;
+ if (!dso->global) continue;
+ sym = lookup(s, h, dso->syms, dso->hashtab, dso->strings);
if (sym && (!need_def || sym->st_shndx) && sym->st_value
&& (1<<(sym->st_info&0xf) & OK_TYPES))
return dso->base + sym->st_value;
@@ -264,10 +273,10 @@ static struct dso *load_library(const char *name)
return p;
}
}
- if (name[0] == '/') {
+ if (strchr(name, '/')) {
fd = open(name, O_RDONLY);
} else {
- if (strlen(name) > NAME_MAX || strchr(name, '/')) return 0;
+ if (strlen(name) > NAME_MAX) return 0;
fd = -1;
if (env_path) fd = path_open(name, env_path);
if (fd < 0) {
@@ -315,7 +324,6 @@ static struct dso *load_library(const char *name)
p->strings = (void *)(base + dyn[DT_STRTAB]);
p->dev = st.st_dev;
p->ino = st.st_ino;
- p->global = 1;
p->refcnt = 1;
p->name = p->buf;
strcpy(p->name, name);
@@ -329,20 +337,34 @@ static struct dso *load_library(const char *name)
static void load_deps(struct dso *p)
{
- size_t i;
+ size_t i, ndeps=0;
+ struct dso ***deps = &p->deps, **tmp, *dep;
for (; p; p=p->next) {
for (i=0; p->dynv[i]; i+=2) {
if (p->dynv[i] != DT_NEEDED) continue;
- if (!load_library(p->strings + p->dynv[i+1])) {
+ dep = load_library(p->strings + p->dynv[i+1]);
+ if (!dep) {
if (runtime) longjmp(rtld_fail, 1);
dprintf(2, "%s: %m (needed by %s)\n",
p->strings + p->dynv[i+1], p->name);
_exit(127);
}
+ if (runtime) {
+ tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
+ if (!tmp) longjmp(rtld_fail, 1);
+ tmp[ndeps++] = dep;
+ tmp[ndeps] = 0;
+ *deps = tmp;
+ }
}
}
}
+static void make_global(struct dso *p)
+{
+ for (; p; p=p->next) p->global = 1;
+}
+
static void reloc_all(struct dso *p)
{
size_t dyn[DYN_CNT] = {0};
@@ -411,6 +433,7 @@ void *__dynlink(int argc, char **argv, size_t *got)
.syms = (void *)(app_dyn[DT_SYMTAB]),
.dynv = (void *)(phdr->p_vaddr),
.name = argv[0],
+ .global = 1,
.next = &lib
};
@@ -421,6 +444,7 @@ void *__dynlink(int argc, char **argv, size_t *got)
.syms = (void *)(aux[AT_BASE]+lib_dyn[DT_SYMTAB]),
.dynv = (void *)(got[0]),
.name = "libc.so",
+ .global = 1,
.relocated = 1
};
@@ -437,11 +461,104 @@ void *__dynlink(int argc, char **argv, size_t *got)
app.next = 0;
load_deps(head);
+ make_global(head);
reloc_all(head);
- free_all(head);
- free(sys_path);
+ if (rtld_used) {
+ runtime = 1;
+ head->next->prev = malloc(sizeof *head);
+ *head->next->prev = *head;
+ head = head->next->prev;
+ libc->prev->next = malloc(sizeof *libc);
+ *libc->prev->next = *libc;
+ libc = libc->prev->next;
+ if (libc->next) libc->next->prev = libc;
+ } else {
+ free_all(head);
+ free(sys_path);
+ }
errno = 0;
return (void *)aux[AT_ENTRY];
}
+
+void *dlopen(const char *file, int mode)
+{
+ struct dso *p, *orig_tail = tail, *next;
+ size_t i;
+
+ if (!file) return head;
+
+ pthread_rwlock_wrlock(&lock);
+
+ if (setjmp(rtld_fail)) {
+ /* Clean up anything new that was (partially) loaded */
+ for (p=orig_tail->next; p; p=next) {
+ next = p->next;
+ munmap(p->map, p->map_len);
+ free(p->deps);
+ free(p);
+ }
+ tail = orig_tail;
+ tail->next = 0;
+ pthread_rwlock_unlock(&lock);
+ return 0;
+ }
+
+ p = load_library(file);
+ if (!p) return 0;
+
+ /* First load handling */
+ if (!p->deps) {
+ load_deps(p);
+ reloc_all(p);
+ }
+
+ if (mode & RTLD_GLOBAL) {
+ for (i=0; p->deps[i]; i++)
+ p->deps[i]->global = 1;
+ p->global = 1;
+ }
+
+ pthread_rwlock_unlock(&lock);
+
+ return p;
+}
+
+static void *do_dlsym(struct dso *p, const char *s)
+{
+ size_t i;
+ uint32_t h;
+ Sym *sym;
+ if (p == head) return find_sym(head, s, 0);
+ h = hash(s);
+ sym = lookup(s, h, p->syms, p->hashtab, p->strings);
+ if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
+ return p->base + sym->st_value;
+ if (p->deps) for (i=0; p->deps[i]; i++) {
+ sym = lookup(s, h, p->deps[i]->syms,
+ p->deps[i]->hashtab, p->deps[i]->strings);
+ if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
+ return p->deps[i]->base + sym->st_value;
+ }
+ return 0;
+}
+
+void *dlsym(void *p, const char *s)
+{
+ void *res;
+ pthread_rwlock_rdlock(&lock);
+ res = do_dlsym(p, s);
+ pthread_rwlock_unlock(&lock);
+ return res;
+}
+
+char *dlerror()
+{
+ return "unknown error";
+}
+
+int dlclose(void *p)
+{
+ return 0;
+}