#include <errno.h>
#include <limits.h>
#include <elf.h>
+#include <setjmp.h>
+#include <pthread.h>
+#include <dlfcn.h>
#include "reloc.h"
ino_t ino;
int global;
int relocated;
- char name[];
+ struct dso **deps;
+ char *name;
+ char buf[];
};
static struct dso *head, *tail, *libc;
-static int trust_env;
+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
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;
sym = syms + sym_index;
name = strings + sym->st_name;
ctx = IS_COPY(type) ? dso->next : dso;
- sym_val = (size_t)find_sym(ctx, name, 1);
+ sym_val = (size_t)find_sym(ctx, name, IS_PLT(type));
+ if (!sym_val && sym->st_info>>4 != STB_WEAK) {
+ if (runtime) longjmp(rtld_fail, 1);
+ dprintf(2, "%s: symbol not found\n", name);
+ _exit(127);
+ }
sym_size = sym->st_size;
}
do_single_reloc(reloc_addr, type, sym_val, sym_size, base, rel[2]);
static void *map_library(int fd, size_t *lenp, unsigned char **basep, size_t *dynp)
{
- size_t buf[896/sizeof(size_t)];
+ Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
size_t phsize;
size_t addr_min=SIZE_MAX, addr_max=0, map_len;
size_t this_min, this_max;
ssize_t l = read(fd, buf, sizeof buf);
if (l<sizeof *eh) return 0;
- eh = (void *)buf;
+ eh = buf;
phsize = eh->e_phentsize * eh->e_phnum;
if (phsize + sizeof *eh > l) return 0;
if (eh->e_phoff + phsize > l) {
- l = pread(fd, buf+sizeof *eh, phsize, eh->e_phoff);
+ l = pread(fd, buf+1, phsize, eh->e_phoff);
if (l != phsize) return 0;
eh->e_phoff = sizeof *eh;
}
return map;
}
+static int path_open(const char *name, const char *search)
+{
+ char buf[2*NAME_MAX+2];
+ const char *s=search, *z;
+ int l, fd;
+ for (;;) {
+ while (*s==':') s++;
+ if (!*s) return -1;
+ z = strchr(s, ':');
+ l = z ? z-s : strlen(s);
+ snprintf(buf, sizeof buf, "%.*s/%s", l, s, name);
+ if ((fd = open(buf, O_RDONLY))>=0) return fd;
+ s += l;
+ }
+}
+
static struct dso *load_library(const char *name)
{
unsigned char *base, *map;
return p;
}
}
- if (name[0] == '/') {
+ if (strchr(name, '/')) {
fd = open(name, O_RDONLY);
} else {
- static const char path[] = "/lib/\0/usr/local/lib/\0/usr/lib/\0";
- const char *s;
- char buf[NAME_MAX+32];
- if (strlen(name) > NAME_MAX || strchr(name, '/')) return 0;
- for (s=path; *s; s+=strlen(s)+1) {
- strcpy(buf, s);
- strcat(buf, name);
- if ((fd = open(buf, O_RDONLY))>=0) break;
+ if (strlen(name) > NAME_MAX) return 0;
+ fd = -1;
+ if (env_path) fd = path_open(name, env_path);
+ if (fd < 0) {
+ if (!sys_path) {
+ FILE *f = fopen(ETC_LDSO_PATH, "r");
+ if (f) {
+ if (getline(&sys_path, (size_t[1]){0}, f) > 0)
+ sys_path[strlen(sys_path)-1]=0;
+ fclose(f);
+ }
+ }
+ if (sys_path) fd = path_open(name, sys_path);
+ else fd = path_open(name, "/lib:/usr/local/lib:/usr/lib");
}
}
if (fd < 0) return 0;
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);
tail->next = p;
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;
- 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};
if (p->relocated) continue;
decode_vec(p->dynv, dyn, DYN_CNT);
do_relocs(p->base, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
- 2+(dyn[DT_PLTREL]==DT_RELA), p->syms, p->strings, p);
+ 2+(dyn[DT_PLTREL]==DT_RELA), p->syms, p->strings, head);
do_relocs(p->base, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ],
- 2, p->syms, p->strings, p);
+ 2, p->syms, p->strings, head);
do_relocs(p->base, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ],
- 3, p->syms, p->strings, p);
+ 3, p->syms, p->strings, head);
p->relocated = 1;
}
}
+static void free_all(struct dso *p)
+{
+ struct dso *n;
+ while (p) {
+ n = p->next;
+ if (p->map) free(p);
+ p = n;
+ }
+}
+
void *__dynlink(int argc, char **argv, size_t *got)
{
size_t *auxv, aux[AUX_CNT] = {0};
struct dso lib, app;
/* Find aux vector just past environ[] */
- for (i=argc+1; argv[i]; i++);
+ for (i=argc+1; argv[i]; i++)
+ if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
+ env_path = argv[i]+16;
auxv = (void *)(argv+i+1);
decode_vec(auxv, aux, AUX_CNT);
+ /* Only trust user/env if kernel says we're not suid/sgid */
+ if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
+ || aux[AT_GID]!=aux[AT_EGID]) {
+ env_path = 0;
+ }
+
/* Relocate ldso's DYNAMIC pointer and load vector */
decode_vec((void *)(got[0] += aux[AT_BASE]), lib_dyn, DYN_CNT);
.hashtab = (void *)(app_dyn[DT_HASH]),
.syms = (void *)(app_dyn[DT_SYMTAB]),
.dynv = (void *)(phdr->p_vaddr),
+ .name = argv[0],
+ .global = 1,
.next = &lib
};
.hashtab = (void *)(aux[AT_BASE]+lib_dyn[DT_HASH]),
.syms = (void *)(aux[AT_BASE]+lib_dyn[DT_SYMTAB]),
.dynv = (void *)(got[0]),
+ .name = "libc.so",
+ .global = 1,
.relocated = 1
};
/* At this point the standard library is fully functional */
- /* Only trust user/env if kernel says we're not suid/sgid */
- trust_env = (aux[0]&0x7800)==0x7800
- && aux[AT_UID]==aux[AT_EUID]
- && aux[AT_GID]==aux[AT_EGID];
-
head = tail = &app;
libc = &lib;
app.next = 0;
load_deps(head);
+ make_global(head);
reloc_all(head);
+ 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 */
+ if (p->deps) for (i=0; p->deps[i]; i++)
+ if (p->deps[i]->global < 0)
+ p->deps[i]->global = 0;
+ 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);
+ for (i=0; p->deps[i]; i++)
+ if (!p->deps[i]->global)
+ p->deps[i]->global = -1;
+ if (!p->global) p->global = -1;
+ reloc_all(p);
+ for (i=0; p->deps[i]; i++)
+ if (p->deps[i]->global < 0)
+ p->deps[i]->global = 0;
+ if (p->global < 0) p->global = 0;
+ }
+
+ 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;
+}
projects / musl / blobdiff