.TH ADB 1 "9 February 1983" .SH NAME adb \- debugger .SH SYNOPSIS .B adb [\fB\-w\fR] [ \fB\-k\fR ] [ \fB-I\fRdir ] [ objfil [ corfil ] ] .ds TW \v'.25m'\s+2~\s-2\v'-.25m' .ds ST \v'.25m'*\v'-.25m' .ds IM \v'.1m'=\v'-.1m'\s-2\h'-.1m'>\h'.1m'\s+2 .ds LE \(<= .ds LT \s-2<\s+2 .ds GT \s-2>\s+2 .SH DESCRIPTION .I Adb is a general purpose debugging program. It may be used to examine files and to provide a controlled environment for the execution of UNIX programs. .PP .I Objfil is normally an executable program file, preferably containing a symbol table; if not then the symbolic features of .I adb cannot be used although the file can still be examined. The default for .I objfil is .B a.out. .I Corfil is assumed to be a core image file produced after executing .IR objfil ; the default for .I corfil is .B core. .PP Requests to .I adb are read from the standard input and responses are to the standard output. If the .B \-w flag is present then both .I objfil and .I corfil are created if necessary and opened for reading and writing so that files can be modified using .IR adb . .PP The \fB\-k\fP option makes \fIadb\fP do UNIX kernel memory mapping; it should be used when \fIcore\fP is a UNIX crash dump or \fI/dev/mem\fP. .PP The \fB\-I\fP option specifies a directory where files to be read with $< or $<< (see below) will be sought; the default is .IR /usr/lib/adb . .PP .I Adb ignores QUIT; INTERRUPT causes return to the next .I adb command. .PP .I Adb saves and restores terminal characteristics when running a sub\-process. This make it possible to debug programs that manipulate the screen. See .IR tty (5). .PP In general requests to .I adb are of the form .PP .if n .ti 16 .if t .ti 1.6i [\|\fIaddress\fR\|] [\|, .IR count \|] [\|\fIcommand\fR\|] [\|;\|] .PP If .I address is present then .I dot is set to .IR address . Initially .I dot is set to 0. For most commands .I count specifies how many times the command will be executed. The default .I count is 1. .I Address and .I count are expressions. .PP The interpretation of an address depends on the context it is used in. If a subprocess is being debugged then addresses are interpreted in the usual way in the address space of the subprocess. If the operating system is being debugged either post-mortem or using the special file .B /dev/kmem to interactive examine and/or modify memory the maps are set to map the kernel virtual addresses which start at 0x80000000(VAX) or 0(SUN). For some commands, the address is not interpreted as a memory address at all, but as an ordered pair representing a file number and a line number within that file. The @ command always takes such a sourcefile address, and several operators are available to convert to and from the more customary core locations. For further details of address mapping see .SM ADDRESSES. .SH EXPRESSIONS .TP 7.2n .B . The value of .IR dot . .TP 7.2n + The value of .I dot incremented by the current increment. .TP 7.2n ^ The value of .I dot decremented by the current increment. .TP 7.2n & The last .I address typed. (Used to be ``"''.) .TP 7.2n .I integer A number. The prefixes 0o and 0O (\*(lqzero oh\*(rq) force interpretation in octal radix; the prefixes 0t and 0T force interpretation in decimal radix; the prefixes 0x and 0X force interpretation in hexadecimal radix. Thus 0o20 = 0t16 = 0x10 = sixteen. If no prefix appears, then the .I 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). .TP 7.2n .IB integer . fraction A 32 bit floating point number. .TP 7.2n .I \'cccc\|\' The ASCII value of up to 4 characters. \e may be used to escape a \'. .TP 7.2n .I \*(LT name The value of .IR name , which is either a variable name or a register name. .I Adb maintains a number of variables (see .SM VARIABLES\*S) named by single letters or digits. If .I name is a register name then the value of the register is obtained from the system header in .IR corfil . The register names are those printed by the $r command. .TP 7.2n .I symbol A .I symbol is a sequence of upper or lower case letters, underscores or digits, not starting with a digit. The backslash character .B \e may be used to escape other characters. The value of the .I symbol is taken from the symbol table in .IR objfil . An initial \_ will be prepended to .I symbol if needed. .TP .I _ symbol In C, the `true name' of an external symbol begins with _. It may be necessary to utter this name to distinguish it from internal or hidden variables of a program. .TP 7.2n .IB routine . name The address of the variable .I name in the specified C routine. Both .I routine and .I name are .IR symbols . If .I name is omitted the value is the address of the most recently activated C stack frame corresponding to .IR routine . (This form is currently broken on the VAX; local variables can be examined only with .IR dbx (1).) .TP 7.2n .RI ( exp \|) The value of the expression .IR exp . .LP .SM .B "Monadic\ operators" .TP 7.2n .RI \*(ST exp The contents of the location addressed by .I exp in .IR corfil . .TP 7.2n .RI % exp The contents of the location addressed by .I exp in .IR objfil . (Used to be @.) .TP 7.2n .RI \- exp Integer negation. .TP 7.2n .RI \*(TW exp Bitwise complement. .TP 7.2n .RI # exp Logical negation. .TP 7.2n .RI ^F exp (Control\-f) Translates program addresses in to sourcefile addresses. .TP 7.2n .RI ^A exp (Control\-a) Translates sourcefile addresses into program addresses. .TP 7.2n .RI \` name (Back\-quote) Translates a procedure name into a sourcefile address. .TP 7.2n .tr '" .I 'filename' A filename enclosed in quotation marks (e.g.: 'main.c') produces the sourcefile address for the zero-th line of that file. Thus to reference the third line of the file main.c, we say: 'main.c'+3. .LP .tr '' .B "Dyadic\ operators" are left associative and are less binding than monadic operators. .TP 7.2n .IR e1 + e2 Integer addition. .TP 7.2n .IR e1 \- e2 Integer subtraction. .TP 7.2n .IR e1 \*(ST e2 Integer multiplication. .TP 7.2n .IR e1 % e2 Integer division. .TP 7.2n .IR e1 & e2 Bitwise conjunction. .TP 7.2n .IR e1 \(bv e2 Bitwise disjunction. .TP 7.2n .IR e1 # e2 .I E1 rounded up to the next multiple of .IR e2 . .DT .SH 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 `\*(ST'; see .SM ADDRESSES for further details.) .TP .5i .RI ? f Locations starting at .I address in .I objfil are printed according to the format .IR f . .I dot is incremented by the sum of the increments for each format letter (q.v.). .TP .RI / f Locations starting at .I address in .I corfil are printed according to the format .I f and .I dot is incremented as for `?'. .TP .RI = f The value of .I address itself is printed in the styles indicated by the format .IR f . (For .B i format `?' is printed for the parts of the instruction that reference subsequent words.) .TP .RI @ f .I address is interpreted as a sourcefile address. Locations in .I objfile or lines of the source text may be printed, depending on the format specified. .PP A .I 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 .I 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. .ta 2.5n .5i .RS .TP .BR o " 2" Print 2 bytes in octal. All octal numbers output by .I adb are preceded by 0. .br .ns .TP .BR O " 4" Print 4 bytes in octal. .br .ns .TP .BR q " 2" Print in signed octal. .br .ns .TP .BR Q " 4" Print long signed octal. .br .ns .TP .BR d " 2" Print in decimal. .br .ns .TP .BR D " 4" Print long decimal. .br .ns .TP .BR x " 2" Print 2 bytes in hexadecimal. .br .ns .TP .BR X " 4" Print 4 bytes in hexadecimal. .br .ns .TP .BR u " 2" Print as an unsigned decimal number. .br .ns .TP .BR U " 4" Print long unsigned decimal. .br .ns .TP .BR f " 4" Print the 32 bit value as a floating point number. .br .ns .TP .BR F " 8" Print double floating point. .br .ns .TP .BR b " 1" Print the addressed byte in octal. .br .ns .TP .BR c " 1" Print the addressed character. .br .ns .TP .BR C " 1" Print the addressed character using the standard escape convention where control characters are printed as ^X and the delete character is printed as ^?. .br .ns .TP .BI s " n" Print the addressed characters until a zero character is reached. .br .ns .TP .BI S " n" Print a string using the ^\fIX\fR escape convention (see \fBC\fR above). .I n is the length of the string including its zero terminator. .br .ns .TP .BR Y " 4" Print 4 bytes in date format (see .IR ctime (3)). .br .ns .TP .BR i " n" Print as machine instructions. .I n is the number of bytes occupied by the instruction. This style of printing causes variables 1 and 2 to be set to the offset parts of the source and destination respectively. .br .ns .TP .BR I " 0" Print the source text line specified by .I dot (@ command) or most closely corresponding to .I dot (? command). .br .ns .TP .BR a " 0" Print the value of .I dot in symbolic form. Symbols are checked to ensure that they have an appropriate type as indicated below. .LP / local or global data symbol .br ? local or global text symbol .br = local or global absolute symbol .TP .BR p " 4" Print the addressed value in symbolic form using the same rules for symbol lookup as .BR a . .br .ns .TP .tr '" .BR A " 0" Print the value of .I dot in sourcefile symbolic form, i.e.: .I 'filename'+nnn. .br .ns .TP .BR P " 4" Print the addressed value in sourcefile symbolic form, i.e.: .I 'filename'+nnn. .br .tr '' .ns .TP .BR t " 0" When preceded by an integer tabs to the next appropriate tab stop. For example, .B 8t moves to the next 8-space tab stop. .br .ns .TP .BR r " 0" Print a space. .br .ns .TP .BR n " 0" Print a newline. .br .ns .tr '" .TP .BR '...' " 0" Print the enclosed string. .br .tr '' .br .ns .TP .B ^ .I Dot is decremented by the current increment. Nothing is printed. .br .ns .TP + .I Dot is incremented by 1. Nothing is printed. .br .ns .TP \- .I Dot is decremented by 1. Nothing is printed. .RE .TP newline Repeat the previous command with a .I count of 1. .TP .RB [ ?/ ] l "\fI value mask\fR" Words starting at .I dot are masked with .I mask and compared with .I value until a match is found. If .B L is used then the match is for 4 bytes at a time instead of 2. If no match is found then .I dot is unchanged; otherwise .I dot is set to the matched location. If .I mask is omitted then \-1 is used. .TP .RB [ ?/ ] w "\fI value ...\fR" Write the 2-byte .I value into the addressed location. If the command is .BR W , write 4 bytes. Odd addresses are not allowed when writing to the subprocess address space. .TP [\fB?/\fR]\fBm\fI b1 e1 f1\fR[\fB?/\fR] .br New values for .RI ( 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 `\*(ST' then the second segment (\fIb2\fR\|,\|\fIe2\fR\|,\|\fIf2\fR) of the mapping is changed. If the list is terminated by `?' or `/' then the file (\fIobjfil\fR or .I corfil respectively) is used for subsequent requests. (So that, for example, `/m?' will cause `/' to refer to .IR objfil .) .TP .BI \*(GT name .I Dot is assigned to the variable or register named. .TP .B ! A shell (/bin/sh) is called to read the rest of the line following `!'. .TP .RI $ modifier Miscellaneous commands. The available .I modifiers are: .RS .TP .BI < f Read commands from the file .IR f . If this command is executed in a file, further commands in the file are not seen. If .I f is omitted, the current input stream is terminated. If a .I count is given, and is zero, the command will be ignored. The value of the count will be placed in variable .I 9 before the first command in .I f is executed. .br .ns .TP .BI << f Similar to .B < except it can be used in a file of commands without causing the file to be closed. Variable .I 9 is saved during the execution of this command, and restored when it completes. There is a (small) finite limit to the number of .B << files that can be open at once. .br .ns .TP .BI > f Append output to the file .IR f , which is created if it does not exist. If .I f is omitted, output is returned to the terminal. .br .ns .TP .B ? Print process id, the signal which caused stoppage or termination, as well as the registers as \fB$r\fR. This is the default if \fImodifier\fR is omitted. .br .ns .TP .B r Print the general registers and the instruction addressed by .BR pc . .I Dot is set to \fBpc\fR. .br .ns .TP .B b Print all breakpoints and their associated counts and commands. .br .ns .TP .B c C stack backtrace. If .I address is given then it is taken as the address of the current frame instead of the contents of the frame\-pointer register. If .B C is used then the names and (32 bit) values of all automatic and static variables are printed for each active function. If .I count is given then only the first .I count frames are printed. .br .ns .TP .B d Set the default radix to .I address and report the new value. Note that .I address is interpreted in the (old) current radix. Thus \*(lq10$d\*(rq never changes the default radix. To make decimal the default radix, use \*(lq0t10$d\*(rq. .br .ns .TP .B e The names and values of external variables are printed. .br .ns .TP .B w Set the page width for output to .I address (default 80). .br .ns .TP .B s Set the limit for symbol matches to .I address (default 255). .br .ns .TP .B o All integers input are regarded as octal. .br .ns .TP .B q Exit from .IR adb . .br .ns .TP .B v Print all non zero variables in octal. .br .ns .TP .B m Print the address map. .br .ns .TP .B f Print a list of known source file names. .br .ns .TP .B p Print a list of known procedure names. .br .ns .TP .B p .RI ( "Kernel debugging" ) Change the current kernel memory mapping to map the designated .B "user structure" to the address given by the symbol .I "_u." The .I address argument is the address of the user's user page table entries (VAX) or the address of the user's .B proc structure (SUN). .br .ns .TP .B i Show which signals are passed to the subprocess with the minimum of .I adb interference. Signals may be added to or deleted from this list using the .B :i and .B :t commands. .br .ns .TP .B W Re-open .I objfile and .I corfile for writing, as though the .B \-w command\-line argument had been given. .RE .TP .BI : modifier Manage a subprocess. Available modifiers are: .RS .TP .BI b c Set breakpoint at .IR address . The breakpoint is executed .IR count \-1 times before causing a stop. Each time the breakpoint is encountered the command .I c is executed. If this command is omitted or sets .I dot to zero then the breakpoint causes a stop. .TP .BI B c Like .I b but takes a sourcefile address. .TP .B d Delete breakpoint at .IR address . .TP .B D Like .I d but takes a sourcefile address. .TP .B r Run .I objfil as a subprocess. If .I address is given explicitly then the program is entered at this point; otherwise the program is entered at its standard entry point. .I 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 > causes the standard input or output to be established for the command. All signals are turned on on entry to the subprocess. .TP .BI c s The subprocess is continued with signal .I s c .I s, see .IR signal (2). If .I address is given then the subprocess is continued at this address. If no signal is specified then the signal that caused the subprocess to stop is sent. Breakpoint skipping is the same as for .BR r . .TP .BI s s As for .B c except that the subprocess is single stepped .I count times. If there is no current subprocess then .I objfil is run as a subprocess as for .BR r . In this case no signal can be sent; the remainder of the line is treated as arguments to the subprocess. .TP .B S Like .B s but single steps source lines, rather than machine instructions. This is acheived by repeatedly single\-stepping machine instructions until the corresponding sourcefile address changes. (Thus procedure calls cause stepping to stop.) .TP .B i Add the signal specified by .I address to the list of signals which are passed directly to the subprocess with the minimum of interference. Normally, .I adb intercepts all signals destined for the subprocess, and the user must use the .B :c command to continue the process with the signal. Signals on this list are handed to the process with an implicit .BI :c s as soon as they are seen. .TP .B t Remove the signal specified by .I address from the list of signals that are implicitly passed to the subprocess. .TP .B k The current subprocess, if any, is terminated. .RE .SH VARIABLES .I Adb provides a number of variables. Named variables are set initially by .I adb but are not used subsequently. Numbered variables are reserved for communication as follows. .TP 0 The last value printed. .br .ns .TP 1 The last offset part of an instruction source. .br .ns .TP 2 The previous value of variable 1. .br .ns .TP 9 The count on the last $< or $<< command. .PP On entry the following are set from the system header in the .IR corfil . If .I corfil does not appear to be a .B core file then these values are set from .IR objfil . .TP b The base address of the data segment. .br .ns .TP d The data segment size. .br .ns .TP e The entry point. .br .ns .TP m The `magic' number (0407, 0410 or 0413). .br .ns .TP s The stack segment size. .br .ns .TP t The text segment size. .SH 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 .RI ( "b1, e1, f1" ) and .RI ( "b2, e2, f2" ) and the .I file address corresponding to a written .I address is calculated as follows. .PP .if t .ti 1.5i .if n .ti 8 .IR b1 \*(LE address < e1 \*(IM .IR "file address" = address + f1\-b1, otherwise, .PP .if t .ti 1.5i .if n .ti 8 .IR b2 \*(LE address < e2 \*(IM .IR "file address" = address + f2\-b2, .PP otherwise, the requested .I address is not legal. In some cases (e.g. for programs with separated I and D space) the two segments for a file may overlap. If a .B ? or .B / is followed by an .B \*(ST then only the second triple is used. .PP The initial setting of both mappings is suitable for normal .B a.out and .B core files. If either file is not of the kind expected then, for that file, .I b1 is set to 0, .I e1 is set to the maximum file size and .I f1 is set to 0; in this way the whole file can be examined with no address translation. .PP .SH FILES a.out .br core .SH SEE\ ALSO cc(1), dbx(1), ptrace(2), a.out(5), core(5) .SH DIAGNOSTICS `Adb' when there is no current command or format. Comments about inaccessible files, syntax errors, abnormal termination of commands, etc. Exit status is 0, unless last command failed or returned nonzero status. .SH BUGS Local variable addresses and names and sourcefile\(emaddress correspondences are recorded in the .I a.out file in a format used by the old .I sdb program. Thus the .I -g flag must be used when programs are compiled for these features to work. .PP There doesn't seem to be any way to clear all breakpoints. .PP .I Adb uses the symbolic information in a format understood by the old .I sdb program, rather than that used by the new .I dbx debugger, necessitating two formats of information. This should change soon. .PP Since no shell is invoked to interpret the arguments of the .B :r command, the customary wild\-card and variable expansions cannot occur. .PP Since there is little type\-checking on addresses, using a sourcefile address in an inappropriate context may lead to unexpected results: .I "`main?i" will almost certainly not do anything useful. .PP The VAX version is currently not as up to date as this manual page.