Strace Hello World 프로그램

Question

이것은 모두 완전히 정상입니다. 실패한 라이브러리 조회가 발생하는 것을 방지해서는 안 됩니다.

execve("./hello", ["./hello"], [/* 62 vars */]) = 0

이것이 프로그램의 시작입니다. 동적으로 연결되어 있으므로 먼저 실행되는 코드는dynamic loader.

brk(0)                                  = 0x85a5000
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb774f000

동적 로더가 일부 힙 공간을 할당하고 있습니다.

access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)

동적 로더는 미리 로드할 동적 라이브러리가 있는지 확인합니다. 아니요.

open("/home/miguel/GNUstep/Library/Libraries/tls/i686/sse2/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/home/miguel/GNUstep/Library/Libraries/tls/i686/sse2", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/home/miguel/GNUstep/Library/Libraries/tls/i686/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/home/miguel/GNUstep/Library/Libraries/tls/i686", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/home/miguel/GNUstep/Library/Libraries/tls/sse2/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/home/miguel/GNUstep/Library/Libraries/tls/sse2", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/home/miguel/GNUstep/Library/Libraries/tls/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/home/miguel/GNUstep/Library/Libraries/tls", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/home/miguel/GNUstep/Library/Libraries/i686/sse2/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/home/miguel/GNUstep/Library/Libraries/i686/sse2", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/home/miguel/GNUstep/Library/Libraries/i686/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/home/miguel/GNUstep/Library/Libraries/i686", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/home/miguel/GNUstep/Library/Libraries/sse2/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/home/miguel/GNUstep/Library/Libraries/sse2", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/home/miguel/GNUstep/Library/Libraries/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/home/miguel/GNUstep/Library/Libraries", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/usr/lib/tls/i686/sse2/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/tls/i686/sse2", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/usr/lib/tls/i686/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/tls/i686", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/usr/lib/tls/sse2/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/tls/sse2", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/usr/lib/tls/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/tls", 0xbf8df160)      = -1 ENOENT (No such file or directory)
open("/usr/lib/i686/sse2/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/i686/sse2", 0xbf8df160) = -1 ENOENT (No such file or directory)
open("/usr/lib/i686/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/i686", 0xbf8df160)     = -1 ENOENT (No such file or directory)
open("/usr/lib/sse2/libc.so.6", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/sse2", 0xbf8df160)     = -1 ENOENT (No such file or directory)
open("/usr/lib/libc.so.6", O_RDONLY|O_CLOEXEC) = 3

동적 로더가 찾고 있는 libc6것은 표준 라이브러리입니다. 여러 디렉터리를 찾습니다. 먼저 에 지정된 디렉터리를 찾은 LD_LIBRARY_PATH다음 에 나열된 디렉터리를 찾습니다 /etc/ld.so.conf. (전체 내용은 매뉴얼을 참조하세요.) 각 디렉터리 내에서 로더는 먼저 여러 하위 디렉터리를 확인합니다. 즉, 어떤 하드웨어 기능이 있는지 확인합니다(P6 설명,상하이 증권거래소 2), 모든 기능을 사용할 수 있는 라이브러리를 찾을 수 없으면 이러한 추가 기능을 사용하여 보다 효율적으로 실행할 수 있는 라이브러리의 바이너리 버전을 찾습니다. 마지막으로 라이브러리의 비독점 버전이 표준 시스템 디렉토리에서 발견되었습니다.

read(3, "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\300\177\1\0004\0\0\0"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=2035943, ...}) = 0
mmap2(NULL, 1801892, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb7573000
mmap2(0xb7724000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1b0000) = 0xb7724000
mmap2(0xb7729000, 7844, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7729000
close(3)                                = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7572000
set_thread_area({entry_number:-1, base_addr:0xb7572700, limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1, seg_not_present:0, useable:1}) = 0 (entry_number:6)
mprotect(0xb7724000, 12288, PROT_READ)  = 0
mprotect(0xb7750000, 4096, PROT_READ)   = 0

표준 라이브러리가 로드된 후 초기화 코드가 실행됩니다.

fstat64(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7571000

이는 호출을 실행한 결과입니다 printf.

write(1, "Hello World!\n", 13)          = 13
exit_group(0)                           = ?

이는 표준 출력 버퍼 플러시를 포함하는 프로그램 종료입니다.

Answer 1