1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Utility routines.
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4 | *
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5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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6 | *
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7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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8 | */
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9 | #include "libbb.h"
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10 |
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11 | ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
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12 | {
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13 | ssize_t n;
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14 |
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15 | do {
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16 | n = read(fd, buf, count);
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17 | } while (n < 0 && errno == EINTR);
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18 |
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19 | return n;
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20 | }
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21 |
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22 | /*
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23 | * Read all of the supplied buffer from a file.
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24 | * This does multiple reads as necessary.
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25 | * Returns the amount read, or -1 on an error.
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26 | * A short read is returned on an end of file.
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27 | */
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28 | ssize_t FAST_FUNC full_read(int fd, void *buf, size_t len)
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29 | {
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30 | ssize_t cc;
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31 | ssize_t total;
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32 |
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33 | total = 0;
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34 |
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35 | while (len) {
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36 | cc = safe_read(fd, buf, len);
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37 |
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38 | if (cc < 0) {
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39 | if (total) {
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40 | /* we already have some! */
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41 | /* user can do another read to know the error code */
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42 | return total;
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43 | }
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44 | return cc; /* read() returns -1 on failure. */
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45 | }
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46 | if (cc == 0)
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47 | break;
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48 | buf = ((char *)buf) + cc;
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49 | total += cc;
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50 | len -= cc;
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51 | }
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52 |
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53 | return total;
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54 | }
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55 |
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56 | ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size)
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57 | {
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58 | /*int e;*/
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59 | size = full_read(fd, buf, size);
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60 | /*e = errno;*/
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61 | close(fd);
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62 | /*errno = e;*/
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63 | return size;
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64 | }
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65 |
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66 | ssize_t FAST_FUNC open_read_close(const char *filename, void *buf, size_t size)
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67 | {
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68 | int fd = open(filename, O_RDONLY);
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69 | if (fd < 0)
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70 | return fd;
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71 | return read_close(fd, buf, size);
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72 | }
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