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authorRich Felker <dalias@aerifal.cx>2015-05-25 19:15:17 -0400
committerRich Felker <dalias@aerifal.cx>2015-05-25 19:15:17 -0400
commit768b82c6de24e480267c4c251c440edfc71800e3 (patch)
tree9b59e909041b2ad6ca35dad514ad9fa5c5379894
parent967bcbf67c3ffac587de4d79abc1e5e072d83e3e (diff)
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move call to dynamic linker stage-3 into stage-2 function
this move eliminates a duplicate "by-hand" symbol lookup loop from the stage-1 code and replaces it with a call to find_sym, which can be used once we're in stage 2. it reduces the size of the stage 1 code, which is helpful because stage 1 will become the crt start file for static-PIE executables, and it will allow stage 3 to access stage 2's automatic storage, which will be important in an upcoming commit.
-rw-r--r--src/internal/dynlink.h2
-rw-r--r--src/ldso/dlstart.c11
-rw-r--r--src/ldso/dynlink.c8
3 files changed, 9 insertions, 12 deletions
diff --git a/src/internal/dynlink.h b/src/internal/dynlink.h
index 53661d62..8621d2dd 100644
--- a/src/internal/dynlink.h
+++ b/src/internal/dynlink.h
@@ -51,7 +51,7 @@ enum {
#define AUX_CNT 32
#define DYN_CNT 32
-typedef void (*stage2_func)(unsigned char *);
+typedef void (*stage2_func)(unsigned char *, size_t *);
typedef _Noreturn void (*stage3_func)(size_t *);
#endif
diff --git a/src/ldso/dlstart.c b/src/ldso/dlstart.c
index 5f84465c..3aaa200f 100644
--- a/src/ldso/dlstart.c
+++ b/src/ldso/dlstart.c
@@ -84,16 +84,7 @@ void _dlstart_c(size_t *sp, size_t *dynv)
&& s[3]=='l' && s[4]=='s' && s[5]=='2' && !s[6])
break;
}
- ((stage2_func)(base + syms[i].st_value))(base);
-
- /* Call dynamic linker stage-3, __dls3 */
- for (i=0; ;i++) {
- const char *s = strings + syms[i].st_name;
- if (s[0]=='_' && s[1]=='_' && s[2]=='d'
- && s[3]=='l' && s[4]=='s' && s[5]=='3' && !s[6])
- break;
- }
- ((stage3_func)(base + syms[i].st_value))(sp);
+ ((stage2_func)(base + syms[i].st_value))(base, sp);
}
#endif
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 93595a0f..3842aeba 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -1116,7 +1116,7 @@ static void update_tls_size()
* linker itself, but some of the relocations performed may need to be
* replaced later due to copy relocations in the main program. */
-void __dls2(unsigned char *base)
+void __dls2(unsigned char *base, size_t *sp)
{
Ehdr *ehdr = (void *)base;
ldso.base = base;
@@ -1134,6 +1134,12 @@ void __dls2(unsigned char *base)
ldso.relocated = 0;
ldso.rel_update_got = 1;
+
+ /* Call dynamic linker stage-3, __dls3, looking it up
+ * symbolically as a barrier against moving the address
+ * load across the above relocation processing. */
+ struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
+ ((stage3_func)(ldso.base+dls3_def.sym->st_value))(sp);
}
/* Stage 3 of the dynamic linker is called with the dynamic linker/libc