ADB(1) COMMAND REFERENCE ADB(1) NAME adb - debugger SYNOPSIS adb [-p prompt] [-w] [-Idir] [-k] [objfil [corfil]] DESCRIPTION Adb is a general purpose debugging program. It may be used to examine files and to provide a controlled environment for the execution of UTek programs. Objfil is normally an executable program file, preferably containing a symbol table; if not, then the symbolic features of adb cannot be used although the file can still be examined. The default for objfil is a.out. Corfil is assumed to be a core image file produced after executing objfil; the default for corfil is core . Requests to adb are read from the standard input and responses are to the standard output. Adb ignores QUIT; INTERRUPT causes return to the next adb command. In general, requests to adb are of the form: [address] [, count] [command] [;] If address is present then dot is set to address. Initially dot is set to 0. For most commands count specifies how many times the command will be executed. The default count is 1. Address and count are expressions. The interpretation of an address depends on the context in which it is used. If a subprocess is being debugged, then addresses are interpreted in the usual way in the address space of the subprocess. Expressions . The value of dot. + The value of dot incremented by the current increment. ^ The value of dot decremented by the current increment. " The last address typed. integer A number. The prefixes 0o and 0O ("zero oh") force interpretation in octal radix; the prefixes 0t and 0T force interpretation in decimal radix; the prefixes 0x Printed 5/12/88 1
ADB(1) COMMAND REFERENCE ADB(1) and 0X force interpretation in hexadecimal radix. Thus, 0o20 = 0t16 = 0x10 = sixteen. If no prefix appears, then the default radix is used (see the $d command.) The default radix is initially hexadecimal. The hexadecimal digits are 0123456789abcdefABCDEF with the obvious values. Note that a hexadecimal number whose most significant digit would otherwise be an alphabetic character must have a 0x (or 0X) prefix (or a leading zero if the default radix is hexadecimal). integer.[fraction][{e|E}exponent] A floating point number, generaly 32 bits. The radix must be set to decimal. See the section on Floating Point Numbers in this document. 'cccc' The ASCII value of up to four characters. The backslash character ( \ ) may be used to escape an apostrophe character ( ' ). < name The value of name, which is either a variable name, a register name or a pseudo-register name. Adb maintains a number of variables named by single letters or digits. (See the section Variables in this document.) If name is a register name then the value of the register is obtained from the system header in corfil. The register names are those printed by the $r command. Accessing a floating point register will return the 32 bits of a single and set the floating point pseudo-registers. Pseudo-registers are covered under the section Floating Point Numbers. symbol A symbol is a sequence of uppercase or lowercase letters, underscores or digits, not starting with a digit. The backslash ( \ ) may be used to escape other characters. The value of symbol is taken from the symbol table in objfil. An initial underscore character ( _ ) will be prepended to symbol if needed. _ symbol In C, the true name of an external symbol begins with an underscore ( _ ). It may be necessary to utter this name to distinguish it from internal or hidden variables of a program. routine.name The address of the variable name in the specified C routine. Both routine and name are symbols. If name is omitted the value is the address of the most recently activated C stack frame corresponding to routine. Printed 5/12/88 2
ADB(1) COMMAND REFERENCE ADB(1) (exp) The value of the expression exp. Monadic Operators *exp The contents of the location addressed by exp in corfil. This can also be used to accessed floating point numbers. See Floating Point Numbers in this document. @exp The contents of the location addressed by exp in objfil. This can also be used to accessed floating point numbers. See Floating Point Numbers in this document. -exp Integer negation. ~exp Bitwise complement. #exp Logical negation. Dyadic Operators These are left associative and are less binding than monadic operators. e1+e2 Integer addition. e1-e2 Integer subtraction. e1*e2 Integer multiplication. e1%e2 Integer division. e1&e2 Bitwise conjunction. e1|e2 Bitwise disjunction. e1#e2 E1 rounded up to the next multiple of e2. Commands Most commands consist of a verb followed by a modifier or list of modifiers. The following verbs are available (the commands ? and / may be followed by *; see the section Addresses for further details): ?f Locations starting at address in objfil are printed according to the format f. Dot is incremented by the sum of the increments for each format letter (q.v.). /f Locations starting at address in corfil are printed Printed 5/12/88 3
ADB(1) COMMAND REFERENCE ADB(1) according to the format f and dot is incremented as for ? (question mark). =f The value of address itself is printed in the styles indicated by the format f. (For i format, ? is printed for the parts of the instruction that reference subsequent words.) A format consists of one or more characters that specify a style of printing. Each format character may be preceded by a decimal integer that is a repeat count for the format character. While stepping through, a format dot is incremented by the amount given for each format letter. If no format is given then the last format is used. The format letters available are as follows: o 2 Print two bytes in octal. All octal numbers output by adb are preceded by 0. O 4 Print four bytes in octal. q 2 Print in signed octal. Q 4 Print long signed octal. d 2 Print in decimal. D 4 Print long decimal. x 2 Print two bytes in hexadecimal. X 4 Print four bytes in hexadecimal. u 2 Print as an unsigned decimal number. U 4 Print long unsigned decimal. f 4 Print the 32 bit value as a floating point number. See the section Floating Point Numbers. F 8 Print the double floating point value contained in the pseudo-registers d_h and d_l. See the section Floating Point Numbers. g 4 Print the contents of the pseudo-registers x_h, x_m, and x_l. See the section Floating Point Numbers. G 8 Print extended floating point value contained in the pseudo-registers x_h, x_m, and x_l. See the section Floating Point Numbers. b 1 Print the addressed byte in octal. Printed 5/12/88 4
ADB(1) COMMAND REFERENCE ADB(1) c 1 Print the addressed character. C 1 Print the addressed character using the standard escape convention where control characters are printed as <CTRL-X> and the delete character is printed as <CTRL- ?> s n Print the addressed characters until a zero character is reached. S n Print a string using the <CTRL-X> escape convention (see the section describing the format letter C). The n is the length of the string including its zero terminator. Y 4 Print four bytes in date format. See ctime(3c). i n Print as machine instructions. The n is the number of bytes occupied by the instruction. This style of printing sets variable 1 to the offset parts of the source and sets variable 2 to the offset parts of the destination. a 0 Print the value of dot in symbolic form. Symbols are checked to ensure that they have an appropriate type as indicated: / Local or global data symbol. ? Local or global text symbol. = Local or global absolute symbol. p 4 Print the addressed value in symbolic form using the same rules for symbol lookup as a. t 0 When preceded by an integer, tab to the next appropriate tab stop. For example, 8t moves to the next eight-space tab stop. r 0 Print a space. n 0 Print a newline. "..." 0 Print the enclosed string. ^ Dot is decremented by the current increment. Nothing is printed. + Dot is incremented by 1. Nothing is printed. - Dot is decremented by 1. Nothing is printed. Printed 5/12/88 5
ADB(1) COMMAND REFERENCE ADB(1) newline Repeat the previous command with a count of 1. [?/]l value [mask] Words starting at dot are masked with mask and compared with value until a match is found. If L is used then the match is for four bytes at a time instead of two. If no match is found then dot is unchanged; otherwise, dot is set to the matched location. If mask is omitted then -1 is used. [?/]w value ... Write the two-byte value into the addressed location. If the command is W, write four bytes. Odd addresses are not allowed when writing to the subprocess address space. [?/]m b1 e1 f1[?/] New values for (b1, e1, f1) are recorded. If less than three expressions are given, then the remaining map parameters are left unchanged. If the ? or / is followed by *, then the second segment (b2,e2,f2) of the mapping is changed. If the list is terminated by ? or / then the file (objfil or corfil respectively) is used for subsequent requests. For example, /m? causes / to refer to objfil. >name Dot is assigned to the variable, register, or pseudo- register named. The only pseudo-register allowed is iat. If name is a floating point register, the extended floating point value in the pseudo-registers x_h, x_m, and x_l are moved to that register. See the section Floating Point Numbers. ! A shell ( /bin/sh ) is called to read the rest of the line following the exclamation point (!). $modifier Miscellaneous commands. The available modifiers are: <f Read commands from the file f. If this command is executed in a file, further commands in the file are not seen. If f is omitted, the current input stream is terminated. If a count is given, and is zero, the command is ignored. The value of the count is placed in variable 9 before the first command in f is executed. <<f Similar to < except it can be used in a file of commands without closing the file. Variable 9 is saved during the execution of this command, and restored when it completes. There is a (small) finite Printed 5/12/88 6
ADB(1) COMMAND REFERENCE ADB(1) limit to the number of << files that can be open at once. >f Append output to the file f, which is created if it does not exist. If f is omitted, output is returned to the terminal. ? Print process ID, the signal which causes stoppage or termination, as well as the registers (such as) $r; this is the default if modifier is omitted. r Print the general registers and the instruction addressed by pc. Dot is set to pc. b Print all breakpoints and their associated counts and commands. c C stack backtrace. If address is given it is taken as the address of the current frame instead of the contents of the frame-pointer register. If count is given, only the first count frames are printed. d Set the default radix to address and report the new value. Note that address is interpreted in the (old) current radix. Thus 10$d never changes the default radix. To make decimal the default radix, use 0t10$d. e The names and values of external variables are printed. w Set the page width for output to address (default 80). s Set the limit for symbol matches to address (default 255). o All integers input are regarded as octal. q Exit from adb. v Print all nonzero variables in the current radix. m Print the address map. t Toggle the virtual to physical trace output. Only useful if -k command line option is also specified. :modifier Manage a subprocess. Available modifiers are: bc Set breakpoint at address. The breakpoint is Printed 5/12/88 7
ADB(1) COMMAND REFERENCE ADB(1) executed count -1 times before causing a stop. Each time the breakpoint is encountered, the command c is executed. If this command is omitted or sets dot to zero, then breakpoint causes a stop. d Delete breakpoint at address. D Delete all breakpoints. r Run objfil as a subprocess. If address is given explicitly the program is entered at this point; otherwise the program is entered at its standard entry point. Count specifies how many breakpoints are to be ignored before stopping. Arguments to the subprocess may be supplied on the same line as the command. An argument starting with < or > establishes the standard input or output for the command. ic Set or clear special signal handling. Take address as the signal number (see the command sigvec(2) ), and set (if c is one) or clear (if c is zero) special signal handling for all signals with that number. If special signal handling is set for a given signal number, any signal with a matching number is not trapped by adb , but sent immediately to the sub- process. If special signal handling is not set for a given signal number, adb will halt on receipt of a signal with that number. The default for special signal handling for all signals is the cleared state. This command is required by programs which make heavy use of signals as real-time events (such as up and down clicks of a mouse key). Since signals are not queued by the operating system, if a subprocess is halted by reception of a signal, all signals of that number which are sent to the subprocess before it is continued would not be detected. To avoid this, if, for example, the subprocess expects to receive SIGEMT (signal number 7) signals for each click (both up and down) of a mouse key, the command 7:i1 would set special signal handling for all SIGEMT signals, and all such signals would immediately be forwarded to the subprocess. cs The subprocess is continued with signal s (see the command sigvec(2) ). If address is given, the subprocess is continued at this address. If no signal is specified, the signal that stopped the subprocess is sent. Breakpoint skipping is the same as for r. Printed 5/12/88 8
ADB(1) COMMAND REFERENCE ADB(1) ss Same as for c except that the subprocess is single- stepped, count times. If there is no current subprocess, objfil is run as a subprocess as for r. In this case no signal can be sent; the remainder of the line is treated as arguments to the subprocess. Ss Same as for s, except that if the instruction to be stepped is a call to a subroutine, the entire subroutine is executed. k The current subprocess, if any, is terminated. Addresses The address in a file, associated with a written address, is determined by a mapping associated with that file. Each mapping is represented by two triples: (b1, e1, f1) and (b2, e2, f2); the filename address corresponding to a written address is calculated as follows: b1 < address < e1 => filename address = address + f1-b1, or b2 < address < e2 => filename address = address + f2-b2 If not in this form, the requested address is not legal. In some cases, such as for programs with separated I and D space, the two segments for a file may overlap. If a ? or / is followed by an * then only the second triple is used. The initial setting of both mappings is suitable for normal a.out and core files. If either file is not of the kind expected, then, for that file, b1 is set to 0, e1 is set to the maximum file size, and f1 is set to 0; in this way the whole file can be examined with no address translation. Variables Adb provides a number of variables. Named variables are set initially by adb but are not used subsequently. Numbered variables are reserved for communication as follows: 0 The last value printed. 1 The last offset part of an instruction source. 2 The previous value of variable 1. 9 The count on the last $< or $<< command. Printed 5/12/88 9
ADB(1) COMMAND REFERENCE ADB(1) On entry, the following are set from the system header in the corfil (if corfil does not appear to be a core file these values are set from objfil): b The base address of the data segment. d The data segment size. e The entry point. m The magic number (0407, 0410 or 0413). s The stack segment size. t The text segment size. Floating Point Numbers Adb provides support for three types of floating point numbers: single (32 bits), double (64 bits), and extended (80 bits, stored and accessed and 96 bits). Singles are treated just like any other 32 bit object. Doubles and extendeds, however, require the use of special read-only "pseudo-registers", two to hold a double and three to hold an extended. The registers d_h and d_l hold the high-order and low-order 32-bits of a double. The registers x_h, x_m, and x_l hold the high, middle, and low parts of an extended. These registers can be loaded with values in three different ways: via a constant entered by the user in the address portion of a command, via an indirect reverence, or by accessing a floating point register with the < operator. In all three cases, the same value is loaded into both sets of registers. When this is not possible, note will be made of that fact in yet another pseudo-register. When a constant is used, the input radix should normally be decimal and the floating point format previously described would be used. The only restriction is that the integer part of the number must fit in a 32 bit integer. If the constant is entered in hexadecimal or octal, the number of bits entered determines how the constant is handled. If 32 bits or less, the constant is taken as a single and is converted to a double and an extended. If 64 bits or less, the constant is taken as a double and is converted to a single (if possible) and an extended. If more than 64 bits are entered, the constant is taken as an extended and is converted to a double and single. If the constant is entered in any other radix, it is converted to a 32 bit object in the normal way. That 32 bit object is then taken as a single and converted to a double and an extended. Printed 5/12/88 10
ADB(1) COMMAND REFERENCE ADB(1) The second way to load the floating point pseudo-registers is by using the indirect operators * and @. Normally these operators will access a 32 bit object, in which case the object is treated as a single and converted to a double and an extended. But if the read-write pseudo-register iat has been set to 1, a double is accessed. The double is then converted to a single and an extended. If iat has the value 2, an extended is accessed, and it is converted to a single and a double. In any case, the "value" of the operation is the 32 bits of the single and iat is reset to a value of 0, indicating a normal 32 bit access. The third way to load the floating point pseudo-register is by accessing one of the hardware floating point registers using the < operator as described under the section Expressions. For each type of floating point number (single, double or extended), there is a pseudo-register ( s_c, d_c, and x_c respectively), that contains an integer specifying the class of the floating point number: -1 Could not form a floating point number. 0 A normal floating point number. 1 A denormalized floating point number. 2 A NAN. 3 A signaling NAN. 4 A positive infinity. 5 A negative infinity. 6 A positive zero. 7 A negative zero. OPTIONS -p Makes adb interpret the string following -p as the prompt to use when it is ready to accept commands from your terminal. -w Both objfil and corfil are created if necessary and opened for reading and writing so that files can be modified using adb. -I Specifies a directory where files read with $< or $<< will be sought; the default is /usr/lib/adb. Printed 5/12/88 11
ADB(1) COMMAND REFERENCE ADB(1) -k Specifies that corfil represents physical memory of a UTek kernel: either /dev/mem or the vmcore.? file generated by savecore(8). Enables virtual-to-physical address translation when looking in corfil . FILES a.out Default binary filename core Default core image filename DIAGNOSTICS adb This is given when there is no current command or format. This command comments about inaccessible files, syntax errors, abnormal termination of commands, and so forth. Exit status is 0, unless the last command failed or returned nonzero status. CAVEATS Since no shell is invoked to interpret the arguments of the :r command, the customary wild-card and variable expansions cannot occur. SEE ALSO cc(1), sdb(1), ptrace(2), a.out(5), core(5), and savecore(8). Printed 5/12/88 12
%%index%% na:216,66; sy:282,299; de:581,2326;3195,2908;6391,2294;8973,2208;11469,2017;13774,2824;16886,2184;19358,2966;22612,2388;25288,2713;28289,1462; op:29751,653;30692,323; fi:31015,157; di:31172,441; ca:31613,230; se:31843,240; %%index%%000000000256