core: if we change RLIMIT_NOFILE, reset it when executing commands

This commit is contained in:
Jeffrey C. Ollie
2025-01-01 14:31:15 -06:00
parent 60611b8a4a
commit 9ea0aa4934
4 changed files with 32 additions and 8 deletions

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@ -18,6 +18,7 @@ const Command = @This();
const std = @import("std"); const std = @import("std");
const builtin = @import("builtin"); const builtin = @import("builtin");
const global_state = &@import("global.zig").state;
const internal_os = @import("os/main.zig"); const internal_os = @import("os/main.zig");
const windows = internal_os.windows; const windows = internal_os.windows;
const TempDir = internal_os.TempDir; const TempDir = internal_os.TempDir;
@ -178,6 +179,10 @@ fn startPosix(self: *Command, arena: Allocator) !void {
// If the user requested a pre exec callback, call it now. // If the user requested a pre exec callback, call it now.
if (self.pre_exec) |f| f(self); if (self.pre_exec) |f| f(self);
if (global_state.rlimits.nofile) |lim| {
internal_os.restoreMaxFiles(lim);
}
// Finally, replace our process. // Finally, replace our process.
_ = posix.execveZ(pathZ, argsZ, envp) catch null; _ = posix.execveZ(pathZ, argsZ, envp) catch null;

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@ -27,6 +27,12 @@ pub const GlobalState = struct {
alloc: std.mem.Allocator, alloc: std.mem.Allocator,
action: ?cli.Action, action: ?cli.Action,
logging: Logging, logging: Logging,
/// If we change any resource limits for our own purposes, we save the
/// old limits so that they can be restored before we execute any child
/// processes.
rlimits: struct {
nofile: ?internal_os.rlimit = null,
} = .{},
/// The app resources directory, equivalent to zig-out/share when we build /// The app resources directory, equivalent to zig-out/share when we build
/// from source. This is null if we can't detect it. /// from source. This is null if we can't detect it.
@ -56,6 +62,7 @@ pub const GlobalState = struct {
.alloc = undefined, .alloc = undefined,
.action = null, .action = null,
.logging = .{ .stderr = {} }, .logging = .{ .stderr = {} },
.rlimits = .{},
.resources_dir = null, .resources_dir = null,
}; };
errdefer self.deinit(); errdefer self.deinit();
@ -124,7 +131,7 @@ pub const GlobalState = struct {
std.log.info("libxev backend={}", .{xev.backend}); std.log.info("libxev backend={}", .{xev.backend});
// First things first, we fix our file descriptors // First things first, we fix our file descriptors
internal_os.fixMaxFiles(); self.rlimits.nofile = internal_os.fixMaxFiles();
// Initialize our crash reporting. // Initialize our crash reporting.
crash.init(self.alloc) catch |err| { crash.init(self.alloc) catch |err| {

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@ -4,23 +4,27 @@ const posix = std.posix;
const log = std.log.scoped(.os); const log = std.log.scoped(.os);
pub const rlimit = if (@hasDecl(posix.system, "rlimit")) posix.rlimit else struct {};
/// This maximizes the number of file descriptors we can have open. We /// This maximizes the number of file descriptors we can have open. We
/// need to do this because each window consumes at least a handful of fds. /// need to do this because each window consumes at least a handful of fds.
/// This is extracted from the Zig compiler source code. /// This is extracted from the Zig compiler source code.
pub fn fixMaxFiles() void { pub fn fixMaxFiles() ?rlimit {
if (!@hasDecl(posix.system, "rlimit")) return; if (!@hasDecl(posix.system, "rlimit")) return null;
var lim = posix.getrlimit(.NOFILE) catch { const old = posix.getrlimit(.NOFILE) catch {
log.warn("failed to query file handle limit, may limit max windows", .{}); log.warn("failed to query file handle limit, may limit max windows", .{});
return; // Oh well; we tried. return null; // Oh well; we tried.
}; };
// If we're already at the max, we're done. // If we're already at the max, we're done.
if (lim.cur >= lim.max) { if (old.cur >= old.max) {
log.debug("file handle limit already maximized value={}", .{lim.cur}); log.debug("file handle limit already maximized value={}", .{old.cur});
return; return old;
} }
var lim = old;
// Do a binary search for the limit. // Do a binary search for the limit.
var min: posix.rlim_t = lim.cur; var min: posix.rlim_t = lim.cur;
var max: posix.rlim_t = 1 << 20; var max: posix.rlim_t = 1 << 20;
@ -41,6 +45,12 @@ pub fn fixMaxFiles() void {
} }
log.debug("file handle limit raised value={}", .{lim.cur}); log.debug("file handle limit raised value={}", .{lim.cur});
return old;
}
pub fn restoreMaxFiles(lim: rlimit) void {
if (!@hasDecl(posix.system, "rlimit")) return;
posix.setrlimit(.NOFILE, lim) catch {};
} }
/// Return the recommended path for temporary files. /// Return the recommended path for temporary files.

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@ -32,7 +32,9 @@ pub const getenv = env.getenv;
pub const setenv = env.setenv; pub const setenv = env.setenv;
pub const unsetenv = env.unsetenv; pub const unsetenv = env.unsetenv;
pub const launchedFromDesktop = desktop.launchedFromDesktop; pub const launchedFromDesktop = desktop.launchedFromDesktop;
pub const rlimit = file.rlimit;
pub const fixMaxFiles = file.fixMaxFiles; pub const fixMaxFiles = file.fixMaxFiles;
pub const restoreMaxFiles = file.restoreMaxFiles;
pub const allocTmpDir = file.allocTmpDir; pub const allocTmpDir = file.allocTmpDir;
pub const freeTmpDir = file.freeTmpDir; pub const freeTmpDir = file.freeTmpDir;
pub const isFlatpak = flatpak.isFlatpak; pub const isFlatpak = flatpak.isFlatpak;