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536bfdab4c
This way, we should be in a slightly better situation if a container is booted up with only a shell as PID 1. In that case /run/systemd/container will not be populated, and a check for it hence be ineffective. Checking /proc/1/environ doesn't fully fix the problem though, as the file is only accessible with privileges. This means if PID 1 is not systemd, and if privileges have been dropped the container detection will continue to fail.
366 lines
11 KiB
C
366 lines
11 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2011 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include "util.h"
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#include "virt.h"
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#include "fileio.h"
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static int detect_vm_cpuid(const char **_id) {
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/* Both CPUID and DMI are x86 specific interfaces... */
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#if defined(__i386__) || defined(__x86_64__)
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static const char cpuid_vendor_table[] =
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"XenVMMXenVMM\0" "xen\0"
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"KVMKVMKVM\0" "kvm\0"
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/* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
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"VMwareVMware\0" "vmware\0"
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/* http://msdn.microsoft.com/en-us/library/ff542428.aspx */
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"Microsoft Hv\0" "microsoft\0";
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uint32_t eax, ecx;
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union {
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uint32_t sig32[3];
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char text[13];
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} sig = {};
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const char *j, *k;
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bool hypervisor;
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/* http://lwn.net/Articles/301888/ */
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#if defined (__i386__)
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#define REG_a "eax"
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#define REG_b "ebx"
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#elif defined (__amd64__)
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#define REG_a "rax"
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#define REG_b "rbx"
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#endif
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/* First detect whether there is a hypervisor */
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eax = 1;
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__asm__ __volatile__ (
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/* ebx/rbx is being used for PIC! */
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" push %%"REG_b" \n\t"
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" cpuid \n\t"
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" pop %%"REG_b" \n\t"
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: "=a" (eax), "=c" (ecx)
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: "0" (eax)
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);
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hypervisor = !!(ecx & 0x80000000U);
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if (hypervisor) {
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/* There is a hypervisor, see what it is */
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eax = 0x40000000U;
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__asm__ __volatile__ (
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/* ebx/rbx is being used for PIC! */
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" push %%"REG_b" \n\t"
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" cpuid \n\t"
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" mov %%ebx, %1 \n\t"
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" pop %%"REG_b" \n\t"
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: "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
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: "0" (eax)
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);
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NULSTR_FOREACH_PAIR(j, k, cpuid_vendor_table)
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if (streq(sig.text, j)) {
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*_id = k;
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return 1;
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}
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*_id = "other";
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return 0;
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}
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#endif
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return 0;
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}
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static int detect_vm_dmi(const char **_id) {
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/* Both CPUID and DMI are x86 specific interfaces... */
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#if defined(__i386__) || defined(__x86_64__)
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static const char *const dmi_vendors[] = {
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"/sys/class/dmi/id/sys_vendor",
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"/sys/class/dmi/id/board_vendor",
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"/sys/class/dmi/id/bios_vendor"
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};
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static const char dmi_vendor_table[] =
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"QEMU\0" "qemu\0"
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/* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
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"VMware\0" "vmware\0"
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"VMW\0" "vmware\0"
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"innotek GmbH\0" "oracle\0"
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"Xen\0" "xen\0"
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"Bochs\0" "bochs\0";
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unsigned i;
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for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) {
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_cleanup_free_ char *s = NULL;
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const char *j, *k;
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int r;
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r = read_one_line_file(dmi_vendors[i], &s);
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if (r < 0) {
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if (r != -ENOENT)
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return r;
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continue;
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}
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NULSTR_FOREACH_PAIR(j, k, dmi_vendor_table)
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if (startswith(s, j)) {
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*_id = k;
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return 1;
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}
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}
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#endif
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return 0;
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}
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/* Returns a short identifier for the various VM implementations */
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int detect_vm(const char **id) {
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_cleanup_free_ char *domcap = NULL, *cpuinfo_contents = NULL;
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static thread_local int cached_found = -1;
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static thread_local const char *cached_id = NULL;
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const char *_id = NULL;
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int r;
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if (_likely_(cached_found >= 0)) {
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if (id)
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*id = cached_id;
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return cached_found;
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}
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/* Try xen capabilities file first, if not found try high-level hypervisor sysfs file:
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*
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* https://bugs.freedesktop.org/show_bug.cgi?id=77271 */
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r = read_one_line_file("/proc/xen/capabilities", &domcap);
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if (r >= 0) {
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char *cap, *i = domcap;
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while ((cap = strsep(&i, ",")))
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if (streq(cap, "control_d"))
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break;
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if (!cap) {
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_id = "xen";
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r = 1;
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}
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goto finish;
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} else if (r == -ENOENT) {
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_cleanup_free_ char *hvtype = NULL;
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r = read_one_line_file("/sys/hypervisor/type", &hvtype);
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if (r >= 0) {
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if (streq(hvtype, "xen")) {
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_id = "xen";
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r = 1;
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goto finish;
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}
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} else if (r != -ENOENT)
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return r;
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} else
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return r;
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/* this will set _id to "other" and return 0 for unknown hypervisors */
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r = detect_vm_cpuid(&_id);
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if (r != 0)
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goto finish;
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r = detect_vm_dmi(&_id);
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if (r != 0)
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goto finish;
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if (_id) {
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/* "other" */
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r = 1;
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goto finish;
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}
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/* Detect User-Mode Linux by reading /proc/cpuinfo */
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r = read_full_file("/proc/cpuinfo", &cpuinfo_contents, NULL);
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if (r < 0)
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return r;
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if (strstr(cpuinfo_contents, "\nvendor_id\t: User Mode Linux\n")) {
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_id = "uml";
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r = 1;
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goto finish;
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}
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#if defined(__s390__)
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{
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_cleanup_free_ char *t = NULL;
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r = get_status_field("/proc/sysinfo", "VM00 Control Program:", &t);
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if (r >= 0) {
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if (streq(t, "z/VM"))
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_id = "zvm";
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else
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_id = "kvm";
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r = 1;
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goto finish;
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}
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}
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#endif
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r = 0;
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finish:
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cached_found = r;
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cached_id = _id;
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if (id)
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*id = _id;
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return r;
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}
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int detect_container(const char **id) {
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static thread_local int cached_found = -1;
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static thread_local const char *cached_id = NULL;
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_cleanup_free_ char *m = NULL;
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const char *_id = NULL, *e = NULL;
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int r;
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if (_likely_(cached_found >= 0)) {
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if (id)
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*id = cached_id;
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return cached_found;
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}
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/* /proc/vz exists in container and outside of the container,
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* /proc/bc only outside of the container. */
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if (access("/proc/vz", F_OK) >= 0 &&
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access("/proc/bc", F_OK) < 0) {
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_id = "openvz";
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r = 1;
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goto finish;
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}
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if (getpid() == 1) {
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/* If we are PID 1 we can just check our own
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* environment variable */
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e = getenv("container");
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if (isempty(e)) {
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r = 0;
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goto finish;
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}
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} else {
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/* Otherwise, PID 1 dropped this information into a
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* file in /run. This is better than accessing
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* /proc/1/environ, since we don't need CAP_SYS_PTRACE
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* for that. */
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r = read_one_line_file("/run/systemd/container", &m);
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if (r == -ENOENT) {
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/* Fallback for cases where PID 1 was not
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* systemd (for example, cases where
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* init=/bin/sh is used. */
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r = getenv_for_pid(1, "container", &m);
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if (r <= 0) {
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/* If that didn't work, give up,
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* assume no container manager.
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*
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* Note: This means we still cannot
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* detect containers if init=/bin/sh
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* is passed but privileges dropped,
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* as /proc/1/environ is only readable
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* with privileges. */
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r = 0;
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goto finish;
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}
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}
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if (r < 0)
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return r;
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e = m;
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}
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/* We only recognize a selected few here, since we want to
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* enforce a redacted namespace */
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if (streq(e, "lxc"))
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_id ="lxc";
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else if (streq(e, "lxc-libvirt"))
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_id = "lxc-libvirt";
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else if (streq(e, "systemd-nspawn"))
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_id = "systemd-nspawn";
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else if (streq(e, "docker"))
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_id = "docker";
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else
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_id = "other";
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r = 1;
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finish:
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cached_found = r;
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cached_id = _id;
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if (id)
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*id = _id;
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return r;
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}
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/* Returns a short identifier for the various VM/container implementations */
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int detect_virtualization(const char **id) {
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int r;
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r = detect_container(id);
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if (r < 0)
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return r;
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if (r > 0)
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return VIRTUALIZATION_CONTAINER;
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r = detect_vm(id);
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if (r < 0)
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return r;
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if (r > 0)
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return VIRTUALIZATION_VM;
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return VIRTUALIZATION_NONE;
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}
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