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proc_pidinfo()-based closefrom() for OS X 

Refactor closefrom() to use a single brute-force close() loop fallback.

Based on patch from likan_999.student@sina.com in bz#3049. ok dtucker@
This commit is contained in:
Damien Miller 2019-08-30 13:21:38 +10:00
parent dc2ca58814
commit 28744182cf
2 changed files with 70 additions and 21 deletions
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3
configure.ac
View File

@ -679,6 +679,9 @@ main() { if (NSVersionOfRunTimeLibrary("System") >= (60 << 16))
AC_CHECK_LIB([sandbox], [sandbox_apply], [
SSHDLIBS="$SSHDLIBS -lsandbox"
])
# proc_pidinfo()-based closefrom() replacement.
AC_CHECK_HEADERS([libproc.h])
AC_CHECK_FUNCS([proc_pidinfo])
;;
*-*-dragonfly*)
SSHDLIBS="$SSHDLIBS -lcrypt"

88
openbsd-compat/bsd-closefrom.c
View File

@ -46,6 +46,9 @@
# include <ndir.h>
# endif
#endif
#if defined(HAVE_LIBPROC_H)
# include <libproc.h>
#endif
#ifndef OPEN_MAX
# define OPEN_MAX 256
@ -55,21 +58,73 @@
__unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";
#endif /* lint */
#ifndef HAVE_FCNTL_CLOSEM
/*
* Close all file descriptors greater than or equal to lowfd.
*/
static void
closefrom_fallback(int lowfd)
{
long fd, maxfd;
/*
* Fall back on sysconf() or getdtablesize(). We avoid checking
* resource limits since it is possible to open a file descriptor
* and then drop the rlimit such that it is below the open fd.
*/
#ifdef HAVE_SYSCONF
maxfd = sysconf(_SC_OPEN_MAX);
#else
maxfd = getdtablesize();
#endif /* HAVE_SYSCONF */
if (maxfd < 0)
maxfd = OPEN_MAX;
for (fd = lowfd; fd < maxfd; fd++)
(void) close((int) fd);
}
#endif /* HAVE_FCNTL_CLOSEM */
#ifdef HAVE_FCNTL_CLOSEM
void
closefrom(int lowfd)
{
(void) fcntl(lowfd, F_CLOSEM, 0);
}
#else
#elif defined(HAVE_LIBPROC_H) && defined(HAVE_PROC_PIDINFO)
void
closefrom(int lowfd)
{
long fd, maxfd;
#if defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
int i, r, sz;
pid_t pid = getpid();
struct proc_fdinfo *fdinfo_buf = NULL;
sz = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, NULL, 0);
if (sz == 0)
return; /* no fds, really? */
else if (sz == -1)
goto fallback;
if ((fdinfo_buf = malloc(sz)) == NULL)
goto fallback;
r = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, fdinfo_buf, sz);
if (r < 0 || r >= sz)
goto fallback;
for (i = 0; i < sz / (int)PROC_PIDLISTFD_SIZE; i++) {
if (fdinfo_buf[i].proc_fd >= lowfd)
close(fdinfo_buf[i].proc_fd);
}
free(fdinfo_buf);
return;
fallback:
free(fdinfo_buf);
closefrom_fallback(lowfd);
return;
}
#elif defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
void
closefrom(int lowfd)
{
long fd;
char fdpath[PATH_MAX], *endp;
struct dirent *dent;
DIR *dirp;
@ -85,25 +140,16 @@ closefrom(int lowfd)
(void) close((int) fd);
}
(void) closedir(dirp);
} else
#endif
{
/*
* Fall back on sysconf() or getdtablesize(). We avoid checking
* resource limits since it is possible to open a file descriptor
* and then drop the rlimit such that it is below the open fd.
*/
#ifdef HAVE_SYSCONF
maxfd = sysconf(_SC_OPEN_MAX);
#else
maxfd = getdtablesize();
#endif /* HAVE_SYSCONF */
if (maxfd < 0)
maxfd = OPEN_MAX;
for (fd = lowfd; fd < maxfd; fd++)
(void) close((int) fd);
return;
}
/* /proc/$$/fd strategy failed, fall back to brute force closure */
closefrom_fallback(lowfd);
}
#else
void
closefrom(int lowfd)
{
closefrom_fallback(lowfd);
}
#endif /* !HAVE_FCNTL_CLOSEM */
#endif /* HAVE_CLOSEFROM */