From: "Vivek Das Mohapatra" <vivek@collabora.com>
To: libc-alpha@sourceware.org
Subject: [RFC][PATCH v10 1/7] Define a new dynamic section tag - DT_GNU_FLAGS_1 (bug 22745)
Date: Mon, 22 Mar 2021 15:41:05 +0000 [thread overview]
Message-ID: <20210322154111.24798-2-vivek@collabora.com> (raw)
In-Reply-To: <20210322154111.24798-1-vivek@collabora.com>
Define a new flags section DT_GNU_FLAGS_1 (no more bits are available
in DT_GNU_FLAGS).
One flag is currently defined: DF_GNU_1_UNIQUE.
libc and its companion DSOs (libpthread et al) should have this
section and flag set.
---
elf/elf.h | 7 ++++++-
elf/get-dynamic-info.h | 12 ++++++++++++
include/elf.h | 2 ++
include/link.h | 1 +
4 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/elf/elf.h b/elf/elf.h
index 2a62b98d4a..448c275d10 100644
--- a/elf/elf.h
+++ b/elf/elf.h
@@ -896,6 +896,7 @@ typedef struct
Dyn.d_un.d_val field of the Elf*_Dyn structure. This follows Sun's
approach. */
#define DT_VALRNGLO 0x6ffffd00
+#define DT_GNU_FLAGS_1 0x6ffffdf4 /* GNU extension flags */
#define DT_GNU_PRELINKED 0x6ffffdf5 /* Prelinking timestamp */
#define DT_GNU_CONFLICTSZ 0x6ffffdf6 /* Size of conflict section */
#define DT_GNU_LIBLISTSZ 0x6ffffdf7 /* Size of library list */
@@ -910,7 +911,7 @@ typedef struct
#define DT_SYMINENT 0x6ffffdff /* Entry size of syminfo */
#define DT_VALRNGHI 0x6ffffdff
#define DT_VALTAGIDX(tag) (DT_VALRNGHI - (tag)) /* Reverse order! */
-#define DT_VALNUM 12
+#define DT_VALNUM 13
/* DT_* entries which fall between DT_ADDRRNGHI & DT_ADDRRNGLO use the
Dyn.d_un.d_ptr field of the Elf*_Dyn structure.
@@ -999,6 +1000,10 @@ typedef struct
#define DF_1_WEAKFILTER 0x20000000
#define DF_1_NOCOMMON 0x40000000
+/* State flags selectable in the `d_un.d_val' element of the DT_GNU_FLAGS_1
+ entry in the dynamic section. */
+#define DF_GNU_1_UNIQUE 0x00000001 /* Load max 1 copy of this DSO. */
+
/* Flags for the feature selection in DT_FEATURE_1. */
#define DTF_1_PARINIT 0x00000001
#define DTF_1_CONFEXP 0x00000002
diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h
index d8ec32377d..8082d84ba1 100644
--- a/elf/get-dynamic-info.h
+++ b/elf/get-dynamic-info.h
@@ -175,6 +175,18 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
if (l->l_flags_1 & DF_1_NOW)
info[DT_BIND_NOW] = info[VERSYMIDX (DT_FLAGS_1)];
}
+ if (info[DT_VALTAGIDX (DT_GNU_FLAGS_1)
+ + DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM + DT_EXTRANUM] != NULL)
+ {
+ l->l_gnu_flags_1 = info[DT_VALTAGIDX (DT_GNU_FLAGS_1)
+ + DT_NUM + DT_THISPROCNUM
+ + DT_VERSIONTAGNUM + DT_EXTRANUM]->d_un.d_val;
+
+ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)
+ && l->l_gnu_flags_1 & ~DT_GNU_1_SUPPORTED_MASK)
+ _dl_debug_printf ("\nWARNING: Unsupported flag value(s) of 0x%x in DT_GNU_FLAGS_1.\n",
+ l->l_gnu_flags_1 & ~DT_GNU_1_SUPPORTED_MASK);
+ }
if (info[DT_RUNPATH] != NULL)
/* If both RUNPATH and RPATH are given, the latter is ignored. */
info[DT_RPATH] = NULL;
diff --git a/include/elf.h b/include/elf.h
index 14ed67ff67..5eee37c294 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -25,5 +25,7 @@
(DF_1_NOW | DF_1_NODELETE | DF_1_INITFIRST | DF_1_NOOPEN \
| DF_1_ORIGIN | DF_1_NODEFLIB | DF_1_PIE)
+#define DT_GNU_1_SUPPORTED_MASK DF_GNU_1_UNIQUE
+
#endif /* !_ISOMAC */
#endif /* elf.h */
diff --git a/include/link.h b/include/link.h
index 4af16cb596..6ed35eb808 100644
--- a/include/link.h
+++ b/include/link.h
@@ -283,6 +283,7 @@ struct link_map
unsigned int l_used;
/* Various flag words. */
+ ElfW(Word) l_gnu_flags_1;
ElfW(Word) l_feature_1;
ElfW(Word) l_flags_1;
ElfW(Word) l_flags;
--
2.20.1
next prev parent reply other threads:[~2021-03-22 15:41 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 15:41 [RFC][PATCH v10 0/7] Implementation of RTLD_SHARED for dlmopen Vivek Das Mohapatra
2021-03-22 15:41 ` Vivek Das Mohapatra [this message]
2021-05-28 14:53 ` [RFC][PATCH v10 1/7] Define a new dynamic section tag - DT_GNU_FLAGS_1 (bug 22745) Adhemerval Zanella
2021-03-22 15:41 ` [RFC][PATCH v10 2/7] Abstract loaded-DSO search code into a helper function Vivek Das Mohapatra
2021-05-28 14:53 ` Adhemerval Zanella
2021-03-22 15:41 ` [RFC][PATCH v10 3/7] Use the new DSO finder " Vivek Das Mohapatra
2021-05-28 14:53 ` Adhemerval Zanella
2021-03-22 15:41 ` [RFC][PATCH v10 4/7] Add DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE to glibc DSOs (bug 22745) Vivek Das Mohapatra
2021-05-28 14:53 ` Adhemerval Zanella
2021-05-28 16:59 ` Adhemerval Zanella
2021-05-28 17:18 ` Andreas Schwab
2021-03-22 15:41 ` [RFC][PATCH v10 5/7] Implement dlmopen RTLD_SHARED flag " Vivek Das Mohapatra
2021-05-28 17:32 ` Adhemerval Zanella
2021-05-28 18:02 ` Adhemerval Zanella
2021-06-02 15:42 ` Vivek Das Mohapatra
2021-05-28 23:22 ` Vivek Das Mohapatra
2021-03-22 15:41 ` [RFC][PATCH v10 6/7] Add dlmopen / RTLD_SHARED tests Vivek Das Mohapatra
2021-03-22 15:41 ` [RFC][PATCH v10 7/7] Restore separate libc loading for the TLS/namespace storage test Vivek Das Mohapatra
2021-03-25 15:15 ` [RFC][PATCH v10 0/7] Implementation of RTLD_SHARED for dlmopen Vivek Das Mohapatra
2021-04-13 17:02 ` Vivek Das Mohapatra
2021-04-29 15:25 ` Vivek Das Mohapatra
2021-05-11 17:42 ` Vivek Das Mohapatra
2021-05-17 19:08 ` [PING][PATCH " Vivek Das Mohapatra
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