When searching the list of modules in a core file, if the core was
generated on a different system to the current one, we need to look
in a sysroot for the various shared objects.
For example, we might be looking at a core file from an ARM system
using elfutils running on an x86 host.
This change adds a new function, dwfl_set_sysroot(), which then
gets used when searching for libraries.
Signed-off-by: Luke Diamand <ldiam...@roku.com>
---
libdw/libdw.map | 7 ++++++-
libdwfl/dwfl_end.c | 1 +
libdwfl/libdwfl.h | 5 +++++
libdwfl/libdwflP.h | 1 +
libdwfl/link_map.c | 26 ++++++++++++++++++++++++--
5 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/libdw/libdw.map b/libdw/libdw.map
index 55482d58..43a9de2e 100644
--- a/libdw/libdw.map
+++ b/libdw/libdw.map
@@ -360,4 +360,9 @@ ELFUTILS_0.173 {
ELFUTILS_0.175 {
global:
dwelf_elf_begin;
-} ELFUTILS_0.173;
\ No newline at end of file
+} ELFUTILS_0.173;
+
+ELFUTILS_0.176 {
+ global:
+ dwfl_set_sysroot;
+} ELFUTILS_0.175;
diff --git a/libdwfl/dwfl_end.c b/libdwfl/dwfl_end.c
index 74ee9e07..345d9947 100644
--- a/libdwfl/dwfl_end.c
+++ b/libdwfl/dwfl_end.c
@@ -45,6 +45,7 @@ dwfl_end (Dwfl *dwfl)
free (dwfl->lookup_addr);
free (dwfl->lookup_module);
free (dwfl->lookup_segndx);
+ free (dwfl->sysroot);
Dwfl_Module *next = dwfl->modulelist;
while (next != NULL)
diff --git a/libdwfl/libdwfl.h b/libdwfl/libdwfl.h
index a0c1d357..c11e2f24 100644
--- a/libdwfl/libdwfl.h
+++ b/libdwfl/libdwfl.h
@@ -807,6 +807,11 @@ int dwfl_getthread_frames (Dwfl *dwfl, pid_t tid,
bool dwfl_frame_pc (Dwfl_Frame *state, Dwarf_Addr *pc, bool *isactivation)
__nonnull_attribute__ (1, 2);
+/* Set the sysroot to use when searching for shared libraries. If not
+ specified, search in the system root. */
+void dwfl_set_sysroot (Dwfl *dwfl, const char *sysroot)
+ __nonnull_attribute__ (1);
+
#ifdef __cplusplus
}
#endif
diff --git a/libdwfl/libdwflP.h b/libdwfl/libdwflP.h
index 941a8b66..db16ab57 100644
--- a/libdwfl/libdwflP.h
+++ b/libdwfl/libdwflP.h
@@ -138,6 +138,7 @@ struct Dwfl
int lookup_tail_ndx;
struct Dwfl_User_Core *user_core;
+ char *sysroot; /* sysroot, or NULL to search standard system paths */
};
#define OFFLINE_REDZONE 0x10000
diff --git a/libdwfl/link_map.c b/libdwfl/link_map.c
index 29307c74..cf18c0a2 100644
--- a/libdwfl/link_map.c
+++ b/libdwfl/link_map.c
@@ -34,6 +34,7 @@
#include <byteswap.h>
#include <endian.h>
#include <fcntl.h>
+#include <stdlib.h>
/* This element is always provided and always has a constant value.
This makes it an easy thing to scan for to discern the format. */
@@ -388,8 +389,21 @@ report_r_debug (uint_fast8_t elfclass, uint_fast8_t
elfdata,
if (name != NULL)
{
/* This code is mostly inlined dwfl_report_elf. */
- // XXX hook for sysroot
- int fd = open (name, O_RDONLY);
+ char *path_name;
+ int rc;
+ const char *sysroot = dwfl->sysroot;
+
+ /* don't look in the sysroot if the path is already inside the
sysroot */
+ bool name_in_sysroot = sysroot && (strncmp(name, sysroot,
strlen(sysroot)) == 0);
+
+ if (!name_in_sysroot && sysroot)
+ rc = asprintf(&path_name, "%s/%s", sysroot, name);
+ else
+ rc = asprintf(&path_name, "%s", name);
+ if (unlikely(rc == -1))
+ return release_buffer(-1);
+
+ int fd = open (path_name, O_RDONLY);
if (fd >= 0)
{
Elf *elf;
@@ -471,6 +485,7 @@ report_r_debug (uint_fast8_t elfclass, uint_fast8_t elfdata,
close (fd);
}
}
+ free(path_name);
}
if (mod != NULL)
@@ -1037,3 +1052,10 @@ dwfl_link_map_report (Dwfl *dwfl, const void *auxv,
size_t auxv_size,
&integrated_memory_callback, &mcb, r_debug_info);
}
INTDEF (dwfl_link_map_report)
+
+void
+dwfl_set_sysroot (Dwfl *dwfl, const char *sysroot)
+{
+ dwfl->sysroot = realpath(sysroot, NULL);
+}
+INTDEF (dwfl_set_sysroot)
--
2.20.1
