linux中的ls命令使用哪個linux系統調用來顯示文件夾/文件名？

我想通過ls命令知道在linux中使用哪個系統調用來顯示文件夾（或文件名）？特別是以「。」開頭的文件/文件夾。（dot）linux中的ls命令使用哪個linux系統調用來顯示文件夾/文件名？

我執行了strace ls -a命令來查看系統調用。有很多fstat調用發生在所有其他屬性（inode to permisisons）中。哪一個實際上給它的名字？

execve("/bin/ls", ["ls", "-a"], [/* 37 vars */]) = 0 
brk(0)         = 0x1762000 
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) = 0x7f1c14025000 
access("/etc/ld.so.preload", R_OK)  = -1 ENOENT (No such file or directory) 
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3 
fstat(3, {st_mode=S_IFREG|0644, st_size=109464, ...}) = 0 
mmap(NULL, 109464, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f1c1400a000 
close(3)        = 0 
access("/etc/ld.so.nohwcap", F_OK)  = -1 ENOENT (No such file or directory) 
open("/lib/x86_64-linux-gnu/libselinux.so.1", O_RDONLY|O_CLOEXEC) = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\20T\0\0\0\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0644, st_size=121936, ...}) = 0 
mmap(NULL, 2221680, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f1c13be6000 
mprotect(0x7f1c13c03000, 2093056, PROT_NONE) = 0 
mmap(0x7f1c13e02000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1c000) = 0x7f1c13e02000 
mmap(0x7f1c13e04000, 1648, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f1c13e04000 
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|O_CLOEXEC) = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340!\0\0\0\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0644, st_size=31752, ...}) = 0 
mmap(NULL, 2128984, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f1c139de000 
mprotect(0x7f1c139e5000, 2093056, PROT_NONE) = 0 
mmap(0x7f1c13be4000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0x7f1c13be4000 
close(3)        = 0 
access("/etc/ld.so.nohwcap", F_OK)  = -1 ENOENT (No such file or directory) 
open("/lib/x86_64-linux-gnu/libacl.so.1", O_RDONLY|O_CLOEXEC) = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\33\0\0\0\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0644, st_size=31096, ...}) = 0 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1c14009000 
mmap(NULL, 2126312, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f1c137d6000 
mprotect(0x7f1c137dd000, 2093056, PROT_NONE) = 0 
mmap(0x7f1c139dc000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0x7f1c139dc000 
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|O_CLOEXEC) = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\200\30\2\0\0\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0755, st_size=1811128, ...}) = 0 
mmap(NULL, 3925208, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f1c13417000 
mprotect(0x7f1c135cc000, 2093056, PROT_NONE) = 0 
mmap(0x7f1c137cb000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1b4000) = 0x7f1c137cb000 
mmap(0x7f1c137d1000, 17624, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f1c137d1000 
close(3)        = 0 
access("/etc/ld.so.nohwcap", F_OK)  = -1 ENOENT (No such file or directory) 
open("/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340\r\0\0\0\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0644, st_size=14768, ...}) = 0 
mmap(NULL, 2109704, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f1c13213000 
mprotect(0x7f1c13215000, 2097152, PROT_NONE) = 0 
mmap(0x7f1c13415000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7f1c13415000 
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|O_CLOEXEC) = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\200l\0\0\0\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0755, st_size=135366, ...}) = 0 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1c14008000 
mmap(NULL, 2212904, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f1c12ff6000 
mprotect(0x7f1c1300e000, 2093056, PROT_NONE) = 0 
mmap(0x7f1c1320d000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x17000) = 0x7f1c1320d000 
mmap(0x7f1c1320f000, 13352, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f1c1320f000 
close(3)        = 0 
access("/etc/ld.so.nohwcap", F_OK)  = -1 ENOENT (No such file or directory) 
open("/lib/x86_64-linux-gnu/libattr.so.1", O_RDONLY|O_CLOEXEC) = 3 
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340\17\0\0\0\0\0\0"..., 832) = 832 
fstat(3, {st_mode=S_IFREG|0644, st_size=18552, ...}) = 0 
mmap(NULL, 2113736, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f1c12df1000 
mprotect(0x7f1c12df5000, 2093056, PROT_NONE) = 0 
mmap(0x7f1c12ff4000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x3000) = 0x7f1c12ff4000 
close(3)        = 0 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1c14007000 
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1c14005000 
arch_prctl(ARCH_SET_FS, 0x7f1c140057c0) = 0 
mprotect(0x7f1c137cb000, 16384, PROT_READ) = 0 
mprotect(0x7f1c12ff4000, 4096, PROT_READ) = 0 
mprotect(0x7f1c1320d000, 4096, PROT_READ) = 0 
mprotect(0x7f1c13415000, 4096, PROT_READ) = 0 
mprotect(0x7f1c139dc000, 4096, PROT_READ) = 0 
mprotect(0x7f1c13be4000, 4096, PROT_READ) = 0 
mprotect(0x7f1c13e02000, 4096, PROT_READ) = 0 
mprotect(0x618000, 4096, PROT_READ)  = 0 
mprotect(0x7f1c14027000, 4096, PROT_READ) = 0 
munmap(0x7f1c1400a000, 109464)   = 0 
set_tid_address(0x7f1c14005a90)   = 4490 
set_robust_list(0x7f1c14005aa0, 0x18) = 0 
futex(0x7fff2e09d99c, FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME, 1, NULL, 7f1c140057c0) = -1 EAGAIN (Resource temporarily unavailable) 
rt_sigaction(SIGRTMIN, {0x7f1c12ffc750, [], SA_RESTORER|SA_SIGINFO, 0x7f1c13005cb0}, NULL, 8) = 0 
rt_sigaction(SIGRT_1, {0x7f1c12ffc7e0, [], SA_RESTORER|SA_RESTART|SA_SIGINFO, 0x7f1c13005cb0}, NULL, 8) = 0 
rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0 
getrlimit(RLIMIT_STACK, {rlim_cur=8192*1024, rlim_max=RLIM_INFINITY}) = 0 
statfs("/selinux", {f_type="EXT2_SUPER_MAGIC", f_bsize=4096, f_blocks=238304997, f_bfree=232078639, f_bavail=219973436, f_files=60530688, f_ffree=60120220, f_fsid={-1173666966, -474985328}, f_namelen=255, f_frsize=4096}) = 0 
brk(0)         = 0x1762000 
brk(0x1783000)       = 0x1783000 
open("/proc/filesystems", O_RDONLY)  = 3 
fstat(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1c14024000 
read(3, "nodev\tsysfs\nnodev\trootfs\nnodev\tb"..., 1024) = 328 
read(3, "", 1024)      = 0 
close(3)        = 0 
munmap(0x7f1c14024000, 4096)   = 0 
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3 
fstat(3, {st_mode=S_IFREG|0644, st_size=7220736, ...}) = 0 
mmap(NULL, 7220736, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f1c1270e000 
close(3)        = 0 
ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0 
ioctl(1, TIOCGWINSZ, {ws_row=41, ws_col=144, ws_xpixel=0, ws_ypixel=0}) = 0 
openat(AT_FDCWD, ".", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3 
getdents(3, /* 2 entries */, 32768)  = 48 
getdents(3, /* 0 entries */, 32768)  = 0 
close(3)        = 0 
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0 
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1c14024000 
write(1, ". ..\n", 6. .. 
)     = 6 
close(1)        = 0 
munmap(0x7f1c14024000, 4096)   = 0 
close(2)        = 0 
exit_group(0)       = ?

來源

2012-10-16 footy

大多數系統調用都存在來自啓動時加載共享庫的噪音。有趣的事情發生在這裏：

openat(AT_FDCWD, ".", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3 
getdents(3, /* 2 entries */, 32768)  = 48 
getdents(3, /* 0 entries */, 32768)  = 0 
close(3)

的openat(2)系統調用是用來打開當前目錄（"."）相對於當前的工作目錄（AT_FDCWD標誌）。 O_DIRECTORY標誌表示它想要打開目錄並讀取目錄的內容。

使用系統調用getdents(2)讀取實際目錄數據。在這種情況下，它調用了兩次，因爲直到它返回0，它不確定是否有更多的數據。最後，文件描述符在完成後關閉。

但是，如果您要編寫自己的程序，則不會直接調用這些程序 - 而應使用opendir(3),readdir(3)和closedir(3)來讀取目錄。它們是可移植的（符合POSIX標準），它們使您免受底層系統調用的細節影響。他們也更容易使用，國際海事組織。

來源

2012-10-16 18:29:14

它是stat(2)系統調用該查詢一些文件（可能是一個目錄）的狀態;如果你有一個文件描述符（一個open(2)系統調用後），您可以使用fstat(2)

要讀取的目錄，你會更好地運用readdir(3)函數調用系統調用getdents(2)。

來源

2012-10-16 18:23:15

linux中的ls命令使用哪個linux系統調用來顯示文件夾/文件名？

回答

相關問題