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From 886e5b028953404f2d924b561c0689d3e50dbbf4 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
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Date: Thu, 13 Sep 2018 09:24:36 +0200
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Subject: [PATCH] detect-virt: do not try to read all of /proc/cpuinfo
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Quoting https://github.com/systemd/systemd/issues/10074:
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> detect_vm_uml() reads /proc/cpuinfo with read_full_file()
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> read_full_file() has a file max limit size of READ_FULL_BYTES_MAX=(4U*1024U*1024U)
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> Unfortunately, the size of my /proc/cpuinfo is bigger, approximately:
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> echo $(( 4* $(cat /proc/cpuinfo | wc -c)))
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> 9918072
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> This causes read_full_file() to fail and the Condition test fallout.
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Let's just read line by line until we find an intersting line. This also
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helps if not running under UML, because we avoid reading as much data.
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(cherry picked from commit 6058516a14ada1748313af6783f5b4e7e3006654)
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Resolves: #1631532
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---
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src/basic/virt.c | 38 ++++++++++++++++++++++++++++----------
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1 file changed, 28 insertions(+), 10 deletions(-)
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diff --git a/src/basic/virt.c b/src/basic/virt.c
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index d347732bb3..e05b3e6d99 100644
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--- a/src/basic/virt.c
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+++ b/src/basic/virt.c
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@@ -11,6 +11,7 @@
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#include "alloc-util.h"
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#include "dirent-util.h"
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+#include "def.h"
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#include "env-util.h"
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#include "fd-util.h"
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#include "fileio.h"
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@@ -259,21 +260,38 @@ static int detect_vm_hypervisor(void) {
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}
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static int detect_vm_uml(void) {
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- _cleanup_free_ char *cpuinfo_contents = NULL;
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+ _cleanup_fclose_ FILE *f = NULL;
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int r;
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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 == -ENOENT) {
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- log_debug("/proc/cpuinfo not found, assuming no UML virtualization.");
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- return VIRTUALIZATION_NONE;
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+ f = fopen("/proc/cpuinfo", "re");
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+ if (!f) {
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+ if (errno == ENOENT) {
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+ log_debug("/proc/cpuinfo not found, assuming no UML virtualization.");
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+ return VIRTUALIZATION_NONE;
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+ }
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+ return -errno;
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}
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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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- log_debug("UML virtualization found in /proc/cpuinfo");
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- return VIRTUALIZATION_UML;
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+ for (;;) {
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+ _cleanup_free_ char *line = NULL;
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+ const char *t;
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+
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+ r = read_line(f, LONG_LINE_MAX, &line);
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+ if (r < 0)
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+ return r;
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+ if (r == 0)
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+ break;
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+
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+ t = startswith(line, "vendor_id\t: ");
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+ if (t) {
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+ if (startswith(t, "User Mode Linux")) {
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+ log_debug("UML virtualization found in /proc/cpuinfo");
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+ return VIRTUALIZATION_UML;
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+ }
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+
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+ break;
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+ }
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}
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log_debug("UML virtualization not found in /proc/cpuinfo.");
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