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authorRich Felker <dalias@aerifal.cx>2013-07-18 19:29:44 -0400
committerRich Felker <dalias@aerifal.cx>2013-07-18 19:29:44 -0400
commitf389c4984a0fee80c5322e4d1ec3aa207e9b5c01 (patch)
tree4d46e10d0503cb6c07caf1fa679eae4dc30a4ab5
parent23815f88df6c45247f3755dc7857f4013264c04f (diff)
downloadmusl-f389c4984a0fee80c5322e4d1ec3aa207e9b5c01.tar.gz
make the dynamic linker find its path file relative to its own location
prior to this change, using a non-default syslibdir was impractical on systems where the ordinary library paths contain musl-incompatible library files. the file containing search paths was always taken from /etc, which would either correspond to a system-wide musl installation, or fail to exist at all, resulting in searching of the default library path. the new search strategy is safe even for suid programs because the pathname used comes from the PT_INTERP header of the program being run, rather than any external input. as part of this change, I have also begun differentiating the names of arch variants that differ by endianness or floating point calling convention. the corresponding changes in the build system and and gcc wrapper script (to use an alternate dynamic linker name) for these configurations have not yet been made.
-rw-r--r--arch/arm/reloc.h15
-rw-r--r--arch/i386/reloc.h2
-rw-r--r--arch/microblaze/reloc.h9
-rw-r--r--arch/mips/reloc.h9
-rw-r--r--arch/powerpc/reloc.h2
-rw-r--r--arch/x86_64/reloc.h2
-rw-r--r--src/ldso/dynlink.c21
7 files changed, 53 insertions, 7 deletions
diff --git a/arch/arm/reloc.h b/arch/arm/reloc.h
index b41314de..9ca0b48c 100644
--- a/arch/arm/reloc.h
+++ b/arch/arm/reloc.h
@@ -1,7 +1,20 @@
#include <string.h>
#include <elf.h>
+#include <endian.h>
-#define ETC_LDSO_PATH "/etc/ld-musl-arm.path"
+#if __BYTE_ORDER == __BIG_ENDIAN
+#define ENDIAN_SUFFIX "eb"
+#else
+#define ENDIAN_SUFFIX ""
+#endif
+
+#if __SOFTFP__
+#define FP_SUFFIX ""
+#else
+#define FP_SUFFIX "hf"
+#endif
+
+#define LDSO_ARCH "arm" ENDIAN_SUFFIX FP_SUFFIX
#define IS_COPY(x) ((x)==R_ARM_COPY)
#define IS_PLT(x) ((x)==R_ARM_JUMP_SLOT)
diff --git a/arch/i386/reloc.h b/arch/i386/reloc.h
index da0bc05d..3923b54b 100644
--- a/arch/i386/reloc.h
+++ b/arch/i386/reloc.h
@@ -1,7 +1,7 @@
#include <string.h>
#include <elf.h>
-#define ETC_LDSO_PATH "/etc/ld-musl-i386.path"
+#define LDSO_ARCH "i386"
#define IS_COPY(x) ((x)==R_386_COPY)
#define IS_PLT(x) ((x)==R_386_JMP_SLOT)
diff --git a/arch/microblaze/reloc.h b/arch/microblaze/reloc.h
index 81add5e9..60f74225 100644
--- a/arch/microblaze/reloc.h
+++ b/arch/microblaze/reloc.h
@@ -1,7 +1,14 @@
#include <string.h>
#include <elf.h>
+#include <endian.h>
-#define ETC_LDSO_PATH "/etc/ld-musl-microblaze.path"
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define ENDIAN_SUFFIX "el"
+#else
+#define ENDIAN_SUFFIX ""
+#endif
+
+#define LDSO_ARCH "microblaze" ENDIAN_SUFFIX
#define IS_COPY(x) ((x)==R_MICROBLAZE_COPY)
#define IS_PLT(x) ((x)==R_MICROBLAZE_JUMP_SLOT)
diff --git a/arch/mips/reloc.h b/arch/mips/reloc.h
index f5e9c77b..4c035f32 100644
--- a/arch/mips/reloc.h
+++ b/arch/mips/reloc.h
@@ -1,7 +1,14 @@
#include <string.h>
#include <elf.h>
+#include <endian.h>
-#define ETC_LDSO_PATH "/etc/ld-musl-mips.path"
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define ENDIAN_SUFFIX "el"
+#else
+#define ENDIAN_SUFFIX ""
+#endif
+
+#define LDSO_ARCH "mips" ENDIAN_SUFFIX
#define IS_COPY(x) ((x)==R_MIPS_COPY)
#define IS_PLT(x) 1
diff --git a/arch/powerpc/reloc.h b/arch/powerpc/reloc.h
index 113dfa15..80b9ebc9 100644
--- a/arch/powerpc/reloc.h
+++ b/arch/powerpc/reloc.h
@@ -1,7 +1,7 @@
#include <string.h>
#include <elf.h>
-#define ETC_LDSO_PATH "/etc/ld-musl-powerpc.path"
+#define LDSO_ARCH "powerpc" ENDIAN_SUFFIX
#define IS_COPY(x) ((x)==R_PPC_COPY)
#define IS_PLT(x) ((x)==R_PPC_JMP_SLOT)
diff --git a/arch/x86_64/reloc.h b/arch/x86_64/reloc.h
index 38a60735..28cf7cc1 100644
--- a/arch/x86_64/reloc.h
+++ b/arch/x86_64/reloc.h
@@ -2,7 +2,7 @@
#include <string.h>
#include <elf.h>
-#define ETC_LDSO_PATH "/etc/ld-musl-x86_64.path"
+#define LDSO_ARCH "x86_64"
#define IS_COPY(x) ((x)==R_X86_64_COPY)
#define IS_PLT(x) ((x)==R_X86_64_JUMP_SLOT)
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index ff5b738d..1d5e2977 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -483,7 +483,26 @@ static struct dso *load_library(const char *name)
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, "rbe");
+ char *prefix = 0;
+ size_t prefix_len;
+ if (ldso->name[0]=='/') {
+ char *s, *t, *z;
+ for (s=t=z=ldso->name; *s; s++)
+ if (*s=='/') z=t, t=s;
+ prefix_len = z-ldso->name;
+ if (prefix_len < PATH_MAX)
+ prefix = ldso->name;
+ }
+ if (!prefix) {
+ prefix = "";
+ prefix_len = 0;
+ }
+ char etc_ldso_path[prefix_len + 1
+ + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
+ snprintf(etc_ldso_path, sizeof etc_ldso_path,
+ "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
+ (int)prefix_len, prefix);
+ FILE *f = fopen(etc_ldso_path, "rbe");
if (f) {
if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
free(sys_path);