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[monojob] Avoid overflow when calculating percentage progress

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Normalise the progress figures to ensure that multiplication by 100
(to produce a percentage) cannot result in integer overflow.

Reported-by: Sven Dreyer <sven@dreyer-net.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown 2011-03-26 13:13:45 +00:00
parent 02a6f46c09
commit 5590faf14a
1 changed files with 7 additions and 3 deletions
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10
src/core/monojob.c
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@ -62,6 +62,8 @@ int monojob_wait ( const char *string ) {
int rc;
unsigned long last_progress;
unsigned long elapsed;
unsigned long completed;
unsigned long total;
unsigned int percentage;
int shown_percentage = 0;
@ -85,9 +87,11 @@ int monojob_wait ( const char *string ) {
if ( shown_percentage )
printf ( "\b\b\b\b \b\b\b\b" );
job_progress ( &monojob, &progress );
if ( progress.total ) {
percentage = ( ( 100 * progress.completed ) /
progress.total );
/* Normalise progress figures to avoid overflow */
completed = ( progress.completed / 128 );
total = ( progress.total / 128 );
if ( total ) {
percentage = ( ( 100 * completed ) / total );
printf ( "%3d%%", percentage );
shown_percentage = 1;
} else {