Daniel Samson
a5fe63c1dd
Processes now start with C-compatible arguments: the kernel builds the System V AMD64 entry block (argc, argv, empty envp, auxiliary vector) at the top of the stack, argv[0] is the path or initial-ramdisk name the process was spawned as, and system_spawn carries an optional NUL-separated blob that becomes argv[1..]. The runtime parses the block (runtime.argumentCount/argument) and its spawn wrappers pass arguments through. The name is also recorded on the task, so a fault report says which binary died, not just its id. The user stack grows from one page to eight (32 KiB, parameters.user_stack_pages), with the page below left unmapped as a guard so an overflow faults into a clean process kill rather than corrupting the image. Task.name_buffer is zero-initialised, not undefined: an undefined default is materialised as a 0xAA fill that moved the static task pool out of .bss and made the whole kernel ~7x slower under QEMU TCG (caught by the affinity test). Proven end to end by the new args test: args-echo respawns itself with arguments via the syscall blob, burns more stack than one page could hold, and echoes its argv intact. Full suite: 44/44.
36 lines
1.6 KiB
Zig
36 lines
1.6 KiB
Zig
//! danos user-space runtime library — a nascent libc. Every user binary (init,
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//! and later the VFS server + device drivers) imports this as `@import("runtime")`:
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//! system_call wrappers, the C-convention heap, IPC helpers, and the process start
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//! shim. It is compiled into each binary (inheriting its `.large` code model and
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//! freestanding target), so all user programs share one implementation.
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//!
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//! A user binary needs three lines:
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//! const runtime = @import("runtime");
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//! pub const panic = runtime.panic;
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//! comptime { _ = &runtime.start._start; } // pull the entry shim in
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//! and a `pub fn main() void`.
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pub const system = @import("system.zig");
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pub const heap = @import("heap.zig");
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pub const ipc = @import("ipc.zig");
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pub const start = @import("start.zig");
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/// The VFS wire protocol (shared with the VFS server).
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pub const vfs_protocol = @import("vfs-protocol");
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/// POSIX-style file API: open/read/write/lseek/stat/close.
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/// C stdio: fopen/fread/fwrite/fseek/ftell/fclose over unistd.
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/// Device access for drivers: enumerate/claim/mmioMap.
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pub const device = @import("device.zig");
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/// DMA-capable memory for drivers: contiguous, pinned, uncacheable buffers.
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pub const dma = @import("dma.zig");
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/// Re-exported so a user binary can `pub const panic = runtime.panic;`.
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pub const panic = start.panic;
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/// Process arguments (argc/argv, parsed from the kernel-built entry stack):
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/// `argument(0)` is the path or name this binary was spawned as.
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pub const argumentCount = start.argumentCount;
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pub const argument = start.argument;
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/// The heap as a `std.mem.Allocator`, for Zig `std` containers in user code.
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pub const allocator = heap.allocator;
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