From ea32c72919e4f3feed0c283283f19c223cc6899c Mon Sep 17 00:00:00 2001
From: Cassie Wang <cassiewang@google.com>
Date: Mon, 2 Feb 2026 23:22:02 +0000
Subject: [PATCH] base: Handle errors during unix system_info calls

BUG=NONE
TEST=./tools/presubmit

Change-Id: Ia528b4dcd478be82db3946ee8ef92b9258d895f0
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/7540107
Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org>
Commit-Queue: Cassie Wang <cassiewang@google.com>
---
 base/src/sys/unix/system_info.rs | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/base/src/sys/unix/system_info.rs b/base/src/sys/unix/system_info.rs
index e4aa01476..3747385d1 100644
--- a/base/src/sys/unix/system_info.rs
+++ b/base/src/sys/unix/system_info.rs
@@ -7,14 +7,23 @@ use libc::_SC_IOV_MAX;
 use libc::_SC_NPROCESSORS_CONF;
 use libc::_SC_PAGESIZE;
 
+use crate::errno_result;
 use crate::Result;
 
+// Comes from UIO_MAXIOV in "uio.h"
+const IOV_MAX_DEFAULT: usize = 1024;
+
 /// Safe wrapper for `sysconf(_SC_IOV_MAX)`.
 #[inline(always)]
 pub fn iov_max() -> usize {
     // SAFETY:
     // Trivially safe
-    unsafe { sysconf(_SC_IOV_MAX) as usize }
+    let iov_max = unsafe { sysconf(_SC_IOV_MAX) };
+    if iov_max < 0 {
+        IOV_MAX_DEFAULT
+    } else {
+        iov_max as usize
+    }
 }
 
 /// Safe wrapper for `sysconf(_SC_PAGESIZE)`.
@@ -22,7 +31,12 @@ pub fn iov_max() -> usize {
 pub fn pagesize() -> usize {
     // SAFETY:
     // Trivially safe
-    unsafe { sysconf(_SC_PAGESIZE) as usize }
+    // man sysconf says return value "Must not be less than 1."
+    let pagesize = unsafe { sysconf(_SC_PAGESIZE) };
+    if pagesize <= 0 {
+        panic!("Error reading system page size, got invalid value.");
+    }
+    pagesize as usize
 }
 
 /// Returns the number of online logical cores on the system.
@@ -30,5 +44,10 @@ pub fn pagesize() -> usize {
 pub fn number_of_logical_cores() -> Result<usize> {
     // SAFETY:
     // Safe because we pass a flag for this call and the host supports this system call
-    Ok(unsafe { sysconf(_SC_NPROCESSORS_CONF) } as usize)
+    let nprocs_conf = unsafe { sysconf(_SC_NPROCESSORS_CONF) };
+    if nprocs_conf < 0 {
+        errno_result()
+    } else {
+        Ok(nprocs_conf as usize)
+    }
 }