51 lines
1.6 KiB
Diff
51 lines
1.6 KiB
Diff
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tcsh can deadlock with itself if savehist is confgured with "merge" and
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"lock", and two SIGHUPs are received in rapid succession. The
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mechanism of the deadlock is the first SIGHUP triggers a rechist() and
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while that rechist() is executing (and after it has created the lock
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file), another SIGHUP triggers a another rechist() which then waits
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forever for the lock the the first rechist() created to be released
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(which will never happen).
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---
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tcsh-6.21.00/sh.hist.c | 8 +++++++-
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1 file changed, 7 insertions(+), 1 deletion(-)
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--- tcsh-6.21.00/sh.hist.c
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+++ tcsh-6.21.00/sh.hist.c 2019-08-22 12:05:25.800474245 +0000
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@@ -1219,7 +1219,7 @@ void
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rechist(Char *fname, int ref)
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{
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Char *snum, *rs;
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- int fp, ftmp, oldidfds;
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+ int fp, ftmp, oldidfds, phup_disabled_tmp;
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struct varent *shist;
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char path[MAXPATHLEN];
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struct stat st;
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@@ -1227,6 +1227,10 @@ rechist(Char *fname, int ref)
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if (fname == NULL && !ref)
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return;
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+
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+ phup_disabled_tmp = phup_disabled;
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+ phup_disabled = 1;
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+
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/*
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* If $savehist is just set, we use the value of $history
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* else we use the value in $savehist
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@@ -1301,6 +1305,7 @@ rechist(Char *fname, int ref)
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if (fp == -1) {
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didfds = oldidfds;
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cleanup_until(fname);
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+ phup_disabled = phup_disabled_tmp;
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return;
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}
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/* Try to preserve ownership and permissions of the original history file */
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@@ -1325,6 +1330,7 @@ rechist(Char *fname, int ref)
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(void)ReplaceFile( short2str(fname),path,NULL,0,NULL,NULL);
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#endif
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cleanup_until(fname);
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+ phup_disabled = phup_disabled_tmp;
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}
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