Hash :
5b92dd0a
Author :
Date :
2024-01-01T10:31:48
maint: run 'make update-copyright'
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/* Determine the parent process of a given process.
Copyright (C) 2019-2024 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2019.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
This file is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "get_ppid_of.h"
#include <stdio.h>
#include <string.h>
#if defined __linux__ || defined __ANDROID__ || (defined __FreeBSD_kernel__ && !defined __FreeBSD__) || defined __GNU__ || defined __FreeBSD__ || defined __DragonFly__ || defined __NetBSD__ || defined __minix || defined __sun /* Linux, GNU/kFreeBSD, GNU/Hurd, FreeBSD, NetBSD, Minix, Solaris */
# include <fcntl.h>
# include <unistd.h>
#endif
#if defined __OpenBSD__ /* OpenBSD */
# include <sys/sysctl.h> /* sysctl, struct kinfo_proc */
#endif
#if defined __APPLE__ && defined __MACH__ /* Mac OS X */
/* Get MAC_OS_X_VERSION_MIN_REQUIRED, MAC_OS_X_VERSION_MAX_ALLOWED.
The version at runtime satisfies
MAC_OS_X_VERSION_MIN_REQUIRED <= version <= MAC_OS_X_VERSION_MAX_ALLOWED. */
# include <AvailabilityMacros.h>
# if MAC_OS_X_VERSION_MAX_ALLOWED >= 1050
# include <libproc.h>
# if MAC_OS_X_VERSION_MIN_REQUIRED < 1050
/* Mac OS X versions < 10.5 don't have this function. Therefore declare it as
weak, in order to avoid a runtime error when the binaries are run on these
older versions. */
extern int proc_pidinfo (int, int, uint64_t, void *, int) WEAK_IMPORT_ATTRIBUTE;
# endif
# endif
#endif
#if defined _AIX /* AIX */
# include <procinfo.h>
#endif
#if defined __hpux /* HP-UX */
# include <unistd.h>
# include <sys/param.h>
# include <sys/pstat.h>
#endif
#if defined __sgi /* IRIX */
# include <unistd.h>
# include <fcntl.h>
# include <sys/procfs.h>
#endif
#if defined __CYGWIN__ /* Cygwin */
# define WIN32_LEAN_AND_MEAN
# include <windows.h> /* needed to get 'struct external_pinfo' defined */
# include <sys/cygwin.h>
#endif
#if defined __BEOS__ || defined __HAIKU__ /* BeOS, Haiku */
# include <unistd.h>
#endif
pid_t
get_ppid_of (pid_t pid)
{
#if defined __linux__ || defined __ANDROID__ || (defined __FreeBSD_kernel__ && !defined __FreeBSD__) || defined __GNU__ /* Linux, GNU/kFreeBSD, GNU/Hurd */
/* GNU/kFreeBSD mounts /proc as linprocfs, which looks like a Linux /proc
file system. */
/* Read the contents of /proc/<pid>/status into memory. */
char filename[6 + 10 + 7 + 1];
int fd;
sprintf (filename, "/proc/%u/status", (unsigned int) pid);
fd = open (filename, O_RDONLY | O_CLOEXEC);
if (fd >= 0)
{
char buf[4096 + 1];
ssize_t nread = read (fd, buf, sizeof (buf) - 1);
close (fd);
if (nread >= 0)
{
char *bufend = buf + nread;
char *p;
/* NUL-terminate the buffer. */
*bufend = '\0';
/* Search for a line that starts with "PPid:". */
for (p = buf;;)
{
if (bufend - p >= 5 && memcmp (p, "PPid:", 5) == 0)
{
unsigned int ppid = 0;
if (sscanf (p + 5, "%u", &ppid) > 0)
return ppid;
}
p = strchr (p, '\n');
if (p != NULL)
p++;
else
break;
}
}
}
#endif
#if defined __FreeBSD__ || defined __DragonFly__ || defined __NetBSD__ /* FreeBSD, NetBSD */
/* Read the contents of /proc/<pid>/status into memory. */
char filename[6 + 10 + 7 + 1];
int fd;
sprintf (filename, "/proc/%u/status", (unsigned int) pid);
fd = open (filename, O_RDONLY | O_CLOEXEC);
if (fd >= 0)
{
char buf[4096 + 1];
ssize_t nread = read (fd, buf, sizeof (buf) - 1);
close (fd);
if (nread >= 0)
{
char *p;
/* NUL-terminate the buffer. */
buf[nread] = '\0';
/* Search for the third space-separated field. */
p = strchr (buf, ' ');
if (p != NULL)
{
p = strchr (p + 1, ' ');
if (p != NULL)
{
unsigned int ppid = 0;
if (sscanf (p + 1, "%u", &ppid) > 0)
return ppid;
}
}
}
}
#endif
#if defined __minix /* Minix */
/* Read the contents of /proc/<pid>/psinfo into memory. */
char filename[6 + 10 + 7 + 1];
int fd;
sprintf (filename, "/proc/%u/psinfo", (unsigned int) pid);
fd = open (filename, O_RDONLY | O_CLOEXEC);
if (fd >= 0)
{
char buf[4096 + 1];
ssize_t nread = read (fd, buf, sizeof (buf) - 1);
close (fd);
if (nread >= 0)
{
char *p;
int count;
/* NUL-terminate the buffer. */
buf[nread] = '\0';
/* Search for the 16th space-separated field. */
p = strchr (buf, ' ');
for (count = 1; p != NULL && count < 15; count++)
p = strchr (p + 1, ' ');
if (p != NULL)
{
unsigned int ppid = 0;
if (sscanf (p + 1, "%u", &ppid) > 0)
return ppid;
}
}
}
#endif
#if defined __sun /* Solaris */
/* Read the contents of /proc/<pid>/psinfo into memory.
Alternatively, we could read the contents of /proc/<pid>/status into
memory. But it contains a lot of information that we don't need. */
char filename[6 + 10 + 7 + 1];
int fd;
sprintf (filename, "/proc/%u/psinfo", (unsigned int) pid);
fd = open (filename, O_RDONLY | O_CLOEXEC);
if (fd >= 0)
{
/* The contents is a 'struct psinfo'. But since 'struct psinfo'
has a different size in a 32-bit and a 64-bit environment, we
avoid it. Nevertheless, the size of this contents depends on
whether the process that reads it is 32-bit or 64-bit! */
#if defined __LP64__
# define PSINFO_SIZE 416
#else
# define PSINFO_SIZE 336
#endif
union { char all[PSINFO_SIZE]; unsigned int header[11]; } buf;
ssize_t nread = read (fd, buf.all, sizeof (buf.all));
close (fd);
if (nread >= (ssize_t) sizeof (buf.header))
return buf.header[3];
}
#endif
#if defined __OpenBSD__ /* OpenBSD */
/* Documentation: https://man.openbsd.org/sysctl.2 */
int info_path[] =
{ CTL_KERN, KERN_PROC, KERN_PROC_PID, pid, sizeof (struct kinfo_proc), 1 };
struct kinfo_proc info;
size_t len;
len = sizeof (info);
if (sysctl (info_path, 6, &info, &len, NULL, 0) >= 0 && len == sizeof (info))
return info.p_ppid;
#endif
#if defined __APPLE__ && defined __MACH__ /* Mac OS X */
# if MAC_OS_X_VERSION_MAX_ALLOWED >= 1050
/* Mac OS X >= 10.7 has PROC_PIDT_SHORTBSDINFO. */
# if defined PROC_PIDT_SHORTBSDINFO
# if MAC_OS_X_VERSION_MIN_REQUIRED < 1050
if (proc_pidinfo != NULL) /* at runtime Mac OS X >= 10.5 ? */
# endif
{
struct proc_bsdshortinfo info;
if (proc_pidinfo (pid, PROC_PIDT_SHORTBSDINFO, 0, &info, sizeof (info))
== sizeof (info))
return info.pbsi_ppid;
}
# endif
# if MAC_OS_X_VERSION_MIN_REQUIRED < 1070
/* For older versions, use PROC_PIDTBSDINFO instead. */
/* Note: The second part of 'struct proc_bsdinfo' differs in size between
32-bit and 64-bit environments, and the kernel of Mac OS X 10.5 knows
only about the 32-bit 'struct proc_bsdinfo'. Fortunately all the info
we need is in the first part, which is the same in 32-bit and 64-bit. */
# if MAC_OS_X_VERSION_MIN_REQUIRED < 1050
if (proc_pidinfo != NULL) /* at runtime Mac OS X >= 10.5 ? */
# endif
{
struct proc_bsdinfo info;
if (proc_pidinfo (pid, PROC_PIDTBSDINFO, 0, &info, 128) == 128)
return info.pbi_ppid;
}
# endif
# endif
#endif
#if defined _AIX /* AIX */
/* Reference: https://www.ibm.com/support/knowledgecenter/en/ssw_aix_61/com.ibm.aix.basetrf1/getprocs.htm
*/
struct procentry64 procs;
if (getprocs64 (&procs, sizeof procs, NULL, 0, &pid, 1) > 0)
return procs.pi_ppid;
#endif
#if defined __hpux /* HP-UX */
struct pst_status status;
if (pstat_getproc (&status, sizeof status, 0, pid) > 0)
return status.pst_ppid;
else
{
# if !defined __LP64__
/* Support for 32-bit programs running in 64-bit HP-UX.
The documented way to do this is to use the same source code
as above, but in a compilation unit where '#define _PSTAT64 1'
is in effect. I prefer a single compilation unit; the struct
size and the offsets are not going to change. */
char status64[1216];
if (__pstat_getproc64 (status64, sizeof status64, 0, pid) > 0)
return *(unsigned long long *)(status64 + 24);
# endif
}
#endif
#if defined __sgi /* IRIX */
char filename[12 + 10 + 1];
int fd;
sprintf (filename, "/proc/pinfo/%u", pid);
fd = open (filename, O_RDONLY | O_CLOEXEC);
if (0 <= fd)
{
prpsinfo_t buf;
int ioctl_ok = 0 <= ioctl (fd, PIOCPSINFO, &buf);
close (fd);
if (ioctl_ok)
return buf.pr_ppid;
}
#endif
#if defined __CYGWIN__ /* Cygwin */
struct external_pinfo *info =
(struct external_pinfo *) cygwin_internal (CW_GETPINFO, pid);
if (info != NULL)
return info->ppid;
#endif
#if defined __BEOS__ || defined __HAIKU__ /* BeOS, Haiku */
if (pid == getpid ())
return getppid ();
#endif
return 0;
}
#ifdef TEST
#include <stdlib.h>
#include <unistd.h>
/* Usage: ./a.out
or: ./a.out PID
*/
int
main (int argc, char *argv[])
{
char *arg = argv[1];
pid_t pid = (arg != NULL ? atoi (arg) : getpid ());
pid_t parent = get_ppid_of (pid);
printf ("PID=%lu PPID=%lu\n", (unsigned long) pid, (unsigned long) parent);
return 0;
}
/*
* Local Variables:
* compile-command: "gcc -ggdb -DTEST -Wall -I.. get_ppid_of.c"
* End:
*/
#endif