NEWS revision 2ee358f27c14dfb25c315237765c709e1716109b
1-*-org-*- 2* Version 0.7.0 3** Tracing 4 5*** Full support for tracing multi-threaded processes 6 7 Ltrace now understands thread groups, and it stops all threads 8 before manipulating breakpoints. The downside is that performance 9 of multi-threaded processes is rather bad, because handling any 10 event implies stopping the whole job. The upside is that 11 individual threads don't get random SIGILL's and SIGSEGV's and 12 events are not missed. 13 14*** Support for tracing inter-library calls 15 16 -e and -x were extended to allow library selectors. See the man 17 page for details. 18 19*** Better support for parameter passing ("fetch backend") 20 21 This version brings a more complete support for parameter passing, 22 including passing structures in registers, passing double on i386, 23 and other edge cases that were unsupported before. The following 24 architectures now have implementation of fetch backend: x86, ppc, 25 ia64, s390, m68k. 26 27*** Awareness of deny_ptrace SELinux boolean 28 29 The deny_ptrace boolean denies all processes from being able to 30 use ptrace to manipulate other processes. Ltrace now understands 31 that this boolean exists, and recommends turning it off, if it is 32 on and ltrace fails to attach to a process. 33 34*** Limited support for tracing returns from tail call functions 35*** -e, -x and -l selectors now allow using globs and regular expressions 36 37 See the man page for details of the selector syntax. This changes 38 the way -x and -l behave with respect to tracing libraries opened 39 by dlopen: 40 41 - In 0.6.0, only those -x symbols that were unmatched in main 42 binary were used to search through symbol table of libraries 43 opened with dlopen. In 0.7.0, -x and -e are applied uniformly 44 to each mapped binary: the main binary, dependent DSO's, and any 45 dlopened libraries. 46 47 - In 0.6.0, -l argument was a filename to open and inspect. In 48 0.7.0, -l is a glob expression matched against each mapped 49 binary. 50 51*** Test suite can now be run under valgrind 52 53 Use --enable-valgrind to turn this on. 54 55*** [ppc] Support both BSS and secure PLTs for 32-bit processes 56*** [mips] Implement software singlestepping 57*** [mips] Add support for CPIC main programs 58*** Support tracing PIE binaries 59 60** Configuration Files 61 62*** New abstraction: parameter pack 63 64 Parameter packs make it much simpler to add specialized decoding 65 logic. The only parameter pack currently implemented is "format" 66 for decoding printf-style format strings. It should be relatively 67 straightforward to add more parameter packs for functions like 68 execl, strftime, and others. 69 70*** New expression: zero 71 72 When used in array length expressions, it means "this array ends 73 at the first element with zero value". C strigs are essentially 74 array(char, zero)*. 75 76*** Lenses: change the way that underlying type is rendered 77 78 Lenses are used similarly to parametrized types, e.g.: 79 | void func(lens(int)); | 80 81**** octal 82 83 "octal", which used to be a separate type, is now lens, which can 84 be used to render any underlying type in base 8. Plain "octal" 85 is still valid and means the same as "octal(int)". 86 87**** hex, hide, bool 88 89 Similarly, "hex" lens was introduced to format as base 16. 90 "hide" was introduced to conceal given argument. "bool" lens was 91 added to format objects as either true, or false. 92 93**** enum 94 95 "enum" became lens as well. Because enum already uses 96 parentheses to denote the list of enumeration values, the 97 underlying type is selected by square brackets: 98 | void func(enum[short](RED,GREEN,BLUE)); | 99 100**** string 101 102 "string" was also turned to lens. The argument can be either a 103 char*, or pointer to array of char, or array of char. The latter 104 is useful in cases like the following: 105 | void func_struct_2(struct(string(array(char, 6)))); | 106 107*** Misspelling of "int" as "itn" temporarily accepted, but deprecated 108 109 Pre-0.7 ltrace shipped a buggy version of ltrace.conf that 110 contained the following prototype: 111 112 | itn acl_valid(addr); | 113 114 To support extant versions of ltrace.conf, that use is now 115 considered valid, and "itn" is a synonym of "int". It is however 116 deprecated, and will produce a warning in future. 117 118*** Using void as top-level function argument now deprecated 119 120 Functions that take no arguments shouldn't pretend to take one 121 parameter of void type. For example the following: 122 123 | int fork(void); | 124 125 ... should be declared like this: 126 127 | int fork(); | 128 129 To support extant versions of ltrace.conf, that use is now 130 considered valid. It is however deprecated, and will produce a 131 warning in future. 132 133*** Using void to hide one argument is now obsolete 134 135 Ltrace needs to know the exact underlying type to decide what the 136 calling convention is. The use of void to mean "hide this 137 argument", such as the following example, is therefore obsolete: 138 139 | void func(void, array(int, arg1)); | 140 141 Instead, rewrite the prototype depending on the exact underlying 142 type: 143 144 | void func(hide(int), array(int, arg1)); | 145 | void func(hide(long), array(int, arg1)); | 146 147 To support extant versions of ltrace.conf, this use is still 148 accepted, and "void" is taken to mean "hide(int)". It is however 149 obsolete, produces a warning, and will be removed in future. 150 151** Documentation 152 153*** New manual page ltrace.conf(5) 154*** README, INSTALL brought up to date 155*** New file CREDITS with a list of contributors 156** Bugfixes 157 158*** Fix detaching from a process 159 160 Earlier, a process that ltrace detached from would sometimes die 161 of SIGSEGV, SIGTRAP, or SIGILL. These were caused by ltrace 162 detaching from the process just after that process hit a 163 breakpoint. Program counter would thus be left pointing 164 mid-instruction, or signals would be left pending. 165 166*** Argument to -n is now checked for validity 167*** Fix tracing across exec in a stripped binary 168*** [x86] ORIG_RAX/ORIG_EAX may not contain original syscall number 169 170 In cases where the system call shouldn't be restarted, these are 171 set to -1. In that case assume that the return is from the 172 topmost syscall. This gets rid of some "unexpected breakpoint" 173 messages on x86_64 and i386. 174 175*** [ppc] Fix races in tracing -e events in 64-bit processes 176 177 As a side effect, events requested via -e now only hit when a PLT 178 call is made, which is consistent with other architectures. 179 180*** [ppc] Allow stepping over lwarx instruction 181 182** Known bugs 183 184*** [arm] Tracing is not supported at all on ARM 185 186 ltrace might work on older kernels, but no attempt was made to 187 fully support it. Newer kernels don't support PTRACE_SINGLESTEP, 188 which ltrace depends on. Before singlestepping is implemented in 189 software, ARM is considered unsupported. 190 191* Version 0.6.0 192 193** General Features 194 195*** Use autotools for building 196*** New option -b: disables output of signals received by the tracee 197*** New option -w: print stack trace of events 198 199 Pass --with-libunwind to configure to enable the feature. This 200 requires libunwind. 201 202*** Support tracing of symbols from libraries opened with dlopen 203 204 These symbols are selected by -x. 205 206** Architecture-specific Changes 207 208*** Various fixes for MIPS and PowerPC 209*** Support for ARM Thumb mode 210*** Implement fetching of 5th and further function arguments on s390 211*** Support fork/exec syscalls on 31-bit s390 212*** Support for float and double arguments on x86_64 213*** Fixes for return arguments (after '+') in nested calls on x86_64 214 215* License 216------------------------------------------------------------------------------- 217Copyright (C) 2012 Petr Machata <pmachata@redhat.com> 218This file is part of ltrace. 219 220ltrace is free software; you can redistribute it and/or modify it 221under the terms of the GNU General Public License as published by the 222Free Software Foundation; either version 2 of the License, or (at your 223option) any later version. 224 225ltrace is distributed in the hope that it will be useful, but WITHOUT 226ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 227FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 228for more details. 229 230You should have received a copy of the GNU General Public License 231along with this program. If not, see <http://www.gnu.org/licenses/>. 232