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Ensure io requests are always capped at 0x7ffff000

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This gives us the Linux behavior across platforms.

Fixes #1189
This commit is contained in:
Justine Tunney 2024-05-26 16:53:13 -07:00
parent 6cf9b9e0fc
commit af3f62a71a
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GPG key ID: BE714B4575D6E328
10 changed files with 268 additions and 81 deletions
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7
libc/calls/pread.c
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@ -30,6 +30,7 @@
#include "libc/macros.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/zipos.internal.h"
#include "libc/stdio/sysparam.h"
#include "libc/sysv/errfuns.h"
/**
@ -39,7 +40,7 @@
*
* @param fd is something open()'d earlier, noting pipes might not work
* @param buf is copied into, cf. copy_file_range(), sendfile(), etc.
* @param size in range [1..0x7ffff000] is reasonable
* @param size is always saturated to 0x7ffff000 automatically
* @param offset is bytes from start of file at which read begins
* @return [1..size] bytes on success, 0 on EOF, or -1 w/ errno; with
* exception of size==0, in which case return zero means no error
@ -58,6 +59,10 @@ ssize_t pread(int fd, void *buf, size_t size, int64_t offset) {
ssize_t rc;
BEGIN_CANCELATION_POINT;
// XNU and BSDs will EINVAL if requested bytes exceeds INT_MAX
// this is inconsistent with Linux which ignores huge requests
size = MIN(size, 0x7ffff000);
if (offset < 0) {
rc = einval();
} else if (fd < 0) {