linux下syscall函数，SYS_gettid，SYS_tgkill

原文：http://blog.chinaunix.net/uid-28458801-id-4630215.html

NAME       
       syscall - 间接系统调用

SYNOPSIS       
       #define _GNU_SOURCE        
       #include
       #include                  /* 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

 #include <unistd.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>

 int
 main(int argc, char *argv[])
 {
      pid_t tid;

      tid = syscall(SYS_gettid);
      printf("tid : %d\n",tid);

      tid = syscall(SYS_tgkill, getpid(), tid, SIGHUP);
      printf("tid : %d ...\n",tid);
 }

测试结果：


SYS_*

点击(此处)折叠或打开

 /* Generated at libc build time from kernel syscall list. */

 #ifndef _SYSCALL_H
 # error "Never use  directly; include  instead."
 #endif

 #include <bits/wordsize.h>

 #define SYS__sysctl __NR__sysctl
 #define SYS_access __NR_access
 #define SYS_acct __NR_acct
 #define SYS_add_key __NR_add_key
 #define SYS_adjtimex __NR_adjtimex
 #define SYS_afs_syscall __NR_afs_syscall
 #define SYS_alarm __NR_alarm
 #define SYS_brk __NR_brk
 #define SYS_capget __NR_capget
 #define SYS_capset __NR_capset
 #define SYS_chdir __NR_chdir
 #define SYS_chmod __NR_chmod
 #define SYS_chown __NR_chown
 #define SYS_chroot __NR_chroot
 #define SYS_clock_getres __NR_clock_getres
 #define SYS_clock_gettime __NR_clock_gettime
 #define SYS_clock_nanosleep __NR_clock_nanosleep
 #define SYS_clock_settime __NR_clock_settime
 #define SYS_clone __NR_clone
 #define SYS_close __NR_close
 #define SYS_creat __NR_creat
 #define SYS_create_module __NR_create_module
 #define SYS_delete_module __NR_delete_module
 #define SYS_dup __NR_dup
 #define SYS_dup2 __NR_dup2
 #define SYS_epoll_create __NR_epoll_create
 #define SYS_epoll_ctl __NR_epoll_ctl
 #define SYS_epoll_wait __NR_epoll_wait
 #define SYS_eventfd __NR_eventfd
 #define SYS_execve __NR_execve
 #define SYS_exit __NR_exit
 #define SYS_exit_group __NR_exit_group
 #define SYS_faccessat __NR_faccessat
 #define SYS_fadvise64 __NR_fadvise64
 #define SYS_fallocate __NR_fallocate
 #define SYS_fchdir __NR_fchdir
 #define SYS_fchmod __NR_fchmod
 #define SYS_fchmodat __NR_fchmodat
 #define SYS_fchown __NR_fchown
 #define SYS_fchownat __NR_fchownat
 #define SYS_fcntl __NR_fcntl
 #define SYS_fdatasync __NR_fdatasync
 #define SYS_fgetxattr __NR_fgetxattr
 #define SYS_flistxattr __NR_flistxattr
 #define SYS_flock __NR_flock
 #define SYS_fork __NR_fork
 #define SYS_fremovexattr __NR_fremovexattr
 #define SYS_fsetxattr __NR_fsetxattr
 #define SYS_fstat __NR_fstat
 #define SYS_fstatfs __NR_fstatfs
 #define SYS_fsync __NR_fsync
 #define SYS_ftruncate __NR_ftruncate
 #define SYS_futex __NR_futex
 #define SYS_futimesat __NR_futimesat
 #define SYS_get_kernel_syms __NR_get_kernel_syms
 #define SYS_get_mempolicy __NR_get_mempolicy
 #define SYS_get_robust_list __NR_get_robust_list
 #define SYS_get_thread_area __NR_get_thread_area
 #define SYS_getcwd __NR_getcwd
 #define SYS_getdents __NR_getdents
 #define SYS_getdents64 __NR_getdents64
 #define SYS_getegid __NR_getegid
 #define SYS_geteuid __NR_geteuid
 #define SYS_getgid __NR_getgid
 #define SYS_getgroups __NR_getgroups
 #define SYS_getitimer __NR_getitimer
 #define SYS_getpgid __NR_getpgid
 #define SYS_getpgrp __NR_getpgrp
 #define SYS_getpid __NR_getpid
 #define SYS_getpmsg __NR_getpmsg
 #define SYS_getppid __NR_getppid
 #define SYS_getpriority __NR_getpriority
 #define SYS_getresgid __NR_getresgid
 #define SYS_getresuid __NR_getresuid
 #define SYS_getrlimit __NR_getrlimit
 #define SYS_getrusage __NR_getrusage
 #define SYS_getsid __NR_getsid
 #define SYS_gettid __NR_gettid
 #define SYS_gettimeofday __NR_gettimeofday
 #define SYS_getuid __NR_getuid
 #define SYS_getxattr __NR_getxattr
 #define SYS_init_module __NR_init_module
 #define SYS_inotify_add_watch __NR_inotify_add_watch
 #define SYS_inotify_init __NR_inotify_init
 #define SYS_inotify_rm_watch __NR_inotify_rm_watch
 #define SYS_io_cancel __NR_io_cancel
 #define SYS_io_destroy __NR_io_destroy
 #define SYS_io_getevents __NR_io_getevents
 #define SYS_io_setup __NR_io_setup
 #define SYS_io_submit __NR_io_submit
 #define SYS_ioctl __NR_ioctl
 #define SYS_ioperm __NR_ioperm
 #define SYS_iopl __NR_iopl
 #define SYS_ioprio_get __NR_ioprio_get
 #define SYS_ioprio_set __NR_ioprio_set
 #define SYS_kexec_load __NR_kexec_load
 #define SYS_keyctl __NR_keyctl
 #define SYS_kill __NR_kill
 #define SYS_lchown __NR_lchown
 #define SYS_lgetxattr __NR_lgetxattr
 #define SYS_link __NR_link
 #define SYS_linkat __NR_linkat
 #define SYS_listxattr __NR_listxattr
 #define SYS_llistxattr __NR_llistxattr
 #define SYS_lookup_dcookie __NR_lookup_dcookie
 #define SYS_lremovexattr __NR_lremovexattr
 #define SYS_lseek __NR_lseek
 #define SYS_lsetxattr __NR_lsetxattr
 #define SYS_lstat __NR_lstat
 #define SYS_madvise __NR_madvise
 #define SYS_mbind __NR_mbind
 #define SYS_migrate_pages __NR_migrate_pages
 #define SYS_mincore __NR_mincore
 #define SYS_mkdir __NR_mkdir
 #define SYS_mkdirat __NR_mkdirat
 #define SYS_mknod __NR_mknod
 #define SYS_mknodat __NR_mknodat
 #define SYS_mlock __NR_mlock
 #define SYS_mlockall __NR_mlockall
 #define SYS_mmap __NR_mmap
 #define SYS_modify_ldt __NR_modify_ldt
 #define SYS_mount __NR_mount
 #define SYS_move_pages __NR_move_pages
 #define SYS_mprotect __NR_mprotect
 #define SYS_mq_getsetattr __NR_mq_getsetattr
 #define SYS_mq_notify __NR_mq_notify
 #define SYS_mq_open __NR_mq_open
 #define SYS_mq_timedreceive __NR_mq_timedreceive
 #define SYS_mq_timedsend __NR_mq_timedsend
 #define SYS_mq_unlink __NR_mq_unlink
 #define SYS_mremap __NR_mremap
 #define SYS_msync __NR_msync
 #define SYS_munlock __NR_munlock
 #define SYS_munlockall __NR_munlockall
 #define SYS_munmap __NR_munmap
 #define SYS_nanosleep __NR_nanosleep
 #define SYS_nfsservctl __NR_nfsservctl
 #define SYS_open __NR_open
 #define SYS_openat __NR_openat
 #define SYS_pause __NR_pause
 #define SYS_personality __NR_personality
 #define SYS_pipe __NR_pipe
 #define SYS_pivot_root __NR_pivot_root
 #define SYS_poll __NR_poll
 #define SYS_ppoll __NR_ppoll
 #define SYS_prctl __NR_prctl
 #define SYS_pread64 __NR_pread64
 #define SYS_pselect6 __NR_pselect6
 #define SYS_ptrace __NR_ptrace
 #define SYS_putpmsg __NR_putpmsg
 #define SYS_pwrite64 __NR_pwrite64
 #define SYS_query_module __NR_query_module
 #define SYS_quotactl __NR_quotactl
 #define SYS_read __NR_read
 #define SYS_readahead __NR_readahead
 #define SYS_readlink __NR_readlink
 #define SYS_readlinkat __NR_readlinkat
 #define SYS_readv __NR_readv
 #define SYS_reboot __NR_reboot
 #define SYS_remap_file_pages __NR_remap_file_pages
 #define SYS_removexattr __NR_removexattr
 #define SYS_rename __NR_rename
 #define SYS_renameat __NR_renameat
 #define SYS_request_key __NR_request_key
 #define SYS_restart_syscall __NR_restart_syscall
 #define SYS_rmdir __NR_rmdir
 #define SYS_rt_sigaction __NR_rt_sigaction
 #define SYS_rt_sigpending __NR_rt_sigpending
 #define SYS_rt_sigprocmask __NR_rt_sigprocmask
 #define SYS_rt_sigqueueinfo __NR_rt_sigqueueinfo
 #define SYS_rt_sigreturn __NR_rt_sigreturn
 #define SYS_rt_sigsuspend __NR_rt_sigsuspend
 #define SYS_rt_sigtimedwait __NR_rt_sigtimedwait
 #define SYS_sched_get_priority_max __NR_sched_get_priority_max
 #define SYS_sched_get_priority_min __NR_sched_get_priority_min
 #define SYS_sched_getaffinity __NR_sched_getaffinity
 #define SYS_sched_getparam __NR_sched_getparam
 #define SYS_sched_getscheduler __NR_sched_getscheduler
 #define SYS_sched_rr_get_interval __NR_sched_rr_get_interval
 #define SYS_sched_setaffinity __NR_sched_setaffinity
 #define SYS_sched_setparam __NR_sched_setparam
 #define SYS_sched_setscheduler __NR_sched_setscheduler
 #define SYS_sched_yield __NR_sched_yield
 #define SYS_select __NR_select
 #define SYS_sendfile __NR_sendfile
 #define SYS_set_mempolicy __NR_set_mempolicy
 #define SYS_set_robust_list __NR_set_robust_list
 #define SYS_set_thread_area __NR_set_thread_area
 #define SYS_set_tid_address __NR_set_tid_address
 #define SYS_setdomainname __NR_setdomainname
 #define SYS_setfsgid __NR_setfsgid
 #define SYS_setfsuid __NR_setfsuid
 #define SYS_setgid __NR_setgid
 #define SYS_setgroups __NR_setgroups
 #define SYS_sethostname __NR_sethostname
 #define SYS_setitimer __NR_setitimer
 #define SYS_setpgid __NR_setpgid
 #define SYS_setpriority __NR_setpriority
 #define SYS_setregid __NR_setregid
 #define SYS_setresgid __NR_setresgid
 #define SYS_setresuid __NR_setresuid
 #define SYS_setreuid __NR_setreuid
 #define SYS_setrlimit __NR_setrlimit
 #define SYS_setsid __NR_setsid
 #define SYS_settimeofday __NR_settimeofday
 #define SYS_setuid __NR_setuid
 #define SYS_setxattr __NR_setxattr
 #define SYS_sigaltstack __NR_sigaltstack
 #define SYS_splice __NR_splice
 #define SYS_stat __NR_stat
 #define SYS_statfs __NR_statfs
 #define SYS_swapoff __NR_swapoff
 #define SYS_swapon __NR_swapon
 #define SYS_symlink __NR_symlink
 #define SYS_symlinkat __NR_symlinkat
 #define SYS_sync __NR_sync
 #define SYS_sync_file_range __NR_sync_file_range
 #define SYS_sysfs __NR_sysfs
 #define SYS_sysinfo __NR_sysinfo
 #define SYS_syslog __NR_syslog
 #define SYS_tee __NR_tee
 #define SYS_tgkill __NR_tgkill
 #define SYS_time __NR_time
 #define SYS_timer_create __NR_timer_create
 #define SYS_timer_delete __NR_timer_delete
 #define SYS_timer_getoverrun __NR_timer_getoverrun
 #define SYS_timer_gettime __NR_timer_gettime
 #define SYS_timer_settime __NR_timer_settime
 #define SYS_times __NR_times
 #define SYS_tkill __NR_tkill
 #define SYS_truncate __NR_truncate
 #define SYS_umask __NR_umask
 #define SYS_umount2 __NR_umount2
 #define SYS_uname __NR_uname
 #define SYS_unlink __NR_unlink
 #define SYS_unlinkat __NR_unlinkat
 #define SYS_unshare __NR_unshare
 #define SYS_uselib __NR_uselib
 #define SYS_ustat __NR_ustat
 #define SYS_utime __NR_utime
 #define SYS_utimes __NR_utimes
 #define SYS_vfork __NR_vfork
 #define SYS_vhangup __NR_vhangup
 #define SYS_vmsplice __NR_vmsplice
 #define SYS_vserver __NR_vserver
 #define SYS_wait4 __NR_wait4
 #define SYS_waitid __NR_waitid
 #define SYS_write __NR_write
 #define SYS_writev __NR_writev
 #if __WORDSIZE == 64
 #define SYS_accept __NR_accept
 #define SYS_arch_prctl __NR_arch_prctl
 #define SYS_bind __NR_bind
 #define SYS_connect __NR_connect
 #define SYS_epoll_ctl_old __NR_epoll_ctl_old
 #define SYS_epoll_pwait __NR_epoll_pwait
 #define SYS_epoll_wait_old __NR_epoll_wait_old
 #define SYS_getpeername __NR_getpeername
 #define SYS_getsockname __NR_getsockname
 #define SYS_getsockopt __NR_getsockopt
 #define SYS_listen __NR_listen
 #define SYS_msgctl __NR_msgctl
 #define SYS_msgget __NR_msgget
 #define SYS_msgrcv __NR_msgrcv
 #define SYS_msgsnd __NR_msgsnd
 #define SYS_newfstatat __NR_newfstatat
 #define SYS_recvfrom __NR_recvfrom
 #define SYS_recvmsg __NR_recvmsg
 #define SYS_security __NR_security
 #define SYS_semctl __NR_semctl
 #define SYS_semget __NR_semget
 #define SYS_semop __NR_semop
 #define SYS_semtimedop __NR_semtimedop
 #define SYS_sendmsg __NR_sendmsg
 #define SYS_sendto __NR_sendto
 #define SYS_setsockopt __NR_setsockopt
 #define SYS_shmat __NR_shmat
 #define SYS_shmctl __NR_shmctl
 #define SYS_shmdt __NR_shmdt
 #define SYS_shmget __NR_shmget
 #define SYS_shutdown __NR_shutdown
 #define SYS_signalfd __NR_signalfd
 #define SYS_socket __NR_socket
 #define SYS_socketpair __NR_socketpair
 #define SYS_timerfd_create __NR_timerfd_create
 #define SYS_tuxcall __NR_tuxcall
 #define SYS_utimensat __NR_utimensat
 #else
 #define SYS__llseek __NR__llseek
 #define SYS__newselect __NR__newselect
 #define SYS_bdflush __NR_bdflush
 #define SYS_break __NR_break
 #define SYS_chown32 __NR_chown32
 #define SYS_fadvise64_64 __NR_fadvise64_64
 #define SYS_fchown32 __NR_fchown32
 #define SYS_fcntl64 __NR_fcntl64
 #define SYS_fstat64 __NR_fstat64
 #define SYS_fstatat64 __NR_fstatat64
 #define SYS_fstatfs64 __NR_fstatfs64
 #define SYS_ftime __NR_ftime
 #define SYS_ftruncate64 __NR_ftruncate64
 #define SYS_getcpu __NR_getcpu
 #define SYS_getegid32 __NR_getegid32
 #define SYS_geteuid32 __NR_geteuid32
 #define SYS_getgid32 __NR_getgid32
 #define SYS_getgroups32 __NR_getgroups32
 #define SYS_getresgid32 __NR_getresgid32
 #define SYS_getresuid32 __NR_getresuid32
 #define SYS_getuid32 __NR_getuid32
 #define SYS_gtty __NR_gtty
 #define SYS_idle __NR_idle
 #define SYS_ipc __NR_ipc
 #define SYS_lchown32 __NR_lchown32
 #define SYS_lock __NR_lock
 #define SYS_lstat64 __NR_lstat64
 #define SYS_madvise1 __NR_madvise1
 #define SYS_mmap2 __NR_mmap2
 #define SYS_mpx __NR_mpx
 #define SYS_nice __NR_nice
 #define SYS_oldfstat __NR_oldfstat
 #define SYS_oldlstat __NR_oldlstat
 #define SYS_oldolduname __NR_oldolduname
 #define SYS_oldstat __NR_oldstat
 #define SYS_olduname __NR_olduname
 #define SYS_prof __NR_prof
 #define SYS_profil __NR_profil
 #define SYS_readdir __NR_readdir
 #define SYS_sendfile64 __NR_sendfile64
 #define SYS_setfsgid32 __NR_setfsgid32
 #define SYS_setfsuid32 __NR_setfsuid32
 #define SYS_setgid32 __NR_setgid32
 #define SYS_setgroups32 __NR_setgroups32
 #define SYS_setregid32 __NR_setregid32
 #define SYS_setresgid32 __NR_setresgid32
 #define SYS_setresuid32 __NR_setresuid32
 #define SYS_setreuid32 __NR_setreuid32
 #define SYS_setuid32 __NR_setuid32
 #define SYS_sgetmask __NR_sgetmask
 #define SYS_sigaction __NR_sigaction
 #define SYS_signal __NR_signal
 #define SYS_sigpending __NR_sigpending
 #define SYS_sigprocmask __NR_sigprocmask
 #define SYS_sigreturn __NR_sigreturn
 #define SYS_sigsuspend __NR_sigsuspend
 #define SYS_socketcall __NR_socketcall
 #define SYS_ssetmask __NR_ssetmask
 #define SYS_stat64 __NR_stat64
 #define SYS_statfs64 __NR_statfs64
 #define SYS_stime __NR_stime
 #define SYS_stty __NR_stty
 #define SYS_truncate64 __NR_truncate64
 #define SYS_ugetrlimit __NR_ugetrlimit
 #define SYS_ulimit __NR_ulimit
 #define SYS_umount __NR_umount
 #define SYS_vm86 __NR_vm86
 #define SYS_vm86old __NR_vm86old
 #define SYS_waitpid __NR_waitpid
 #endif