77 lines
1.5 KiB
C
77 lines
1.5 KiB
C
#include <errno.h>
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#include "runtime.h"
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#include "malloc.h"
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#ifndef MAP_ANON
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#ifdef MAP_ANONYMOUS
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#define MAP_ANON MAP_ANONYMOUS
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#else
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#define USE_DEV_ZERO
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#define MAP_ANON 0
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#endif
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#endif
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#ifdef USE_DEV_ZERO
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static int dev_zero = -1;
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#endif
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void*
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runtime_SysAlloc(uintptr n)
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{
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void *p;
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int fd = -1;
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mstats.sys += n;
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#ifdef USE_DEV_ZERO
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if (dev_zero == -1) {
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dev_zero = open("/dev/zero", O_RDONLY);
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if (dev_zero < 0) {
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printf("open /dev/zero: errno=%d\n", errno);
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exit(2);
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}
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}
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fd = dev_zero;
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#endif
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p = runtime_mmap(nil, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, fd, 0);
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if (p == MAP_FAILED) {
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if(errno == EACCES) {
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printf("mmap: access denied\n");
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printf("If you're running SELinux, enable execmem for this process.\n");
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} else {
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printf("mmap: errno=%d\n", errno);
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}
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exit(2);
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}
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return p;
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}
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void
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runtime_SysUnused(void *v, uintptr n)
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{
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USED(v);
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USED(n);
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// TODO(rsc): call madvise MADV_DONTNEED
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}
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void
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runtime_SysFree(void *v, uintptr n)
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{
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mstats.sys -= n;
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runtime_munmap(v, n);
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}
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void
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runtime_SysMemInit(void)
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{
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// Code generators assume that references to addresses
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// on the first page will fault. Map the page explicitly with
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// no permissions, to head off possible bugs like the system
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// allocating that page as the virtual address space fills.
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// Ignore any error, since other systems might be smart
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// enough to never allow anything there.
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runtime_mmap(nil, 4096, PROT_NONE, MAP_FIXED|MAP_ANON|MAP_PRIVATE, -1, 0);
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}
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