add support for RTLD_NOLOAD to dlopen

[musl] / src / ldso / dynlink.c

diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 66f22be..b1a4409 100644 (file)
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -99,6 +99,7 @@ static int ssp_used;
 static int runtime;
 static int ldd_mode;
 static int ldso_fail;
+static int noload;
 static jmp_buf rtld_fail;
 static pthread_rwlock_t lock;
 static struct debug debug;
@@ -433,7 +434,7 @@ static struct dso *load_library(const char *name)
 {
        char buf[2*NAME_MAX+2];
        const char *pathname;
-       unsigned char *base, *map;
+       unsigned char *map;
        size_t map_len;
        struct dso *p, temp_dso = {0};
        int fd;
@@ -508,7 +509,7 @@ static struct dso *load_library(const char *name)
                        return p;
                }
        }
-       map = map_library(fd, &temp_dso);
+       map = noload ? 0 : map_library(fd, &temp_dso);
        close(fd);
        if (!map) return 0;
 
@@ -566,7 +567,7 @@ static struct dso *load_library(const char *name)
        p->prev = tail;
        tail = p;
 
-       if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, base);
+       if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 
        return p;
 }
@@ -927,7 +928,8 @@ void *__dynlink(int argc, char **argv)
                        if (phdr->p_type == PT_LOAD)
                                vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
                }
-               vdso->name = vdso->shortname = "linux-gate.so.1";
+               vdso->name = "";
+               vdso->shortname = "linux-gate.so.1";
                vdso->global = 1;
                decode_dyn(vdso);
                vdso->prev = lib;
@@ -998,13 +1000,16 @@ void *__dynlink(int argc, char **argv)
 
        if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
 
-       atexit(do_fini);
-       do_init_fini(tail);
-
        errno = 0;
        return (void *)aux[AT_ENTRY];
 }
 
+void __init_ldso_ctors(void)
+{
+       atexit(do_fini);
+       do_init_fini(tail);
+}
+
 void *dlopen(const char *file, int mode)
 {
        struct dso *volatile p, *orig_tail, *next;
@@ -1023,6 +1028,7 @@ void *dlopen(const char *file, int mode)
        orig_tls_offset = tls_offset;
        orig_tls_align = tls_align;
        orig_tail = tail;
+       noload = mode & RTLD_NOLOAD;
 
        if (setjmp(rtld_fail)) {
                /* Clean up anything new that was (partially) loaded */
@@ -1046,8 +1052,10 @@ void *dlopen(const char *file, int mode)
        } else p = load_library(file);
 
        if (!p) {
-               snprintf(errbuf, sizeof errbuf,
-                       "Error loading shared library %s: %m", file);
+               snprintf(errbuf, sizeof errbuf, noload ?
+                       "Library %s is not already loaded" :
+                       "Error loading shared library %s: %m",
+                       file);
                errflag = 1;
                goto end;
        }
@@ -1087,6 +1095,15 @@ end:
        return p;
 }
 
+static int invalid_dso_handle(void *h)
+{
+       struct dso *p;
+       for (p=head; p; p=p->next) if (h==p) return 0;
+       snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
+       errflag = 1;
+       return 1;
+}
+
 static void *do_dlsym(struct dso *p, const char *s, void *ra)
 {
        size_t i;
@@ -1106,6 +1123,8 @@ static void *do_dlsym(struct dso *p, const char *s, void *ra)
                        return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
                return def.dso->base + def.sym->st_value;
        }
+       if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
+               return 0;
        if (p->ghashtab) {
                gh = gnu_hash(s);
                sym = gnu_lookup(s, gh, p);
@@ -1174,7 +1193,7 @@ int __dladdr(void *addr, Dl_info *info)
        }
 
        for (; nsym; nsym--, sym++) {
-               if (sym->st_shndx && sym->st_value
+               if (sym->st_value
                 && (1<<(sym->st_info&0xf) & OK_TYPES)
                 && (1<<(sym->st_info>>4) & OK_BINDS)) {
                        void *symaddr = p->base + sym->st_value;
@@ -1232,6 +1251,12 @@ int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void
        return ret;
 }
 #else
+static int invalid_dso_handle(void *h)
+{
+       snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
+       errflag = 1;
+       return 1;
+}
 void *dlopen(const char *file, int mode)
 {
        return 0;
@@ -1255,5 +1280,5 @@ char *dlerror()
 
 int dlclose(void *p)
 {
-       return 0;
+       return invalid_dso_handle(p);
 }