Durch die gemeinsame Verwendung von ld und ldd unter Linux können wir die Gründe für das Scheitern des Ladens von Bibliotheksdateien zur Laufzeit analysieren.

Wenn Entwickler sowie Betriebs- und Wartungspersonal mit dem Problem konfrontiert sind, dass abhängige Bibliotheken beim Ausführen von Software nicht gefunden werden können, können sie normalerweise einige Tools verwenden, um den Startladevorgang zu verfolgen, z. B. Strace, GDB usw. Darüber hinaus können Sie auch die Befehle ld und ldd verwenden, um die Situation abhängiger Bibliotheken zu analysieren und das Problem schneller zu lösen. Diese Tools können dabei helfen, fehlende Abhängigkeitsbibliotheken zu finden und Benutzer dabei zu unterstützen, geeignete Maßnahmen zur Lösung von Software-Laufzeitproblemen zu ergreifen.

Hier analysieren wir die dynamische Bibliotheksdatei libmpi_usempif80.so und welche anderen dynamischen Bibliotheken als Ursache des Problems davon abhängig sind.

Stellen Sie zunächst vor, wie der Befehl ld uns bei der Analyse helfen kann, von welchen anderen Bibliotheken die Bibliothek mpi_usempif80 abhängt. Nach welchen Pfaden im aktuellen System wird beim Laden der mpi_usempif80-Bibliothek nach diesen Bibliotheken gesucht?

#ld -lmpi_usempif08 –verbose

GNU ld (GNU Binutils for Ubuntu) 2.38
Supported emulations:
 elf_x86_64
 elf32_x86_64
 elf_i386
 elf_iamcu
 elf_l1om
 elf_k1om
 i386pep
 i386pe
using internal linker script:
==================================================
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}


==================================================
ld: mode elf_x86_64
attempt to open /usr/local/lib/x86_64-linux-gnu/libmpi_usempif08.so failed
attempt to open /usr/local/lib/x86_64-linux-gnu/libmpi_usempif08.a failed
attempt to open /lib/x86_64-linux-gnu/libmpi_usempif08.so succeeded
/lib/x86_64-linux-gnu/libmpi_usempif08.so
libmpi_mpifh.so.40 needed by /lib/x86_64-linux-gnu/libmpi_usempif08.so
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/mpi/fortran/mpif-h/.libs/libmpi_mpifh.so.40 failed
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/.libs/libmpi_mpifh.so.40 failed
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libmpi_mpifh.so.40 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libmpi_mpifh.so.40 failed
attempt to open /usr/local/lib/libmpi_mpifh.so.40 failed
found libmpi_mpifh.so.40 at /usr/lib/x86_64-linux-gnu/libmpi_mpifh.so.40
libmpi.so.40 needed by /lib/x86_64-linux-gnu/libmpi_usempif08.so
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/mpi/fortran/mpif-h/.libs/libmpi.so.40 failed
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/.libs/libmpi.so.40 failed
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libmpi.so.40 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libmpi.so.40 failed
attempt to open /usr/local/lib/libmpi.so.40 failed
found libmpi.so.40 at /usr/lib/x86_64-linux-gnu/libmpi.so.40
libc.so.6 needed by /lib/x86_64-linux-gnu/libmpi_usempif08.so
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/mpi/fortran/mpif-h/.libs/libc.so.6 failed
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/.libs/libc.so.6 failed
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libc.so.6 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libc.so.6 failed
attempt to open /usr/local/lib/libc.so.6 failed
attempt to open /usr/lib/x86_64-linux-gnu/fortran/gfortran/libc.so.6 failed
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libc.so.6 failed
attempt to open /usr/local/lib/x86_64-linux-gnu/libc.so.6 failed
attempt to open /usr/local/lib/x86_64-linux-gnu/libc.so.6 failed
attempt to open /usr/lib/x86_64-linux-gnu64/libc.so.6 failed
attempt to open /usr/local/lib64/libc.so.6 failed
attempt to open /lib64/libc.so.6 failed
attempt to open /usr/lib64/libc.so.6 failed
attempt to open /usr/local/lib/libc.so.6 failed
attempt to open /lib/libc.so.6 failed
attempt to open /usr/lib/libc.so.6 failed
attempt to open /usr/x86_64-linux-gnu/lib64/libc.so.6 failed
attempt to open /usr/x86_64-linux-gnu/lib/libc.so.6 failed
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/mpi/fortran/mpif-h/.libs/libc.so.6 failed
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/.libs/libc.so.6 failed
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libc.so.6 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libc.so.6 failed
attempt to open /usr/local/lib/libc.so.6 failed
found libc.so.6 at /usr/lib/x86_64-linux-gnu/libc.so.6
libopen-pal.so.40 needed by /usr/lib/x86_64-linux-gnu/libmpi_mpifh.so.40
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/.libs/libopen-pal.so.40 failed
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/opal/.libs/libopen-pal.so.40 failed
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libopen-pal.so.40 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libopen-pal.so.40 failed
attempt to open /usr/local/lib/libopen-pal.so.40 failed
found libopen-pal.so.40 at /usr/lib/x86_64-linux-gnu/libopen-pal.so.40
libopen-rte.so.40 needed by /usr/lib/x86_64-linux-gnu/libmpi.so.40
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libopen-rte.so.40 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libopen-rte.so.40 failed
attempt to open /usr/local/lib/libopen-rte.so.40 failed
found libopen-rte.so.40 at /usr/lib/x86_64-linux-gnu/libopen-rte.so.40
libm.so.6 needed by /usr/lib/x86_64-linux-gnu/libmpi.so.40
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libm.so.6 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libm.so.6 failed
attempt to open /usr/local/lib/libm.so.6 failed
found libm.so.6 at /usr/lib/x86_64-linux-gnu/libm.so.6
libhwloc.so.15 needed by /usr/lib/x86_64-linux-gnu/libmpi.so.40
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libhwloc.so.15 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libhwloc.so.15 failed
attempt to open /usr/local/lib/libhwloc.so.15 failed
found libhwloc.so.15 at /usr/lib/x86_64-linux-gnu/libhwloc.so.15
ld-linux-x86-64.so.2 needed by /usr/lib/x86_64-linux-gnu/libc.so.6
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/ld-linux-x86-64.so.2 failed
attempt to open /usr/local/lib/ld-linux-x86-64.so.2 failed
found ld-linux-x86-64.so.2 at /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
libevent_core-2.1.so.7 needed by /usr/lib/x86_64-linux-gnu/libopen-pal.so.40
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libevent_core-2.1.so.7 failed
attempt to open /usr/local/lib/libevent_core-2.1.so.7 failed
found libevent_core-2.1.so.7 at /usr/lib/x86_64-linux-gnu/libevent_core-2.1.so.7
libevent_pthreads-2.1.so.7 needed by /usr/lib/x86_64-linux-gnu/libopen-pal.so.40
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libevent_pthreads-2.1.so.7 failed
attempt to open /usr/local/lib/libevent_pthreads-2.1.so.7 failed
found libevent_pthreads-2.1.so.7 at /usr/lib/x86_64-linux-gnu/libevent_pthreads-2.1.so.7
libz.so.1 needed by /usr/lib/x86_64-linux-gnu/libopen-rte.so.40
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libz.so.1 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libz.so.1 failed
attempt to open /usr/local/lib/libz.so.1 failed
found libz.so.1 at /usr/lib/x86_64-linux-gnu/libz.so.1
libudev.so.1 needed by /usr/lib/x86_64-linux-gnu/libhwloc.so.15
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libudev.so.1 failed
attempt to open /usr/local/lib/libudev.so.1 failed
found libudev.so.1 at /usr/lib/x86_64-linux-gnu/libudev.so.1


ld -lmpi_usempif08 --verbose | grep found
found libmpi_mpifh.so.40 at /usr/lib/x86_64-linux-gnu/libmpi_mpifh.so.40
found libmpi.so.40 at /usr/lib/x86_64-linux-gnu/libmpi.so.40
ld: warning: cannot find entry symbol _start; not setting start address
found libc.so.6 at /usr/lib/x86_64-linux-gnu/libc.so.6
found libopen-pal.so.40 at /usr/lib/x86_64-linux-gnu/libopen-pal.so.40
found libopen-rte.so.40 at /usr/lib/x86_64-linux-gnu/libopen-rte.so.40
found libm.so.6 at /usr/lib/x86_64-linux-gnu/libm.so.6
found libhwloc.so.15 at /usr/lib/x86_64-linux-gnu/libhwloc.so.15
found ld-linux-x86-64.so.2 at /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
found libevent_core-2.1.so.7 at /usr/lib/x86_64-linux-gnu/libevent_core-2.1.so.7
found libevent_pthreads-2.1.so.7 at /usr/lib/x86_64-linux-gnu/libevent_pthreads-2.1.so.7
found libz.so.1 at /usr/lib/x86_64-linux-gnu/libz.so.1
found libudev.so.1 at /usr/lib/x86_64-linux-gnu/libudev.so.1

Die oben genannten Informationen sind sehr lang und enthalten viele wertvolle Informationen. Wenn Sie nur die wichtigsten Teile sehen möchten, behalte ich den Hauptinhalt bei und erstelle eine komprimierte Version der Ausgabeinformationen:

#ld -lmpi_usempif08 –verbose

GNU ld (GNU Binutils for Ubuntu) 2.38
Supported emulations:
 elf_x86_64
……
using internal linker script:

 notice and this notice are preserved.*/
OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64",
 "elf64-x86-64")
OUTPUT_ARCH(i386:x86-64)
ENTRY(_start)# 运行时可执行文件从代码段的 _start 位置开始运行。

# 运行时需从哪些目录找动态库文件
SEARCH_DIR("=/usr/local/lib/x86_64-linux-gnu"); SEARCH_DIR("=/lib/x86_64-linux-gnu"); SEARCH_DIR("=/usr/lib/x86_64-linux-gnu"); SEARCH_DIR("=/usr/lib/x86_64-linux-gnu64"); SEARCH_DIR("=/usr/local/lib64"); SEARCH_DIR("=/lib64"); SEARCH_DIR("=/usr/lib64"); SEARCH_DIR("=/usr/local/lib"); SEARCH_DIR("=/lib"); SEARCH_DIR("=/usr/lib"); SEARCH_DIR("=/usr/x86_64-linux-gnu/lib64"); SEARCH_DIR("=/usr/x86_64-linux-gnu/lib");

# 二进制文件有哪些的代码段、数据段
SECTIONS
{
PROVIDE (__executable_start = SEGMENT_START("text-segment", 0x400000)); . = SEGMENT_START("text-segment", 0x400000) + SIZEOF_HEADERS;
.interp : { *(.interp) }
……
.rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) }

……
/* Thread Local Storage sections*/
# 线程本地存储区域
.tdata :
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.tbss: { *(.tbss .tbss.* .gnu.linkonce.tb.*) *(.tcommon) }
.preinit_array:
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PROVIDE_HIDDEN (__preinit_array_start = .);
KEEP (*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);
}
# 数据区
.data :
{
*(.data .data.* .gnu.linkonce.d.*)
SORT(CONSTRUCTORS)
}
.data1: { *(.data1) }
_edata = .; PROVIDE (edata = .);
. = .;
__bss_start = .;

# BSS区
.bss:
{
 ……
}
 ……
}

# 下面是本文的重点关注部分
==================================================

# 文件1：逐个目录匹配是否找到被依赖的libmpi_usempif08.so 库文件
ld: mode elf_x86_64
attempt to open /usr/local/lib/x86_64-linux-gnu/libmpi_usempif08.so failed
attempt to open /usr/local/lib/x86_64-linux-gnu/libmpi_usempif08.a failed
attempt to open /lib/x86_64-linux-gnu/libmpi_usempif08.so succeeded
# 找到了 libmpi_usempif08.so 库文件

# 文件2：逐个目录匹配是否找到被依赖的 libmpi_mpifh.so 库文件
libmpi_mpifh.so.40 needed by /lib/x86_64-linux-gnu/libmpi_usempif08.so
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/mpi/fortran/mpif-h/.libs/libmpi_mpifh.so.40 failed
attempt to open /build/openmpi-RCkqwI/openmpi-4.1.2/debian/build-gfortran/ompi/.libs/libmpi_mpifh.so.40 failed
attempt to open /usr/lib/x86_64-linux-gnu/openmpi/lib/libmpi_mpifh.so.40 failed
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libmpi_mpifh.so.40 failed
attempt to open /usr/local/lib/libmpi_mpifh.so.40 failed
found libmpi_mpifh.so.40 at /usr/lib/x86_64-linux-gnu/libmpi_mpifh.so.40
# 找到了 libmpi_mpifh.so 库文件

# 找 libmpi.so.40 
libmpi.so.40 needed by /lib/x86_64-linux-gnu/libmpi_usempif08.so
……
found libmpi.so.40 at /usr/lib/x86_64-linux-gnu/libmpi.so.40

# 找 libc.so.6 
libc.so.6 needed by /lib/x86_64-linux-gnu/libmpi_usempif08.so
……
found libc.so.6 at /usr/lib/x86_64-linux-gnu/libc.so.6

# 找 libopen-pal.so.40
libopen-pal.so.40 needed by /usr/lib/x86_64-linux-gnu/libmpi_mpifh.so.40
……
found libopen-pal.so.40 at /usr/lib/x86_64-linux-gnu/libopen-pal.so.40

# 找 libopen-rte.so.40
libopen-rte.so.40 needed by /usr/lib/x86_64-linux-gnu/libmpi.so.40
……
found libopen-rte.so.40 at /usr/lib/x86_64-linux-gnu/libopen-rte.so.40

# 找 libm.so.6
libm.so.6 needed by /usr/lib/x86_64-linux-gnu/libmpi.so.40
……
found libm.so.6 at /usr/lib/x86_64-linux-gnu/libm.so.6
libhwloc.so.15 needed by /usr/lib/x86_64-linux-gnu/libmpi.so.40

# 找 libhwloc.so.15
……略

# 找 libudev.so.1
libudev.so.1 needed by /usr/lib/x86_64-linux-gnu/libhwloc.so.15
attempt to open /usr/lib/x86_64-linux-gnu/libfakeroot/libudev.so.1 failed
attempt to open /usr/local/lib/libudev.so.1 failed
found libudev.so.1 at /usr/lib/x86_64-linux-gnu/libudev.so.1

Darüber hinaus können wir grep zum Filtern verwenden, um nur Informationen zu Bibliotheken anzuzeigen, die tatsächlich von mpi_usempif08 gefunden wurden:

#ld -lmpi_usempif08 –verbose |. grep gefunden

found libmpi_mpifh.so.40 at /usr/lib/x86_64-linux-gnu/libmpi_mpifh.so.40
found libmpi.so.40 at /usr/lib/x86_64-linux-gnu/libmpi.so.40
ld: warning: cannot find entry symbol _start; not setting start address
found libc.so.6 at /usr/lib/x86_64-linux-gnu/libc.so.6
found libopen-pal.so.40 at /usr/lib/x86_64-linux-gnu/libopen-pal.so.40
found libopen-rte.so.40 at /usr/lib/x86_64-linux-gnu/libopen-rte.so.40
found libm.so.6 at /usr/lib/x86_64-linux-gnu/libm.so.6
found libhwloc.so.15 at /usr/lib/x86_64-linux-gnu/libhwloc.so.15
found ld-linux-x86-64.so.2 at /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
found libevent_core-2.1.so.7 at /usr/lib/x86_64-linux-gnu/libevent_core-2.1.so.7
found libevent_pthreads-2.1.so.7 at /usr/lib/x86_64-linux-gnu/libevent_pthreads-2.1.so.7
found libz.so.1 at /usr/lib/x86_64-linux-gnu/libz.so.1
found libudev.so.1 at /usr/lib/x86_64-linux-gnu/libudev.so.1

Und ldd ist anders als ld. ldd analysiert die Abhängigkeiten von Linux-Laufzeitbibliotheken. ld ist ein Linker für ausführbare Dateien, der häufig in der Verknüpfungsphase der Generierung ausführbarer Dateien aus C/C++/Fortran und anderen Sprachcodes verwendet wird.

Werfen wir einen Blick auf die Verwendung von ldd zur Analyse anderer Bibliotheken, von denen dieselbe dynamische Bibliothek abhängt:

#ldd/usr/lib/x86_64-linux-gnu/libmpi_usempif08.so.40.30.0

 linux-vdso.so.1 (0x00007ffd2f3fd000)
 libmpi_mpifh.so.40 => /usr/lib/x86_64-linux-gnu/libmpi_mpifh.so.40 (0x00007f34366bf000)
 libmpi.so.40 => /usr/lib/x86_64-linux-gnu/libmpi.so.40 (0x00007f3436588000)
 libc.so.6 => /usr/lib/x86_64-linux-gnu/libc.so.6 (0x00007f3436200000)
 libopen-pal.so.40 => /usr/lib/x86_64-linux-gnu/libopen-pal.so.40 (0x00007f34364d5000)
 libopen-rte.so.40 => /usr/lib/x86_64-linux-gnu/libopen-rte.so.40 (0x00007f3436143000)
 libm.so.6 => /usr/lib/x86_64-linux-gnu/libm.so.6 (0x00007f343605c000)
 libhwloc.so.15 => /usr/lib/x86_64-linux-gnu/libhwloc.so.15 (0x00007f3436477000)
 /lib64/ld-linux-x86-64.so.2 (0x00007f343677c000)
 libevent_core-2.1.so.7 => /usr/lib/x86_64-linux-gnu/libevent_core-2.1.so.7 (0x00007f3436442000)
 libevent_pthreads-2.1.so.7 => /usr/lib/x86_64-linux-gnu/libevent_pthreads-2.1.so.7 (0x00007f343643d000)
 libz.so.1 => /usr/lib/x86_64-linux-gnu/libz.so.1 (0x00007f3436040000)
 libudev.so.1 => /usr/lib/x86_64-linux-gnu/libudev.so.1 (0x00007f3436016000)

Die Reihenfolge hier stimmt mit dem Ergebnis von ld -lmpi_usempif08 –verbose grep | überein.

Das obige ist der detaillierte Inhalt vonDurch die gemeinsame Verwendung von ld und ldd unter Linux können wir die Gründe für das Scheitern des Ladens von Bibliotheksdateien zur Laufzeit analysieren.. Für weitere Informationen folgen Sie bitte anderen verwandten Artikeln auf der PHP chinesischen Website!