如何測試應用程序正在使用 POSIX 的哪些部分？

我已經獲得了 C 語言的原始碼，並且想查看其中使用了 POSIX 的哪些部分（函式、系統呼叫）。

是否有測試套件或其他程序，可以給我一個概述？

strace跟踪系統呼叫。POSIX 包括系統呼叫和函式。一些平台支持類似的ltrace（跟踪庫呼叫）。

例如，date命令行實用程序ltrace將顯示如下內容：

__libc_start_main(0x401a50, 1, 0x7ffe41310418, 0x40a100, 0x40a0f0 <unfinished ...>
strrchr("date", '/')                             = NULL
setlocale(6, "")                                 = "en_US.UTF-8"
bindtextdomain("coreutils", "/usr/share/locale") = "/usr/share/locale"
textdomain("coreutils")                          = "coreutils"
__cxa_atexit(0x402b60, 0, 0, 0x736c6974756572, 0x7f8c29d9bea8) = 0
getenv("POSIXLY_CORRECT")                        = NULL
nl_langinfo(131180, 0x40b6b9, 0, 0, 0)           = 0x7f8c23e98955
clock_gettime(0, 0x7ffe41310260, 0x20ef440, 0, 0) = 0
localtime(0x7ffe413101d0)                        = 0x7f8c29d9f380
strftime("", 140239874654731, NULL, 0x7ffe4130fd63) = 4
fwrite("Mon", 3, 1, 0x7f8c29d9a7a0)              = 1
fputc(' ', 0x7f8c29d9a7a0)                       = 32
strftime("", 140239874654844, NULL, 0x7ffe4130fd63) = 4
fwrite("Sep", 3, 1, 0x7f8c29d9a7a0)              = 1
fputc(' ', 0x7f8c29d9a7a0)                       = 32
fwrite("12\004\200\0011A\376\177", 2, 1, 0x7f8c29d9a7a0) = 1
fputc(' ', 0x7f8c29d9a7a0)                       = 32
fwrite("17\004\200\0011A\376\177", 2, 1, 0x7f8c29d9a7a0) = 1
fputc(':', 0x7f8c29d9a7a0)                       = 58
fwrite("43\004\200\0011A\376\177", 2, 1, 0x7f8c29d9a7a0) = 1
fputc(':', 0x7f8c29d9a7a0)                       = 58
fwrite("52\004\200\0011A\376\177", 2, 1, 0x7f8c29d9a7a0) = 1
fputc(' ', 0x7f8c29d9a7a0)                       = 32
strlen("EDT")                                    = 3
fwrite("EDT", 3, 1, 0x7f8c29d9a7a0)              = 1
fputc(' ', 0x7f8c29d9a7a0)                       = 32
fwrite("2016\004\200\0011A\376\177", 4, 1, 0x7f8c29d9a7a0) = 1
__overflow(0x7f8c29d9a7a0, 10, 4, 54, 0x7f8c2a1c401c) = 10
exit(0 <unfinished ...>
...

而strace顯示不同的東西：

execve("/bin/date", ["date"], [/* 60 vars */]) = 0
brk(0)                                  = 0x1ac9000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff3eed91000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=132177, ...}) = 0
mmap(NULL, 132177, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff3eed70000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/librt.so.1", O_RDONLY) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\220!\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=31744, ...}) = 0
mmap(NULL, 2128856, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff3ee96c000
mprotect(0x7ff3ee973000, 2093056, PROT_NONE) = 0
mmap(0x7ff3eeb72000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0x7ff3eeb72000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\300\357\1\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1607696, ...}) = 0
mmap(NULL, 3721272, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff3ee5df000
mprotect(0x7ff3ee763000, 2093056, PROT_NONE) = 0
mmap(0x7ff3ee962000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x183000) = 0x7ff3ee962000
mmap(0x7ff3ee967000, 18488, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7ff3ee967000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libpthread.so.0", O_RDONLY) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0@\\\0\0\0\0\0\0"..., 832) = 832
...

對於這兩種情況，我只給出了一個樣本。但是，如果您要比較兩條完整的軌跡，您將不會看到兩者之間有太大的相關性。這並不總是正確的：執行 I/O 的函式可以在兩者之間相當接近地匹配。但是只有日誌的最後才strace顯示可以與ltrace日誌匹配的任何 I/O。所有這些fwrite和fputc呼叫都會在記憶體中工作，直到最後的write系統呼叫：

open("/usr/lib/locale/locale-archive", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=110939968, ...}) = 0
mmap(NULL, 110939968, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff3e79f6000
close(3)
open("/etc/localtime", O_RDONLY)        = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=3519, ...}) = 0
fstat(3, {st_mode=S_IFREG|0644, st_size=3519, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff3eed90000
read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\0\0\0\4\0\0\0\0"..., 4096) = 3519
lseek(3, -2252, SEEK_CUR)               = 1267
read(3, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\5\0\0\0\5\0\0\0\0"..., 4096) = 2252
close(3)                                = 0
munmap(0x7ff3eed90000, 4096)            = 0
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff3eed90000
write(1, "Mon Sep 12 17:43:41 EDT 2016\n", 29) = 29
close(1)                                = 0
munmap(0x7ff3eed90000, 4096)            = 0
close(2)                                = 0
exit_group(0)                           = ?

在這兩個跟踪中，以下劃線開頭的名稱肯定是非 POSIX。其他一些也是特定於實現的，例如exit_group呼叫。

如果您沒有應用程序的原始碼並且只能觀察二進製文件，則沒有可行的方法來改進這種方法。POSIX 基於使用應用程序原始碼的各種功能。例如，一些特性依賴於編譯應用程序的系統標頭檔，而其他特性依賴於命令行實用程序的行為。POSIX 認證測試使用給定原始碼的應用程序的可觀察行為，使用標準介面。內部細節可能不同，這些是 strace/ltrace 向您顯示的內容，如exit_group.

進一步閱讀：

• ltrace- 庫呼叫跟踪器
• strace- 跟踪系統呼叫和信號
• exit_group- 退出程序中的所有執行緒
• 開放組：測試套件

如果您可以編譯和執行程式碼，並且如果查看 sys 呼叫它的內容就足夠了（即您可以練習您需要了解的所有內容），那麼

strace myapp

將執行myapp並列出它所做的所有系統呼叫（POSIX 和其他）。

引用自：https://unix.stackexchange.com/questions/309374