diff options
Diffstat (limited to 'TODO')
| -rw-r--r-- | TODO | 174 |
1 files changed, 138 insertions, 36 deletions
@@ -1,36 +1,138 @@ -* BFD: - + New executable formats - + Read list of libraries needed - + Read list of undefined symbols in executables - + Read list of exported symbols in libraries - + Read debugging info from executables/libraries -* Automatically update list of syscalls? -* Improve documentation -* Improve -e/-x options (regexp?) -* Improve -l option -* Improve C++ name demangling -* Display different argument types -* Update /etc/ltrace.conf -* More architectures, cleaner way to port -* More operating systems (solaris?) -* Option -I (inter-library calls) -* Modify ARGTYPE_STRING[0-5] types so that they don't stop displaying chars when '\0' is seen -* Get rid of EVENT_ARCH_SYSCALL and EVENT_ARCH_SYSRET -* Cleaner way to use breakpoints: - + BP is placed in the PLT - + When control hits there: - - write down return address - - change return address with another one (handled by ltrace) - - get arguments... - - change the process' PC to be in the correct place, - without removing breakpoint - + When control hits one of our return addresses: - - get return value... - - change PC to the right place -* To be able to work with processes sharing memory, we must: - + ptrace() every single thread - + place breakpoints only in places where the process control can continue - without having to remove it -* List source dependencies in Makefile -* Create different ltrace processes to trace different children -* After a clone(), syscalls may be seen as sysrets in s390 (see trace.c:syscall_p()) +-*-org-*- +* TODO +** Automatic prototype discovery: +*** Use debuginfo if available + Alternatively, use debuginfo to generate configure file. +*** Demangled identifiers contain partial prototypes themselves +** Automatically update list of syscalls? +** Update /etc/ltrace.conf + In particular, we could use a config directory, where packages + would install their ltrace config scripts. The config file could + be named after SONAME, and automatically read when corresponding + library is mapped. +** More operating systems (solaris?) +** Get rid of EVENT_ARCH_SYSCALL and EVENT_ARCH_SYSRET +** Implement displaced tracing + A technique used in GDB (and in uprobes, I believe), whereby the + instruction under breakpoint is moved somewhere else, and followed + by a jump back to original place. When the breakpoint hits, the IP + is moved to the displaced instruction, and the process is + continued. We avoid all the fuss with singlestepping and + reenablement. +** Create different ltrace processes to trace different children +** Config file syntax +*** named arguments + This would be useful for replacing the arg1, emt2 etc. + +*** parameter pack improvements + The above format tweaks require that packs that expand to no types + at all be supported. If this works, then it should be relatively + painless to implement conditionals: + + | void ptrace(REQ=enum(PTRACE_TRACEME=0,...), + | if[REQ==0](pack(),pack(pid_t, void*, void *))) + + This is of course dangerously close to a programming language, and + I think ltrace should be careful to stay as simple as possible. + (We can hook into Lua, or TinyScheme, or some such if we want more + general scripting capabilities. Implementing something ad-hoc is + undesirable.) But the above can be nicely expressed by pattern + matching: + + | void ptrace(REQ=enum[int](...)): + | [REQ==0] => () + | [REQ==1 or REQ==2] => (pid_t, void*) + | [true] => (pid_t, void*, void*); + + Or: + + | int open(string, FLAGS=flags[int](O_RDONLY=00,...,O_CREAT=0100,...)): + | [(FLAGS & 0100) != 0] => (flags[int](S_IRWXU,...)) + + This would still require pretty complete expression evaluation. + _Including_ pointer dereferences and such. And e.g. in accept, we + need subtraction: + + | int accept(int, +struct(short, +array(hex(char), X-2))*, (X=uint)*); + + Perhaps we should hook to something after all. + +*** errno tracking + Some calls result in setting errno. Somehow mark those, and on + failure, show errno. + +*** second conversions? + This definitely calls for some general scripting. The goal is to + have seconds in adjtimex calls show as e.g. 10s, 1m15s or some + such. + +*** format should take arguments like string does + Format should take value argument describing the value that should + be analyzed. The following overwriting rules would then apply: + + | format | format(array(char, zero)*) | + | format(LENS) | X=LENS, format[X] | + + The latter expanded form would be canonical. + + This depends on named arguments and parameter pack improvements + (we need to be able to construct parameter packs that expand to + nothing). + +*** More fine-tuned control of right arguments + Combination of named arguments and some extensions could take care + of that: + + | void func(X=hide(int*), long*, +pack(X)); | + + This would show long* as input argument (i.e. the function could + mangle it), and later show the pre-fetched X. The "pack" syntax is + utterly undeveloped as of now. The general idea is to produce + arguments that expand to some mix of types and values. But maybe + all we need is something like + + | void func(out int*, long*); | + + ltrace would know that out/inout/in arguments are given in the + right order, but left pass should display in and inout arguments + only, and right pass then out and inout. + would be + backward-compatible syntactic sugar, expanded like so: + + | void func(int*, int*, +long*, long*); | + | void func(in int*, in int*, out long*, out long*); | + + But sometimes we may want to see a different type on the way in and + on the way out. E.g. in asprintf, what's interesting on the way in + is the address, but on the way out we want to see buffer contents. + Does something like the following make sense? + + | void func(X=void*, long*, out string(X)); | + +** Support for functions that never return + This would be useful for __cxa_throw, presumably also for longjmp + (do we handle that at all?) and perhaps a handful of others. + +** Support flag fields + enum-like syntax, except disjunction of several values is assumed. +** Support long long + We currently can't define time_t on 32bit machines. That mean we + can't describe a range of time-related functions. + +** Support signed char, unsigned char, char + Also, don't format it as characted by default, string lens can do + it. Perhaps introduce byte and ubyte and leave 'char' as alias of + one of those with string lens applied by default. + +** Support fixed-width types + Really we should keep everything as {u,}int{8,16,32,64} internally, + and have long, short and others be translated to one of those + according to architecture rules. Maybe this could be achieved by a + per-arch config file with typedefs such as: + + | typedef ulong = uint8_t | + +** Some more functions in vect might be made to take const* + Or even marked __attribute__((pure)). + +* BUGS +** After a clone(), syscalls may be seen as sysrets in s390 (see trace.c:syscall_p()) |