#include <elf.h>
#include <setjmp.h>
#include <pthread.h>
+#include <ctype.h>
#include <dlfcn.h>
-#include "reloc.h"
+static int errflag;
+static char errbuf[128];
+
+#ifdef SHARED
#if ULONG_MAX == 0xffffffff
typedef Elf32_Ehdr Ehdr;
#define R_SYM(x) ((x)>>32)
#endif
-struct dso
-{
+struct debug {
+ int ver;
+ void *head;
+ void (*bp)(void);
+ int state;
+ void *base;
+};
+
+struct dso {
+ unsigned char *base;
+ char *name;
+ size_t *dynv;
struct dso *next, *prev;
+
int refcnt;
- size_t *dynv;
Sym *syms;
uint32_t *hashtab;
+ uint32_t *ghashtab;
char *strings;
- unsigned char *base;
unsigned char *map;
size_t map_len;
dev_t dev;
ino_t ino;
- int global;
- int relocated;
+ signed char global;
+ char relocated;
+ char constructed;
struct dso **deps;
- char *name;
+ char *shortname;
char buf[];
};
+#include "reloc.h"
+
+void __init_ssp(size_t *);
+
static struct dso *head, *tail, *libc;
-static char *env_path, *sys_path;
+static char *env_path, *sys_path, *r_path;
static int rtld_used;
+static int ssp_used;
static int runtime;
+static int ldd_mode;
+static int ldso_fail;
static jmp_buf rtld_fail;
static pthread_rwlock_t lock;
+static struct debug debug;
+
+struct debug *_dl_debug_addr = &debug;
-#define AUX_CNT 15
+#define AUX_CNT 24
#define DYN_CNT 34
static void decode_vec(size_t *v, size_t *a, size_t cnt)
}
}
-static uint32_t hash(const char *s)
+static int search_vec(size_t *v, size_t *r, size_t key)
{
+ for (; v[0]!=key; v+=2)
+ if (!v[0]) return 0;
+ *r = v[1];
+ return 1;
+}
+
+static uint32_t sysv_hash(const char *s0)
+{
+ const unsigned char *s = (void *)s0;
uint_fast32_t h = 0;
while (*s) {
h = 16*h + *s++;
return h & 0xfffffff;
}
-static Sym *lookup(const char *s, uint32_t h, Sym *syms, uint32_t *hashtab, char *strings)
+static uint32_t gnu_hash(const char *s0)
+{
+ const unsigned char *s = (void *)s0;
+ uint_fast32_t h = 5381;
+ for (; *s; s++)
+ h = h*33 + *s;
+ return h;
+}
+
+static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
{
size_t i;
+ Sym *syms = dso->syms;
+ uint32_t *hashtab = dso->hashtab;
+ char *strings = dso->strings;
for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
if (!strcmp(s, strings+syms[i].st_name))
return syms+i;
return 0;
}
+static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
+{
+ Sym *sym;
+ char *strings;
+ uint32_t *hashtab = dso->ghashtab;
+ uint32_t nbuckets = hashtab[0];
+ uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
+ uint32_t h2;
+ uint32_t *hashval;
+ uint32_t n = buckets[h1 % nbuckets];
+
+ if (!n) return 0;
+
+ strings = dso->strings;
+ sym = dso->syms + n;
+ hashval = buckets + nbuckets + (n - hashtab[1]);
+
+ for (h1 |= 1; ; sym++) {
+ h2 = *hashval++;
+ if ((h1 == (h2|1)) && !strcmp(s, strings + sym->st_name))
+ return sym;
+ if (h2 & 1) break;
+ }
+
+ return 0;
+}
+
#define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON)
+#define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK)
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;
+ uint32_t h = 0, gh = 0;
+ void *def = 0;
+ if (dso->ghashtab) {
+ gh = gnu_hash(s);
+ if (gh == 0xf9040207 && !strcmp(s, "dlopen")) rtld_used = 1;
+ if (gh == 0xf4dc4ae && !strcmp(s, "dlsym")) rtld_used = 1;
+ if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
+ } else {
+ h = sysv_hash(s);
+ if (h == 0x6b366be && !strcmp(s, "dlopen")) rtld_used = 1;
+ if (h == 0x6b3afd && !strcmp(s, "dlsym")) rtld_used = 1;
+ if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
+ }
for (; dso; dso=dso->next) {
Sym *sym;
if (!dso->global) continue;
- sym = lookup(s, h, dso->syms, dso->hashtab, dso->strings);
+ if (dso->ghashtab) {
+ if (!gh) gh = gnu_hash(s);
+ sym = gnu_lookup(s, gh, dso);
+ } else {
+ if (!h) h = sysv_hash(s);
+ sym = sysv_lookup(s, h, dso);
+ }
if (sym && (!need_def || sym->st_shndx) && sym->st_value
- && (1<<(sym->st_info&0xf) & OK_TYPES))
- return dso->base + sym->st_value;
+ && (1<<(sym->st_info&0xf) & OK_TYPES)
+ && (1<<(sym->st_info>>4) & OK_BINDS)) {
+ if (def && sym->st_info>>4 == STB_WEAK) continue;
+ def = dso->base + sym->st_value;
+ if (sym->st_info>>4 == STB_GLOBAL) break;
+ }
}
- return 0;
+ return def;
}
-static void do_relocs(unsigned char *base, size_t *rel, size_t rel_size, size_t stride, Sym *syms, char *strings, struct dso *dso)
+static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
{
+ unsigned char *base = dso->base;
+ Sym *syms = dso->syms;
+ char *strings = dso->strings;
Sym *sym;
const char *name;
size_t sym_val, sym_size;
if (sym_index) {
sym = syms + sym_index;
name = strings + sym->st_name;
- ctx = IS_COPY(type) ? dso->next : dso;
+ ctx = IS_COPY(type) ? head->next : head;
sym_val = (size_t)find_sym(ctx, name, IS_PLT(type));
if (!sym_val && sym->st_info>>4 != STB_WEAK) {
+ snprintf(errbuf, sizeof errbuf,
+ "Error relocating %s: %s: symbol not found",
+ dso->name, name);
if (runtime) longjmp(rtld_fail, 1);
- dprintf(2, "%s: symbol not found\n", name);
- _exit(127);
+ dprintf(2, "%s\n", errbuf);
+ ldso_fail = 1;
+ continue;
}
sym_size = sym->st_size;
+ } else {
+ sym_val = sym_size = 0;
}
do_single_reloc(reloc_addr, type, sym_val, sym_size, base, rel[2]);
}
}
+/* A huge hack: to make up for the wastefulness of shared libraries
+ * needing at least a page of dirty memory even if they have no global
+ * data, we reclaim the gaps at the beginning and end of writable maps
+ * and "donate" them to the heap by setting up minimal malloc
+ * structures and then freeing them. */
+
+static void reclaim(unsigned char *base, size_t start, size_t end)
+{
+ size_t *a, *z;
+ start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
+ end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
+ if (start>end || end-start < 4*sizeof(size_t)) return;
+ a = (size_t *)(base + start);
+ z = (size_t *)(base + end);
+ a[-2] = 1;
+ a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
+ z[1] = 1;
+ free(a);
+}
+
+static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
+{
+ for (; phcnt--; ph=(void *)((char *)ph+phent)) {
+ if (ph->p_type!=PT_LOAD) continue;
+ if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
+ reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
+ reclaim(base, ph->p_vaddr+ph->p_memsz,
+ ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
+ }
+}
+
static void *map_library(int fd, size_t *lenp, unsigned char **basep, size_t *dynp)
{
Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
* the length of the file. This is okay because we will not
* use the invalid part; we just need to reserve the right
* amount of virtual address space to map over later. */
- map = mmap(0, map_len, prot, MAP_PRIVATE, fd, off_start);
+ 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);
prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
((ph->p_flags&PF_X) ? PROT_EXEC : 0));
- if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED) {
- munmap(map, map_len);
- return 0;
- }
+ if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
+ goto error;
if (ph->p_memsz > ph->p_filesz) {
size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
- if (pgbrk-(size_t)base < this_max && mmap((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED) {
- munmap(map, map_len);
- return 0;
- }
+ if (pgbrk-(size_t)base < this_max && mmap((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
+ goto error;
}
}
+ for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
+ if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
+ if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
+ goto error;
+ break;
+ }
+ if (!runtime) reclaim_gaps(base, (void *)((char *)buf + eh->e_phoff),
+ eh->e_phentsize, eh->e_phnum);
*lenp = map_len;
*basep = base;
*dynp = dyn;
return map;
+error:
+ munmap(map, map_len);
+ return 0;
}
-static int path_open(const char *name, const char *search)
+static int path_open(const char *name, const char *search, char *buf, size_t buf_size)
{
- char buf[2*NAME_MAX+2];
const char *s=search, *z;
int l, fd;
for (;;) {
if (!*s) return -1;
z = strchr(s, ':');
l = z ? z-s : strlen(s);
- snprintf(buf, sizeof buf, "%.*s/%s", l, s, name);
+ snprintf(buf, buf_size, "%.*s/%s", l, s, name);
if ((fd = open(buf, O_RDONLY))>=0) return fd;
s += l;
}
}
+static void decode_dyn(struct dso *p)
+{
+ size_t dyn[DYN_CNT] = {0};
+ decode_vec(p->dynv, dyn, DYN_CNT);
+ p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
+ p->strings = (void *)(p->base + dyn[DT_STRTAB]);
+ if (dyn[0]&(1<<DT_HASH))
+ p->hashtab = (void *)(p->base + dyn[DT_HASH]);
+ if (search_vec(p->dynv, dyn, DT_GNU_HASH))
+ p->ghashtab = (void *)(p->base + *dyn);
+}
+
static struct dso *load_library(const char *name)
{
+ char buf[2*NAME_MAX+2];
+ const char *pathname;
unsigned char *base, *map;
size_t dyno, map_len;
struct dso *p;
- size_t dyn[DYN_CNT] = {0};
int fd;
struct stat st;
if (!libc->prev) {
tail->next = libc;
libc->prev = tail;
- tail = libc;
+ tail = libc->next ? libc->next : libc;
}
return libc;
}
}
}
- /* Search for the name to see if it's already loaded */
- for (p=head->next; p; p=p->next) {
- if (!strcmp(p->name, name)) {
- p->refcnt++;
- return p;
- }
- }
if (strchr(name, '/')) {
+ pathname = name;
fd = open(name, O_RDONLY);
} else {
+ /* Search for the name to see if it's already loaded */
+ for (p=head->next; p; p=p->next) {
+ if (p->shortname && !strcmp(p->shortname, name)) {
+ p->refcnt++;
+ return p;
+ }
+ }
if (strlen(name) > NAME_MAX) return 0;
fd = -1;
- if (env_path) fd = path_open(name, env_path);
+ if (r_path) fd = path_open(name, r_path, buf, sizeof buf);
+ 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, "r");
fclose(f);
}
}
- if (sys_path) fd = path_open(name, sys_path);
- else fd = path_open(name, "/lib:/usr/local/lib:/usr/lib");
+ if (sys_path) fd = path_open(name, sys_path, buf, sizeof buf);
+ else fd = path_open(name, "/lib:/usr/local/lib:/usr/lib", buf, sizeof buf);
}
+ pathname = buf;
}
if (fd < 0) return 0;
if (fstat(fd, &st) < 0) {
}
for (p=head->next; p; p=p->next) {
if (p->dev == st.st_dev && p->ino == st.st_ino) {
+ /* If this library was previously loaded with a
+ * pathname but a search found the same inode,
+ * setup its shortname so it can be found by name. */
+ if (!p->shortname) p->shortname = strrchr(p->name, '/')+1;
close(fd);
p->refcnt++;
return p;
map = map_library(fd, &map_len, &base, &dyno);
close(fd);
if (!map) return 0;
- p = calloc(1, sizeof *p + strlen(name) + 1);
+ p = calloc(1, sizeof *p + strlen(pathname) + 1);
if (!p) {
munmap(map, map_len);
return 0;
p->map_len = map_len;
p->base = base;
p->dynv = (void *)(base + dyno);
- decode_vec(p->dynv, dyn, DYN_CNT);
+ decode_dyn(p);
- p->syms = (void *)(base + dyn[DT_SYMTAB]);
- p->hashtab = (void *)(base + dyn[DT_HASH]);
- p->strings = (void *)(base + dyn[DT_STRTAB]);
p->dev = st.st_dev;
p->ino = st.st_ino;
p->refcnt = 1;
p->name = p->buf;
- strcpy(p->name, name);
+ strcpy(p->name, pathname);
+ /* Add a shortname only if name arg was not an explicit pathname. */
+ if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
tail->next = p;
p->prev = tail;
tail = p;
+ if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, base);
+
return 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_RPATH) continue;
+ r_path = (void *)(p->strings + p->dynv[i+1]);
+ }
for (i=0; p->dynv[i]; i+=2) {
if (p->dynv[i] != DT_NEEDED) continue;
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",
+ snprintf(errbuf, sizeof errbuf,
+ "Error loading shared library %s: %m (needed by %s)",
p->strings + p->dynv[i+1], p->name);
- _exit(127);
+ if (runtime) longjmp(rtld_fail, 1);
+ dprintf(2, "%s\n", errbuf);
+ ldso_fail = 1;
+ continue;
}
if (runtime) {
tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
*deps = tmp;
}
}
+ r_path = 0;
+ }
+}
+
+static void load_preload(char *s)
+{
+ int tmp;
+ char *z;
+ for (z=s; *z; s=z) {
+ for ( ; *s && isspace(*s); s++);
+ for (z=s; *z && !isspace(*z); z++);
+ tmp = *z;
+ *z = 0;
+ load_library(s);
+ *z = tmp;
}
}
for (; p; p=p->next) {
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, head);
- do_relocs(p->base, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ],
- 2, p->syms, p->strings, head);
- do_relocs(p->base, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ],
- 3, p->syms, p->strings, head);
+#ifdef NEED_ARCH_RELOCS
+ do_arch_relocs(p, head);
+#endif
+ do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
+ 2+(dyn[DT_PLTREL]==DT_RELA));
+ do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
+ do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
p->relocated = 1;
}
}
}
}
-void *__dynlink(int argc, char **argv, size_t *got)
+static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
+{
+ for (; cnt--; ph = (void *)((char *)ph + stride))
+ if (ph->p_type == PT_DYNAMIC)
+ return ph->p_vaddr;
+ return 0;
+}
+
+static void do_init_fini(struct dso *p)
+{
+ size_t dyn[DYN_CNT] = {0};
+ for (; p; p=p->prev) {
+ if (p->constructed) return;
+ decode_vec(p->dynv, dyn, DYN_CNT);
+ if (dyn[0] & (1<<DT_FINI))
+ atexit((void (*)(void))(p->base + dyn[DT_FINI]));
+ if (dyn[0] & (1<<DT_INIT))
+ ((void (*)(void))(p->base + dyn[DT_INIT]))();
+ p->constructed = 1;
+ }
+}
+
+void _dl_debug_state(void)
+{
+}
+
+void *__dynlink(int argc, char **argv)
{
size_t *auxv, aux[AUX_CNT] = {0};
- size_t app_dyn[DYN_CNT] = {0};
- size_t lib_dyn[DYN_CNT] = {0};
size_t i;
Phdr *phdr;
- struct dso lib, app;
+ Ehdr *ehdr;
+ static struct dso builtin_dsos[3];
+ struct dso *const app = builtin_dsos+0;
+ struct dso *const lib = builtin_dsos+1;
+ struct dso *const vdso = builtin_dsos+2;
+ char *env_preload=0;
/* Find aux vector just past environ[] */
for (i=argc+1; argv[i]; i++)
if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
env_path = argv[i]+16;
+ else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
+ env_preload = argv[i]+11;
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]) {
+ || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
env_path = 0;
+ env_preload = 0;
}
- /* Relocate ldso's DYNAMIC pointer and load vector */
- decode_vec((void *)(got[0] += aux[AT_BASE]), lib_dyn, DYN_CNT);
+ /* If the dynamic linker was invoked as a program itself, AT_BASE
+ * will not be set. In that case, we assume the base address is
+ * the start of the page containing the PHDRs; I don't know any
+ * better approach... */
+ if (!aux[AT_BASE]) {
+ aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
+ aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
+ }
- /* Find the program image's DYNAMIC section and decode it */
- phdr = (void *)aux[AT_PHDR];
- for (i=aux[AT_PHNUM]; i--; phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
- if (phdr->p_type == PT_DYNAMIC) {
- decode_vec((void *)phdr->p_vaddr, app_dyn, DYN_CNT);
- break;
+ /* The dynamic linker load address is passed by the kernel
+ * in the AUX vector, so this is easy. */
+ lib->base = (void *)aux[AT_BASE];
+ lib->name = lib->shortname = "libc.so";
+ lib->global = 1;
+ ehdr = (void *)lib->base;
+ lib->dynv = (void *)(lib->base + find_dyn(
+ (void *)(aux[AT_BASE]+ehdr->e_phoff),
+ ehdr->e_phnum, ehdr->e_phentsize));
+ decode_dyn(lib);
+
+ if (aux[AT_PHDR]) {
+ size_t interp_off = 0;
+ /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
+ phdr = (void *)aux[AT_PHDR];
+ for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
+ if (phdr->p_type == PT_PHDR)
+ app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
+ else if (phdr->p_type == PT_INTERP)
+ interp_off = (size_t)phdr->p_vaddr;
+ }
+ if (interp_off) lib->name = (char *)app->base + interp_off;
+ app->name = argv[0];
+ app->dynv = (void *)(app->base + find_dyn(
+ (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
+ } else {
+ int fd;
+ char *ldname = argv[0];
+ size_t dyno, l = strlen(ldname);
+ if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
+ *argv++ = (void *)-1;
+ if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
+ if (!argv[0]) {
+ dprintf(2, "musl libc/dynamic program loader\n");
+ dprintf(2, "usage: %s pathname%s\n", ldname,
+ ldd_mode ? "" : " [args]");
+ _exit(1);
+ }
+ fd = open(argv[0], O_RDONLY);
+ if (fd < 0) {
+ dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
+ _exit(1);
+ }
+ runtime = 1;
+ ehdr = (void *)map_library(fd, &app->map_len, &app->base, &dyno);
+ if (!ehdr) {
+ dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
+ _exit(1);
+ }
+ runtime = 0;
+ close(fd);
+ lib->name = ldname;
+ app->name = argv[0];
+ app->dynv = (void *)(app->base + dyno);
+ aux[AT_ENTRY] = ehdr->e_entry;
+ }
+ app->global = 1;
+ app->constructed = 1;
+ decode_dyn(app);
+
+ /* Attach to vdso, if provided by the kernel */
+ for (i=0; auxv[i]; i+=2) {
+ size_t vdso_base = auxv[i+1];
+ if (auxv[i] != AT_SYSINFO_EHDR) continue;
+ ehdr = (void *)vdso_base;
+ phdr = (void *)(vdso_base + ehdr->e_phoff);
+ for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
+ if (phdr->p_type == PT_DYNAMIC)
+ vdso->dynv = (void *)(vdso_base + phdr->p_offset);
+ 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->global = 1;
+ decode_dyn(vdso);
+ vdso->prev = lib;
+ lib->next = vdso;
+ break;
}
- app = (struct dso){
- .base = 0,
- .strings = (void *)(app_dyn[DT_STRTAB]),
- .hashtab = (void *)(app_dyn[DT_HASH]),
- .syms = (void *)(app_dyn[DT_SYMTAB]),
- .dynv = (void *)(phdr->p_vaddr),
- .name = argv[0],
- .global = 1,
- .next = &lib
- };
-
- lib = (struct dso){
- .base = (void *)aux[AT_BASE],
- .strings = (void *)(aux[AT_BASE]+lib_dyn[DT_STRTAB]),
- .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
- };
-
- /* Relocate the dynamic linker/libc */
- do_relocs((void *)aux[AT_BASE], (void *)(aux[AT_BASE]+lib_dyn[DT_REL]),
- lib_dyn[DT_RELSZ], 2, lib.syms, lib.strings, &app);
- do_relocs((void *)aux[AT_BASE], (void *)(aux[AT_BASE]+lib_dyn[DT_RELA]),
- lib_dyn[DT_RELASZ], 3, lib.syms, lib.strings, &app);
-
- /* At this point the standard library is fully functional */
-
- 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 {
+ /* Initial dso chain consists only of the app. We temporarily
+ * append the dynamic linker/libc so we can relocate it, then
+ * restore the initial chain in preparation for loading third
+ * party libraries (preload/needed). */
+ head = tail = app;
+ libc = lib;
+ app->next = lib;
+ reloc_all(lib);
+ app->next = 0;
+
+ /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
+
+ /* Donate unused parts of app and library mapping to malloc */
+ reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
+ ehdr = (void *)lib->base;
+ reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
+ ehdr->e_phentsize, ehdr->e_phnum);
+
+ /* Load preload/needed libraries, add their symbols to the global
+ * namespace, and perform all remaining relocations. The main
+ * program must be relocated LAST since it may contain copy
+ * relocations which depend on libraries' relocations. */
+ if (env_preload) load_preload(env_preload);
+ load_deps(app);
+ make_global(app);
+ reloc_all(app->next);
+ reloc_all(app);
+
+ if (ldso_fail) _exit(127);
+ if (ldd_mode) _exit(0);
+
+ /* Switch to runtime mode: any further failures in the dynamic
+ * linker are a reportable failure rather than a fatal startup
+ * error. If the dynamic loader (dlopen) will not be used, free
+ * all memory used by the dynamic linker. */
+ runtime = 1;
+
+#ifndef DYNAMIC_IS_RO
+ for (i=0; app->dynv[i]; i+=2)
+ if (app->dynv[i]==DT_DEBUG)
+ app->dynv[i+1] = (size_t)&debug;
+#endif
+ debug.ver = 1;
+ debug.bp = _dl_debug_state;
+ debug.head = head;
+ debug.base = lib->base;
+ debug.state = 0;
+ _dl_debug_state();
+
+ if (ssp_used) __init_ssp(auxv);
+
+ do_init_fini(tail);
+
+ if (!rtld_used) {
free_all(head);
free(sys_path);
+ reclaim((void *)builtin_dsos, 0, sizeof builtin_dsos);
}
errno = 0;
void *dlopen(const char *file, int mode)
{
- struct dso *p, *orig_tail = tail, *next;
+ struct dso *volatile p, *orig_tail = tail, *next;
size_t i;
+ int cs;
if (!file) return head;
+ pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
pthread_rwlock_wrlock(&lock);
if (setjmp(rtld_fail)) {
}
tail = orig_tail;
tail->next = 0;
- pthread_rwlock_unlock(&lock);
- return 0;
- }
+ p = 0;
+ errflag = 1;
+ goto end;
+ } else p = load_library(file);
- p = load_library(file);
- if (!p) goto end;
+ if (!p) {
+ snprintf(errbuf, sizeof errbuf,
+ "Error loading shared library %s: %m", file);
+ errflag = 1;
+ goto end;
+ }
/* First load handling */
if (!p->deps) {
p->global = 1;
}
+ _dl_debug_state();
+
+ do_init_fini(tail);
end:
pthread_rwlock_unlock(&lock);
+ pthread_setcancelstate(cs, 0);
return p;
}
-static void *do_dlsym(struct dso *p, const char *s)
+static void *do_dlsym(struct dso *p, const char *s, void *ra)
{
size_t i;
- uint32_t h;
+ uint32_t h = 0, gh = 0;
Sym *sym;
- if (p == head || p == RTLD_DEFAULT)
- return find_sym(head, s, 0);
- h = hash(s);
- sym = lookup(s, h, p->syms, p->hashtab, p->strings);
+ if (p == RTLD_NEXT) {
+ for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
+ if (!p) p=head;
+ void *res = find_sym(p->next, s, 0);
+ if (!res) goto failed;
+ return res;
+ }
+ if (p == head || p == RTLD_DEFAULT) {
+ void *res = find_sym(head, s, 0);
+ if (!res) goto failed;
+ return res;
+ }
+ if (p->ghashtab) {
+ gh = gnu_hash(s);
+ sym = gnu_lookup(s, gh, p);
+ } else {
+ h = sysv_hash(s);
+ sym = sysv_lookup(s, h, p);
+ }
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 (p->deps[i]->ghashtab) {
+ if (!gh) gh = gnu_hash(s);
+ sym = gnu_lookup(s, h, p->deps[i]);
+ } else {
+ if (!h) h = sysv_hash(s);
+ sym = sysv_lookup(s, h, p->deps[i]);
+ }
if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
return p->deps[i]->base + sym->st_value;
}
+failed:
+ errflag = 1;
+ snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
return 0;
}
-void *dlsym(void *p, const char *s)
+void *__dlsym(void *p, const char *s, void *ra)
{
void *res;
pthread_rwlock_rdlock(&lock);
- res = do_dlsym(p, s);
+ res = do_dlsym(p, s, ra);
pthread_rwlock_unlock(&lock);
return res;
}
+#else
+void *dlopen(const char *file, int mode)
+{
+ return 0;
+}
+void *__dlsym(void *p, const char *s, void *ra)
+{
+ return 0;
+}
+#endif
char *dlerror()
{
- return "unknown error";
+ if (!errflag) return 0;
+ errflag = 0;
+ return errbuf;
}
int dlclose(void *p)
projects / musl / blobdiff