fix and overhaul dlsym depedency order, always record direct deps

[musl] / ldso / dynlink.c

diff --git a/ldso/dynlink.c b/ldso/dynlink.c
index e499b40..34775b8 100644 (file)
--- a/ldso/dynlink.c
+++ b/ldso/dynlink.c
@@ -71,7 +71,10 @@ struct dso {
        char relocated;
        char constructed;
        char kernel_mapped;
+       char mark;
+       char bfs_built;
        struct dso **deps, *needed_by;
+       size_t ndeps_direct;
        char *rpath_orig, *rpath;
        struct tls_module tls;
        size_t tls_id;
@@ -127,7 +130,6 @@ static size_t static_tls_cnt;
 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 static struct fdpic_loadmap *app_loadmap;
 static struct fdpic_dummy_loadmap app_dummy_loadmap;
-static struct dso *const nodeps_dummy;
 
 struct debug *_dl_debug_addr = &debug;
 
@@ -1140,30 +1142,76 @@ static struct dso *load_library(const char *name, struct dso *needed_by)
        return p;
 }
 
+static void load_direct_deps(struct dso *p)
+{
+       size_t i, cnt;
+       if (p->deps) return;
+       for (i=cnt=0; p->dynv[i]; i+=2)
+               if (p->dynv[i] == DT_NEEDED) cnt++;
+       p->deps = calloc(cnt+1, sizeof *p->deps);
+       if (!p->deps) {
+               error("Error loading dependencies for %s", p->name);
+               if (runtime) longjmp(*rtld_fail, 1);
+       }
+       for (i=cnt=0; p->dynv[i]; i+=2) {
+               if (p->dynv[i] != DT_NEEDED) continue;
+               struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
+               if (!dep) {
+                       error("Error loading shared library %s: %m (needed by %s)",
+                               p->strings + p->dynv[i+1], p->name);
+                       if (runtime) longjmp(*rtld_fail, 1);
+                       continue;
+               }
+               p->deps[cnt++] = dep;
+               p->deps[cnt] = 0;
+       }
+       p->ndeps_direct = cnt;
+}
+
 static void load_deps(struct dso *p)
 {
-       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;
-                       dep = load_library(p->strings + p->dynv[i+1], p);
-                       if (!dep) {
-                               error("Error loading shared library %s: %m (needed by %s)",
-                                       p->strings + p->dynv[i+1], p->name);
-                               if (runtime) longjmp(*rtld_fail, 1);
-                               continue;
-                       }
-                       if (runtime) {
-                               tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
-                               if (!tmp) longjmp(*rtld_fail, 1);
-                               tmp[ndeps++] = dep;
-                               tmp[ndeps] = 0;
-                               *deps = tmp;
-                       }
+       if (p->deps) return;
+       for (; p; p=p->next)
+               load_direct_deps(p);
+}
+
+static void extend_bfs_deps(struct dso *p)
+{
+       size_t i, j, cnt, ndeps_all;
+       struct dso **tmp;
+
+       if (p->bfs_built) return;
+       ndeps_all = p->ndeps_direct;
+
+       /* Mark existing (direct) deps so they won't be duplicated. */
+       for (i=0; p->deps[i]; i++)
+               p->deps[i]->mark = 1;
+
+       /* For each dependency already in the list, copy its list of direct
+        * dependencies to the list, excluding any items already in the
+        * list. Note that the list this loop iterates over will grow during
+        * the loop, but since duplicates are excluded, growth is bounded. */
+       for (i=0; p->deps[i]; i++) {
+               struct dso *dep = p->deps[i];
+               for (j=cnt=0; j<dep->ndeps_direct; j++)
+                       if (!dep->deps[j]->mark) cnt++;
+               tmp = realloc(p->deps, sizeof(*p->deps) * (ndeps_all+cnt+1));
+               if (!tmp) {
+                       error("Error recording dependencies for %s", p->name);
+                       if (runtime) longjmp(*rtld_fail, 1);
+                       continue;
                }
+               p->deps = tmp;
+               for (j=0; j<dep->ndeps_direct; j++) {
+                       if (dep->deps[j]->mark) continue;
+                       dep->deps[j]->mark = 1;
+                       p->deps[ndeps_all++] = dep->deps[j];
+               }
+               p->deps[ndeps_all] = 0;
        }
-       if (!*deps) *deps = (struct dso **)&nodeps_dummy;
+       p->bfs_built = 1;
+       for (p=head; p; p=p->next)
+               p->mark = 0;
 }
 
 static void load_preload(char *s)
@@ -1816,8 +1864,7 @@ void *dlopen(const char *file, int mode)
                        free(p->funcdescs);
                        if (p->rpath != p->rpath_orig)
                                free(p->rpath);
-                       if (p->deps != &nodeps_dummy)
-                               free(p->deps);
+                       free(p->deps);
                        unmap_library(p);
                        free(p);
                }
@@ -1843,24 +1890,22 @@ void *dlopen(const char *file, int mode)
        }
 
        /* First load handling */
-       int first_load = !p->deps;
-       if (first_load) {
-               load_deps(p);
-               if (!p->relocated && (mode & RTLD_LAZY)) {
-                       prepare_lazy(p);
-                       for (i=0; p->deps[i]; i++)
-                               if (!p->deps[i]->relocated)
-                                       prepare_lazy(p->deps[i]);
-               }
+       load_deps(p);
+       extend_bfs_deps(p);
+       if (!p->relocated && (mode & RTLD_LAZY)) {
+               prepare_lazy(p);
+               for (i=0; p->deps[i]; i++)
+                       if (!p->deps[i]->relocated)
+                               prepare_lazy(p->deps[i]);
        }
-       if (first_load || (mode & RTLD_GLOBAL)) {
+       if (!p->relocated || (mode & RTLD_GLOBAL)) {
                /* Make new symbols global, at least temporarily, so we can do
                 * relocations. If not RTLD_GLOBAL, this is reverted below. */
                add_syms(p);
                for (i=0; p->deps[i]; i++)
                        add_syms(p->deps[i]);
        }
-       if (first_load) {
+       if (!p->relocated) {
                reloc_all(p);
        }