1strace of "sleep 1 | sleep 2" being run from interactive bash 3.0
2
3
4Synopsis:
5open /dev/tty [, if fails, open ttyname(0)]; close /* helps re-establish ctty */
6get current signal mask
7TCGETS on fd# 0
8TCGETS on fd# 2 /* NB: if returns ENOTTY (2>/dev/null), sh seems to disable job control,
9                   does not show prompt, but still executes cmds from fd# 0 */
10install default handlers for CHLD QUIT TERM
11install common handler for HUP INT ILL TRAP ABRT FPE BUS SEGV SYS PIPE ALRM TERM XCPU XFSZ VTALRM USR1 USR2
12ignore QUIT
13install handler for INT
14ignore TERM
15install handler for INT
16ignore TSTP TTOU TTIN
17install handler for WINCH
18get pid, ppid
19block all signals
20unblock all signals
21get our pprocess group
22    minidoc:
23    Each process group is a member of a session and each process is a member
24    of the session of which its process group is a member.
25    Process groups are used for distribution of signals, and by terminals
26    to arbitrate requests for their input: processes that have the same
27    process group as the terminal are foreground and may read, while others
28    will block with a signal if they attempt to read.  These calls are thus used
29    by programs (shells) to create process groups in implementing job control.
30    The TIOCGPGRP and TIOCSPGRP calls described in termios(3) are used to get/set
31    the process group of the control terminal.
32    If a session has a controlling terminal, CLOCAL is not set and a hangup occurs,
33    then the session leader is sent a SIGHUP.  If the session leader exits,
34    the SIGHUP signal will be sent to each process in the foreground process
35    group of the controlling terminal.
36    If the exit of the process causes a process group to become orphaned,
37    and if any member of the newly-orphaned process group is stopped, then a SIGHUP
38    signal followed by a SIGCONT signal will be sent to each process
39    in the newly-orphaned process group.
40...
41dup stderr to fd# 255
42move ourself to our own process group
43block CHLD TSTP TTIN TTOU
44set tty's (255, stderr's) foreground process group to our group
45allow all signals
46mark 255 CLOEXEC
47set CHLD handler
48get signal mask
49get fd#0 flags
50get signal mask
51set INT handler
52block CHLD TSTP TTIN TTOU
53set fd #255 foreground process group to our group
54allow all signals
55set INT handler
56block all signals
57allow all signals
58block INT
59allow all signals
60lotsa sigactions: set INT,ALRM,WINCH handlers, ignore TERM,QUIT,TSTP,TTOU,TTIN
61block all signals
62allow all signals
63block all signals
64allow all signals
65block all signals
66allow all signals
67read "sleep 1 | sleep 2\n"
68block INT
69TCSETSW on fd# 0
70allow all signals
71lotsa sigactions: set INT,ALRM,WINCH handlers, ignore TERM,QUIT,TSTP,TTOU,TTIN
72block CHLD
73pipe([4, 5])  /* oops seems I lost another pipe() in editing... */
74fork child #1
75put child in it's own process group
76block only CHLD
77close(5)
78block only INT CHLD
79fork child #2
80put child in the same process group as first one
81block only CHLD
82close(4)
83block only CHLD
84block only CHLD TSTP TTIN TTOU
85set fd# 255 foreground process group to first child's one
86block only CHLD
87block only CHLD
88block only CHLD
89/* note: because shell is not in foreground now, e.g. Ctrl-C will send INT to children only! */
90wait4 for children to die or stop - first child exits
91wait4 for children to die or stop - second child exits
92block CHLD TSTP TTIN TTOU
93set fd# 255 foreground process group to our own one
94block only CHLD
95block only CHLD
96block nothing
97--- SIGCHLD (Child exited) @ 0 (0) ---
98    wait for it - no child (already waited for)
99    sigreturn()
100read signal mask
101lotsa sigactions...
102read next command
103
104
105execve("/bin/sh", ["sh"], [/* 34 vars */]) = 0
106rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
107ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
108ioctl(2, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
109rt_sigaction(SIGCHLD, {SIG_DFL}, {SIG_DFL}, 8) = 0
110rt_sigaction(SIGQUIT, {SIG_DFL}, {SIG_DFL}, 8) = 0
111rt_sigaction(SIGTERM, {SIG_DFL}, {SIG_DFL}, 8) = 0
112rt_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
113rt_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
114rt_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
115rt_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
116rt_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
117rt_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
118rt_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
119rt_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
120rt_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
121rt_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
122rt_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
123rt_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
124rt_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
125rt_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
126rt_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
127rt_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
128rt_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
129rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
130rt_sigaction(SIGQUIT, {SIG_IGN}, {SIG_DFL}, 8) = 0
131rt_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
132rt_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
133rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
134rt_sigaction(SIGTSTP, {SIG_IGN}, {SIG_DFL}, 8) = 0
135rt_sigaction(SIGTTOU, {SIG_IGN}, {SIG_DFL}, 8) = 0
136rt_sigaction(SIGTTIN, {SIG_IGN}, {SIG_DFL}, 8) = 0
137rt_sigaction(SIGWINCH, {0x807dc33, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
138getpid()                = 19473
139getppid()               = 19472
140rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
141rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
142getpgrp()               = 1865
143dup(2)                  = 4
144fcntl64(255, F_GETFD)   = -1 EBADF (Bad file descriptor)
145dup2(4, 255)            = 255
146close(4)                = 0
147ioctl(255, TIOCGPGRP, [1865]) = 0
148getpid()                = 19473
149setpgid(0, 19473)       = 0
150rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
151ioctl(255, TIOCSPGRP, [19473]) = 0
152rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
153fcntl64(255, F_SETFD, FD_CLOEXEC) = 0
154rt_sigaction(SIGCHLD, {0x807c922, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_DFL}, 8) = 0
155rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
156fcntl64(0, F_GETFL)     = 0x2 (flags O_RDWR)
157...
158rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
159rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
160rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
161ioctl(255, TIOCSPGRP, [19473]) = 0
162rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
163rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
164rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
165rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
166rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
167rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
168rt_sigaction(SIGINT, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
169rt_sigaction(SIGTERM, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
170rt_sigaction(SIGTERM, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
171rt_sigaction(SIGQUIT, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
172rt_sigaction(SIGQUIT, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
173rt_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
174rt_sigaction(SIGTSTP, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
175rt_sigaction(SIGTSTP, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
176rt_sigaction(SIGTTOU, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
177rt_sigaction(SIGTTOU, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
178rt_sigaction(SIGTTIN, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
179rt_sigaction(SIGTTIN, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
180rt_sigaction(SIGWINCH, {0x80ca5cd, [], SA_RESTORER|SA_RESTART, 0x6ff7a4f8}, {0x807dc33, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
181rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
182rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
183rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
184rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
185rt_sigprocmask(SIG_BLOCK, ~[], [], 8) = 0
186rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
187write(2, "sh-3.00# ", 9) = 9
188rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
189read(0, "s", 1)         = 1
190write(2, "s", 1)        = 1
191rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
192read(0, "l", 1)         = 1
193write(2, "l", 1)        = 1
194rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
195... rest of "sleep 1 | sleep 2" entered...
196rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
197read(0, "2", 1)         = 1
198write(2, "2", 1)        = 1
199rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
200read(0, "\r", 1)        = 1
201write(2, "\n", 1)       = 1
202rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
203ioctl(0, SNDCTL_TMR_STOP or TCSETSW, {B38400 opost isig icanon echo ...}) = 0
204rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
205rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
206rt_sigaction(SIGTERM, {SIG_IGN}, {SIG_IGN}, 8) = 0
207rt_sigaction(SIGQUIT, {SIG_IGN}, {SIG_IGN}, 8) = 0
208rt_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
209rt_sigaction(SIGTSTP, {SIG_IGN}, {SIG_IGN}, 8) = 0
210rt_sigaction(SIGTTOU, {SIG_IGN}, {SIG_IGN}, 8) = 0
211rt_sigaction(SIGTTIN, {SIG_IGN}, {SIG_IGN}, 8) = 0
212rt_sigaction(SIGWINCH, {0x807dc33, [], SA_RESTORER, 0x6ff7a4f8}, {0x80ca5cd, [], SA_RESTORER|SA_RESTART, 0x6ff7a4f8}, 8) = 0
213rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
214rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
215pipe([4, 5])            = 0
216rt_sigprocmask(SIG_BLOCK, [INT CHLD], [CHLD], 8) = 0
217fork()                  = 19755
218setpgid(19755, 19755)                = 0
219rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
220close(5)                = 0
221rt_sigprocmask(SIG_BLOCK, [INT CHLD], [CHLD], 8) = 0
222fork()                  = 19756
223setpgid(19756, 19755)   = 0
224rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
225close(4)                = 0
226rt_sigprocmask(SIG_BLOCK, [CHLD], [CHLD], 8) = 0
227rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [CHLD], 8) = 0
228ioctl(255, TIOCSPGRP, [19755]) = 0
229rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
230rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
231rt_sigprocmask(SIG_BLOCK, [CHLD], [CHLD], 8) = 0
232wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], WUNTRACED, NULL) = 19755
233wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], WUNTRACED, NULL) = 19756
234rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [CHLD], 8) = 0
235ioctl(255, TIOCSPGRP, [19473]) = 0
236rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
237rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0
238rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
239--- SIGCHLD (Child exited) @ 0 (0) ---
240wait4(-1, 0x77fc9c54, WNOHANG|WUNTRACED, NULL) = -1 ECHILD (No child processes)
241sigreturn()             = ? (mask now [])
242rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
243rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
244rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
245ioctl(255, TIOCSPGRP, [19473]) = 0
246rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
247rt_sigaction(SIGINT, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
248rt_sigprocmask(SIG_BLOCK, [INT], [], 8) = 0
249rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
250rt_sigaction(SIGINT, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
251rt_sigaction(SIGTERM, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
252rt_sigaction(SIGTERM, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
253rt_sigaction(SIGQUIT, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
254rt_sigaction(SIGQUIT, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
255rt_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
256rt_sigaction(SIGTSTP, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
257rt_sigaction(SIGTSTP, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
258rt_sigaction(SIGTTOU, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
259rt_sigaction(SIGTTOU, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
260rt_sigaction(SIGTTIN, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, {SIG_IGN}, 8) = 0
261rt_sigaction(SIGTTIN, {SIG_IGN}, {0x80ca530, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
262rt_sigaction(SIGWINCH, {0x80ca5cd, [], SA_RESTORER|SA_RESTART, 0x6ff7a4f8}, {0x807dc33, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
263write(2, "sh-3.00# ", 9) = 9
264
265
266getpid() = 19755
267rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
268rt_sigaction(SIGTSTP, {SIG_DFL}, {SIG_IGN}, 8)    = 0
269rt_sigaction(SIGTTIN, {SIG_DFL}, {SIG_IGN}, 8) = 0
270rt_sigaction(SIGTTOU, {SIG_DFL}, {SIG_IGN}, 8) = 0
271setpgid(19755, 19755) = 0
272rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
273ioctl(255, TIOCSPGRP, [19755]) = 0
274rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
275close(4)   = 0
276dup2(5, 1) = 1
277close(5)              = 0
278rt_sigaction(SIGINT, {SIG_DFL}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
279rt_sigaction(SIGQUIT, {SIG_DFL}, {SIG_IGN}, 8) = 0
280rt_sigaction(SIGTERM, {SIG_DFL}, {SIG_IGN}, 8) = 0
281rt_sigaction(SIGCHLD, {SIG_DFL}, {0x807c922, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
282execve("/bin/sleep", ["sleep", "1"], [/* 34 vars */]) = 0
283...
284_exit(0)                = ?
285
286
287getpid() = 19756
288rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
289rt_sigaction(SIGTSTP, {SIG_DFL}, {SIG_IGN}, 8) = 0
290rt_sigaction(SIGTTIN, {SIG_DFL}, {SIG_IGN}, 8) = 0
291rt_sigaction(SIGTTOU, {SIG_DFL}, {SIG_IGN}, 8) = 0
292setpgid(19756, 19755) = 0
293rt_sigprocmask(SIG_BLOCK, [CHLD TSTP TTIN TTOU], [], 8) = 0
294ioctl(255, TIOCSPGRP, [19755]) = 0
295rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
296dup2(4, 0) = 0
297close(4) = 0
298rt_sigaction(SIGINT, {SIG_DFL}, {0x808f7d7, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
299rt_sigaction(SIGQUIT, {SIG_DFL}, {SIG_IGN}, 8) = 0
300rt_sigaction(SIGTERM, {SIG_DFL}, {SIG_IGN}, 8) = 0
301rt_sigaction(SIGCHLD, {SIG_DFL}, {0x807c922, [], SA_RESTORER, 0x6ff7a4f8}, 8) = 0
302execve("/bin/sleep", ["sleep", "2"], [/* 34 vars */]) = 0
303...
304_exit(0)                = ?
305