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diff --git a/man/man1/db.html b/man/man1/db.html new file mode 100644 index 00000000..eed2c3f9 --- /dev/null +++ b/man/man1/db.html @@ -0,0 +1,548 @@ +<head> +<title>db(1) - Plan 9 from User Space</title> +<meta content="text/html; charset=utf-8" http-equiv=Content-Type> +</head> +<body bgcolor=#ffffff> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=10><td> +<tr><td width=20><td> +<tr><td width=20><td><b>DB(1)</b><td align=right><b>DB(1)</b> +<tr><td width=20><td colspan=2> + <br> +<p><font size=+1><b>NAME </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + db – debugger<br> + +</table> +<p><font size=+1><b>SYNOPSIS </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>db</font></tt> [ <i>option ...</i> ] [ <i>textfile</i> ] [ <i>pid</i> | <i>corefile</i> ]<br> + +</table> +<p><font size=+1><b>DESCRIPTION </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <i>Db</i> is a general purpose debugging program. It may be used to examine + files and to provide a controlled environment for the execution + of programs. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + A <i>textfile</i> is a file containing the text and initialized data + of an executable program. A <i>pid</i> or <i>corefile</i> specifies the memory + image of a process. A <i>pid</i> gives the id of an executing process + to be accessed via <a href="../man2/ptrace.html"><i>ptrace</i>(2)</a>. A <i>corefile</i> specifies the name of + a core dump (see <a href="../man5/core.html"><i>core</i>(5)</a> on your system of choice) containing + the + memory image of a terminated process. This manual refers to the + memory image specified by <i>pid</i> or <i>corefile</i> as a <i>memfile</i>. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + A <i>map</i> associated with each <i>textfile</i> or <i>memfile</i> supports accesses + to instructions and data in the file; see ‘Addresses’. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + An argument consisting entirely of digits is assumed to be a process + id; otherwise, it is the name of a <i>textfile</i> or <i>corefile</i>. When + a <i>textfile</i> is given, the textfile map is associated with it. If + only a <i>memfile</i> is given, the textfile map is derived from the + corresponding <i>textfile</i>, if it can be determined (this varies from + system to + system). When a <i>memfile</i> is given, the memfile map is associated + with it; otherwise the map is undefined and accesses to it are + not permitted. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Commands to <i>db</i> are read from the standard input and responses + are to the standard output. The options are<br> + <tt><font size=+1>−w</font></tt> Open <i>textfile</i> and <i>memfile</i> for writing as well as reading.<br> + <tt><font size=+1>−I</font></tt><i>path<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Directory in which to look for relative path names in <tt><font size=+1>$<</font></tt> and <tt><font size=+1>$<<</font></tt> + commands.<br> + + </table> + <tt><font size=+1>−m</font></tt><i>machine<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Assume instructions are for the given CPU type (possible names + include <tt><font size=+1>386</font></tt> and <tt><font size=+1>powerpc</font></tt>; adding the suffix <tt><font size=+1>−co</font></tt> as in <tt><font size=+1>386−co</font></tt> and + <tt><font size=+1>powerpc−co</font></tt> selects disassembly in the manufacturer’s syntax, if + available, rather than the default Plan 9 syntax). + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + + </table> + Most <i>db</i> commands have the following form:<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + [<i>address</i>] [<tt><font size=+1>,</font></tt> <i>count</i>] [<i>command</i>] + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + + </table> + If <i>address</i> is present then the current position, called ‘dot’, + is set to <i>address</i>. Initially dot is set to 0. Most commands are + repeated <i>count</i> times with dot advancing between repetitions. The + default <i>count</i> is 1. <i>Address</i> and <i>count</i> are expressions. Multiple + commands on one line must be separated by <tt><font size=+1>;</font></tt>. + <p><font size=+1><b>Expressions </b></font><br> + Expressions are evaluated as long <i>ints</i>.<br> + <tt><font size=+1>.</font></tt> The value of dot.<br> + <tt><font size=+1>+</font></tt> The value of dot incremented by the current increment.<br> + <tt><font size=+1>^</font></tt> The value of dot decremented by the current increment.<br> + <tt><font size=+1>"</font></tt> The last <i>address</i> typed.<br> + <i>integer<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + A number, in decimal radix by default. The prefixes <tt><font size=+1>0</font></tt> and <tt><font size=+1>0o</font></tt> and + <tt><font size=+1>0O</font></tt> (zero oh) force interpretation in octal radix; the prefixes + <tt><font size=+1>0t</font></tt> and <tt><font size=+1>0T</font></tt> force interpretation in decimal radix; the prefixes + <tt><font size=+1>0x</font></tt>, <tt><font size=+1>0X</font></tt>, and <tt><font size=+1>#</font></tt> force interpretation in hexadecimal radix. Thus + <tt><font size=+1>020</font></tt>, <tt><font size=+1>0o20</font></tt>, <tt><font size=+1>0t16</font></tt>, and <tt><font size=+1>#10</font></tt> all represent sixteen. + + </table> + <i>integer</i><tt><font size=+1>.</font></tt><i>fraction<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + A single-precision floating point number.<br> + + </table> + <tt><font size=+1>'</font></tt><i>c</i><tt><font size=+1>'</font></tt> The 16-bit value of a character. <tt><font size=+1>\</font></tt> may be used to escape a + <tt><font size=+1>'</font></tt>.<br> + <tt><font size=+1><</font></tt><i>name<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + The value of <i>name</i>, which is a register name. The register names + are those printed by the <tt><font size=+1>$r</font></tt> command.<br> + + </table> + <i>symbol<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + A <i>symbol</i> is a sequence of upper or lower case letters, underscores + or digits, not starting with a digit. <tt><font size=+1>\</font></tt> may be used to escape + other characters. The location of the <i>symbol</i> is calculated from + the symbol table in <i>textfile</i>.<br> + + </table> + <i>routine</i><tt><font size=+1>.</font></tt><i>name<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + The address of the variable <i>name</i> in the specified C routine. Both + <i>routine</i> and <i>name</i> are <i>symbols</i>. If <i>name</i> is omitted the value is + the address of the most recently activated stack frame corresponding + to <i>routine</i>; if <i>routine</i> is omitted, the active procedure is assumed.<br> + + </table> + <i>file</i><tt><font size=+1>:</font></tt><i>integer<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + The address of the instruction corresponding to the source statement + at the indicated line number of the file. If the source line contains + no executable statement, the address of the instruction associated + with the nearest executable source line is returned. Files begin + at line 1. If multiple files of the same name + are loaded, an expression of this form resolves to the first file + encountered in the symbol table.<br> + + </table> + <tt><font size=+1>(</font></tt><i>exp</i><tt><font size=+1>)<br> + </font></tt> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + The value of the expression <i>exp</i>. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + + </table> + <i>Monadic operators<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>*</font></tt><i>exp</i> The contents of the location addressed by <i>exp</i> in <i>memfile</i>.<br> + <tt><font size=+1>@</font></tt><i>exp</i> The contents of the location addressed by <i>exp</i> in <i>textfile</i>.<br> + <tt><font size=+1>−</font></tt><i>exp</i> Integer negation.<br> + <tt><font size=+1>~</font></tt><i>exp</i> Bitwise complement.<br> + <tt><font size=+1>%</font></tt><i>exp</i> When used as an <i>address</i>, <i>exp</i> is an offset into the segment + named <i>ublock</i>; see ‘Addresses’.<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + + </table> + <i>Dyadic operators</i> are left-associative and are less binding than + monadic operators.<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <i>e1</i><tt><font size=+1>+</font></tt><i>e2</i>Integer addition.<br> + <i>e1</i><tt><font size=+1>−</font></tt><i>e2</i>Integer subtraction.<br> + <i>e1</i><tt><font size=+1>*</font></tt><i>e2</i>Integer multiplication.<br> + <i>e1</i><tt><font size=+1>%</font></tt><i>e2</i>Integer division.<br> + <i>e1</i><tt><font size=+1>&</font></tt><i>e2</i>Bitwise conjunction.<br> + <i>e1</i><tt><font size=+1>|</font></tt><i>e2</i>Bitwise disjunction.<br> + <i>e1</i><tt><font size=+1>#</font></tt><i>e2E1</i> rounded up to the next multiple of <i>e2</i>.<br> + + </table> + <p><font size=+1><b>Commands </b></font><br> + Most commands have the following syntax:<br> + <tt><font size=+1>?</font></tt><i>f</i> Locations starting at <i>address</i> in <i>textfile</i> are printed according + to the format <i>f</i>.<br> + <tt><font size=+1>/</font></tt><i>f</i> Locations starting at <i>address</i> in <i>memfile</i> are printed according + to the format <i>f</i>.<br> + <tt><font size=+1>=</font></tt><i>f</i> The value of <i>address</i> itself is printed according to the format + <i>f</i>. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + A <i>format</i> 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. If no + format is given then the last format is used. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Most format letters fetch some data, print it, and advance (a + local copy of) dot by the number of bytes fetched. The total number + of bytes in a format becomes the <i>current</i>increment<i>.<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>o</font></tt> Print two-byte integer in octal.<br> + <tt><font size=+1>O</font></tt> Print four-byte integer in octal.<br> + <tt><font size=+1>q</font></tt> Print two-byte integer in signed octal.<br> + <tt><font size=+1>Q</font></tt> Print four-byte integer in signed octal.<br> + <tt><font size=+1>d</font></tt> Print two-byte integer in decimal.<br> + <tt><font size=+1>D</font></tt> Print four-byte integer in decimal.<br> + <tt><font size=+1>V</font></tt> Print eight-byte integer in decimal.<br> + <tt><font size=+1>Z</font></tt> Print eight-byte integer in unsigned decimal.<br> + <tt><font size=+1>x</font></tt> Print two-byte integer in hexadecimal.<br> + <tt><font size=+1>X</font></tt> Print four-byte integer in hexadecimal.<br> + <tt><font size=+1>Y</font></tt> Print eight-byte integer in hexadecimal.<br> + <tt><font size=+1>u</font></tt> Print two-byte integer in unsigned decimal.<br> + <tt><font size=+1>U</font></tt> Print four-byte integer in unsigned decimal.<br> + <tt><font size=+1>f</font></tt> Print as a single-precision floating point number.<br> + <tt><font size=+1>F</font></tt> Print double-precision floating point.<br> + <tt><font size=+1>b</font></tt> Print the addressed byte in hexadecimal.<br> + <tt><font size=+1>c</font></tt> Print the addressed byte as an ASCII character.<br> + <tt><font size=+1>C</font></tt> Print the addressed byte as a character. Printable ASCII characters + are represented normally; others are printed in the form <tt><font size=+1>\xnn</font></tt>.<br> + <tt><font size=+1>s</font></tt> Print the addressed characters, as a UTF string, until a zero + byte is reached. Advance dot by the length of the string, including + the zero terminator.<br> + <tt><font size=+1>S</font></tt> Print a string using the escape convention (see <tt><font size=+1>C</font></tt> above).<br> + <tt><font size=+1>r</font></tt> Print as UTF the addressed two-byte integer (rune).<br> + <tt><font size=+1>R</font></tt> Print as UTF the addressed two-byte integers as runes until a + zero rune is reached. Advance dot by the length of the string, + including the zero terminator.<br> + <tt><font size=+1>i</font></tt> Print as machine instructions. Dot is incremented by the size + of the instruction.<br> + <tt><font size=+1>I</font></tt> As <tt><font size=+1>i</font></tt> above, but print the machine instructions in an alternate + form if possible.<br> + <tt><font size=+1>M</font></tt> Print the addressed machine instruction in a machine-dependent + hexadecimal form.<br> + <tt><font size=+1>a</font></tt> Print the value of dot in symbolic form. Dot is unaffected.<br> + <tt><font size=+1>A</font></tt> Print the value of dot in hexadecimal. Dot is unaffected.<br> + <tt><font size=+1>z</font></tt> Print the function name, source file, and line number corresponding + to dot (textfile only). Dot is unaffected.<br> + <tt><font size=+1>p</font></tt> Print the addressed value in symbolic form. Dot is advanced by + the size of a machine address.<br> + <tt><font size=+1>t</font></tt> When preceded by an integer, tabs to the next appropriate tab + stop. For example, <tt><font size=+1>8t</font></tt> moves to the next 8-space tab stop. Dot + is unaffected.<br> + <tt><font size=+1>n</font></tt> Print a newline. Dot is unaffected.<br> + <tt><font size=+1>"</font></tt>...<tt><font size=+1>"</font></tt> Print the enclosed string. Dot is unaffected.<br> + <tt><font size=+1>^</font></tt> Dot is decremented by the current increment. Nothing is printed.<br> + <tt><font size=+1>+</font></tt> Dot is incremented by 1. Nothing is printed.<br> + <tt><font size=+1>−</font></tt> Dot is decremented by 1. Nothing is printed.<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + + </table> + Other commands include:<br> + newline<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Update dot by the current increment. Repeat the previous command + with a <i>count</i> of 1.<br> + + </table> + [<tt><font size=+1>?/</font></tt>]<tt><font size=+1>l</font></tt> <i>value mask<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Words starting at dot are masked with <i>mask</i> and compared with <i>value</i> + until a match is found. If <tt><font size=+1>l</font></tt> is used, the match is for a two-byte + integer; <tt><font size=+1>L</font></tt> matches four bytes. If no match is found then dot is + unchanged; otherwise dot is set to the matched location. If <i>mask</i> + is omitted then ~0 is used. + + </table> + [<tt><font size=+1>?/</font></tt>]<tt><font size=+1>w</font></tt> <i>value ...<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Write the two-byte <i>value</i> into the addressed location. If the command + is <tt><font size=+1>W</font></tt>, write four bytes.<br> + + </table> + [<tt><font size=+1>?/</font></tt>]<tt><font size=+1>m</font></tt> <i>s b e f</i> [<tt><font size=+1>?</font></tt>]<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + New values for (<i>b, e, f</i>) in the segment named <i>s</i> are recorded. + Valid segment names are <i>text</i>, <i>data</i>, or <i>ublock</i>. If less than three + address expressions are given, the remaining parameters are left + unchanged. If the list is terminated by <tt><font size=+1>?</font></tt> or <tt><font size=+1>/</font></tt> then the file (<i>textfile</i> + or <i>memfile</i> respectively) is used for subsequent + requests. For example, <tt><font size=+1>/m?</font></tt> causes <tt><font size=+1>/</font></tt> to refer to <i>textfile</i>.<br> + + </table> + <tt><font size=+1>></font></tt><i>name<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Dot is assigned to the variable or register named.<br> + + </table> + <tt><font size=+1>!</font></tt> The rest of the line is passed to <a href="../man1/rc.html"><i>rc</i>(1)</a> for execution.<br> + <tt><font size=+1>$</font></tt><i>modifier<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Miscellaneous commands. The available <i>modifiers</i> are:<br> + <tt><font size=+1><</font></tt><i>f</i> Read commands from the file <i>f</i>. If this command is executed in + a file, further commands in the file are not seen. If <i>f</i> is omitted, + the current input stream is terminated. If a <i>count</i> is given, and + is zero, the command is ignored.<br> + <tt><font size=+1><<</font></tt><i>f</i> Similar to <tt><font size=+1><</font></tt> except it can be used in a file of commands without + causing the file to be closed. There is a (small) limit to the + number of <tt><font size=+1><<</font></tt> files that can be open at once.<br> + <tt><font size=+1>></font></tt><i>f</i> Append output to the file <i>f</i>, which is created if it does not + exist. If <i>f</i> is omitted, output is returned to the terminal.<br> + <tt><font size=+1>?</font></tt> Print process id, the condition which caused stopping or termination, + the registers and the instruction addressed by <tt><font size=+1>pc</font></tt>. This is the + default if <i>modifier</i> is omitted.<br> + <tt><font size=+1>r</font></tt> Print the general registers and the instruction addressed by + <tt><font size=+1>pc</font></tt>. Dot is set to <tt><font size=+1>pc</font></tt>.<br> + <tt><font size=+1>R</font></tt> Like <tt><font size=+1>$r</font></tt>, but include miscellaneous processor control registers + and floating point registers.<br> + <tt><font size=+1>f</font></tt> Print floating-point register values as single-precision floating + point numbers.<br> + <tt><font size=+1>F</font></tt> Print floating-point register values as double-precision floating + point numbers.<br> + <tt><font size=+1>b</font></tt> Print all breakpoints and their associated counts and commands. + ‘B’ produces the same results.<br> + <tt><font size=+1>c</font></tt> Stack backtrace. If <i>address</i> is given, it specifies the address + of a pair of 32-bit values containing the <tt><font size=+1>sp</font></tt> and <tt><font size=+1>pc</font></tt> of an active + process. This allows selecting among various contexts of a multi-threaded + process. If <tt><font size=+1>C</font></tt> is used, the names and (long) values of all parameters, + automatic and static variables are + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + printed for each active function. If <i>count</i> is given, only the + first <i>count</i> frames are printed.<br> + + </table> + <tt><font size=+1>a</font></tt> Attach to the running process whose pid is contained in <i>address</i>.<br> + <tt><font size=+1>e</font></tt> The names and values of all external variables are printed.<br> + <tt><font size=+1>w</font></tt> Set the page width for output to <i>address</i> (default 80).<br> + <tt><font size=+1>q</font></tt> Exit from <i>db</i>.<br> + <tt><font size=+1>m</font></tt> Print the address maps.<br> + <tt><font size=+1>k</font></tt> Simulate kernel memory management.<br> + <tt><font size=+1>M</font></tt><i>machine<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Set the <i>machine</i> type used for disassembling instructions.<br> + + </table> + + </table> + <tt><font size=+1>:</font></tt><i>modifier<br> + </i> + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Manage a subprocess. Available modifiers are:<br> + <tt><font size=+1>h</font></tt> Halt an asynchronously running process to allow breakpointing. + Unnecessary for processes created under <i>db</i>, e.g. by <tt><font size=+1>:r</font></tt>.<br> + <tt><font size=+1>b</font></tt><i>c</i> Set breakpoint at <i>address</i>. The breakpoint is executed <i>count</i>–1 + times before causing a stop. Also, if a command <i>c</i> is given it + is executed at each breakpoint and if it sets dot to zero the + breakpoint causes a stop.<br> + <tt><font size=+1>d</font></tt> Delete breakpoint at <i>address</i>.<br> + <tt><font size=+1>r</font></tt> Run <i>textfile</i> as a subprocess. If <i>address</i> is given the program + is entered at that point; otherwise the standard entry point is + used. <i>Count</i> 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 + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + starting with < or > causes the standard input or output to be established + for the command.<br> + + </table> + <tt><font size=+1>c</font></tt><i>s</i> The subprocess is continued. If <i>s</i> is omitted or nonzero, the + subprocess is sent the note that caused it to stop. If 0 is specified, + no note is sent. (If the stop was due to a breakpoint or single-step, + the corresponding note is elided before continuing.) Breakpoint + skipping is the same as for <tt><font size=+1>r</font></tt>. + <tt><font size=+1>s</font></tt><i>s</i> As for <tt><font size=+1>c</font></tt> except that the subprocess is single stepped for <i>count</i> + machine instructions. If a note is pending, it is received before + the first instruction is executed. If there is no current subprocess + then <i>textfile</i> is run as a subprocess as for <tt><font size=+1>r</font></tt>. In this case no + note can be sent; the remainder of the line is + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + treated as arguments to the subprocess.<br> + + </table> + <tt><font size=+1>S</font></tt><i>s</i> Identical to <tt><font size=+1>s</font></tt> except the subprocess is single stepped for <i>count</i> + lines of C source. In optimized code, the correspondence between + C source and the machine instructions is approximate at best.<br> + <tt><font size=+1>x</font></tt> The current subprocess, if any, is released by <i>db</i> and allowed + to continue executing normally.<br> + <tt><font size=+1>k</font></tt> The current subprocess, if any, is terminated.<br> + <tt><font size=+1>n</font></tt><i>c</i> Display the pending notes for the process. If <i>c</i> is specified, + first delete <i>c’th</i> pending note.<br> + + </table> + <p><font size=+1><b>Addresses </b></font><br> + The location in a file or memory image associated with an address + is calculated from a map associated with the file. Each map contains + one or more quadruples (<i>t, f, b, e, o</i>), defining a segment named + <i>t</i> (usually, <i>text</i>, <i>data</i>, or <i>core</i>) in file <i>f</i> mapping addresses in + the range <i>b</i> through <i>e</i> to the part of the file beginning at + offset <i>o</i>. If segments overlap, later segments obscure earlier + ones. An address <i>a</i> is translated to a file address by finding + the last segment in the list for which <i>b</i>≤<i>a</i><<i>e</i>; the location in the + file is then <i>address</i>+<i>f</i>–<i>b</i>. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Usually, the text and initialized data of a program are mapped + by segments called <i>text</i>, <i>data</i>, and <i>bss</i>. Since a program file does + not contain stack data, this data is not mapped. The text segment + is mapped similarly in a normal (i.e., non-kernel) <i>memfile</i>. However, + one or more segments called <i>data</i> provide access to + process memory. This region contains the program’s static data, + the bss, the heap and the stack. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Sometimes it is useful to define a map with a single segment mapping + the region from 0 to 0xFFFFFFFF; a map of this type allows an + entire file to be examined without address translation. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + The <tt><font size=+1>$m</font></tt> command dumps the currently active maps. The <tt><font size=+1>?m</font></tt> and <tt><font size=+1>/m</font></tt> + commands modify the segment parameters in the <i>textfile</i> and <i>memfile</i> + maps, respectively.<br> + +</table> +<p><font size=+1><b>EXAMPLES </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + To set a breakpoint at the beginning of <tt><font size=+1>write()</font></tt> in extant process + 27:<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>% db 27<br> + :h<br> + write:b<br> + :c<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + </font></tt> + + </table> + To set a breakpoint at the entry of function <tt><font size=+1>parse</font></tt> when the local + variable <tt><font size=+1>argc</font></tt> in <tt><font size=+1>main</font></tt> is equal to 1:<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>parse:b *main.argc−1=X<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + </font></tt> + + </table> + This prints the value of <tt><font size=+1>argc−1</font></tt> which as a side effect sets dot; + when <tt><font size=+1>argc</font></tt> is one the breakpoint will fire. Beware that local variables + may be stored in registers; see the BUGS section.<br> + +</table> +<p><font size=+1><b>SEE ALSO </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <a href="../man1/acid.html"><i>acid</i>(1)</a><br> + +</table> +<p><font size=+1><b>SOURCE </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>/usr/local/plan9/src/cmd/db<br> + </font></tt> +</table> +<p><font size=+1><b>DIAGNOSTICS </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Exit status is 0, unless the last command failed or returned non-zero + status.<br> + +</table> +<p><font size=+1><b>BUGS </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + Examining a local variable with <i>routine.name</i> returns the contents + of the memory allocated for the variable, but with optimization, + variables often reside in registers. Also, on some architectures, + the first argument is always passed in a register. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Variables and parameters that have been optimized away do not + appear in the symbol table, returning the error <i>bad local variable</i> + when accessed by <i>db</i>. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Breakpoints should not be set on instructions scheduled in delay + slots. When a program stops on such a breakpoint, it is usually + impossible to continue its execution.<br> + +</table> + +<td width=20> +<tr height=20><td> +</table> +<!-- TRAILER --> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=15><td width=10><td><td width=10> +<tr><td><td> +<center> +<a href="../../"><img src="../../dist/spaceglenda100.png" alt="Space Glenda" border=1></a> +</center> +</table> +<!-- TRAILER --> +</body></html> |