gdbで絶対秒を日付で表示する

gdbでデバッグ時に、対象のプログラムが内部で持っている絶対秒(Unix時間)を
日付に変換して表示する方法。

バグ等でcoreファイルから原因を調査する際に欲しくなったので作ってみた。
具体的には~/.gdbinitにユーザ定義のコマンドを作って実現する。

#普通にgdbでプログラムを動かしている場合は、glibcの関数等を呼び出して変換できるはず。

coreファイル出力用のソースコード

解析用のソースコードとcoreファイルが必要なので、
グローバル変数に時刻と項番を書き込んだらabort()で自爆する単純なプログラムを作る。

printime.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>

#define ENTRY_MAX 10

typedef struct {
    struct timeval tv;
    int entno;
} entry_t;

static entry_t ent[ENTRY_MAX];

int main(int argc, char* argv[])
{
    int i = 0;
    for(i = 0; i < ENTRY_MAX; i++) {
        gettimeofday(&ent[i].tv, NULL);
        ent[i].entno = i;
    }

    abort();

    return 0;
}

#include <stdio.h>

#include <stdlib.h>

#include <sys/time.h>

#define ENTRY_MAX 10

typedef struct {

struct timeval tv;

int entno;

} entry_t;

static entry_t ent[ENTRY_MAX];

int main(int argc, char* argv[])

{

int i = 0;

for(i = 0; i < ENTRY_MAX; i++) {

gettimeofday(&ent[i].tv, NULL);

ent[i].entno = i;

}

abort();

return 0;

}

~/.gdbinitの作成

gdbinitにユーザコマンドを定義する際のフォーマットは次の通り。

define <コマンド名>
    #実行したい処理
    <処理1>
    <処理2>
    ...
end

define <コマンド名>

#実行したい処理

<処理1>

<処理2>

...

end

↓みたいな秒とマイクロ秒の引数を渡すと日付で表示してくれるコマンドを作る。

(gdb) ShowClock <sec> <usec>
2017/04/14 00:45:12.246025(JST)

1 2	(gdb) ShowClock <sec> <usec> 2017/04/14 00:45:12.246025(JST)

実際に作成したgdbinitは下記。
Unix時間から表示する各要素を求めるのがとっても面倒だった。

~/.gdbinit

#
# Convert Unix-Time (tv_sec, tv_usec) to date(yy/mm/dd hh:mm:ss)
#
define ConvertUnixTime2Date
    set $__acdays1  = 31
    set $__acdays2  = 59
    set $__acdays3  = 90
    set $__acdays4  = 120
    set $__acdays5  = 151
    set $__acdays6  = 181
    set $__acdays7  = 212
    set $__acdays8  = 243
    set $__acdays9  = 273
    set $__acdays10 = 304
    set $__acdays11 = 334
    set $__acdays12 = 365

    set $__leapdays = ((($__year-1)/4) - (($__year-1)/100) + (($__year-1)/400)) - 477
    set $__year = 1970 + (($__daycount - $__leapdays)/365)
    set $__restdays = $__daycount - ((($__year - 1970) * 365) + $__leapdays)

    if (($__year % 400 == 0) || (($__year % 4 == 0) && ($__year % 100 !=0 )))
        set $__acdays2++
        set $__acdays3++
        set $__acdays4++
        set $__acdays5++
        set $__acdays6++
        set $__acdays7++
        set $__acdays8++
        set $__acdays9++
        set $__acdays10++
        set $__acdays11++
        set $__acdays12++
    end

    if ($__restdays <= $__acdays1)
        set $__mon = 1
        set $__day = $__restdays
    end

    if ($__acdays1 < $__restdays && $__restdays <= $__acdays2)
        set $__mon = 2
        set $__day = $__restdays - $__acdays1
    end

    if ($__acdays2 < $__restdays && $__restdays <= $__acdays3)
        set $__mon = 3
        set $__day = $__restdays - $__acdays2
    end

    if ($__acdays3 < $__restdays && $__restdays <= $__acdays4)
        set $__mon = 4
        set $__day = $__restdays - $__acdays3
    end

    if ($__acdays4 < $__restdays && $__restdays <= $__acdays5)
        set $__mon = 5
        set $__day = $__restdays - $__acdays4
    end

    if ($__acdays5 < $__restdays && $__restdays <= $__acdays6)
        set $__mon = 6
        set $__day = $__restdays - $__acdays5
    end

    if ($__acdays6 < $__restdays && $__restdays <= $__acdays7)
        set $__mon = 7
        set $__day = $__restdays - $__acdays6
    end

    if ($__acdays7 < $__restdays && $__restdays <= $__acdays8)
        set $__mon = 8
        set $__day = $__restdays - $__acdays7
    end

    if ($__acdays8 < $__restdays && $__restdays <= $__acdays9)
        set $__mon = 9
        set $__day = $__restdays - $__acdays8
    end

    if ($__acdays9 < $__restdays && $__restdays <= $__acdays10)
        set $__mon = 10
        set $__day = $__restdays - $__acdays9
    end

    if ($__acdays10 < $__restdays && $__restdays <= $__acdays11)
        set $__mon = 11
        set $__day = $__restdays - $__acdays10
    end

    if ($__acdays11 < $__restdays && $__restdays <= $__acdays12)
        set $__mon = 12
        set $__day = $__restdays - $__acdays11
    end

end

#
# Show clock form Unix-Time
# This command requires 2 arguments (tv_sec, tv_usec)
#
define ShowClock

    set $__tv_sec = $arg0
    set $__tv_usec = $arg1

    # Set Time-Zone(JST)
    set $__timezone = 9
    set $__tv_sec = $__tv_sec + ($__timezone * 60 * 60)

    set $__mon        = 0
    set $__day      = 0
    set $__daycount = ($__tv_sec / 86400) + 1
    set $__year     = (1970 + ($__daycount / 365))
    set $__hour     = (($__tv_sec % 86400) / 3600)
    set $__min        = ((($__tv_sec % 86400) / 60) % 60)
    set $__sec        = (($__tv_sec % 86400) % 60)

    ConvertUnixTime2Date

    if ($__timezone == 0)
        printf "%04d/%02d/%02d %02d:%02d:%02d.%06d(UTC)  ", \
               $__year, $__mon, $__day, $__hour, $__min, $__sec, $__tv_usec
    end

    if ($__timezone == 9)
        printf "%04d/%02d/%02d %02d:%02d:%02d.%06d(JST)  ", \
               $__year, $__mon, $__day, $__hour, $__min, $__sec, $__tv_usec
    end
end


define ShowEntryDump

    set $__index = 0

    while ($__index < 10)
        set $__ent = &ent[$__index]
        ShowClock $__ent->tv.tv_sec $__ent->tv.tv_usec
        printf "entno=%d\n", $__ent->entno
        set $__index++
    end
end

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

# Convert Unix-Time (tv_sec, tv_usec) to date(yy/mm/dd hh:mm:ss)

define ConvertUnixTime2Date

set $__acdays1 = 31

set $__acdays2 = 59

set $__acdays3 = 90

set $__acdays4 = 120

set $__acdays5 = 151

set $__acdays6 = 181

set $__acdays7 = 212

set $__acdays8 = 243

set $__acdays9 = 273

set $__acdays10 = 304

set $__acdays11 = 334

set $__acdays12 = 365

set $__leapdays = ((($__year-1)/4) - (($__year-1)/100) + (($__year-1)/400)) - 477

set $__year = 1970 + (($__daycount - $__leapdays)/365)

set $__restdays = $__daycount - ((($__year - 1970) * 365) + $__leapdays)

if (($__year % 400 == 0) || (($__year % 4 == 0) && ($__year % 100 !=0 )))

set $__acdays2++

set $__acdays3++

set $__acdays4++

set $__acdays5++

set $__acdays6++

set $__acdays7++

set $__acdays8++

set $__acdays9++

set $__acdays10++

set $__acdays11++

set $__acdays12++

end

if ($__restdays <= $__acdays1)

set $__mon = 1

set $__day = $__restdays

end

if ($__acdays1 < $__restdays && $__restdays <= $__acdays2)

set $__mon = 2

set $__day = $__restdays - $__acdays1

end

if ($__acdays2 < $__restdays && $__restdays <= $__acdays3)

set $__mon = 3

set $__day = $__restdays - $__acdays2

end

if ($__acdays3 < $__restdays && $__restdays <= $__acdays4)

set $__mon = 4

set $__day = $__restdays - $__acdays3

end

if ($__acdays4 < $__restdays && $__restdays <= $__acdays5)

set $__mon = 5

set $__day = $__restdays - $__acdays4

end

if ($__acdays5 < $__restdays && $__restdays <= $__acdays6)

set $__mon = 6

set $__day = $__restdays - $__acdays5

end

if ($__acdays6 < $__restdays && $__restdays <= $__acdays7)

set $__mon = 7

set $__day = $__restdays - $__acdays6

end

if ($__acdays7 < $__restdays && $__restdays <= $__acdays8)

set $__mon = 8

set $__day = $__restdays - $__acdays7

end

if ($__acdays8 < $__restdays && $__restdays <= $__acdays9)

set $__mon = 9

set $__day = $__restdays - $__acdays8

end

if ($__acdays9 < $__restdays && $__restdays <= $__acdays10)

set $__mon = 10

set $__day = $__restdays - $__acdays9

end

if ($__acdays10 < $__restdays && $__restdays <= $__acdays11)

set $__mon = 11

set $__day = $__restdays - $__acdays10

end

if ($__acdays11 < $__restdays && $__restdays <= $__acdays12)

set $__mon = 12

set $__day = $__restdays - $__acdays11

end

# Show clock form Unix-Time

# This command requires 2 arguments (tv_sec, tv_usec)

define ShowClock

set $__tv_sec = $arg0

set $__tv_usec = $arg1

# Set Time-Zone(JST)

set $__timezone = 9

set $__tv_sec = $__tv_sec + ($__timezone * 60 * 60)

set $__mon = 0

set $__day = 0

set $__daycount = ($__tv_sec / 86400) + 1

set $__year = (1970 + ($__daycount / 365))

set $__hour = (($__tv_sec % 86400) / 3600)

set $__min = ((($__tv_sec % 86400) / 60) % 60)

set $__sec = (($__tv_sec % 86400) % 60)

ConvertUnixTime2Date

if ($__timezone == 0)

printf "%04d/%02d/%02d %02d:%02d:%02d.%06d(UTC) ", \

$__year, $__mon, $__day, $__hour, $__min, $__sec, $__tv_usec

end

if ($__timezone == 9)

printf "%04d/%02d/%02d %02d:%02d:%02d.%06d(JST) ", \

$__year, $__mon, $__day, $__hour, $__min, $__sec, $__tv_usec

end

define ShowEntryDump

set $__index = 0

while ($__index < 10)

set $__ent = &ent[$__index]

ShowClock $__ent->tv.tv_sec $__ent->tv.tv_usec

printf "entno=%d\n", $__ent->entno

set $__index++

end

実行結果

$ ulimit -c unlimited
$ ./printime
$ gdb printime corefile
$ (gdb) showentrydump

$ ulimit -c unlimited

$ ./printime

$ gdb printime corefile

$ (gdb) showentrydump

coreファイル出力用のソースコード

~/.gdbinitの作成

実行結果

Nginx+uWSGI+viewvcでSubversionのリポジトリをブラウザから...

Python3サンプルコード集(その1)

gdbで動作中のプロセスをデバッグしてみる