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authorGravatar Denis Vlasenko <vda.linux@googlemail.com>2007-04-19 17:26:34 +0000
committerGravatar Denis Vlasenko <vda.linux@googlemail.com>2007-04-19 17:26:34 +0000
commit05a6d9cbb202b8aa7379e39dfd09baccfbfc6c4b (patch)
treeb520bc162f092155e277ccd1151ca370529ccdd5 /shell/README.job
parent8581863a1b536e2db20036e680b58cc07c54ad55 (diff)
downloadbusybox-05a6d9cbb202b8aa7379e39dfd09baccfbfc6c4b.tar.gz
busybox-05a6d9cbb202b8aa7379e39dfd09baccfbfc6c4b.tar.bz2
doc: add README on shell job control
Diffstat (limited to 'shell/README.job')
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diff --git a/shell/README.job b/shell/README.job
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+strace of "sleep 1 | sleep 2" being run from interactive bash 3.0
+
+
+Synopsis:
+get current signal mask
+install default handlers for GHLD QUIT TERM
+install common handler for HUP INT ILL TRAP ABRT FPE BUS SEGV SYS PIPE ALRM TERM XCPU XFSZ VTALRM USR1 USR2
+ignore QUIT
+install handler for INT
+ignore TERM
+install handler for INT
+ignore TSTP TTOU TTIN
+install handler for WINCH
+get pid, ppid
+block all signals
+unblock all signals
+get our pprocess group
+ minidoc:
+ Each process group is a member of a session and each process is a member
+ of the session of which its process group is a member.
+ Process groups are used for distribution of signals, and by terminals
+ to arbitrate requests for their input: processes that have the same
+ process group as the terminal are foreground and may read, while others
+ will block with a signal if they attempt to read. These calls are thus used
+ by programs (shells) to create process groups in implementing job control.
+ The TIOCGPGRP and TIOCSPGRP calls described in termios(3) are used to get/set
+ the process group of the control terminal.
+ If a session has a controlling terminal, CLOCAL is not set and a hangup occurs,
+ then the session leader is sent a SIGHUP. If the session leader exits,
+ the SIGHUP signal will be sent to each process in the foreground process
+ group of the controlling terminal.
+ If the exit of the process causes a process group to become orphaned,
+ and if any member of the newly-orphaned process group is stopped, then a SIGHUP
+ signal followed by a SIGCONT signal will be sent to each process
+ in the newly-orphaned process group.
+...
+
+
+
+execve("/bin/sh", ["sh"], [/* 34 vars */]) = 0
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+rt_sigaction(SIGCHLD, {SIG_DFL}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGQUIT, {SIG_DFL}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGTERM, {SIG_DFL}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGHUP, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGINT, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGILL, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGTRAP, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGABRT, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGFPE, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGBUS, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGSEGV, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGSYS, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGPIPE, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGALRM, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGTERM, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGXCPU, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGXFSZ, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGVTALRM, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGUSR1, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGUSR2, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+rt_sigaction(SIGQUIT, {SIG_IGN}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTERM, {SIG_IGN}, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTSTP, {SIG_IGN}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGTTOU, {SIG_IGN}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGTTIN, {SIG_IGN}, {SIG_DFL}, 8) = 0
+rt_sigaction(SIGWINCH, {0x807dc33, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+getpid() = 19473
+getppid() = 19472
+rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+getpgrp() = 1865
+dup(2) = 4
+fcntl64(255, F_GETFD) = -1 EBADF (Bad file descriptor)
+dup2(4, 255) = 255
+close(4) = 0
+ioctl(255, TIOCGPGRP, [1865]) = 0
+getpid() = 19473
+setpgid(0, 19473) = 0
+rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
+ioctl(255, TIOCSPGRP, [19473]) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+fcntl64(255, F_SETFD, FD_CLOEXEC) = 0
+rt_sigaction(SIGCHLD, {0x807c922, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+fcntl64(0, F_GETFL) = 0x2 (flags O_RDWR)
+...
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
+ioctl(255, TIOCSPGRP, [19473]) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigaction(SIGINT, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTERM, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTERM, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGQUIT, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGQUIT, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGALRM, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTSTP, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTSTP, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTTOU, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTOU, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTTIN, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTIN, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGWINCH, {0x80ca5cd, [], SA_RESTORER|SA_RESTART, 0x6ff7a4f8}, {0x807dc33, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+write(2, "sh-3.00# ", 9) = 9
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+read(0, "s", 1) = 1
+write(2, "s", 1) = 1
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+read(0, "l", 1) = 1
+write(2, "l", 1) = 1
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+... rest of "sleep 1 | sleep 2" entered...
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+read(0, "2", 1) = 1
+write(2, "2", 1) = 1
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+read(0, "\r", 1) = 1
+write(2, "\n", 1) = 1
+rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
+ioctl(0, SNDCTL_TMR_STOP or TCSETSW, {B38400 opost isig icanon echo ...}) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTERM, {SIG_IGN}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGQUIT, {SIG_IGN}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGALRM, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTSTP, {SIG_IGN}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTOU, {SIG_IGN}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTIN, {SIG_IGN}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGWINCH, {0x807dc33, [], SA_RESTORER, 0x6ff7a4f8}, {0x80ca5cd, [], SA_RESTORER|SA_RESTART, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
+pipe([4, 5]) = 0
+rt_sigprocmask(SIG_BLOCK, [INT CHLD], [CHLD], 8) = 0
+fork() = 19755
+setpgid(19755, 19755) = 0
+rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
+close(5) = 0
+rt_sigprocmask(SIG_BLOCK, [INT CHLD], [CHLD], 8) = 0
+fork() = 19756
+setpgid(19756, 19755) = 0
+rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
+close(4) = 0
+rt_sigprocmask(SIG_BLOCK, [CHLD], [CHLD], 8) = 0
+rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [CHLD], 8) = 0
+ioctl(255, TIOCSPGRP, [19755]) = 0
+rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
+rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
+rt_sigprocmask(SIG_BLOCK, [CHLD], [CHLD], 8) = 0
+wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], WUNTRACED, NULL) = 19755
+wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], WUNTRACED, NULL) = 19756
+rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [CHLD], 8) = 0
+ioctl(255, TIOCSPGRP, [19473]) = 0
+rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
+rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+--- SIGCHLD (Child exited) @ 0 (0) ---
+wait4(-1, 0x77fc9c54, WNOHANG|WUNTRACED, NULL) = -1 ECHILD (No child processes)
+sigreturn() = ? (mask now [])
+rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
+rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
+ioctl(255, TIOCSPGRP, [19473]) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigaction(SIGINT, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTERM, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTERM, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGQUIT, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGQUIT, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGALRM, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f752, [HUP INT ILL TRAP ABRT BUS FPE USR1 SEGV USR2 PIPE ALRM TERM XCPU XFSZ VTALRM SYS], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTSTP, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTSTP, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTTOU, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTOU, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGTTIN, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTIN, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGWINCH, {0x80ca5cd, [], SA_RESTORER|SA_RESTART, 0x6ff7a4f8}, {0x807dc33, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+write(2, "sh-3.00# ", 9) = 9
+
+
+getpid() = 19755
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigaction(SIGTSTP, {SIG_DFL}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTIN, {SIG_DFL}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTOU, {SIG_DFL}, {SIG_IGN}, 8) = 0
+setpgid(19755, 19755) = 0
+rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
+ioctl(255, TIOCSPGRP, [19755]) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+close(4) = 0
+dup2(5, 1) = 1
+close(5) = 0
+rt_sigaction(SIGINT, {SIG_DFL}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGQUIT, {SIG_DFL}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTERM, {SIG_DFL}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGCHLD, {SIG_DFL}, {0x807c922, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+execve("/bin/sleep", ["sleep", "1"], [/* 34 vars */]) = 0
+...
+_exit(0) = ?
+
+
+getpid() = 19756
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+rt_sigaction(SIGTSTP, {SIG_DFL}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTIN, {SIG_DFL}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTTOU, {SIG_DFL}, {SIG_IGN}, 8) = 0
+setpgid(19756, 19755) = 0
+rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
+ioctl(255, TIOCSPGRP, [19755]) = 0
+rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
+dup2(4, 0) = 0
+close(4) = 0
+rt_sigaction(SIGINT, {SIG_DFL}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+rt_sigaction(SIGQUIT, {SIG_DFL}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGTERM, {SIG_DFL}, {SIG_IGN}, 8) = 0
+rt_sigaction(SIGCHLD, {SIG_DFL}, {0x807c922, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
+execve("/bin/sleep", ["sleep", "2"], [/* 34 vars */]) = 0
+...
+_exit(0) = ?