NAME       
       syscall - 间接系统调用

SYNOPSIS       
       #define _GNU_SOURCE        
       #include <unistd.h>
       #include <sys/syscall.h>                 /* For SYS_xxx definitions */

       int syscall(int number, ...);

DESCRIPTION    
       syscall() 执行一个系统调用，根据指定的参数number和所有系统调用的汇编语言接口来确定调用哪个系统调用。
       系统调用所使用的符号常量可以在头文件<sys/syscll.h>里面找到。

 

Linux中，每个进程有一个pid，类型pid_t，由getpid()取得。Linux下的POSIX线程也有一个id，类型 pthread_t，由pthread_self()取得，该id由线程库维护，其id空间是各个进程独立的（即不同进程中的线程可能有相同的id）。Linux中的POSIX线程库实现的线程其实也是一个进程（LWP），只是该进程与主进程（启动线程的进程）共享一些资源而已，比如代码段，数据段等。

有时候我们可能需要知道线程的真实pid。比如进程P1要向另外一个进程P2中的某个线程发送信号时，既不能使用P2的pid，更不能使用线程的pthread id，而只能使用该线程的真实pid，称为tid。

有一个函数gettid()可以得到tid，但glibc并没有实现该函数，只能通过Linux的系统调用syscall来获取。

测试实例：

点击(此处)折叠或打开

1. #include <unistd.h>
2. #include <sys/syscall.h>
3. #include <sys/types.h>
4. #include <signal.h>
5. #include <stdio.h>
6. #include <stdlib.h>
7.  
8. int
9. main(int argc, char *argv[])
10. {
11.      pid_t tid;
12.  
13.      tid = syscall(SYS_gettid);
14.      printf("tid : %d\n",tid);
15.  
16.      tid = syscall(SYS_tgkill, getpid(), tid, SIGHUP);
17.      printf("tid : %d ...\n",tid);
18. }

 

测试结果：


SYS_*

 

点击(此处)折叠或打开

1. /* Generated at libc build time from kernel syscall list. */
2.  
3. #ifndef _SYSCALL_H
4. # error "Never use <bits/syscall.h> directly; include <sys/syscall.h> instead."
5. #endif
6.  
7. #include <bits/wordsize.h>
8.  
9. #define SYS__sysctl __NR__sysctl
10. #define SYS_access __NR_access
11. #define SYS_acct __NR_acct
12. #define SYS_add_key __NR_add_key
13. #define SYS_adjtimex __NR_adjtimex
14. #define SYS_afs_syscall __NR_afs_syscall
15. #define SYS_alarm __NR_alarm
16. #define SYS_brk __NR_brk
17. #define SYS_capget __NR_capget
18. #define SYS_capset __NR_capset
19. #define SYS_chdir __NR_chdir
20. #define SYS_chmod __NR_chmod
21. #define SYS_chown __NR_chown
22. #define SYS_chroot __NR_chroot
23. #define SYS_clock_getres __NR_clock_getres
24. #define SYS_clock_gettime __NR_clock_gettime
25. #define SYS_clock_nanosleep __NR_clock_nanosleep
26. #define SYS_clock_settime __NR_clock_settime
27. #define SYS_clone __NR_clone
28. #define SYS_close __NR_close
29. #define SYS_creat __NR_creat
30. #define SYS_create_module __NR_create_module
31. #define SYS_delete_module __NR_delete_module
32. #define SYS_dup __NR_dup
33. #define SYS_dup2 __NR_dup2
34. #define SYS_epoll_create __NR_epoll_create
35. #define SYS_epoll_ctl __NR_epoll_ctl
36. #define SYS_epoll_wait __NR_epoll_wait
37. #define SYS_eventfd __NR_eventfd
38. #define SYS_execve __NR_execve
39. #define SYS_exit __NR_exit
40. #define SYS_exit_group __NR_exit_group
41. #define SYS_faccessat __NR_faccessat
42. #define SYS_fadvise64 __NR_fadvise64
43. #define SYS_fallocate __NR_fallocate
44. #define SYS_fchdir __NR_fchdir
45. #define SYS_fchmod __NR_fchmod
46. #define SYS_fchmodat __NR_fchmodat
47. #define SYS_fchown __NR_fchown
48. #define SYS_fchownat __NR_fchownat
49. #define SYS_fcntl __NR_fcntl
50. #define SYS_fdatasync __NR_fdatasync
51. #define SYS_fgetxattr __NR_fgetxattr
52. #define SYS_flistxattr __NR_flistxattr
53. #define SYS_flock __NR_flock
54. #define SYS_fork __NR_fork
55. #define SYS_fremovexattr __NR_fremovexattr
56. #define SYS_fsetxattr __NR_fsetxattr
57. #define SYS_fstat __NR_fstat
58. #define SYS_fstatfs __NR_fstatfs
59. #define SYS_fsync __NR_fsync
60. #define SYS_ftruncate __NR_ftruncate
61. #define SYS_futex __NR_futex
62. #define SYS_futimesat __NR_futimesat
63. #define SYS_get_kernel_syms __NR_get_kernel_syms
64. #define SYS_get_mempolicy __NR_get_mempolicy
65. #define SYS_get_robust_list __NR_get_robust_list
66. #define SYS_get_thread_area __NR_get_thread_area
67. #define SYS_getcwd __NR_getcwd
68. #define SYS_getdents __NR_getdents
69. #define SYS_getdents64 __NR_getdents64
70. #define SYS_getegid __NR_getegid
71. #define SYS_geteuid __NR_geteuid
72. #define SYS_getgid __NR_getgid
73. #define SYS_getgroups __NR_getgroups
74. #define SYS_getitimer __NR_getitimer
75. #define SYS_getpgid __NR_getpgid
76. #define SYS_getpgrp __NR_getpgrp
77. #define SYS_getpid __NR_getpid
78. #define SYS_getpmsg __NR_getpmsg
79. #define SYS_getppid __NR_getppid
80. #define SYS_getpriority __NR_getpriority
81. #define SYS_getresgid __NR_getresgid
82. #define SYS_getresuid __NR_getresuid
83. #define SYS_getrlimit __NR_getrlimit
84. #define SYS_getrusage __NR_getrusage
85. #define SYS_getsid __NR_getsid
86. #define SYS_gettid __NR_gettid
87. #define SYS_gettimeofday __NR_gettimeofday
88. #define SYS_getuid __NR_getuid
89. #define SYS_getxattr __NR_getxattr
90. #define SYS_init_module __NR_init_module
91. #define SYS_inotify_add_watch __NR_inotify_add_watch
92. #define SYS_inotify_init __NR_inotify_init
93. #define SYS_inotify_rm_watch __NR_inotify_rm_watch
94. #define SYS_io_cancel __NR_io_cancel
95. #define SYS_io_destroy __NR_io_destroy
96. #define SYS_io_getevents __NR_io_getevents
97. #define SYS_io_setup __NR_io_setup
98. #define SYS_io_submit __NR_io_submit
99. #define SYS_ioctl __NR_ioctl
100. #define SYS_ioperm __NR_ioperm
101. #define SYS_iopl __NR_iopl
102. #define SYS_ioprio_get __NR_ioprio_get
103. #define SYS_ioprio_set __NR_ioprio_set
104. #define SYS_kexec_load __NR_kexec_load
105. #define SYS_keyctl __NR_keyctl
106. #define SYS_kill __NR_kill
107. #define SYS_lchown __NR_lchown
108. #define SYS_lgetxattr __NR_lgetxattr
109. #define SYS_link __NR_link
110. #define SYS_linkat __NR_linkat
111. #define SYS_listxattr __NR_listxattr
112. #define SYS_llistxattr __NR_llistxattr
113. #define SYS_lookup_dcookie __NR_lookup_dcookie
114. #define SYS_lremovexattr __NR_lremovexattr
115. #define SYS_lseek __NR_lseek
116. #define SYS_lsetxattr __NR_lsetxattr
117. #define SYS_lstat __NR_lstat
118. #define SYS_madvise __NR_madvise
119. #define SYS_mbind __NR_mbind
120. #define SYS_migrate_pages __NR_migrate_pages
121. #define SYS_mincore __NR_mincore
122. #define SYS_mkdir __NR_mkdir
123. #define SYS_mkdirat __NR_mkdirat
124. #define SYS_mknod __NR_mknod
125. #define SYS_mknodat __NR_mknodat
126. #define SYS_mlock __NR_mlock
127. #define SYS_mlockall __NR_mlockall
128. #define SYS_mmap __NR_mmap
129. #define SYS_modify_ldt __NR_modify_ldt
130. #define SYS_mount __NR_mount
131. #define SYS_move_pages __NR_move_pages
132. #define SYS_mprotect __NR_mprotect
133. #define SYS_mq_getsetattr __NR_mq_getsetattr
134. #define SYS_mq_notify __NR_mq_notify
135. #define SYS_mq_open __NR_mq_open
136. #define SYS_mq_timedreceive __NR_mq_timedreceive
137. #define SYS_mq_timedsend __NR_mq_timedsend
138. #define SYS_mq_unlink __NR_mq_unlink
139. #define SYS_mremap __NR_mremap
140. #define SYS_msync __NR_msync
141. #define SYS_munlock __NR_munlock
142. #define SYS_munlockall __NR_munlockall
143. #define SYS_munmap __NR_munmap
144. #define SYS_nanosleep __NR_nanosleep
145. #define SYS_nfsservctl __NR_nfsservctl
146. #define SYS_open __NR_open
147. #define SYS_openat __NR_openat
148. #define SYS_pause __NR_pause
149. #define SYS_personality __NR_personality
150. #define SYS_pipe __NR_pipe
151. #define SYS_pivot_root __NR_pivot_root
152. #define SYS_poll __NR_poll
153. #define SYS_ppoll __NR_ppoll
154. #define SYS_prctl __NR_prctl
155. #define SYS_pread64 __NR_pread64
156. #define SYS_pselect6 __NR_pselect6
157. #define SYS_ptrace __NR_ptrace
158. #define SYS_putpmsg __NR_putpmsg
159. #define SYS_pwrite64 __NR_pwrite64
160. #define SYS_query_module __NR_query_module
161. #define SYS_quotactl __NR_quotactl
162. #define SYS_read __NR_read
163. #define SYS_readahead __NR_readahead
164. #define SYS_readlink __NR_readlink
165. #define SYS_readlinkat __NR_readlinkat
166. #define SYS_readv __NR_readv
167. #define SYS_reboot __NR_reboot
168. #define SYS_remap_file_pages __NR_remap_file_pages
169. #define SYS_removexattr __NR_removexattr
170. #define SYS_rename __NR_rename
171. #define SYS_renameat __NR_renameat
172. #define SYS_request_key __NR_request_key
173. #define SYS_restart_syscall __NR_restart_syscall
174. #define SYS_rmdir __NR_rmdir
175. #define SYS_rt_sigaction __NR_rt_sigaction
176. #define SYS_rt_sigpending __NR_rt_sigpending
177. #define SYS_rt_sigprocmask __NR_rt_sigprocmask
178. #define SYS_rt_sigqueueinfo __NR_rt_sigqueueinfo
179. #define SYS_rt_sigreturn __NR_rt_sigreturn
180. #define SYS_rt_sigsuspend __NR_rt_sigsuspend
181. #define SYS_rt_sigtimedwait __NR_rt_sigtimedwait
182. #define SYS_sched_get_priority_max __NR_sched_get_priority_max
183. #define SYS_sched_get_priority_min __NR_sched_get_priority_min
184. #define SYS_sched_getaffinity __NR_sched_getaffinity
185. #define SYS_sched_getparam __NR_sched_getparam
186. #define SYS_sched_getscheduler __NR_sched_getscheduler
187. #define SYS_sched_rr_get_interval __NR_sched_rr_get_interval
188. #define SYS_sched_setaffinity __NR_sched_setaffinity
189. #define SYS_sched_setparam __NR_sched_setparam
190. #define SYS_sched_setscheduler __NR_sched_setscheduler
191. #define SYS_sched_yield __NR_sched_yield
192. #define SYS_select __NR_select
193. #define SYS_sendfile __NR_sendfile
194. #define SYS_set_mempolicy __NR_set_mempolicy
195. #define SYS_set_robust_list __NR_set_robust_list
196. #define SYS_set_thread_area __NR_set_thread_area
197. #define SYS_set_tid_address __NR_set_tid_address
198. #define SYS_setdomainname __NR_setdomainname
199. #define SYS_setfsgid __NR_setfsgid
200. #define SYS_setfsuid __NR_setfsuid
201. #define SYS_setgid __NR_setgid
202. #define SYS_setgroups __NR_setgroups
203. #define SYS_sethostname __NR_sethostname
204. #define SYS_setitimer __NR_setitimer
205. #define SYS_setpgid __NR_setpgid
206. #define SYS_setpriority __NR_setpriority
207. #define SYS_setregid __NR_setregid
208. #define SYS_setresgid __NR_setresgid
209. #define SYS_setresuid __NR_setresuid
210. #define SYS_setreuid __NR_setreuid
211. #define SYS_setrlimit __NR_setrlimit
212. #define SYS_setsid __NR_setsid
213. #define SYS_settimeofday __NR_settimeofday
214. #define SYS_setuid __NR_setuid
215. #define SYS_setxattr __NR_setxattr
216. #define SYS_sigaltstack __NR_sigaltstack
217. #define SYS_splice __NR_splice
218. #define SYS_stat __NR_stat
219. #define SYS_statfs __NR_statfs
220. #define SYS_swapoff __NR_swapoff
221. #define SYS_swapon __NR_swapon
222. #define SYS_symlink __NR_symlink
223. #define SYS_symlinkat __NR_symlinkat
224. #define SYS_sync __NR_sync
225. #define SYS_sync_file_range __NR_sync_file_range
226. #define SYS_sysfs __NR_sysfs
227. #define SYS_sysinfo __NR_sysinfo
228. #define SYS_syslog __NR_syslog
229. #define SYS_tee __NR_tee
230. #define SYS_tgkill __NR_tgkill
231. #define SYS_time __NR_time
232. #define SYS_timer_create __NR_timer_create
233. #define SYS_timer_delete __NR_timer_delete
234. #define SYS_timer_getoverrun __NR_timer_getoverrun
235. #define SYS_timer_gettime __NR_timer_gettime
236. #define SYS_timer_settime __NR_timer_settime
237. #define SYS_times __NR_times
238. #define SYS_tkill __NR_tkill
239. #define SYS_truncate __NR_truncate
240. #define SYS_umask __NR_umask
241. #define SYS_umount2 __NR_umount2
242. #define SYS_uname __NR_uname
243. #define SYS_unlink __NR_unlink
244. #define SYS_unlinkat __NR_unlinkat
245. #define SYS_unshare __NR_unshare
246. #define SYS_uselib __NR_uselib
247. #define SYS_ustat __NR_ustat
248. #define SYS_utime __NR_utime
249. #define SYS_utimes __NR_utimes
250. #define SYS_vfork __NR_vfork
251. #define SYS_vhangup __NR_vhangup
252. #define SYS_vmsplice __NR_vmsplice
253. #define SYS_vserver __NR_vserver
254. #define SYS_wait4 __NR_wait4
255. #define SYS_waitid __NR_waitid
256. #define SYS_write __NR_write
257. #define SYS_writev __NR_writev
258. #if __WORDSIZE == 64
259. #define SYS_accept __NR_accept
260. #define SYS_arch_prctl __NR_arch_prctl
261. #define SYS_bind __NR_bind
262. #define SYS_connect __NR_connect
263. #define SYS_epoll_ctl_old __NR_epoll_ctl_old
264. #define SYS_epoll_pwait __NR_epoll_pwait
265. #define SYS_epoll_wait_old __NR_epoll_wait_old
266. #define SYS_getpeername __NR_getpeername
267. #define SYS_getsockname __NR_getsockname
268. #define SYS_getsockopt __NR_getsockopt
269. #define SYS_listen __NR_listen
270. #define SYS_msgctl __NR_msgctl
271. #define SYS_msgget __NR_msgget
272. #define SYS_msgrcv __NR_msgrcv
273. #define SYS_msgsnd __NR_msgsnd
274. #define SYS_newfstatat __NR_newfstatat
275. #define SYS_recvfrom __NR_recvfrom
276. #define SYS_recvmsg __NR_recvmsg
277. #define SYS_security __NR_security
278. #define SYS_semctl __NR_semctl
279. #define SYS_semget __NR_semget
280. #define SYS_semop __NR_semop
281. #define SYS_semtimedop __NR_semtimedop
282. #define SYS_sendmsg __NR_sendmsg
283. #define SYS_sendto __NR_sendto
284. #define SYS_setsockopt __NR_setsockopt
285. #define SYS_shmat __NR_shmat
286. #define SYS_shmctl __NR_shmctl
287. #define SYS_shmdt __NR_shmdt
288. #define SYS_shmget __NR_shmget
289. #define SYS_shutdown __NR_shutdown
290. #define SYS_signalfd __NR_signalfd
291. #define SYS_socket __NR_socket
292. #define SYS_socketpair __NR_socketpair
293. #define SYS_timerfd_create __NR_timerfd_create
294. #define SYS_tuxcall __NR_tuxcall
295. #define SYS_utimensat __NR_utimensat
296. #else
297. #define SYS__llseek __NR__llseek
298. #define SYS__newselect __NR__newselect
299. #define SYS_bdflush __NR_bdflush
300. #define SYS_break __NR_break
301. #define SYS_chown32 __NR_chown32
302. #define SYS_fadvise64_64 __NR_fadvise64_64
303. #define SYS_fchown32 __NR_fchown32
304. #define SYS_fcntl64 __NR_fcntl64
305. #define SYS_fstat64 __NR_fstat64
306. #define SYS_fstatat64 __NR_fstatat64
307. #define SYS_fstatfs64 __NR_fstatfs64
308. #define SYS_ftime __NR_ftime
309. #define SYS_ftruncate64 __NR_ftruncate64
310. #define SYS_getcpu __NR_getcpu
311. #define SYS_getegid32 __NR_getegid32
312. #define SYS_geteuid32 __NR_geteuid32
313. #define SYS_getgid32 __NR_getgid32
314. #define SYS_getgroups32 __NR_getgroups32
315. #define SYS_getresgid32 __NR_getresgid32
316. #define SYS_getresuid32 __NR_getresuid32
317. #define SYS_getuid32 __NR_getuid32
318. #define SYS_gtty __NR_gtty
319. #define SYS_idle __NR_idle
320. #define SYS_ipc __NR_ipc
321. #define SYS_lchown32 __NR_lchown32
322. #define SYS_lock __NR_lock
323. #define SYS_lstat64 __NR_lstat64
324. #define SYS_madvise1 __NR_madvise1
325. #define SYS_mmap2 __NR_mmap2
326. #define SYS_mpx __NR_mpx
327. #define SYS_nice __NR_nice
328. #define SYS_oldfstat __NR_oldfstat
329. #define SYS_oldlstat __NR_oldlstat
330. #define SYS_oldolduname __NR_oldolduname
331. #define SYS_oldstat __NR_oldstat
332. #define SYS_olduname __NR_olduname
333. #define SYS_prof __NR_prof
334. #define SYS_profil __NR_profil
335. #define SYS_readdir __NR_readdir
336. #define SYS_sendfile64 __NR_sendfile64
337. #define SYS_setfsgid32 __NR_setfsgid32
338. #define SYS_setfsuid32 __NR_setfsuid32
339. #define SYS_setgid32 __NR_setgid32
340. #define SYS_setgroups32 __NR_setgroups32
341. #define SYS_setregid32 __NR_setregid32
342. #define SYS_setresgid32 __NR_setresgid32
343. #define SYS_setresuid32 __NR_setresuid32
344. #define SYS_setreuid32 __NR_setreuid32
345. #define SYS_setuid32 __NR_setuid32
346. #define SYS_sgetmask __NR_sgetmask
347. #define SYS_sigaction __NR_sigaction
348. #define SYS_signal __NR_signal
349. #define SYS_sigpending __NR_sigpending
350. #define SYS_sigprocmask __NR_sigprocmask
351. #define SYS_sigreturn __NR_sigreturn
352. #define SYS_sigsuspend __NR_sigsuspend
353. #define SYS_socketcall __NR_socketcall
354. #define SYS_ssetmask __NR_ssetmask
355. #define SYS_stat64 __NR_stat64
356. #define SYS_statfs64 __NR_statfs64
357. #define SYS_stime __NR_stime
358. #define SYS_stty __NR_stty
359. #define SYS_truncate64 __NR_truncate64
360. #define SYS_ugetrlimit __NR_ugetrlimit
361. #define SYS_ulimit __NR_ulimit
362. #define SYS_umount __NR_umount
363. #define SYS_vm86 __NR_vm86
364. #define SYS_vm86old __NR_vm86old
365. #define SYS_waitpid __NR_waitpid
366. #endif