bootstrap: use nix crate to get rusage on unix

Author: GrigorenkoPV

src/bootstrap/Cargo.lock

@@ -52,6 +52,7 @@ dependencies = [
  "ignore",
  "junction",
  "libc",
+ "nix",
  "object",
  "opener",
  "pretty_assertions",
@@ -100,6 +101,12 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "cfg_aliases"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
+
 [[package]]
 name = "clap"
 version = "4.4.13"
@@ -360,6 +367,18 @@ version = "2.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "523dc4f511e55ab87b694dc30d0f820d60906ef06413f93d4d7a1385599cc149"
 
+[[package]]
+name = "nix"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
+dependencies = [
+ "bitflags 2.4.1",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+]
+
 [[package]]
 name = "ntapi"
 version = "0.4.1"

src/bootstrap/Cargo.toml

@@ -47,6 +47,7 @@ fd-lock = "4.0"
 home = "0.5"
 ignore = "0.4"
 libc = "0.2"
+nix = { version = "0.29.0", features = ["resource"] }
 object = { version = "0.32", default-features = false, features = ["archive", "coff", "read_core", "unaligned"] }
 opener = "0.5"
 semver = "1.0"

src/bootstrap/src/bin/rustc.rs

@@ -382,29 +382,25 @@ fn format_rusage_data(child: Child) -> Option<String> {
 /// supplied on Linux (the `rusage` struct has other fields in it but they are
 /// currently unsupported by Linux).
 fn format_rusage_data(_child: Child) -> Option<String> {
-    let rusage: libc::rusage = unsafe {
-        let mut recv = std::mem::zeroed();
-        // -1 is RUSAGE_CHILDREN, which means to get the rusage for all children
-        // (and grandchildren, etc) processes that have respectively terminated
-        // and been waited for.
-        let retval = libc::getrusage(-1, &mut recv);
-        if retval != 0 {
-            return None;
-        }
-        recv
-    };
+    use nix::sys::resource::{getrusage, UsageWho};
+
+    // RUSAGE_CHILDREN (= -1)  means to get the rusage for all children
+    // (and grandchildren, etc) processes that have respectively terminated
+    // and been waited for.
+    let rusage = getrusage(UsageWho::RUSAGE_CHILDREN).ok()?;
+
     // Mac OS X reports the maxrss in bytes, not kb.
     let divisor = if env::consts::OS == "macos" { 1024 } else { 1 };
-    let maxrss = (rusage.ru_maxrss + (divisor - 1)) / divisor;
+    let maxrss = (rusage.max_rss() + (divisor - 1)) / divisor;
 
     let mut init_str = format!(
         "user: {USER_SEC}.{USER_USEC:03} \
          sys: {SYS_SEC}.{SYS_USEC:03} \
          max rss (kb): {MAXRSS}",
-        USER_SEC = rusage.ru_utime.tv_sec,
-        USER_USEC = rusage.ru_utime.tv_usec,
-        SYS_SEC = rusage.ru_stime.tv_sec,
-        SYS_USEC = rusage.ru_stime.tv_usec,
+        USER_SEC = rusage.user_time().tv_sec(),
+        USER_USEC = rusage.user_time().tv_usec(),
+        SYS_SEC = rusage.system_time().tv_sec(),
+        SYS_USEC = rusage.system_time().tv_usec(),
         MAXRSS = maxrss
     );
 
@@ -413,20 +409,20 @@ fn format_rusage_data(_child: Child) -> Option<String> {
     // either means no events of that type occurred, or that the platform
     // does not support it.
 
-    let minflt = rusage.ru_minflt;
-    let majflt = rusage.ru_majflt;
+    let minflt = rusage.minor_page_faults();
+    let majflt = rusage.major_page_faults();
     if minflt != 0 || majflt != 0 {
         init_str.push_str(&format!(" page reclaims: {minflt} page faults: {majflt}"));
     }
 
-    let inblock = rusage.ru_inblock;
-    let oublock = rusage.ru_oublock;
+    let inblock = rusage.block_reads();
+    let oublock = rusage.block_writes();
     if inblock != 0 || oublock != 0 {
         init_str.push_str(&format!(" fs block inputs: {inblock} fs block outputs: {oublock}"));
     }
 
-    let nvcsw = rusage.ru_nvcsw;
-    let nivcsw = rusage.ru_nivcsw;
+    let nvcsw = rusage.voluntary_context_switches();
+    let nivcsw = rusage.involuntary_context_switches();
     if nvcsw != 0 || nivcsw != 0 {
         init_str.push_str(&format!(
             " voluntary ctxt switches: {nvcsw} involuntary ctxt switches: {nivcsw}"