| 1 | |
| 2 | #include <unistd.h>
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| 3 | #include <stdbool.h>
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| 4 | #include <errno.h>
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| 5 | #include <linux/kernel.h>
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| 6 | #include <internal/lib.h>
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| 7 |
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| 8 | unsigned int page_size;
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| 9 |
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| 10 | static ssize_t ion(bool is_read, int fd, void *buf, size_t n)
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| 11 | {
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| 12 | void *buf_start = buf;
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| 13 | size_t left = n;
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| 14 |
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| 15 | while (left) {
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| 16 |
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| 17 | ssize_t ret = is_read ? read(fd, buf, left) :
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| 18 | write(fd, buf, left);
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| 19 |
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| 20 | if (ret < 0 && errno == EINTR)
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| 21 | continue;
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| 22 | if (ret <= 0)
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| 23 | return ret;
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| 24 |
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| 25 | left -= ret;
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| 26 | buf += ret;
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| 27 | }
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| 28 |
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| 29 | BUG_ON((size_t)(buf - buf_start) != n);
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| 30 | return n;
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| 31 | }
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| 32 |
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| 33 | |
| 34 | * Read exactly 'n' bytes or return an error.
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| 35 |
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| 36 | ssize_t readn(int fd, void *buf, size_t n)
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| 37 | {
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| 38 | return ion(true, fd, buf, n);
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| 39 | }
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| 40 |
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| 41 | ssize_t preadn(int fd, void *buf, size_t n, off_t offs)
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| 42 | {
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| 43 | size_t left = n;
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| 44 |
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| 45 | while (left) {
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| 46 | ssize_t ret = pread(fd, buf, left, offs);
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| 47 |
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| 48 | if (ret < 0 && errno == EINTR)
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| 49 | continue;
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| 50 | if (ret <= 0)
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| 51 | return ret;
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| 52 |
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| 53 | left -= ret;
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| 54 | buf += ret;
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| 55 | offs += ret;
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| 56 | }
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| 57 |
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| 58 | return n;
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| 59 | }
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| 60 |
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| 61 | |
| 62 | * Write exactly 'n' bytes or return an error.
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| 63 |
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| 64 | ssize_t writen(int fd, const void *buf, size_t n)
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| 65 | {
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| 66 |
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| 67 | return ion(false, fd, (void *)buf, n);
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| 68 | }
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