1Noteworthy changes in release 4.16 (2017-02-14)
2===============================================
3
4* Improvements
5  * Implemented syscall return value injection (-e inject=SET:retval= option).
6  * Implemented signal injection (-e inject=SET:signal= option).
7  * Implemented decoding of SUID_DUMP_* constants in PR_[GS]ET_DUMPABLE.
8  * Implemented decoding of all SG_* ioctl commands.
9  * Implemented decoding of ustat syscall.
10  * Implemented decoding of BPF_OBJ_PIN, BPF_OBJ_GET, BPF_PROG_ATTACH,
11    and BPF_PROG_DETACH commands of bpf syscall.
12  * Enhanced decoding of sg_io_hdr and sg_io_v4 structures.
13  * Enhanced decoding of get_robust_list, getrandom, io_submit, set_robust_list
14    syscalls.
15  * Enhanced decoding of entities of kernel long type on x32 and mips n32 ABIs.
16  * Updated lists of IP_*, IPV6_*, and LOOP_* constants.
17  * Updated lists of ioctl commands from Linux 4.10.
18  * Added decoding of recently added syscalls on avr32, microblaze, ppc,
19    and ppc64.
20
21* Bug fixes
22  * Fixed pathmatch of oldselect syscall on 64-bit architectures.
23  * Fixed decoding of mmap2 syscall on s390 when arguments are not available.
24  * Fixed decoding of kexec_file_load, mprotect, pkey_mprotect, prctl, preadv*,
25    and pwritev* syscalls on x32.
26  * Fixed printing of string arguments of getxattr and setxattr syscalls
27    when -s option is used to limit the printed string size.
28  * Fixed decoding of ifconf, ifreq, and loop_info structures on non-native
29    personalities.
30  * Fixed decoding of SG_* and LOOP_* ioctl commands.
31  * Fixed build on mips with musl libc.
32  * Fixed cross-building of ioctlsort.
33  * Applied minor formatting fixes to the manual page.
34
35Noteworthy changes in release 4.15 (2016-12-14)
36===============================================
37
38* Changes in behavior
39  * Time stamps are now printed according to ISO 8601.
40  * Changed output format of val3 parameter of futex FUTEX_WAKE_OP operation.
41  * The last argument of mincore, sched_getaffinity, and sched_setaffinity
42    syscalls is now formatted as an array.
43
44* Improvements
45  * Implemented syscall fault injection (-e fault=... option).
46  * Implemented decoding of DM_* ioctl commands.
47  * Implemented decoding of attr parameter of perf_event_open syscall.
48  * Implemented decoding of pkey_alloc, pkey_free, and pkey_mprotect syscalls.
49  * Implemented dumping of mq_timedsend and mq_timedreceive syscalls.
50  * Implemented decoding of PR_SET_FP_MODE and PR_GET_FP_MODE operations
51    of prctl syscall.
52  * Implemented PTRACE_GETREGS API support on m68k.
53  * Updated lists of ARCH_*, BPF_*, BTRFS_*, FALLOC_*, MS_*, *_MAGIC,
54    and V4L2_* constants.
55  * Updated lists of ioctl commands from Linux 4.9.
56  * Added decoding of recently added syscalls on arc, x32, and xtensa.
57  * Enhanced manual page.
58
59* Bug fixes
60  * Fixed corner cases in decoding of exit, exit_group, futimesat, getgroups,
61    getresuid, init_module, inotify_init1, kcmp, kexec_load, lookup_dcookie,
62    mq_getsetattr, mq_notify, mq_open, mq_timedreceive, mq_timedsend,
63    name_to_handle_at, prctl, process_vm_readv, process_vm_writev, setfsuid,
64    setgroups, setns, unshare, and utimes syscalls.
65  * Fixed handling of verbose flag in printing of controls array
66    of struct v4l2_ext_controls.
67  * Fixed omission of field names in the output of capability, sigaction,
68    sigevent, statfs, timespec, timeval, and utimbuf structures.
69  * Fixed printing of unknown syscalls in siginfo structure.
70  * Fixed decoding of ioctl constants on m68k.
71  * Fixed cris architecture support.
72  * Fixed cross build when host compiler does not support the same
73    set of warning flags as the cross compiler.
74  * Fixed build on SLE10 and SLE11.
75
76Noteworthy changes in release 4.14 (2016-10-04)
77===============================================
78
79* Changes in behavior
80  * When using -p option without a command and no processes has been attached,
81    strace exits with exit status 1.
82
83* Improvements
84  * Added printing of the mode argument of open and openat syscalls
85    when O_TMPFILE flag is set.  (Addresses Fedora bug #1377846).
86  * Enhanced -e abbrev=set, -e raw=set, and -e verbose=set.
87  * Enhanced decoding of futex, keyctl, quotactl, timerfd_settime,
88    and aio family syscalls.
89  * Implemented fetching of the 7th subcall argument on mips o32.
90  * Updated lists of BPF_*, ETH_P_*, KEXEC_ARCH_*, SCTP_*, TCP_*, and *_MAGIC
91    constants.
92  * Updated lists of ioctl commands from Linux 4.8.
93  * Added decoding of new syscalls on sh and sh64.
94  * Added RISC-V architecture support.
95
96* Bug fixes
97  * Marked io_setup and io_destroy as memory mapping related syscalls.
98  * Fixed leakage of placeholder descriptors to tracees.
99  * Fixed printing of mode_t, umode_t, and umask types.
100  * Fixed decoding of iovec arrays without a limit on total data size.
101  * Fixed decoding of fadvise64, fallocate, futex, keyctl, quotactl, readahead,
102    and ipc family syscalls.
103  * Fixed decoding of invalid syscalls mapped to indirect subcalls.
104  * Fixed decoding of struct btrfs_ioctl_vol_args_v2 on non-native
105    personalities.
106  * Fixed decoding of PTRACE_DETACH on sparc and sparc64.
107  * Fixed decoding of struct stat64 on sparc64.
108  * Fixed decoding of uid and gid-related syscalls on sparc64.
109  * Fixed decoding of the forth argument of semctl syscall on sparc64.
110  * Fixed values of tty ioctl constants on sparc64.
111  * Fixed sparc personality support on sparc64.
112
113Noteworthy changes in release 4.13 (2016-07-26)
114===============================================
115
116* Improvements
117  * Implemented a general netlink socket parser.
118  * Enhanced decoding of socket addresses.
119  * Enhanced decoding of cmsghdr, msghdr, and mmsghdr structures.
120  * Enhanced decoding of accept, accept4, bind, getpeername, getsockname,
121    ipc, recvfrom, recvmsg, recvmmsg, sendto, sendmmsg, and socketcall syscalls.
122  * Updated lists of AF_*, BPF_MAP_TYPE_*, KEY_*, KEYCTL_*, RWF_*, SS_*,
123    and *_MAGIC constants.
124  * Updated lists of ioctl commands from Linux 4.7.
125
126* Bug fixes
127  * Fixed decoding of pid_t argument of prlimit64 syscall.
128  * Fixed sign extension issues in the parser of struct rusage.
129  * Fixed race condition in decoding of timeout argument of recvmmsg and
130    rt_sigtimedwait syscalls.
131  * Fixed build with fresh linux kernel headers.
132
133Noteworthy changes in release 4.12 (2016-05-31)
134===============================================
135
136* Improvements
137  * Implemented simultaneous use of -p option and tracing of a command.
138    (addresses Debian bug #549942).
139  * Implemented caching of netlink conversations to reduce amount of time
140    spent in decoding socket details in -yy mode.
141  * Implemented -yy mode decoding of protocol:portid pairs associated with
142    netlink socket descriptors.
143  * Implemented decoding of copy_file_range, preadv2, and pwritev2 syscalls.
144  * Implemented dumping of preadv, preadv2, pwritev, pwritev2, and vmsplice
145    syscalls.
146  * Implemented decoding of BTRFS_* and UFFDIO_* ioctl commands.
147  * Enhanced decoding of BLK*, EVIOC*, RTC_*, and VIDIOC_* ioctl commands.
148  * Enhanced decoding of fstatfs, fstatfs64, get_mempolicy, getdents,
149    getdents64, getgroups, getpriority, kill, mbind, migrate_pages, mknod,
150    mknodat, personality, poll, ppoll, quotactl, rt_sigpending,
151    rt_sigqueueinfo, rt_sigtimedwait, rt_tgsigqueueinfo, sched_getaffinity,
152    sched_setaffinity, seccomp, set_mempolicy, setgroups, setpriority, statfs,
153    statfs64, tgkill, waitid, and xattr family syscalls.
154  * Enhanced decoding of getxpid, getxuid, and getxgid syscalls on alpha.
155  * Enhanced decoding of pipe syscall on alpha, ia64, mips, sh, and sparc.
156  * Added decoding of bind, listen, and setsockopt direct syscalls on sparc.
157  * Added decoding of osf_statfs64 and osf_fstatfs64 syscalls on alpha.
158  * Added decoding of fadvise64 and fadvise64_64 on s390.
159  * Updated lists of AF_*, BPF_MAP_TYPE_*, CLONE_*, EPOLL*, IPV6_*, MADV_*,
160    MSG_*, PTRACE_*, SEGV_*, SO_*, SOL_*, *_MAGIC, and quotactl constants.
161  * Updated lists of ioctl commands from Linux 4.6.
162
163* Bug fixes
164  * Fixed build on arc, metag, nios2, or1k, and tile architectures.
165  * Fixed decoding of 32-bit times syscall return value on 64-bit architectures.
166  * Fixed decoding of mlock2 syscall on sparc.
167  * Fixed decoding of osf_shmat syscall on alpha.
168  * Fixed decoding of syscalls unknown to the kernel on s390/s390x.
169    (addresses Debian bug #485979 and Fedora bug #1298294).
170  * Fixed decoding of preadv syscall in case of short read.
171  * Fixed decoding and dumping of readv syscall in case of short read.
172  * Fixed dumping of recvmsg and recvmmsg syscalls in case of short read.
173  * Fixed decoding of mincore syscall's last argument.
174  * Fixed remaining errors in mapping between syscall numbers and numbers
175    of syscall arguments.
176  * Applied various fixes to strace-graph script.
177
178Noteworthy changes in release 4.11 (2015-12-21)
179===============================================
180
181* Changes in behavior
182  * Some syscalls have different names depending on architecture and
183    personality.  In these cases, syscall filtering and printing now
184    consistently uses the names that match corresponding __NR_* kernel
185    macros of the tracee's architecture and personality.
186  * Added strace prefix to all diagnostic messages.
187
188* Improvements
189  * Enhanced and extended test suite.
190  * Implemented reliable tracing of processes whose personality differs
191    from the personality of strace, fixed decoding of 32-bit personality
192    syscalls on 64-bit architectures.
193  * When some data referenced by syscall arguments is irrelevant or cannot
194    be read from tracee's memory, strace now prints its address consistently.
195  * When a syscall is restarted using restart_syscall mechanism, strace now
196    shows the syscall name on architectures that expose this information.
197  * Print values returned by epoll_create1, eventfd, eventfd2, fanotify_init,
198    inotify_init1, perf_event_open, pipe, pipe2, signalfd, signalfd4, socket,
199    socketpair, timerfd, and timerfd_create syscalls, as well as F_DUPFD and
200    F_DUPFD_CLOEXEC fcntl commands, as file descriptors.
201  * Optimized decoding of indirect socket syscalls.
202  * Implemented decoding of nanoseconds along with seconds in stat family
203    syscalls (addresses Fedora bug #1251176).
204  * Implemented decoding of struct statfs.f_flags in statfs syscall.
205  * Implemented decoding of siginfo_t.si_syscall and siginfo_t.si_arch
206    in SIGSYS signal.
207  * Implemented decoding of indirect syscall on mips o32.
208  * Implemented decoding of IPPROTO_IP control messages.
209  * Implemented decoding of setsockopt syscall multicast arguments.
210  * Enhanced decoding of struct sigevent.
211  * Enhanced decoding of block, loop, mtd, ptp, rtc, SG_IO, socket, tty,
212    and v4l2 ioctl syscall arguments.
213  * Enhanced decoding of epoll_create, fcntl, fcntl64, futex, getdents,
214    getdents64, getsockopt, io_*, mount, msgctl, prctl, quotactl, recvfrom,
215    sendfile, setsockopt, and shmctl syscalls.
216  * Implemented decoding of bpf, execveat, ioperm, iopl, kcmp, kexec_file_load,
217    lookup_dcookie, membarrier, memfd_create, mlock2, name_to_handle_at,
218    open_by_handle_at, sched_getattr, sched_setattr, and userfaultfd syscalls.
219  * Updated lists of AF_*, EPOLL_*, FALLOC_FL_*, F_*, INPUT_PROP_*, IPPROTO_*,
220    IPV6_*, IP_*, KEY_*, LOCK_*, MNT_*, MS_*, PACKET_*, PERF_FLAG_*, PF_*,
221    PR_*, PTRACE_O_*, RENAME_*, SCTP_*, SECBIT_*, SO_*, TCP_*, and siginfo_t
222    constants.
223  * Added Nios II architecture support.
224  * Added new syscall entries to match Linux 4.4.
225
226* Bug fixes
227  * Fixed potential short read of strings from tracee's memory.
228  * Fixed -qq option in conjunction with -o option.
229  * Fixed filtering of <unavailable> syscalls.
230  * Fixed decoding of ioctl syscall command on aarch64 and 32-bit architectures
231    with 64-bit aligned structures.
232  * Fixed decoding of eventfd2, epoll_create1, signalfd4, and sync_file_range2
233    syscall flags arguments.
234  * Fixed decoding of 4th argument of clock_nanosleep syscall.
235  * Fixed decoding of getpagesize syscall on m68k.
236  * Fixed decoding of getrandom and seccomp syscalls on aarch64.
237  * Fixed decoding of timezone argument of gettimeofday and settimeofday
238  * syscalls.
239  * Fixed decoding of offset argument of mmap2 syscall on arm, sparc,
240    and sparc64.
241  * Fixed decoding of pipe syscall on alpha and mips.
242  * Fixed decoding of pipe2 syscall on ia64, sh, sparc, and sparc64.
243  * Fixed decoding of signal mask argument of pselect6 syscall on x32.
244  * Fixed decoding of signal mask of rt_sigreturn syscall on aarch64, m68k,
245    and x32.
246  * Fixed decoding of 4th argument of semctl indirect syscall.
247  * Fixed decoding of sa_restorer and sa_mask of sigaction syscall on m68k.
248  * Fixed decoding of statfs64 and fstatfs64 syscalls on arm eabi.
249  * Fixed decoding of struct dirent on x32.
250  * Fixed decoding of times syscall return value on mips n32 and x32.
251  * Fixed decoding of path argument of umount2 syscall
252    (addresses Debian bug #785050).
253  * Worked around a kernel bug in tracing privileged executables.
254  * Fixed various errors in mapping between syscall numbers and associated
255    information like the number of syscall arguments, the name of syscall,
256    and syscall decoder.
257
258Noteworthy changes in release 4.10 (2015-03-06)
259===============================================
260
261* Improvements
262  * Added -yy option to print protocol and address information associated with
263    socket descriptors.
264  * Extended "-e read=set" and "-e write=set" options to cover sendmsg,
265    recvmsg, sendmmsg, and recvmmsg syscalls.
266  * Implemented full 32-bit decoding of ioctl commands
267    (addresses Debian bug #692913 and Fedora bug #902788).
268  * Implemented PTRACE_GETREGS API support on ia64.
269  * Implemented PTRACE_GETREGS API support on mips.
270  * Implemented PTRACE_GETREGSET API support on s390/s390x.
271  * Implemented decoding of getrandom and seccomp syscalls.
272  * Implemented full decoding of 64-bit capability sets.
273  * Implemented decoding of all prctl commands.
274  * Implemented decoding of parametrized ioctl commands.
275  * Implemented decoding of evdev ioctl commands.
276  * Implemented decoding of v4l ioctl commands.
277  * Implemented decoding of SG_IO v4 ioctl commands.
278  * Implemented decoding of FIFREEZE/FITHAW/FITRIM ioctl commands.
279  * Implemented decoding of FALLOC_FL_* fallocate flags.
280  * Implemented decoding of rt_sigreturn signal mask on aarch64,
281    x32, and x86_64.
282  * Enhanced socket decoder to support bluetooth sockets.
283  * Enhanced decoding of unlisted ioctl commands.
284  * Enhanced decoding of getsockopt and setsockopt syscall.
285  * Enhanced decoding of sysinfo syscall.
286  * Enhanced decoding of struct cmsghdr.
287  * Enhanced decoding of wait status.
288  * Enhanced aio support on non-x86 architectures by using external libaio.h.
289  * Added O_TMPFILE to the list of recognized open mode flags.
290  * Updated the list of filesystem type constants that is used in decoding
291    statfs family syscalls.
292  * Updated lists of CAP_*, PR_*, PTRACE_*, SCHED_*, SO_*, SOL_*, SWAP_FLAG_*,
293    and TFD_* constants.
294  * Updated lists of signal constants from Linux 3.19.
295  * Updated lists of errno constants from Linux 3.19.
296  * Updated lists of ioctl commands from Linux 3.9.
297  * Added new syscall entries to match Linux 3.19.
298
299* Bug fixes
300  * Fixed various errors in mapping between syscall numbers and associated
301    information like the number of syscall arguments, the name of syscall,
302    and syscall decoder.
303  * Fixed quoting issues in printing descriptors, filenames, network interface
304    names, struct utsname members, device/volume names of BLK* ioctl commands.
305  * Fixed uid_t/git_t decoding.
306  * Fixed potential out-of-bounds read issues in getdents/getdents64 decoders.
307  * Fixed potential open flags truncation on some architectures.
308  * Fixed decoding of struct ifreq.ifr_name.
309  * Fixed decoding of SIOCSIFNAME ioctl command.
310  * Fixed decoding of RENAME_* renameat2 flags.
311  * Fixed decoding of UTIME_NOW/UTIME_OMIT timeval structures.
312  * Fixed decoding of indirect ipc subcalls on some architectures.
313  * Fixed decoding of fanotify_mark syscall on 32-bit architectures.
314  * Fixed decoding of 32-bit stat structures on 64-bit architectures.
315  * Fixed decoding of 32-bit struct cmsghdr on 64-bit architectures.
316  * Fixed decoding of 32-bit preadv/pwritev offset on 64-bit architectures.
317  * Fixed decoding of sigreturn/rt_sigreturn signal mask on ia64, ppc, ppc64,
318    sparc, sparc64, mips, and s390.
319  * Fixed instruction pointer output (-i option) on architectures that support
320    several personalities.
321  * Fixed behaviour of "-e read=set" and "-e write=set" when read and write
322    sets intersect.
323  * Fixed build on systems where struct sigaction has no sa_restorer member.
324  * Fixed build with uclibc and musl libc.
325
326* Portability
327  * Linux kernel >= 2.5.46 is required.
328    Older versions without a decent PTRACE_SETOPTIONS support will not work.
329  * On mips, linux kernel >= 2.6.15 is required.
330    Older versions without a decent PTRACE_GETREGS support will not work.
331  * On s390 and s390x, linux kernel >= 2.6.27 is required.
332    Older versions without a decent PTRACE_GETREGSET support will not work.
333
334Noteworthy changes in release 4.9 (2014-08-15)
335==============================================
336
337* Changes in behavior
338  * Disabled OABI support on ARM EABI systems by default,
339    added --enable-arm-oabi option to enable it at configure time.
340
341* Improvements
342  * Added experimental -k option to print stack trace after each traced syscall.
343  * Added -w option to produce stats on syscall latency.
344    (addresses Debian bug #457497).
345  * Added ARC architecture support.
346  * Added PTRACE_GETREGS API support on PowerPC.
347  * Enhanced Bionic libc and musl libc support.
348  * Enhanced tracing of x86 personality processes on x86_64 and x32.
349  * Enhanced tracing of ARM personality processes on AArch64.
350  * Enhanced 32/64bit personality detection on PowerPC.
351  * Implemented decoding of add_key, ioprio_get, ioprio_set, kexec_load, keyctl,
352    renameat2, and request_key syscalls.
353  * Robustified decoding of select, pselect, and io_submit syscalls.
354  * Enhanced decoding of delete_module, fanotify_init, fanotify_mark, fcntl,
355    setdomainname, sethostname, setns, and sync_file_range syscalls.
356  * Enhanced decoding of signal bitmasks.
357  * Enhanced decoding of file descriptors.
358  * Enhanced siginfo_t decoding.
359  * Enhanced PF_NETLINK decoding.
360  * Updated CLOCK_* constants
361    (addresses Fedora bug #1088455).
362  * Added new syscall entries to match Linux 3.16.
363
364* Bug fixes
365  * Added shmat and shmdt to the set of memory mapping related syscalls.
366  * Fixed detaching from stopped processes.
367  * Fixed fanotify_mark decoding on 32bit architectures.
368  * Fixed offset decoding in preadv and pwritev syscalls.
369  * Fixed select decoding for glibc in _FORTIFY_SOURCE mode.
370  * Fixed decoding of epoll_ctl syscall with EPOLL_CTL_DEL argument.
371  * Fixed build when <sys/ptrace.h> and <linux/ptrace.h> conflict
372    (addresses Fedora bug #993384).
373  * Miscellaneous corrections in the manual page.
374    (Addresses Debian bug #725987).
375
376Noteworthy changes in release 4.8 (2013-06-03)
377==============================================
378
379* Changes in behavior
380  * In case of normal strace termination, when the trace output is
381    redirected to a pipe, strace now closes it and waits for the pipe
382    process termination before exit.
383
384* Improvements
385  * Implemented tracing using PTRACE_SEIZE API (when available).
386  * Implemented more reliable PTRACE_GETREGSET-based process personality
387    detection on x86-64 and x32 (when available).
388  * Added -e trace=memory option for tracing memory mapping related syscalls.
389  * Documented -b option.
390  * Allowed exit status messages to be suppressed by giving -q option twice.
391  * Added AArch64 architecture support
392    (addresses Debian bug #693074 and Fedora bug #969858).
393  * Added support for OpenRISC 1000, Meta, and Xtensa architectures.
394  * Added tilegx personality support for Tile.
395  * Enhanced support of NOMMU architectures.
396  * Enhanced decoding of getdents, mmap, perf_event_open, ptrace, and
397    quotactl syscalls.
398  * Added new syscall entries to match Linux 3.9.
399  * Regenerated the list of common ioctl names from Linux 3.9.
400  * Updated the list of errno constants.
401  * Updated lists of AF_*, MADV_*, MAP_*, MSG_*, MS_*, PF_*, PR_*,
402    PTRACE_O_*, and TCP_* constants.
403  * Implemented decoding of UBI ioctls.
404  * Removed redundant "*32" ioctl names.
405
406* Bug fixes
407  * Fixed ERESTARTNOINTR leaking to userspace on ancient kernels
408    (addresses Fedora bug #659382).
409  * Fixed kernel release string parsing
410    (addresses Debian bug #702309).
411  * Fixed decoding of *xattr syscalls
412    (addresses Fedora bug #885233).
413  * Fixed handling of files with 64-bit inode numbers by 32-bit strace
414    (addresses Fedora bug #912790).
415  * Fixed tracing forks on SPARC.
416  * Fixed decoding of fadvise64, fallocate, ftruncate64, io_submit, pread,
417    preadv, pwrite, pwritev, readahead, sigaltstack, sync_file_range, sysctl,
418    and truncate64 syscalls.
419  * Fixed categories of multiple syscalls on most of supported architectures.
420  * Fixed decoding of non-native 32-bit personality recv[m]msg syscalls.
421  * Fixed decoding of multiple 32-bit personality syscalls on x32.
422  * Fixed decoding of long long syscall arguments on ARM, MIPS/o32, PowerPC,
423    S390x, and Tile architectures.
424  * Fixed semtimedop decoding on S390x.
425  * Fixed sram_alloc decoding on Blackfin.
426  * Fixed build when process_vm_readv is a stab.
427  * Fixed build with older versions of libaio.h.
428
429Noteworthy changes in release 4.7 (2012-05-02)
430==============================================
431
432* Changes in behavior
433  * strace no longer suspends waitpid until there is a child
434    for waitpid'ing process to collect status from.
435  * strace no longer detaches from a tracee which is supposed
436    to be going to die.
437  * strace now issues a new message: "+++ exited with EXITCODE +++"
438    which shows exact moment strace got exit notification,
439    analogous to existing "+++ killed by SIG +++" message.
440
441* Improvements
442  * Added x32 personality support (x86_64 architecture).
443  * Added -y and -P options to print file descriptor paths and
444    filter by those paths.
445  * Added -I option to control strace interactivity.
446  * Allowed -p option to take comma or whitespace-separated list of PIDs.
447  * Added strace_log_merge script helper to merge timestamped "strace -ff"
448    log files.
449  * Implemented decoding of clock_adjtime, get_robust_list, migrate_pages,
450    preadv, prlimit64, process_vm_readv, process_vm_writev, pwritev,
451    recvmmsg, recvmsg, rt_tgsigqueueinfo, sendmmsg, setns, set_robust_list,
452    sched_rr_get_interval, splice, syslog, tee and vmsplice syscalls.
453  * Enhanced decoding of capget, capset, getrlimit, flistxattr, io_submit,
454    listxattr, setrlimit and swapon syscalls.
455  * Implemented decoding of loop and mtd ioctls.
456  * Added syscall entries for new linux syscalls.
457  * Added syscall entries for direct socket system calls on powerpc.
458  * Updated the list of errno constants.
459  * Updated lists of MSG_*, STA_*, and TCP_* constants.
460  * Regenerated the list of ioctl names from Linux 3.3.
461  * Enhanced switching between processes with different personalities.
462  * Enhanced signals reporting by using short signal names.
463  * Made ERESTART* messages more descriptive.
464  * Made parsing of numbers from strings more robust.
465  * Added support for compat_statfs64 and statfs64.f_flags.
466  * Changed read of data blocks to use single process_vm_readv syscall
467    (when available) instead of several PTRACE_PEEKDATA operations.
468  * Changed read of registers on x86 and x86-64 to use single PTRACE_GETREGS
469    operation instead of several PTRACE_PEEKUSER operations.
470  * Applied various optimizations to make strace work faster.
471
472* Bug fixes
473  * Implemented proper handling of real SIGTRAPs on kernels supporting
474    PTRACE_O_TRACESYSGOOD.
475    (Addresses Fedora bug #162774).
476  * Fixed sockaddr_un.sun_path name in decoded output.
477    (Addresses Debian bug #554946).
478  * Fixed to avoid potential core file clobbering on exit.
479    (Addresses Debian bug #656398).
480  * Fixed a typo in documentation.
481    (Addresses Debian bug #653309).
482  * Fixed decoding of timer id returned by timer_create.
483  * Fixed epoll_create1, epoll_wait and epoll_pwait decoding.
484  * Fixed *at syscalls flags decoding.
485  * Fixed ARM EABI 64-bit syscall's arguments decoding.
486  * Fixed semtimedop decoding on s390.
487  * Fixed osf_sigprocmask decoding on alpha.
488  * Fixed ipc and socket subcall decoding on several architectures.
489  * Corrected syscall entries for epoll_pwait, epoll_create, epoll_ctl,
490    epoll_wait, mincore, mlockall, prctl, reboot, sendfile, sendfile64,
491    sendmsg, sgetmask, ssetmask, swapon, tgkill and tkill syscalls.
492  * Corrected io_* syscall entries on ARM.
493  * Fixed PID prefix printing in "strace -oLOG -ff -p1 -p2 -p3" case.
494  * Fixed logging of unfinished lines in "strace -oLOG -ff" case.
495  * Fixed build when libaio-devel is not available.
496  * Fixed configure checks for PTRACE_* constants.
497  * Fixed compilation warnings remained on several architectures.
498
499* Portability
500  * Removed all non-Linux code.  After years of neglect, that dead code
501    just hampered further strace development.
502  * Linux kernel >= 2.6.18 is recommended.  Older versions might still
503    work but they haven't been thoroughly tested with this release.
504
505Noteworthy changes in release 4.6 (2011-03-15)
506==============================================
507
508* Changes in behavior
509  * Print diagnostic information about changes in personality mode to
510    standard error instead of standard output.
511
512* Improvements
513  * Implemented a new method of following clone, fork, and vfork
514    syscalls using the Linux kernel's explicit facilities for tracing
515    creation of threads and child processes.
516  * Implemented CLONE_PARENT and CLONE_UNTRACED flags handling.
517  * Implemented decoding of TLS syscalls on m68k.
518  * Implemented biarch support on powerpc64.
519  * Implemented biarch support for getrlimit() and setrlimit().
520  * Implemented decoding of struct ucred in getsockopt SO_PEERCRED.
521  * Implemented SOL_SCTP socket options decoding.
522  * Added HDIO_* ioctl names.
523    (Addresses Debian bug #450953).
524  * Added LOOP_* ioctl names.
525  * Updated lists of CLOCK_*, CLONE_*, MS_*, and SOL_* constants
526    to match Linux 2.6.37.
527  * Updated the list of IPPROTO_* constants to match netinet/in.h.
528  * Implemented decoding of HDIO_* and BLK* ioctls.
529  * Added MicroBlaze architecture support.
530  * Added new syscall entries to match Linux 2.6.37.
531  * Regenerated list of ioctl names from Linux 2.6.37.
532  * Enhanced signal notification decoding.
533  * Documented -C and -D options.
534
535* Bug fixes
536  * Fixed fetching syscall arguments on m68k.
537  * Fixed an error when judging whether a process has children.
538  * Fixed get/set_robust_list syscall numbers for powerpc.
539  * Fixed a corner case in printing clone flags.
540  * Fixed cross-compiling issues.
541  * Fixed build issues on powerpc64, SH and SPARC.
542  * Fixed syscall flags of fstatat*, mmap, mmap2, fadvise64*, swapoff,
543    fgetxattr, flistxattr, fremovexattr, epoll_create, fallocate,
544    fanotify_init, and fanotify_mark syscalls.
545  * Fixed decoding of get[ug]id, gete[ug]id and setfs[ug]id return values.
546  * Fixed biarch support in IO dumping.
547  * Fixed raw exit_group decoding.
548  * Fixed decoding of file descriptors on 64-bit architectures.
549  * Fixed a corner case in waitpid handling.
550    (Addresses Red Hat bug #663547).
551  * Fixed stat64 decoding on mips
552    (Addresses Debian bug #599028).
553  * Fixed misleading italics in the manual page.
554    (Addresses Debian bug #589323).
555
556Noteworthy changes in release 4.5.20 (2010-04-13)
557=================================================
558
559* Improvements
560  * Implemented decoding of new linux syscalls: inotify_init1, recvmmsg.
561  * Implemented basic decoding of new linux syscalls: preadv, pwritev,
562    rt_tgsigqueueinfo, perf_event_open.
563  * Enhanced decoding of recently added syscalls on non-x86 architectures
564    by replacing a bare decoder with elaborate parsers enabled earlier
565    for x86/x86-64.
566  * Implemented -C option to combine regular and -c output.
567    (Addresses Debian bug #466196)
568  * Enhanced decoding of mbind and mremap syscalls.
569  * Enhanced SOL_PACKET socket options decoding.
570  * Regenerated list of ioctl names from linux 2.6.33.
571  * Added TILE architecture support.
572
573* Bug fixes
574  * Fixed build with Linux kernel headers 2.6.32-rc5+.
575    (Addresses Debian bug #560516 and Fedora bug #539044)
576  * Fixed build on mips.
577  * Fixed handling of Linux systems without struct statfs64.
578  * Fixed reporting signal mask by sigreturn on powerpc.
579  * Fixed potential stack buffer overflow in select decoder.
580    (Addresses Fedora bug #556678)
581  * Corrected msgsnd indirect ipccall decoding.
582  * Corrected decoding of 64bit syscalls.
583    (Addresses Debian bug #570603)
584  * Corrected getsockopt decoding on architectures where
585    sizeof(long) > sizeof(int).
586    (Addresses Debian bug #494844)
587  * Corrected decoding of epoll_pwait.
588    (Addresses Debian bug #513014)
589  * Corrected handling of killed threads.
590
591Noteworthy changes in release 4.5.19 (2009-10-21)
592=================================================
593
594* Changes in behavior
595  * When command exits, strace now exits with the same exit status.
596    If command is terminated by a signal, strace terminates itself
597    with the same signal, so that strace can be used as a wrapper
598    process transparent to the invoking parent process.
599    When using -p option, the exit status of strace is zero unless
600    there was an unexpected error in doing the tracing.
601    (Addresses Fedora bug #105371 and Debian bug #37665)
602
603* Improvements
604  * Implemented decoding of new Linux syscalls: accept4, dup3,
605    epoll_create1, eventfd2, inotify_init1, pipe2, signalfd4.
606  * Implemented decoding of socket type flags introduced in Linux 2.6.27.
607  * Implemented decoding of accept4 socketcall.
608  * Enhanced prctl decoding.
609  * Enhanced nanosleep decoding.
610  * Enhanced ptrace decoding.
611  * Enhanced futex decoding.
612  * Enhanced CAP_* decoding.
613  * Enhanced SIOCS* ioctls decoding.
614  * Enhanced fcntl F_* flags decoding.
615  * Enhanced semop/semtimedop decoding.
616  * Updated ARM architecture support.
617  * Added Blackfin architecture support.
618  * Added AVR32 architecture support.
619  * Added CRIS architecture support.
620  * Made strace detect when traced process suddenly disappeared.
621
622* Bug fixes
623  * Fixed syscall numbers for tee and sync_file_range.
624    (Addresses Debian bug #503124)
625  * Fixed several bugs in strings decoder, including potential heap
626    memory corruption.
627    (Addresses Fedora bugs #470529, #478324 and #511035)
628  * Marked sendfile(2) as a network syscall.
629    (Addresses Debian bug #509499)
630  * Fixed accept(2) decoding.
631    (Addresses Debian bug #507573)
632  * Fixed sigtimedwait(2) decoding.
633  * Fixed build on ARM EABI.
634    (Addresses Debian bugs #520084 and #535564, and Fedora bug #507576)
635  * Fixed display of 32-bit fcntl(F_SETLK) on 64-bit architectures.
636    (Addresses Red Hat bug #471169)
637  * Fixed display of 32-bit argv array on 64-bit architectures.
638    (Addresses Fedora bug #519480)
639  * Fixed display of 32-bit struct sigaction on 64-bit architectures.
640  * Fixed HPPA architecture support.
641    (Addresses Debian bugs #437928 and #546619)
642
643Changes in 4.5.18
644==============
645* Bug fixes.
646* Support new Linux/PPC system call subpage_prot and PROT_SAO flag.
647* In sigaction system call, display sa_flags value along with SIG_DFL/SIG_IGN.
648
649Changes in 4.5.17
650==============
651* Many bug fixes.
652* -F is now deprecated, -f has traced vfork too on Linux for a long time now.
653* Print O_CLOEXEC, MSG_CMSG_CLOEXEC flag bits.
654* Improved output for prctl system call on Linux.
655* Improved support for Linux/ARM.
656* SA_NOMASK is now spelled SA_NODEFER, and SA_ONESHOT is spelled SA_RESETHAND.
657
658Changes in 4.5.16
659==============
660* Bug fixes.
661* Improved output for delete_module, futex, and mbind system calls on Linux.
662* Improved output for SG_IO ioctls on Linux.
663* Support new Linux system calls move_pages, utimensat, signalfd, timerfd,
664  eventfd, getcpu, epoll_pwait.
665
666Changes in 4.5.15
667==============
668* Bug fixes.
669* Several biarch improvements.
670* Improved output for adjtimex, sysctl, quotactl, mount, umount.
671* Support new Linux system calls *at, inotify*, pselect6, ppoll and unshare.
672
673Changes in 4.5.14
674==============
675* Bug fixes.
676* Accept numeric system calls in -e.
677
678Changes in 4.5.13
679==============
680* Bug fixes.
681* Introduce "-e trace=desc".
682
683Changes in 4.5.12
684==============
685* Bug fixes.
686* Better x86-64 support for IA32 processes.
687* Update PowerPC system calls.
688* Better printing for Linux aio system calls.
689
690Changes in 4.5.11
691==============
692* Quick fix release for build issues.
693* One fix for Linux/ARM system call table.
694
695Changes in 4.5.10
696==============
697* Bug fixes.
698* Print fault address for SIGSEGV/SIGBUS signals when available.
699
700Changes in 4.5.9
701==============
702* Bug fixes.
703* Improve socket ioctl printing.
704* Update Linux/IA64 syscall list.
705* Fix Linux/x86-64 syscall argument extraction for 32-bit processes.
706* Improve mount flags printing.
707* Support symbolic printing of x86_64 arch_prctl parameters.
708
709Changes in 4.5.8
710==============
711* Bug fixes.
712* Update syscall tables for Alpha, ARM, HPPA.
713* Support new Linux syscalls mbind, set_mempolicy, get_mempolicy, waitid.
714* Support Linux syscalls fadvise64, fadvise64_64, and epoll_*.
715* Improve ioctl command name matching.
716* Print RTC_* ioctl structure contents.
717* Support newer RLIMIT_* values.
718* Print struct cmsghdr details in sendmsg.
719
720Changes in 4.5.7
721==============
722* Bug fixes.
723* Print attribute values in *xattr system calls on Linux.
724* Include pread and pwrite calls in -e read and -e write tracing.
725* Update SO_* and IP_* value lists and add IPV6_* values for socket options.
726* Print clock_t values symbolically in Linux clock_* system calls.
727
728Changes in 4.5.6
729==============
730* Bug fixes, Linux ioctl updates.
731* David Miller contributed support for Linux/SPARC64.
732
733Changes in 4.5.5
734==============
735* Just bug fixes.
736
737Changes in 4.5.4
738==============
739* Update Linux ioctl lists.
740* Update PF_* and AF_* value lists.
741* The 4.5.3 -p behavior for NPTL threads applies only under -f, and got fixed.
742
743Changes in 4.5.3
744==============
745* Bug fixes.
746* On Linux using NPTL threads, -p will now attach to all threads in a process.
747* Handle new mq_* system calls in Linux 2.6.6 and later.
748
749Changes in 4.5.2
750==============
751* Bug fixes.
752* Report some new VM_* bit values on Linux.
753* Better output for Linux sched_* system calls.
754
755Changes in 4.5.1
756==============
757* Bug fixes.
758* Display multiple ioctl name matches on Linux.
759
760Changes in 4.5
761==============
762* New port to AMD's x86-64 architecture. One strace binary can
763  handle both new x86-64 and old i386 processes.
764* Fixed support for LFS64 calls.
765* New switch -E to add/remove environment variables for the command.
766* Merged s390/s390x port.
767* Trace an unbounded number of processes.
768* Handle numerous new system calls in Linux 2.5, and new threads semantics.
769* Fixed bugs with attach/detach leaving things stopped.
770* Fixed traced process seeing ECHILD despite live, traced children
771  in waitpid calls with WNOHANG.
772* Stuart Menefy contributed a port to Linux/SH.
773* Stephen Thomas contributed a port to Linux/SH64.
774* Many other bug fixes.
775
776Changes in 4.4
777==============
778* Fix Linux/ia64 support, looks like someone renamed a few things on us
779* Fix the ioctl setup for Linux, turned out it did not really work.
780  Improve the ioctl extracter as well so we decode some more ones.
781
782Changes in 4.3.1
783================
784* compile fixes for Linux/mips
785
786Changes in 4.3
787==============
788* Linux ia64 and hppa ports added
789* The usual Linux syscall updates (includes 32bit uid/gid support),
790* Linux ioctl list updated
791* Support IPv6 scope ids
792* FreeBSD/i386 port added
793* UnixWare and Solaris updates
794* Better support for tracing multithreaded processes in Linux
795
796Changes in 4.2
797==============
798* Compiles on glibc2.0 systems again
799* Linux/S390 port added
800* The usual Linux syscall updates
801* we can follow fork on arm now
802
803Changes in 4.1
804================
805* Linux/MIPS port added
806* Lots of Linux updates again
807* Improved IPv6 support
808* Add strace-graph
809
810Changes in 4.0.1
811================
812* Minor bugfixes
813* Compiles on glibc2.0 systems again
814
815Changes in 4.0
816==============
817* Get stat structure properly on Linux 64bit archs
818* Personalities work again
819* Compile correctly on SunOS again
820* IRIX64 updates
821* Solaris updates
822
823Changes in 3.99.1
824=================
825* Linux (ultra)sparc fixes
826* Linux alpha fixes
827* Minor cleanups
828
829Changes in 3.99
830===============
831* New maintainer
832* add support for more Linux architectures (powerpc, sparc, arm)
833* support lots more Linux syscalls
834* fix signal handling
835* add IPX and IPIP support
836* check stray syscall after execv
837* fix hanging children
838
839Changes in version 3.1
840======================
841
842* Irix5 is supported
843* Linux 68k is supported
844* Linux alpha is supported
845* configure is upgraded to autoconf 2.x
846* using -f in combination with -e now works correctly
847* output can be piped to a program
848* tracing setuid programs works better
849* it is now reasonable to install strace setuid to root in some circumstances
850* new useful tracing names like file and process to trace whole
851  classes of system calls, e.g. -efile traces all system calls that
852  take a file name as an argument
853* IPC calls on SunOS 4.1.x are decoded
854* Linux program memory is reliably dereferenced
855* Linux decodes at least the name of all syscalls as of pre2.0.4
856* various cosmetic changes and bug fixes
857
858Changes from versions 2.x to version 3.0
859========================================
860
861* filename arguments are neither abbreviated nor stringified
862* string arguments are now true C strings using octal instead of hex by default
863* preprocessor constants are never shortened (e.g. was RDONLY => now O_RDONLY)
864* by default the output for multiple processes now goes into one file
865* all structures, vectors, bitsets, etc. use consistent output formats
866* the -c option now means count calls, -i does what the old -c used to do
867
868New Features in version 3.0
869===========================
870
871* non-ascii strings can be optionally printed entirely in hex
872* the output format is readable when mutiple processes are generating output
873* exit values are printed in an alignment column
874* is is possible to suppress messages about attaching and detaching
875* various tracing features can be enabled on a per syscall/signal/desc basis
876* selective tracing of syscalls
877* selective printing of syscall structures
878* selective abbreviation of long structures on a per syscall basis
879* selective printing of raw syscall arguments and results
880* selective tracing of signals
881* selective dumping of all I/O read from file descriptors
882* selective dumping of all I/O written to file descriptors
883* optional counting of time, calls, and errors for each syscall
884