tools/dbus_exporter: set LD_ORIGIN_PATH if procfs is not available

The script runs the binaries which try to find the internal libs via /proc/self/exe due
to glibc's RPATH resolution and fail:

/var/cache/src/systemd/tools/dbus_exporter.py interfaces
 /var/cache/src/systemd/build/systemd
 /var/cache/src/systemd/build/systemd-homed
 /var/cache/src/systemd/build/systemd-hostnamed
 /var/cache/src/systemd/build/systemd-importd
 /var/cache/src/systemd/build/systemd-localed
 /var/cache/src/systemd/build/systemd-logind
 /var/cache/src/systemd/build/systemd-machined
 /var/cache/src/systemd/build/systemd-networkd
 /var/cache/src/systemd/build/systemd-oomd
 /var/cache/src/systemd/build/systemd-portabled
 /var/cache/src/systemd/build/systemd-resolved
 /var/cache/src/systemd/build/systemd-sysupdated
 /var/cache/src/systemd/build/systemd-timedated
execve("/var/cache/src/systemd/build/systemd", ["/var/cache/src/systemd/build/sys"..., "--bus-introspect", "list"], 0x7ffc7ab68600 /* 20 vars */) = 0
brk(NULL)                               = 0x56265bf70000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f56ced7f000
readlinkat(AT_FDCWD, "/proc/self/exe", 0x7ffedeaa7a90, 4096) = -1 ENOENT (No such file or directory)
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=20293, ...}) = 0
mmap(NULL, 20293, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f56ced7a000
close(3)                                = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v4/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v4/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v3/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v3/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v2/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v2/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/lib/x86_64-linux-gnu/", {st_mode=S_IFDIR|0755, st_size=19312, ...}, 0) = 0
openat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v4/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v4/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v3/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v3/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v2/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/glibc-hwcaps/x86-64-v2/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/usr/lib/x86_64-linux-gnu/", {st_mode=S_IFDIR|0755, st_size=19312, ...}, 0) = 0
openat(AT_FDCWD, "/lib/glibc-hwcaps/x86-64-v4/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/lib/glibc-hwcaps/x86-64-v4/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/lib/glibc-hwcaps/x86-64-v3/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/lib/glibc-hwcaps/x86-64-v3/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/lib/glibc-hwcaps/x86-64-v2/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/lib/glibc-hwcaps/x86-64-v2/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/lib/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/lib/", {st_mode=S_IFDIR|0755, st_size=642, ...}, 0) = 0
openat(AT_FDCWD, "/usr/lib/glibc-hwcaps/x86-64-v4/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/usr/lib/glibc-hwcaps/x86-64-v4/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/lib/glibc-hwcaps/x86-64-v3/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/usr/lib/glibc-hwcaps/x86-64-v3/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/lib/glibc-hwcaps/x86-64-v2/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/usr/lib/glibc-hwcaps/x86-64-v2/", 0x7ffedeaa80b0, 0) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/lib/libsystemd-core-258.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
newfstatat(AT_FDCWD, "/usr/lib/", {st_mode=S_IFDIR|0755, st_size=642, ...}, 0) = 0
writev(2, [{iov_base="/var/cache/src/systemd/build/sys"..., iov_len=36},
           {iov_base=": ", iov_len=2},
           {iov_base="error while loading shared libra"..., iov_len=36},
           {iov_base=": ", iov_len=2},
           {iov_base="libsystemd-core-258.so", iov_len=22},
           {iov_base=": ", iov_len=2},
           {iov_base="cannot open shared object file", iov_len=30},
           {iov_base=": ", iov_len=2},
           {iov_base="No such file or directory", iov_len=25},
           {iov_base="\n", iov_len=1}],
           10/var/cache/src/systemd/build/systemd: error while loading shared libraries: libsystemd-core-258.so: cannot open shared object file: No such file or directory
) = 158

diff --git a/tools/dbus_exporter.py b/tools/dbus_exporter.py
index db95a58950d96649eaa3d5e6e6014cfbeb2eac85..854c7a848bbcb6354db1c61e2334a1ffd726fc4f 100755 (executable)
--- a/tools/dbus_exporter.py
+++ b/tools/dbus_exporter.py
@@ -1,14 +1,22 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: LGPL-2.1-or-later
+import os
 from argparse import ArgumentParser
 from pathlib import Path
 from subprocess import PIPE, run
 
 
 def extract_interfaces_xml(output_dir, executable):
+    # If proc is not mounted, set LD_ORIGIN_PATH so that shared/core libs can be found,
+    # as glibc looks at /proc/self/exe when resolving RPATH
+    env = os.environ.copy()
+    if not os.path.exists('/proc/self'):
+        env["LD_ORIGIN_PATH"] = executable.parent.as_posix()
+
     proc = run(
         args=[executable.absolute(), '--bus-introspect', 'list'],
         stdout=PIPE,
+        env=env,
         check=True,
         universal_newlines=True)
 
@@ -18,6 +26,7 @@ def extract_interfaces_xml(output_dir, executable):
         proc = run(
             args=[executable.absolute(), '--bus-introspect', interface_name],
             stdout=PIPE,
+            env=env,
             check=True,
             universal_newlines=True)