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Make last(1) display the full log file.

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I must have misread when I ported the original last(1) source code.
Instead of only processing the last 1024 entries, it reads them in in
chucks of 1024 entries at a time.

Unfortunately we cannot walk through the log file in reverse order,
which means we have to allocate a piece of memory to hold all the
entries. Call realloc() for each 128 entries we read.

Reported by:	Andrzej Tobola <ato iem pw edu pl>
This commit is contained in:
Ed Schouten 2010-01-19 19:53:05 +00:00
parent 2d5ea05a45
commit 6628ca0a98
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=202643
1 changed files with 9 additions and 10 deletions
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19
usr.bin/last/last.c
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@ -196,8 +196,6 @@ main(int argc, char *argv[])
exit(0); exit(0);
} }
#define MAXUTXENTRIES 1024
/* /*
* wtmp -- * wtmp --
* read through the wtmp file * read through the wtmp file
@ -205,9 +203,9 @@ main(int argc, char *argv[])
void void
wtmp(void) wtmp(void)
{ {
struct utmpx buf[MAXUTXENTRIES]; struct utmpx *buf = NULL;
struct utmpx *ut; struct utmpx *ut;
static unsigned int first = 0, amount = 0; static unsigned int amount = 0;
time_t t; time_t t;
char ct[80]; char ct[80];
struct tm *tm; struct tm *tm;
@ -219,11 +217,12 @@ wtmp(void)
if (setutxdb(UTXDB_LOG, file) != 0) if (setutxdb(UTXDB_LOG, file) != 0)
err(1, "%s", file); err(1, "%s", file);
while ((ut = getutxent()) != NULL) { while ((ut = getutxent()) != NULL) {
memcpy(&buf[(first + amount) % MAXUTXENTRIES], ut, sizeof *ut); if (amount % 128 == 0) {
if (amount == MAXUTXENTRIES) buf = realloc(buf, (amount + 128) * sizeof *ut);
first++; if (buf == NULL)
else err(1, "realloc");
amount++; }
memcpy(&buf[amount++], ut, sizeof *ut);
if (t > ut->ut_tv.tv_sec) if (t > ut->ut_tv.tv_sec)
t = ut->ut_tv.tv_sec; t = ut->ut_tv.tv_sec;
} }
@ -231,7 +230,7 @@ wtmp(void)
/* Display them in reverse order. */ /* Display them in reverse order. */
while (amount > 0) while (amount > 0)
doentry(&buf[(first + amount--) % MAXUTXENTRIES]); doentry(&buf[--amount]);
tm = localtime(&t); tm = localtime(&t);
(void) strftime(ct, sizeof(ct), "\nwtmp begins %+\n", tm); (void) strftime(ct, sizeof(ct), "\nwtmp begins %+\n", tm);