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unix veryold() file handling

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Fix another analyzer complaint, about potentially calling close(fd)
for a file descriptor number that has already been closed.  This time
it was right, although I think nothing bad would happen if that
occurred.

With the original code, veryold() might succeed and close the file,
then clearoldlocks() fail so skip 'goto gotlock'.  Then the already
closed file would passed to close() again.

Normal usage still works.  No testing using failure conditions has
been done.
This commit is contained in:
PatR
2023-06-18 14:43:43 -07:00
parent 97a1724f17
commit 90f9b0742e
1 changed files with 24 additions and 18 deletions
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42
sys/unix/unixunix.c
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@@ -1,4 +1,4 @@
/* NetHack 3.7 unixunix.c $NHDT-Date: 1605493693 2020/11/16 02:28:13 $ $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.32 $ */
/* NetHack 3.7 unixunix.c $NHDT-Date: 1687124609 2023/06/18 21:43:29 $ $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.39 $ */
/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
/*-Copyright (c) Kenneth Lorber, Kensington, Maryland, 2015. */
/* NetHack may be freely redistributed. See license for details. */
@@ -14,6 +14,9 @@
#endif
#include <signal.h>
static int veryold(int *);
static int eraseoldlocks(void);
#ifdef _M_UNIX
extern void sco_mapon(void);
extern void sco_mapoff(void);
@@ -32,11 +35,11 @@ static struct stat buf;
/* see whether we should throw away this xlock file;
if yes, close it, otherwise leave it open */
static int
veryold(int fd)
veryold(int *fd_p)
{
time_t date;
if (fstat(fd, &buf))
if (fstat(*fd_p, &buf))
return 0; /* cannot get status */
#ifndef INSURANCE
if (buf.st_size != sizeof (int))
@@ -50,7 +53,7 @@ veryold(int fd)
if (date - buf.st_mtime < 3L * 24L * 60L * 60L) { /* recent */
int lockedpid; /* should be the same size as hackpid */
if (read(fd, (genericptr_t) &lockedpid, sizeof lockedpid)
if (read(*fd_p, (genericptr_t) &lockedpid, sizeof lockedpid)
!= sizeof lockedpid)
/* strange ... */
return 0;
@@ -65,7 +68,7 @@ veryold(int fd)
#endif
return 0;
}
(void) close(fd);
(void) close(*fd_p), *fd_p = -1;
return 1;
}
@@ -95,7 +98,9 @@ eraseoldlocks(void)
void
getlock(void)
{
register int i = 0, fd, c;
static const char destroy_old_game_prompt[] =
"There is already a game in progress under your name. Destroy old game?";
int i = 0, fd, c;
const char *fq_lock;
#ifdef TTY_GRAPHICS
@@ -142,10 +147,12 @@ getlock(void)
error("Cannot open %s", fq_lock);
}
/* veryold() closes fd if true */
if (veryold(fd) && eraseoldlocks())
/* veryold() closes fd if true and sets fd to -1; we'll need to
close it here if veryold() fails or if eraseoldlocks() fails */
if (veryold(&fd) && eraseoldlocks())
goto gotlock;
(void) close(fd);
if (fd >= 0)
(void) close(fd);
} while (i < gl.locknum);
unlock_file(HLOCK);
@@ -160,14 +167,12 @@ getlock(void)
error("Cannot open %s", fq_lock);
}
/* veryold() closes fd if true */
if (veryold(fd) && eraseoldlocks())
/* veryold() closes fd if true and sets fd to -1; we'll need to
close it here if veryold() fails or if eraseoldlocks() fails */
if (veryold(&fd) && eraseoldlocks())
goto gotlock;
(void) close(fd);
{
const char destroy_old_game_prompt[] =
"There is already a game in progress under your name. Destroy old game?";
if (fd >= 0)
(void) close(fd);
if (iflags.window_inited) {
/* this is a candidate for paranoid_confirmation */
@@ -184,7 +189,6 @@ getlock(void)
; /* eat rest of line and newline */
}
}
}
if (c == 'y' || c == 'Y') {
if (eraseoldlocks()) {
goto gotlock;
@@ -198,7 +202,7 @@ getlock(void)
}
}
gotlock:
gotlock:
fd = creat(fq_lock, FCMASK);
unlock_file(HLOCK);
if (fd == -1) {
@@ -399,3 +403,5 @@ file_exists(const char *path)
return TRUE;
}
#endif
/*unixunix.c*/