X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;ds=sidebyside;f=lib%2Fvirt_mem.ml;h=0a956f1257b8fd9bb6b45c5726a4f389978428b6;hb=89d41f7614612cf991d6005e7c1e20cd502a5404;hp=dd3c18a304dd567190ce3ff890049730dd236803;hpb=35f68724b76ea85e9b949f05ad82b82a7144989c;p=virt-mem.git diff --git a/lib/virt_mem.ml b/lib/virt_mem.ml index dd3c18a..0a956f1 100644 --- a/lib/virt_mem.ml +++ b/lib/virt_mem.ml @@ -27,10 +27,7 @@ module D = Libvirt.Domain open Virt_mem_gettext.Gettext open Virt_mem_utils -module MMap = Virt_mem_mmap - -let min_kallsyms_tabsize = 1_000L -let max_kallsyms_tabsize = 250_000L +open Virt_mem_types (* Make the kernel size around 16 MB, but just a bit smaller than * maximum string length so we can still run this on a 32 bit platform. @@ -40,21 +37,120 @@ let kernel_size = else 0x100_0000 let max_memory_peek = 65536 (* XXX Use D.max_peek function *) -type ksym = string - -type image = - string - * Virt_mem_utils.architecture - * ([`Wordsize], [`Endian]) Virt_mem_mmap.t - * (ksym -> MMap.addr) - -type kallsyms_compr = - | Compressed of (string * MMap.addr) list * MMap.addr - | Uncompressed of (string * MMap.addr) list - -let start usage_msg = - (* Debug messages. *) +(* When tools register themselves, they are added to this list. + * Later, we will alphabetize the list. + *) +let tools = ref [] + +(* Registration function used by the tools. *) +let register ?(external_cmd = true) ?(extra_args = []) + ?argcheck ?beforeksyms ?run + name summary description = + tools := + (name, (name, summary, description, external_cmd, extra_args, + argcheck, beforeksyms, run)) + :: !tools + +(* Main program, called from mem/virt_mem_main.ml when all the + * tools have had a chance to register themselves. + *) +let main () = + (* Get the registered tools, alphabetically. *) + let tools = !tools in + let tools = List.sort ~cmp:(fun (a,_) (b,_) -> compare a b) tools in + + (* Which tool did the user want to run? Look at the executable + * name (eg. 'virt-dmesg' => tool == dmesg). If we don't recognise + * the executable name then we must look for the first parameter + * which doesn't begin with a '-' character. + * + * Note that we must do all of this before using the OCaml Arg + * module to properly parse the command line (below), so that + * we can have a usage message ready. + *) + let tool, ignore_first_anon_arg = + let prog = Sys.executable_name in (* eg. "/usr/bin/virt-dmesg.opt" *) + let prog = Filename.basename prog in(* eg. "virt-dmesg.opt" *) + let prog = (* eg. "virt-dmesg" *) + try Filename.chop_extension prog with Invalid_argument _ -> prog in + let prog = (* eg. "dmesg" *) + if String.starts_with prog "virt-" then + String.sub prog 5 (String.length prog - 5) + else prog in + try Some (List.assoc prog tools), false + with Not_found -> + let arg1 = (* First non-option argument. *) + match Array.to_list Sys.argv with + | [] -> None + | _::args -> + let rec loop = function + | [] -> None + | a::args when String.length a > 0 && a.[0] = '-' -> loop args + | a::_ -> Some a + in + loop args in + match arg1 with + | None -> None, false + | Some prog -> (* Recognisable first argument? *) + let prog = + try Filename.chop_extension prog with Invalid_argument _ -> prog in + let prog = + if String.starts_with prog "virt-" then + String.sub prog 5 (String.length prog - 5) + else prog in + (try Some (List.assoc prog tools), true + with Not_found -> None, false) in + + (* Make a usage message. *) + let usage_msg = + match tool with + | None -> (* Generic usage message. *) + let tools = List.map ( + fun (name, (_, summary, _, external_cmd, _, _, _, _)) -> + if external_cmd then "virt-"^name, summary + else "virt-mem "^name, summary + ) tools in + (* Maximum width of field in the left hand column. *) + let max_width = + List.fold_left max 0 (List.map String.length (List.map fst tools)) in + let tools = List.map (fun (l,r) -> pad max_width l, r) tools in + let tools = List.map (fun (l,r) -> " " ^ l ^ " - " ^ r) tools in + let tools = String.concat "\n" tools in + + sprintf (f_"\ + +virt-mem: Tools for providing information about virtual machines + +Currently available tools include: +%s + +General usage is: + [-options] [domains...] + +To display extra help for a single tool, do: + virt-mem help + +Options:") tools + + (* Tool-specific usage message. *) + | Some (name, summary, description, external_cmd, _, _, _, _) -> + let cmd = + if external_cmd then "virt-" ^ name else "virt-mem " ^ name in + + sprintf (f_"\ + +%s: %s + +Description: +%s + +Options:") cmd summary description in + + (* Now begin proper parsing of the command line arguments. *) let debug = ref false in + let testimages = ref [] in + let uri = ref "" in + let anon_args = ref [] in (* Default wordsize. *) let def_wordsize = ref None in @@ -70,9 +166,9 @@ let start usage_msg = let set_endian = function | "auto" -> def_endian := None | "le" | "little" | "littleendian" | "intel" -> - def_endian := Some Bitmatch.LittleEndian + def_endian := Some Bitstring.LittleEndian | "be" | "big" | "bigendian" | "motorola" -> - def_endian := Some Bitmatch.BigEndian + def_endian := Some Bitstring.BigEndian | str -> failwith (sprintf (f_"set_endian: %s: unknown endianness") str) in @@ -96,17 +192,14 @@ let start usage_msg = | str -> def_text_addr := Int64.of_string str in - (* List of kernel images. *) - let images = ref [] in - let uri = ref "" in - let anon_args = ref [] in - + (* Handle -t option. *) let memory_image filename = - images := + testimages := (!def_wordsize, !def_endian, !def_architecture, !def_text_addr, filename) - :: !images + :: !testimages in + (* Handle --version option. *) let version () = printf "virt-mem %s\n" Virt_mem_version.version; @@ -117,39 +210,86 @@ let start usage_msg = exit 0 in - let argspec = Arg.align [ - "-A", Arg.String set_architecture, - "arch " ^ s_"Set kernel architecture, endianness and word size"; - "-E", Arg.String set_endian, - "endian " ^ s_"Set kernel endianness"; - "-T", Arg.String set_text_addr, - "addr " ^ s_"Set kernel text address"; - "-W", Arg.String set_wordsize, - "addr " ^ s_"Set kernel word size"; - "-c", Arg.Set_string uri, - "uri " ^ s_ "Connect to URI"; - "--connect", Arg.Set_string uri, - "uri " ^ s_ "Connect to URI"; - "--debug", Arg.Set debug, - " " ^ s_"Debug mode (default: false)"; - "-t", Arg.String memory_image, - "image " ^ s_"Use saved kernel memory image"; - "--version", Arg.Unit version, - " " ^ s_"Display version and exit"; - ] in - + (* Function to collect up any anonymous args (domain names/IDs). *) let anon_arg str = anon_args := str :: !anon_args in - let usage_msg = usage_msg ^ s_"\n\nOPTIONS" in + + (* Construct the argspec. + * May include extra arguments specified by the tool. + *) + let argspec = + let extra_args = match tool with + | None -> [] + | Some (_, _, _, _, extra_args, _, _, _) -> extra_args in + let argspec = [ + "-A", Arg.String set_architecture, + "arch " ^ s_"Set kernel architecture, endianness and word size"; + "-E", Arg.String set_endian, + "endian " ^ s_"Set kernel endianness"; + "-T", Arg.String set_text_addr, + "addr " ^ s_"Set kernel text address"; + "-W", Arg.String set_wordsize, + "addr " ^ s_"Set kernel word size"; + "-c", Arg.Set_string uri, + "uri " ^ s_ "Connect to URI"; + "--connect", Arg.Set_string uri, + "uri " ^ s_ "Connect to URI"; + "--debug", Arg.Set debug, + " " ^ s_"Debug mode (default: false)"; + "-t", Arg.String memory_image, + "image " ^ s_"Use saved kernel memory image"; + "--version", Arg.Unit version, + " " ^ s_"Display version and exit"; + ] @ extra_args in + + (* Sort options alphabetically on first alpha character. *) + let cmp (a,_,_) (b,_,_) = + let chars = "-" in + let a = String.strip ~chars a and b = String.strip ~chars b in + compare a b + in + let argspec = List.sort ~cmp argspec in + (* Make the options line up nicely. *) + Arg.align argspec in + + (* Parse the command line. This will exit if --version or --help found. *) Arg.parse argspec anon_arg usage_msg; - let images = !images in + let testimages = !testimages in let debug = !debug in let uri = if !uri = "" then None else Some !uri in + + (* Discard the first anonymous argument if, above, we previously + * found it contained the tool name. + *) let anon_args = List.rev !anon_args in + let anon_args = + if ignore_first_anon_arg then List.tl anon_args else anon_args in + + (* At this point, either --help was specified on the command line + * (and so the program has exited) or we must have determined tool, + * or the user didn't give us a valid tool (eg. "virt-mem foobar"). + * Detect that final case now and give an error. + *) + let name, _, _, _, _, argcheck, beforeksyms, run = + match tool with + | Some t -> t + | None -> + prerr_endline (s_"\ +virt-mem: I could not work out which tool you are trying to run. +Use 'virt-mem --help' for more help or read the manual page virt-mem(1)"); + exit 1 + in + if debug then eprintf "tool = %s\n%!" name; + + (* Optional argument checking in the tool. *) + (match argcheck with + | None -> () + | Some argcheck -> argcheck debug + ); (* Get the kernel images. *) let images = - if images = [] then ( + if testimages = [] then ( let conn = let name = uri in try C.connect_readonly ?name () @@ -210,6 +350,7 @@ let start usage_msg = List.map ( fun (dom, _) -> + let id = D.get_id dom in let name = D.get_name dom in let wordsize = @@ -262,13 +403,13 @@ let start usage_msg = ); (* Map the virtual memory. *) - let mem = MMap.of_string str !def_text_addr in + let mem = Virt_mem_mmap.of_string str !def_text_addr in (* Force the wordsize and endianness. *) - let mem = MMap.set_wordsize mem wordsize in - let mem = MMap.set_endian mem endian in + let mem = Virt_mem_mmap.set_wordsize mem wordsize in + let mem = Virt_mem_mmap.set_endian mem endian in - (name, arch, mem) + ((Some id, name, arch, mem) : image0) ) xmls ) else ( (* One or more -t options passed. *) @@ -310,409 +451,45 @@ let start usage_msg = (* Map the virtual memory. *) let fd = openfile filename [O_RDONLY] 0 in - let mem = MMap.of_file fd text_addr in + let mem = Virt_mem_mmap.of_file fd text_addr in (* Force the wordsize and endianness. *) - let mem = MMap.set_wordsize mem wordsize in - let mem = MMap.set_endian mem endian in + let mem = Virt_mem_mmap.set_wordsize mem wordsize in + let mem = Virt_mem_mmap.set_endian mem endian in - (filename, arch, mem) - ) images + ((None, filename, arch, mem) : image0) + ) testimages ) in + (* Optional callback into the tool before we start looking for + * kernel symbols. + *) + (match beforeksyms with + | None -> () + | Some beforeksyms -> beforeksyms debug images + ); + + (* If there is no run function, then there is no point continuing + * with the rest of the program (kernel symbol analysis) ... + *) + if run = None then exit 0; + + (* Do the kernel symbol analysis. *) let images = List.map ( - fun (name, arch, mem) -> - (* Look for some common entries in the exported symbol table and - * from that find the symbol table itself. These are just - * supposed to be symbols which are very likely to be present - * in any Linux kernel, although we only need one of them to be - * present to find the symbol table. - * - * NB. Must not be __initdata, must be in EXPORT_SYMBOL. - *) - let common_ksyms = [ - "init_task"; (* first task_struct *) - "root_mountflags"; (* flags for mounting root fs *) - "init_uts_ns"; (* uname strings *) - "sys_open"; (* open(2) entry point *) - "sys_chdir"; (* chdir(2) entry point *) - "sys_chroot"; (* chroot(2) entry point *) - "sys_umask"; (* umask(2) entry point *) - "schedule"; (* scheduler entry point *) - ] in - (* Searching for string *) - let common_ksyms_nul = List.map (sprintf "\000%s\000") common_ksyms in - - let start_t = gettimeofday () in - - (* Search for these strings in the memory image. *) - let ksym_strings = List.map (MMap.find_all mem) common_ksyms_nul in - let ksym_strings = List.concat ksym_strings in - (* Adjust found addresses to start of the string (skip ). *) - let ksym_strings = List.map Int64.succ ksym_strings in - - if debug then ( - let end_t = gettimeofday () in - eprintf "timing: searching for common_ksyms took %f seconds\n%!" - (end_t -. start_t) - ); - - let start_t = gettimeofday () in - - (* For any we found, try to look up the symbol table - * base addr and size. - *) - let ksymtabs = List.map ( - fun addr -> - (* Search for 'addr' appearing in the image. *) - let addrs = MMap.find_pointer_all mem addr in - - (* Now consider each of these addresses and search back - * until we reach the beginning of the (possible) symbol - * table. - * - * Kernel symbol table struct is: - * struct kernel_symbol { - * unsigned long value; - * const char *name; <-- initial pointer - * } symbols[]; - *) - let pred_long2 addr = - MMap.pred_long mem (MMap.pred_long mem addr) - in - let base_addrs = List.map ( - fun addr -> - let rec loop addr = - (* '*addr' should point to a C identifier. If it does, - * step backwards to the previous symbol table entry. - *) - let addrp = MMap.follow_pointer mem addr in - if MMap.is_C_identifier mem addrp then - loop (pred_long2 addr) - else - MMap.succ_long mem addr - in - loop addr - ) addrs in - - (* Also look for the end of the symbol table and - * calculate its size. - *) - let base_addrs_sizes = List.map ( - fun base_addr -> - let rec loop addr = - let addr2 = MMap.succ_long mem addr in - let addr2p = MMap.follow_pointer mem addr2 in - if MMap.is_C_identifier mem addr2p then - loop (MMap.succ_long mem addr2) - else - addr - in - let end_addr = loop base_addr in - base_addr, end_addr -^ base_addr - ) base_addrs in - - base_addrs_sizes - ) ksym_strings in - let ksymtabs = List.concat ksymtabs in - - (* Simply ignore any symbol table candidates which are too small. *) - let ksymtabs = List.filter (fun (_, size) -> size > 64L) ksymtabs in - - if debug then ( - eprintf "%s: candidate symbol tables at:\n" name; - List.iter ( - fun (addr, size) -> - eprintf "\t%Lx\t%Lx\t%!" addr size; - eprintf "first symbol: %s\n%!" - (MMap.get_string mem - (MMap.follow_pointer mem - (MMap.succ_long mem addr))) - ) ksymtabs - ); - - (* Vote for the most popular symbol table candidate and from this - * generate a function to look up ksyms. - *) - let lookup_ksym = - let freqs = frequency ksymtabs in - match freqs with - | [] -> - eprintf (f_"%s: cannot find start of kernel symbol table\n") name; - (fun _ -> raise Not_found) - - | (_, (ksymtab_addr, ksymtab_size)) :: _ -> - if debug then - eprintf - "%s: Kernel symbol table found at %Lx, size %Lx bytes\n%!" - name ksymtab_addr ksymtab_size; - - (* Load the whole symbol table as a bitstring. *) - let ksymtab = - Bitmatch.bitstring_of_string - (MMap.get_bytes mem ksymtab_addr - (Int64.to_int ksymtab_size)) in - - (* Function to look up an address in the symbol table. *) - let lookup_ksym sym = - let bits = bits_of_wordsize (MMap.get_wordsize mem) in - let e = MMap.get_endian mem in - let rec loop bs = - bitmatch bs with - | { value : bits : endian(e); - name_ptr : bits : endian(e) } - when MMap.get_string mem name_ptr = sym -> - value - | { _ : bits : endian(e); - _ : bits : endian(e); - bs : -1 : bitstring } -> - loop bs - | { _ } -> raise Not_found - in - loop ksymtab - in - - lookup_ksym - in - - if debug then ( - let end_t = gettimeofday () in - eprintf "timing: searching for ordinary ksyms took %f seconds\n%!" - (end_t -. start_t) - ); - - let start_t = gettimeofday () in - - (* Now try to find the /proc/kallsyms table. This is in an odd - * compressed format (but not a very successful compression - * format). However if it exists we know that it will contain - * addresses of the common ksyms above, and it has some - * characteristics which make it easy to detect in the - * memory. - * - * kallsyms contains a complete list of symbols so is much - * more useful than the basic list of exports. - *) - let ksym_addrs = List.filter_map ( - fun ksym -> try Some (lookup_ksym ksym) with Not_found -> None - ) common_ksyms in + fun image -> - (* Search for those kernel addresses in the image. We're looking - * for the table kallsyms_addresses followed by kallsyms_num_syms - * (number of symbols in the table). - *) - let ksym_addrs = List.map (MMap.find_pointer_all mem) ksym_addrs in - let ksym_addrs = List.concat ksym_addrs in + (* Look for ordinary kernel symbols: *) + let image = Virt_mem_ksyms.find_kernel_symbols debug image in + (* Look for kallsyms: *) + let image = Virt_mem_kallsyms.find_kallsyms debug image in - (* Test each one to see if it's a candidate list of kernel - * addresses followed by length of list. - *) - let kallsymtabs = List.filter_map ( - fun addr -> - (* Search upwards from address until we find the length field. - * If found, jump backwards by length and check all addresses. - *) - if debug then - eprintf "%s: testing candidate kallsyms at %Lx\n" name addr; - let rec loop addr = - let addrp = MMap.follow_pointer mem addr in - if MMap.is_mapped mem addrp then - loop (MMap.succ_long mem addr) (* continue up the table *) - else - if addrp >= min_kallsyms_tabsize && - addrp <= max_kallsyms_tabsize then ( - (* addrp might be the symbol count. Count backwards and - * check the full table. - *) - let num_entries = Int64.to_int addrp in - let entry_size = bytes_of_wordsize (MMap.get_wordsize mem) in - let start_addr = - addr -^ Int64.of_int (entry_size * num_entries) in - let end_addr = addr in - let rec loop2 addr = - if addr < end_addr then ( - let addrp = MMap.follow_pointer mem addr in - if MMap.is_mapped mem addrp then - loop2 (MMap.succ_long mem addr) - else - None (* can't verify the full address table *) - ) else - (* ok! *) - let names_addr = MMap.succ_long mem end_addr in - if debug then - eprintf "%s: candidate kallsyms found at %Lx (names_addr at %Lx, num_entries %d)\n" - name start_addr names_addr num_entries; - Some (start_addr, num_entries, names_addr) - in - loop2 start_addr - ) - else - None (* forget it *) - in - match loop addr with - | None -> None - | Some (start_addr, num_entries, names_addr) -> - (* As an additional verification, check the list of - * kallsyms_names. - *) - try - (* If the first byte is '\000' and is followed by a - * C identifier, then this is old-school list of - * symbols with prefix compression as in 2.6.9. - * Otherwise Huffman-compressed kallsyms as in - * 2.6.25. - *) - if MMap.get_byte mem names_addr = 0 && - MMap.is_C_identifier mem (names_addr+^1L) then ( - let names = ref [] in - let prev = ref "" in - let rec loop names_addr start_addr num = - if num > 0 then ( - let prefix = MMap.get_byte mem names_addr in - let prefix = String.sub !prev 0 prefix in - let name = MMap.get_string mem (names_addr+^1L) in - let len = String.length name in - let name = prefix ^ name in - prev := name; - let names_addr = names_addr +^ Int64.of_int len +^ 2L in - let sym_value = MMap.follow_pointer mem start_addr in - let start_addr = MMap.succ_long mem start_addr in - (*eprintf "%S -> %Lx\n" name sym_value;*) - names := (name, sym_value) :: !names; - loop names_addr start_addr (num-1) - ) - in - loop names_addr start_addr num_entries; - let names = List.rev !names in - - Some (start_addr, num_entries, names_addr, - Uncompressed names) - ) - else ( (* new-style "compressed" names. *) - let compressed_names = ref [] in - let rec loop names_addr start_addr num = - if num > 0 then ( - let len = MMap.get_byte mem names_addr in - let name = MMap.get_bytes mem (names_addr+^1L) len in - let names_addr = names_addr +^ Int64.of_int len +^ 1L in - let sym_value = MMap.follow_pointer mem start_addr in - let start_addr = MMap.succ_long mem start_addr in - compressed_names := - (name, sym_value) :: !compressed_names; - loop names_addr start_addr (num-1) - ) else - names_addr - in - let markers_addr = loop names_addr start_addr num_entries in - let markers_addr = MMap.align mem markers_addr in - let compressed_names = List.rev !compressed_names in - - Some (start_addr, num_entries, names_addr, - Compressed (compressed_names, markers_addr)) - ) - with - Invalid_argument _ -> None (* bad names list *) - ) ksym_addrs in - - if debug then ( - eprintf "%s: candidate kallsyms at:\n" name; - List.iter ( - function - | (start_addr, num_entries, names_addr, Uncompressed _) -> - eprintf "\t%Lx %d entries names_addr=%Lx old-style\n%!" - start_addr num_entries names_addr - | (start_addr, num_entries, names_addr, - Compressed (_, markers_addr)) -> - eprintf "\t%Lx %d entries names_addr=%Lx markers_addr=%Lx\n%!" - start_addr num_entries names_addr markers_addr - ) kallsymtabs - ); - - (* Vote for the most popular symbol table candidate and - * enhance the function for looking up ksyms. - *) - let lookup_ksym = - let freqs = frequency kallsymtabs in - match freqs with - | [] -> - (* Can't find any kallsymtabs, just return the lookup_ksym - * function generated previously from the exported symbols. - *) - lookup_ksym - - | (_, (_, _, _, Uncompressed names)) :: _ -> - let lookup_ksym name = - try (* first look it up in kallsyms table. *) - List.assoc name names - with Not_found -> (* try the old exports table instead *) - lookup_ksym name - in - lookup_ksym - - | (_, (start_addr, num_entries, names_addr, - Compressed (compressed_names, markers_addr))) :: _ -> - (* Skip the markers and look for the token table. *) - let num_markers = Int64.of_int ((num_entries + 255) / 256) in - let marker_size = - Int64.of_int (bytes_of_wordsize (MMap.get_wordsize mem)) in - let tokens_addr = markers_addr +^ marker_size *^ num_markers in - - (* Now read out the compression tokens, which are just - * 256 ASCIIZ strings that map bytes in the compression - * names to substrings. - *) - let tokens = Array.make 256 "" in - let rec loop i addr = - if i < 256 then ( - let str = MMap.get_string mem addr in - let len = String.length str in - let addr = addr +^ Int64.of_int (len+1) in - tokens.(i) <- str; - loop (i+1) addr - ) - in - loop 0 tokens_addr; - - (* Expand the compressed names using the tokens. *) - let names = List.filter_map ( - fun (name, sym_value) -> - let f c = tokens.(Char.code c) in - let name = String.replace_chars f name in - (* First character in uncompressed output is the symbol - * type, eg. 'T'/'t' for text etc. - *) - (* NOTE: Symbol names are NOT unique - * (eg. 'con_start' is both a function and data in - * some kernels). XXX We need to handle this situation - * better. - *) - (*let typ = name.[0] in*) - let name = String.sub name 1 (String.length name - 1) in - (*eprintf "%S -> %Lx\n" name sym_value;*) - Some (name, sym_value) - ) compressed_names in - - let lookup_ksym name = - try (* first look it up in kallsyms table. *) - List.assoc name names - with Not_found -> (* try the old exports table instead *) - lookup_ksym name - in - - lookup_ksym in - - if debug then ( - let end_t = gettimeofday () in - eprintf "timing: searching for kallsyms took %f seconds\n%!" - (end_t -. start_t) - ); - - (* Just wrap the lookup_ksym call in something which prints - * the query when debug is set. + (* Finally, just wrap the lookup_ksym call in something + * which prints the query when debug is set. *) - let lookup_ksym = + let image = if debug then + let (domid, name, arch, mem, lookup_ksym) = image in let lookup_ksym sym = try let value = lookup_ksym sym in @@ -722,12 +499,16 @@ let start usage_msg = eprintf "lookup_ksym %S failed\n%!" sym; raise Not_found in - lookup_ksym + (domid, name, arch, mem, lookup_ksym) else - lookup_ksym - in + image in - ((name, arch, mem, lookup_ksym) : image) + image ) images in - debug, images + (* Run the tool's main function. *) + (match run with + | None -> () + | Some run -> + run debug images + )