add support for init_array/fini_array ctors/dtors to dynamic linker

[musl] / src / ldso / dynlink.c

diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index d197473..dbf404e 100644 (file)
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -309,7 +309,7 @@ static void *map_library(int fd, struct dso *dso)
        size_t this_min, this_max;
        off_t off_start;
        Ehdr *eh;
-       Phdr *ph;
+       Phdr *ph, *ph0;
        unsigned prot;
        unsigned char *map, *base;
        size_t dyn;
@@ -324,11 +324,10 @@ static void *map_library(int fd, struct dso *dso)
        if (eh->e_phoff + phsize > l) {
                l = pread(fd, buf+1, phsize, eh->e_phoff);
                if (l != phsize) return 0;
-               eh->e_phoff = sizeof *eh;
+               ph = ph0 = (void *)(buf + 1);
+       } else {
+               ph = ph0 = (void *)((char *)buf + eh->e_phoff);
        }
-       ph = (void *)((char *)buf + eh->e_phoff);
-       dso->phdr = ph;
-       dso->phnum = eh->e_phnum;
        for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
                if (ph->p_type == PT_DYNAMIC)
                        dyn = ph->p_vaddr;
@@ -363,9 +362,18 @@ static void *map_library(int fd, struct dso *dso)
        map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
        if (map==MAP_FAILED) return 0;
        base = map - addr_min;
-       ph = (void *)((char *)buf + eh->e_phoff);
-       for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
+       dso->phdr = 0;
+       dso->phnum = 0;
+       for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
                if (ph->p_type != PT_LOAD) continue;
+               /* Check if the programs headers are in this load segment, and
+                * if so, record the address for use by dl_iterate_phdr. */
+               if (!dso->phdr && eh->e_phoff >= ph->p_offset
+                   && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
+                       dso->phdr = (void *)(base + ph->p_vaddr
+                               + (eh->e_phoff-ph->p_offset));
+                       dso->phnum = eh->e_phnum;
+               }
                /* Reuse the existing mapping for the lowest-address LOAD */
                if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
                this_min = ph->p_vaddr & -PAGE_SIZE;
@@ -390,8 +398,7 @@ static void *map_library(int fd, struct dso *dso)
                                goto error;
                        break;
                }
-       if (!runtime) reclaim_gaps(base, (void *)((char *)buf + eh->e_phoff),
-               eh->e_phentsize, eh->e_phnum);
+       if (!runtime) reclaim_gaps(base, ph0, eh->e_phentsize, eh->e_phnum);
        dso->map = map;
        dso->map_len = map_len;
        dso->base = base;
@@ -476,7 +483,26 @@ static struct dso *load_library(const char *name)
                if (fd < 0 && env_path) fd = path_open(name, env_path, buf, sizeof buf);
                if (fd < 0) {
                        if (!sys_path) {
-                               FILE *f = fopen(ETC_LDSO_PATH, "rbe");
+                               char *prefix = 0;
+                               size_t prefix_len;
+                               if (ldso->name[0]=='/') {
+                                       char *s, *t, *z;
+                                       for (s=t=z=ldso->name; *s; s++)
+                                               if (*s=='/') z=t, t=s;
+                                       prefix_len = z-ldso->name;
+                                       if (prefix_len < PATH_MAX)
+                                               prefix = ldso->name;
+                               }
+                               if (!prefix) {
+                                       prefix = "";
+                                       prefix_len = 0;
+                               }
+                               char etc_ldso_path[prefix_len + 1
+                                       + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
+                               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) {
                                                free(sys_path);
@@ -670,7 +696,13 @@ static void do_fini()
        for (p=fini_head; p; p=p->fini_next) {
                if (!p->constructed) continue;
                decode_vec(p->dynv, dyn, DYN_CNT);
-               ((void (*)(void))(p->base + dyn[DT_FINI]))();
+               if (dyn[0] & (1<<DT_FINI_ARRAY)) {
+                       size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
+                       size_t *fn = (void *)(p->base + dyn[DT_FINI_ARRAY]);
+                       while (n--) ((void (*)(void))*fn++)();
+               }
+               if (dyn[0] & (1<<DT_FINI))
+                       ((void (*)(void))(p->base + dyn[DT_FINI]))();
        }
 }
 
@@ -686,12 +718,21 @@ static void do_init_fini(struct dso *p)
                if (p->constructed) continue;
                p->constructed = 1;
                decode_vec(p->dynv, dyn, DYN_CNT);
-               if (dyn[0] & (1<<DT_FINI)) {
+               if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
                        p->fini_next = fini_head;
                        fini_head = p;
                }
                if (dyn[0] & (1<<DT_INIT))
                        ((void (*)(void))(p->base + dyn[DT_INIT]))();
+               if (dyn[0] & (1<<DT_INIT_ARRAY)) {
+                       size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
+                       size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
+                       while (n--) ((void (*)(void))*fn++)();
+               }
+               if (!need_locking && libc.threads_minus_1) {
+                       need_locking = 1;
+                       pthread_mutex_lock(&init_fini_lock);
+               }
        }
        if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 }
@@ -1269,6 +1310,18 @@ int __dladdr (void *addr, Dl_info *info)
 }
 #endif
 
+int __dlinfo(void *dso, int req, void *res)
+{
+       if (invalid_dso_handle(dso)) return -1;
+       if (req != RTLD_DI_LINKMAP) {
+               snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
+               errflag = 1;
+               return -1;
+       }
+       *(struct link_map **)res = dso;
+       return 0;
+}
+
 char *dlerror()
 {
        if (!errflag) return 0;