From: musl <b.brezillon.musl@gmail.com>
To: musl@lists.openwall.com
Subject: ldso : dladdr support
Date: Tue, 07 Aug 2012 11:04:19 +0200 [thread overview]
Message-ID: <5020DA13.6080803@gmail.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 120 bytes --]
Hi,
This patch adds support for dladdr function.
It is based on my previous patch (gnu hash support).
Regards,
Boris
[-- Attachment #2: ldso-dladdr-support.patch --]
[-- Type: text/x-patch, Size: 4844 bytes --]
From 1ac52fe3a7e934223ec887b6d95bb74ecc0477b1 Mon Sep 17 00:00:00 2001
From: Boris BREZILLON <b.brezillon@overkiz.com>
Date: Tue, 7 Aug 2012 10:57:26 +0200
Subject: [PATCH] ldso : dladdr support
---
include/dlfcn.h | 15 ++++++++
src/ldso/dynlink.c | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 119 insertions(+), 1 deletion(-)
diff --git a/include/dlfcn.h b/include/dlfcn.h
index dea74c7..8c45822 100644
--- a/include/dlfcn.h
+++ b/include/dlfcn.h
@@ -18,6 +18,21 @@ char *dlerror(void);
void *dlopen(const char *, int);
void *dlsym(void *, const char *);
+#ifdef _GNU_SOURCE
+typedef struct {
+ const char *dli_fname; /* Pathname of shared object that
+ contains address */
+ void *dli_fbase; /* Address at which shared object
+ is loaded */
+ const char *dli_sname; /* Name of nearest symbol with address
+ lower than addr */
+ void *dli_saddr; /* Exact address of symbol named
+ in dli_sname */
+} Dl_info;
+
+int dladdr (void *addr, Dl_info *info);
+#endif
+
#ifdef __cplusplus
}
#endif
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 0c8d75a..acf8e56 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -28,12 +29,14 @@ typedef Elf32_Phdr Phdr;
typedef Elf32_Sym Sym;
#define R_TYPE(x) ((x)&255)
#define R_SYM(x) ((x)>>8)
+#define ELF_ST_TYPE ELF32_ST_TYPE
#else
typedef Elf64_Ehdr Ehdr;
typedef Elf64_Phdr Phdr;
typedef Elf64_Sym Sym;
#define R_TYPE(x) ((x)&0xffffffff)
#define R_SYM(x) ((x)>>32)
+#define ELF_ST_TYPE ELF64_ST_TYPE
#endif
struct debug {
@@ -69,7 +72,8 @@ struct dso {
struct hash_algo {
uint32_t (*hash) (const char *);
- Sym *(*lookup) (const char *s, uint32_t h, struct dso *dso);
+ Sym *(*lookup) (const char *, uint32_t, struct dso *);
+ void (*iterate) (struct dso *, int (*) (struct dso *, Sym *, void *), void *);
};
#define SYSV_HASH_ALG_IDX 0
@@ -178,14 +182,50 @@ static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
return 0;
}
+static void sysv_iterate (struct dso *dso, int (*func) (struct dso *, Sym *, void *), void *data)
+{
+ size_t i;
+ Sym *syms = dso->syms;
+ uint32_t *hashtab = dso->hashtab;
+ uint32_t nbucket = hashtab[0];
+ uint32_t nchain = hashtab[1];
+ for (i = 0; i < hashtab[1]; i++) {
+ if (!func (dso, syms + i, data))
+ return;
+ }
+}
+
+static void gnu_iterate (struct dso *dso, int (*func) (struct dso *, Sym *, void *), void *data)
+{
+ uint32_t i;
+ Sym *syms = dso->syms;
+ uint32_t *hashtab = dso->hashtab;
+ uint32_t *buckets = hashtab + 4 + (hashtab[2] * (sizeof(size_t) / sizeof(uint32_t)));
+ uint32_t nbuckets = hashtab[0];
+ uint32_t *hashvals = buckets + nbuckets;
+ uint32_t symndx = hashtab[1];
+
+ for (i = 0; i < nbuckets; ++i) {
+ uint32_t n = buckets[i];
+ Sym *sym = syms + n;
+ uint32_t *hashval = hashvals + n - symndx;
+ do {
+ if (!func (dso, sym++, data))
+ return;
+ }while (!(*hashval++ & 1));
+ }
+}
+
static struct hash_algo hashalgs[] = {
{
.hash = sysv_hash,
.lookup = sysv_lookup,
+ .iterate = sysv_iterate,
},
{
.hash = gnu_hash,
.lookup = gnu_lookup,
+ .iterate = gnu_iterate,
},
};
@@ -918,6 +958,69 @@ failed:
return 0;
}
+struct sym_search {
+ void *addr;
+ Dl_info *info;
+};
+
+static int find_closest_sym (struct dso *dso, Sym *sym, void *data)
+{
+ struct sym_search *search = data;
+ void *symaddr = dso->base + sym->st_value;
+ char *strings = dso->strings;
+ Dl_info *info = search->info;
+ void *addr = search->addr;
+ void *prevaddr = info->dli_saddr;
+
+ if (sym->st_value == 0 && sym->st_shndx == SHN_UNDEF)
+ return 1;
+
+ if (ELF_ST_TYPE(sym->st_info) == STT_TLS)
+ return 1;
+
+ if (addr < symaddr)
+ return 1;
+
+ if (prevaddr && (addr - symaddr) > (addr - prevaddr))
+ return 1;
+
+ info->dli_saddr = symaddr;
+ info->dli_sname = strings + sym->st_name;
+
+ if (addr == symaddr)
+ return 0;
+
+ return 1;
+
+}
+
+static int do_dladdr (void *addr, Dl_info *info)
+{
+ struct sym_search search;
+ struct dso *p;
+ memset (info, 0, sizeof (*info));
+ search.info = info;
+ search.addr = addr;
+ for (p=head; p; p=p->next) {
+ if ((unsigned char *)addr >= p->map && (unsigned char *)addr < p->map + p->map_len) {
+ info->dli_fname = p->name;
+ info->dli_fbase = p->base;
+ hashalgs[p->hashalg].iterate (p, find_closest_sym, &search);
+ return 1;
+ }
+ }
+ return 0;
+}
+
+int dladdr (void *addr, Dl_info *info)
+{
+ int res;
+ pthread_rwlock_rdlock(&lock);
+ res = do_dladdr (addr, info);
+ pthread_rwlock_unlock(&lock);
+ return res;
+}
+
void *__dlsym(void *p, const char *s, void *ra)
{
void *res;
--
1.7.9.5
[-- Attachment #3: gnu-hash-support.patch --]
[-- Type: text/x-patch, Size: 6101 bytes --]
From 28edcc77f5096d17be29da1be1c3972c2356d269 Mon Sep 17 00:00:00 2001
From: Boris BREZILLON <b.brezillon@overkiz.com>
Date: Mon, 6 Aug 2012 20:17:01 +0200
Subject: [PATCH] Add gnu hash support.
---
src/ldso/dynlink.c | 125 +++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 115 insertions(+), 10 deletions(-)
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 31ef684..0c8d75a 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -52,6 +52,7 @@ struct dso {
int refcnt;
Sym *syms;
+ uint32_t hashalg;
uint32_t *hashtab;
char *strings;
unsigned char *map;
@@ -66,6 +67,15 @@ struct dso {
char buf[];
};
+struct hash_algo {
+ uint32_t (*hash) (const char *);
+ Sym *(*lookup) (const char *s, uint32_t h, struct dso *dso);
+};
+
+#define SYSV_HASH_ALG_IDX 0
+#define GNU_HASH_ALG_IDX 1
+#define HASH_ALG_CNT 2
+
#include "reloc.h"
void __init_ssp(size_t *);
@@ -94,7 +104,7 @@ static void decode_vec(size_t *v, size_t *a, size_t cnt)
}
}
-static uint32_t hash(const char *s0)
+static uint32_t sysv_hash(const char *s0)
{
const unsigned char *s = (void *)s0;
uint_fast32_t h = 0;
@@ -105,7 +115,16 @@ static uint32_t hash(const char *s0)
return h & 0xfffffff;
}
-static Sym *lookup(const char *s, uint32_t h, struct dso *dso)
+static uint32_t gnu_hash (const char *s0)
+{
+ const unsigned char *s = (void *)s0;
+ uint_fast32_t h = 5381;
+ for (unsigned char c = *s; c != '\0'; c = *++s)
+ h = h * 33 + c;
+ return h & 0xffffffff;
+}
+
+static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
{
size_t i;
Sym *syms = dso->syms;
@@ -118,20 +137,86 @@ static Sym *lookup(const char *s, uint32_t h, struct dso *dso)
return 0;
}
+static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
+{
+ size_t i;
+ Sym *sym;
+ char *strings = dso->strings;
+ uint32_t *hashtab = dso->hashtab;
+ uint32_t nbuckets = hashtab[0];
+ size_t *maskwords = (size_t *)(hashtab + 4);
+ uint32_t *buckets = hashtab + 4 + (hashtab[2] * (sizeof(size_t) / sizeof(uint32_t)));
+ uint32_t symndx = hashtab[1];
+ Sym *syms = dso->syms;
+ uint32_t shift2 = hashtab[3];
+ uint32_t h2 = h1 >> shift2;
+ uint32_t *hashvals = buckets + nbuckets;
+ uint32_t *hashval;
+ size_t c = sizeof(size_t) * 8;
+ size_t n = (h1 / c) & (hashtab[2] - 1);
+ size_t bitmask = (1 << (h1 % c)) | (1 << (h2 % c));
+
+ if ((maskwords[n] & bitmask) != bitmask)
+ return 0;
+
+ n = buckets[h1 % nbuckets];
+ if (!n)
+ return 0;
+
+ sym = syms + n;
+ hashval = hashvals + n - symndx;
+
+ for (h1 &= ~1; 1; sym++) {
+ h2 = *hashval++;
+ if ((h1 == (h2 & ~1)) && !strcmp(s, strings + sym->st_name))
+ return sym;
+
+ if (h2 & 1)
+ break;
+ }
+
+ return 0;
+}
+
+static struct hash_algo hashalgs[] = {
+ {
+ .hash = sysv_hash,
+ .lookup = sysv_lookup,
+ },
+ {
+ .hash = gnu_hash,
+ .lookup = gnu_lookup,
+ },
+};
+
+
#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;
- if (h==0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
+ uint32_t computed[HASH_ALG_CNT / 32 + 1];
+ uint32_t hashes[HASH_ALG_CNT];
+ memset (computed, 0, sizeof (computed));
+ if (!strcmp(s, "dlopen")) rtld_used = 1;
+ if (!strcmp(s, "dlsym")) rtld_used = 1;
+ if (!strcmp(s, "__stack_chk_fail")) ssp_used = 1;
for (; dso; dso=dso->next) {
Sym *sym;
+ uint32_t h;
if (!dso->global) continue;
- sym = lookup(s, h, dso);
+
+ if (!(computed[dso->hashalg / 32] & (1 << (dso->hashalg % 32)))) {
+ h = hashalgs[dso->hashalg].hash(s);
+ hashes[dso->hashalg] = h;
+ computed[dso->hashalg / 32] |= (1 << (dso->hashalg % 32));
+ }
+ else {
+ h = hashes[dso->hashalg];
+ }
+
+ sym = hashalgs[dso->hashalg].lookup(s, h, dso);
if (sym && (!need_def || sym->st_shndx) && sym->st_value
&& (1<<(sym->st_info&0xf) & OK_TYPES)
&& (1<<(sym->st_info>>4) & OK_BINDS)) {
@@ -320,11 +405,17 @@ static int path_open(const char *name, const char *search, char *buf, size_t buf
static void decode_dyn(struct dso *p)
{
+ size_t *v = p->dynv;
size_t dyn[DYN_CNT] = {0};
decode_vec(p->dynv, dyn, DYN_CNT);
p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
p->hashtab = (void *)(p->base + dyn[DT_HASH]);
+ p->hashalg = SYSV_HASH_ALG_IDX;
p->strings = (void *)(p->base + dyn[DT_STRTAB]);
+ for (; v[0]; v+=2) if (v[0] == DT_GNU_HASH) {
+ p->hashtab = (void *)(p->base + v[1]);
+ p->hashalg = GNU_HASH_ALG_IDX;
+ }
}
static struct dso *load_library(const char *name)
@@ -786,6 +877,9 @@ static void *do_dlsym(struct dso *p, const char *s, void *ra)
size_t i;
uint32_t h;
Sym *sym;
+ uint32_t computed[HASH_ALG_CNT / 32 + 1];
+ uint32_t hashes[HASH_ALG_CNT];
+
if (p == RTLD_NEXT) {
for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
if (!p) p=head;
@@ -798,12 +892,23 @@ static void *do_dlsym(struct dso *p, const char *s, void *ra)
if (!res) goto failed;
return res;
}
- h = hash(s);
- sym = lookup(s, h, p);
+ memset (computed, 0, sizeof (computed));
+ h = hashalgs[p->hashalg].hash(s);
+ computed[p->hashalg / 32] |= (1 << (p->hashalg % 32));
+ hashes[p->hashalg] = h;
+ sym = hashalgs[p->hashalg].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);
+ if (!(computed[p->deps[i]->hashalg / 32] & (1 << (p->deps[i]->hashalg % 32)))) {
+ h = hashalgs[p->deps[i]->hashalg].hash(s);
+ hashes[p->deps[i]->hashalg] = h;
+ computed[p->deps[i]->hashalg / 32] |= (1 << (p->deps[i]->hashalg % 32));
+ }
+ else {
+ h = hashes[p->deps[i]->hashalg];
+ }
+ sym = hashalgs[p->deps[i]->hashalg].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;
}
--
1.7.9.5
next reply other threads:[~2012-08-07 9:04 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-07 9:04 musl [this message]
2012-08-07 11:46 ` Szabolcs Nagy
2012-08-07 14:15 ` musl
2012-08-07 14:53 ` Szabolcs Nagy
2012-08-07 23:09 ` Rich Felker
2012-08-08 9:55 ` musl
2012-08-08 11:52 ` Szabolcs Nagy
2012-08-08 12:54 ` Rich Felker
2012-08-08 13:57 ` musl
2012-08-11 23:05 ` Rich Felker
2012-08-15 22:41 ` boris brezillon
2012-08-17 5:39 ` Rich Felker
2012-08-19 16:42 ` musl
2012-08-20 2:06 ` Rich Felker
2012-08-20 12:55 ` musl
2012-08-20 14:32 ` musl
2012-08-23 21:39 ` Rich Felker
2012-08-23 22:21 ` Rich Felker
2012-08-24 7:29 ` musl
2012-08-24 18:38 ` Rich Felker
2012-08-25 7:42 ` boris brezillon
2012-08-25 12:35 ` Rich Felker
2012-08-25 22:13 ` musl
2012-08-25 22:37 ` musl
2012-08-26 0:00 ` musl
2012-08-24 8:12 ` Szabolcs Nagy
2012-08-24 8:56 ` musl
2012-08-24 9:38 ` Szabolcs Nagy
2012-08-25 21:34 ` musl
2012-08-25 21:42 ` Rich Felker
2012-08-16 18:03 ` musl
2012-08-17 16:35 ` musl
2012-08-08 12:49 ` Rich Felker
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