X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fldso%2Fdynlink.c;h=3fafb181a728528afeda74711571714053828878;hp=226e174f6de6af2d24d0529ca2a698f8a61ac33b;hb=623753ad64a3625b010c10c00c45262d2eec2495;hpb=a53de812d258a7b0be44ce5dfc96e0f8ce137817

diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 226e174f..3fafb181 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -14,6 +14,7 @@
 #include <elf.h>
 #include <setjmp.h>
 #include <pthread.h>
+#include <ctype.h>
 #include <dlfcn.h>
 
 #include "reloc.h"
@@ -92,10 +93,12 @@ static Sym *lookup(const char *s, uint32_t h, Sym *syms, uint32_t *hashtab, char
 }
 
 #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);
+	void *def = 0;
 	if (h==0x6b366be && !strcmp(s, "dlopen")) rtld_used = 1;
 	if (h==0x6b3afd && !strcmp(s, "dlsym")) rtld_used = 1;
 	for (; dso; dso=dso->next) {
@@ -103,10 +106,14 @@ static void *find_sym(struct dso *dso, const char *s, int need_def)
 		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;
+		 && (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)
@@ -298,7 +305,7 @@ static struct dso *load_library(const char *name)
 				if (!libc->prev) {
 					tail->next = libc;
 					libc->prev = tail;
-					tail = libc;
+					tail = libc->next ? libc->next : libc;
 				}
 				return libc;
 			}
@@ -404,6 +411,20 @@ static void load_deps(struct dso *p)
 	}
 }
 
+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;
+	}
+}
+
 static void make_global(struct dso *p)
 {
 	for (; p; p=p->next) p->global = 1;
@@ -440,25 +461,39 @@ void *__dynlink(int argc, char **argv, size_t *got)
 	size_t *auxv, aux[AUX_CNT] = {0};
 	size_t app_dyn[DYN_CNT] = {0};
 	size_t lib_dyn[DYN_CNT] = {0};
+	size_t vdso_dyn[DYN_CNT] = {0};
 	size_t i;
 	Phdr *phdr;
 	Ehdr *ehdr;
-	static struct dso builtin_dsos[2];
+	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;
+	size_t vdso_base=0;
+	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);
 
+	for (i=0; auxv[i]; i+=2) {
+		if (auxv[i]==AT_SYSINFO_EHDR) {
+			vdso_base = auxv[i+1];
+			break;
+		}
+	}
+
 	/* 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;
+		env_preload = 0;
 	}
 
 	/* Relocate ldso's DYNAMIC pointer and load vector */
@@ -495,6 +530,26 @@ void *__dynlink(int argc, char **argv, size_t *got)
 		.relocated = 1
 	};
 
+	if (vdso_base) {
+		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);
+		}
+		decode_vec(vdso->dynv, vdso_dyn, DYN_CNT);
+		vdso->syms = (void *)(vdso->base + vdso_dyn[DT_SYMTAB]);
+		vdso->hashtab = (void *)(vdso->base + vdso_dyn[DT_HASH]);
+		vdso->strings = (void *)(vdso->base + vdso_dyn[DT_STRTAB]);
+		vdso->name = "linux-gate.so.1";
+		vdso->global = 1;
+
+		vdso->prev = lib;
+		lib->next = vdso;
+	}
+
 	/* 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);
@@ -511,6 +566,7 @@ void *__dynlink(int argc, char **argv, size_t *got)
 	head = tail = app;
 	libc = lib;
 	app->next = 0;
+	if (env_preload) load_preload(env_preload);
 	load_deps(head);
 
 	make_global(head);
@@ -582,11 +638,16 @@ end:
 	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;
 	Sym *sym;
+	if (p == RTLD_NEXT) {
+		for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
+		if (!p) p=head;
+		p=p->next;
+	}
 	if (p == head || p == RTLD_DEFAULT)
 		return find_sym(head, s, 0);
 	h = hash(s);
@@ -602,11 +663,11 @@ static void *do_dlsym(struct dso *p, const char *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;
 }