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-rw-r--r--libelf/ChangeLog9
-rw-r--r--libelf/elf_getdata.c76
-rw-r--r--libelf/elf_newdata.c39
-rw-r--r--libelf/libelfP.h6
4 files changed, 89 insertions, 41 deletions
diff --git a/libelf/ChangeLog b/libelf/ChangeLog
index 0ee94d4e..15485029 100644
--- a/libelf/ChangeLog
+++ b/libelf/ChangeLog
@@ -1,5 +1,14 @@
2015-01-20 Mark Wielaard <[email protected]>
+ * libelfP.h (__elf_strptr_internal): New function declaration.
+ * elf_getdata.c (__libelf_set_data_list_rdlock): New internal
+ function extracted from...
+ (__elf_getdata_rdlock): ... here.
+ * elf_newdata.c (elf_newdata): Check scn->rawdata_base and update
+ datalist if necessary.
+
+2015-01-20 Mark Wielaard <[email protected]>
+
* elf_strptr.c (elf_strptr): Call __elf[32|64]_getshdr_rdlock if
necessary.
diff --git a/libelf/elf_getdata.c b/libelf/elf_getdata.c
index 0aeb9972..e8f022f9 100644
--- a/libelf/elf_getdata.c
+++ b/libelf/elf_getdata.c
@@ -337,6 +337,44 @@ __libelf_set_rawdata (Elf_Scn *scn)
return result;
}
+void
+internal_function
+__libelf_set_data_list_rdlock (Elf_Scn *scn, int wrlocked)
+{
+ if (scn->rawdata.d.d_buf != NULL && scn->rawdata.d.d_size > 0)
+ {
+ Elf *elf = scn->elf;
+
+ /* Upgrade the lock to a write lock if necessary and check
+ nobody else already did the work. */
+ if (!wrlocked)
+ {
+ rwlock_unlock (elf->lock);
+ rwlock_wrlock (elf->lock);
+ if (scn->data_list_rear != NULL)
+ return;
+ }
+
+ /* Convert according to the version and the type. */
+ convert_data (scn, __libelf_version, elf->class,
+ (elf->class == ELFCLASS32
+ || (offsetof (struct Elf, state.elf32.ehdr)
+ == offsetof (struct Elf, state.elf64.ehdr))
+ ? elf->state.elf32.ehdr->e_ident[EI_DATA]
+ : elf->state.elf64.ehdr->e_ident[EI_DATA]),
+ scn->rawdata.d.d_size, scn->rawdata.d.d_type);
+ }
+ else
+ {
+ /* This is an empty or NOBITS section. There is no buffer but
+ the size information etc is important. */
+ scn->data_list.data.d = scn->rawdata.d;
+ scn->data_list.data.s = scn;
+ }
+
+ scn->data_list_rear = &scn->data_list;
+}
+
Elf_Data *
internal_function
__elf_getdata_rdlock (scn, data)
@@ -427,42 +465,10 @@ __elf_getdata_rdlock (scn, data)
empty in case the section has size zero (for whatever reason).
Now create the converted data in case this is necessary. */
if (scn->data_list_rear == NULL)
- {
- if (scn->rawdata.d.d_buf != NULL && scn->rawdata.d.d_size > 0)
- {
- if (!locked)
- {
- rwlock_unlock (elf->lock);
- rwlock_wrlock (elf->lock);
- if (scn->data_list_rear != NULL)
- goto pass;
- }
-
- /* Convert according to the version and the type. */
- convert_data (scn, __libelf_version, elf->class,
- (elf->class == ELFCLASS32
- || (offsetof (struct Elf, state.elf32.ehdr)
- == offsetof (struct Elf, state.elf64.ehdr))
- ? elf->state.elf32.ehdr->e_ident[EI_DATA]
- : elf->state.elf64.ehdr->e_ident[EI_DATA]),
- scn->rawdata.d.d_size, scn->rawdata.d.d_type);
- }
- else
- {
- /* This is an empty or NOBITS section. There is no buffer but
- the size information etc is important. */
- scn->data_list.data.d = scn->rawdata.d;
- scn->data_list.data.s = scn;
- }
-
- scn->data_list_rear = &scn->data_list;
- }
+ __libelf_set_data_list_rdlock (scn, locked);
- /* If no data is present we cannot return any. */
- if (scn->data_list_rear != NULL)
- pass:
- /* Return the first data element in the list. */
- result = &scn->data_list.data.d;
+ /* Return the first data element in the list. */
+ result = &scn->data_list.data.d;
out:
return result;
diff --git a/libelf/elf_newdata.c b/libelf/elf_newdata.c
index 90d18133..f6609a80 100644
--- a/libelf/elf_newdata.c
+++ b/libelf/elf_newdata.c
@@ -1,5 +1,5 @@
/* Create new, empty section data.
- Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
+ Copyright (C) 1998, 1999, 2000, 2001, 2002, 2015 Red Hat, Inc.
This file is part of elfutils.
Contributed by Ulrich Drepper <[email protected]>, 1998.
@@ -64,6 +64,25 @@ elf_newdata (Elf_Scn *scn)
rwlock_wrlock (scn->elf->lock);
+ /* data_read is set when data has been read from the ELF image or
+ when a new section has been created by elf_newscn. If data has
+ been read from the ELF image, then rawdata_base will point to raw
+ data. If data_read has been set by elf_newscn, then rawdata_base
+ will be NULL. data_list_rear will be set by elf_getdata if the
+ data has been converted, or by this function, elf_newdata, when
+ new data has been added.
+
+ Currently elf_getdata and elf_update rely on the fact that when
+ data_list_read is not NULL all they have to do is walk the data
+ list. They will ignore any (unread) raw data in that case.
+
+ So we need to make sure the data list is setup if there is
+ already data available. */
+ if (scn->data_read
+ && scn->rawdata_base != NULL
+ && scn->data_list_rear == NULL)
+ __libelf_set_data_list_rdlock (scn, 1);
+
if (scn->data_read && scn->data_list_rear == NULL)
{
/* This means the section was created by the user and this is the
@@ -73,6 +92,19 @@ elf_newdata (Elf_Scn *scn)
}
else
{
+ /* It would be more efficient to create new data without
+ reading/converting the data from the file. But then we
+ have to remember this. Currently elf_getdata and
+ elf_update rely on the fact that they don't have to
+ load/convert any data if data_list_rear is set. */
+ if (scn->data_read == 0)
+ {
+ if (__libelf_set_rawdata_wrlock (scn) != 0)
+ /* Something went wrong. The error value is already set. */
+ goto out;
+ __libelf_set_data_list_rdlock (scn, 1);
+ }
+
/* Create a new, empty data descriptor. */
result = (Elf_Data_List *) calloc (1, sizeof (Elf_Data_List));
if (result == NULL)
@@ -82,11 +114,6 @@ elf_newdata (Elf_Scn *scn)
}
result->flags = ELF_F_DIRTY | ELF_F_MALLOCED;
-
- if (scn->data_list_rear == NULL)
- /* We create new data without reading/converting the data from the
- file. That is fine but we have to remember this. */
- scn->data_list_rear = &scn->data_list;
}
/* Set the predefined values. */
diff --git a/libelf/libelfP.h b/libelf/libelfP.h
index 3b24e75c..0ad4071d 100644
--- a/libelf/libelfP.h
+++ b/libelf/libelfP.h
@@ -532,6 +532,12 @@ extern Elf_Data *__elf_getdata_rdlock (Elf_Scn *__scn, Elf_Data *__data)
internal_function;
extern Elf_Data *__elf_rawdata_internal (Elf_Scn *__scn, Elf_Data *__data)
attribute_hidden;
+/* Should be called to setup first section data element if
+ data_list_rear is NULL and we know data_read is set and there is
+ raw data available. Might upgrade the ELF lock from a read to a
+ write lock. If the lock is already a write lock set wrlocked. */
+extern void __libelf_set_data_list_rdlock (Elf_Scn *scn, int wrlocked)
+ attribute_hidden;
extern char *__elf_strptr_internal (Elf *__elf, size_t __index,
size_t __offset) attribute_hidden;
extern Elf_Data *__elf32_xlatetom_internal (Elf_Data *__dest,
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-23 01:03:19 +0000