a1c965da1e
Sixty-five headers sat side by side in include/, so `#include "irq.h"` said nothing about where irq.h was or what it belonged to, and errno.h, stat.h and fcntl.h at the top shadowed the system's for any host tool built with -I./include. They are in folders now -- arch/ core/ fs/ dev/ gfx/ net/ uapi/ (and ldls/ for the Linux driver layer) -- and every include names the folder, as Linux's do: "core/proc.h". Done mechanically and checked the hard way: the kernel built from this tree disassembles identically to the one built from the tree before it. The full image boots, and userland is the same set of programs. Paths in docs and comments follow; docs/guides/layout.md has a table of what is where, and tools/fix-includes.py rewrites old-style includes from the folders in the tree, for code written before this. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4
79 lines
1.8 KiB
C
79 lines
1.8 KiB
C
// User-memory access helpers — see include/core/uaccess.h for the rules.
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//
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// Everything here validates against the *current* process's page table
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// (myproc()->pgdir), which is also the live CR3 while a syscall runs, so a
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// range that passes access_ok() can be dereferenced directly by kernel
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// code for the remainder of the syscall (single-threaded processes can't
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// unmap it out from under us mid-call).
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#include "core/types.h"
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#include "core/defs.h"
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#include "core/param.h"
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#include "arch/memlayout.h"
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#include "arch/mmu.h"
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#include "core/proc.h"
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#include "uapi/errno.h"
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#include "core/uaccess.h"
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int
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access_ok(addr_t uaddr, uint64 size)
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{
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addr_t a, end;
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if(size == 0)
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return 1;
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end = uaddr + size;
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if(end < uaddr || end > KERNBASE)
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return 0;
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for(a = PGROUNDDOWN(uaddr); a < end; a += PGSIZE)
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if(uva2ka(myproc()->pgdir, (char*)a) == 0)
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return 0;
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return 1;
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}
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void*
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user_ptr(addr_t uaddr, uint64 size)
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{
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if(uaddr == 0 || !access_ok(uaddr, size))
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return 0;
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return (void*)uaddr;
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}
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int
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copy_from_user(void *dst, addr_t uaddr, uint64 n)
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{
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if(uaddr + n < uaddr || uaddr + n > KERNBASE)
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return -EFAULT;
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if(copyin(myproc()->pgdir, uaddr, dst, n) < 0)
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return -EFAULT;
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return 0;
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}
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int
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copy_to_user(addr_t uaddr, const void *src, uint64 n)
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{
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if(uaddr + n < uaddr || uaddr + n > KERNBASE)
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return -EFAULT;
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if(copyout(myproc()->pgdir, uaddr, (void*)src, n) < 0)
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return -EFAULT;
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return 0;
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}
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long
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strlen_user(addr_t uaddr)
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{
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addr_t a = uaddr;
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while(a - uaddr < USER_STR_MAX){
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// Scan through the per-page kernel alias so an unmapped page is a
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// clean failure instead of a fault.
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char *ka = uva2ka(myproc()->pgdir, (char*)a);
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if(ka == 0)
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return -EFAULT;
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addr_t pgend = PGROUNDDOWN(a) + PGSIZE;
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for(; a < pgend; a++, ka++)
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if(*ka == 0)
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return a - uaddr;
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}
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return -EFAULT;
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}
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