9a074144c9
Favor readability over bare-metal.
280 lines
6.9 KiB
C
280 lines
6.9 KiB
C
/* See LICENSE file for copyright and license details. */
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#include <sys/stat.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "util.h"
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static int mflag = 0;
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static int oflag = 0;
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static FILE *
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parsefile(const char *fname)
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{
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struct stat st;
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int ret;
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if (!strcmp(fname, "/dev/stdout") || !strcmp(fname, "-"))
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return stdout;
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ret = lstat(fname, &st);
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/* if it is a new file, try to open it */
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if (ret < 0 && errno == ENOENT)
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goto tropen;
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if (ret < 0) {
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weprintf("lstat %s:", fname);
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return NULL;
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}
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if (!S_ISREG(st.st_mode)) {
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weprintf("for safety uudecode operates only on regular files and /dev/stdout\n");
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return NULL;
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}
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tropen:
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return fopen(fname, "w");
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}
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static void
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parseheader(FILE *fp, const char *s, char **header, mode_t *mode, char **fname)
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{
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char bufs[PATH_MAX + 18]; /* len header + mode + maxname */
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char *p, *q;
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size_t n;
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if (!fgets(bufs, sizeof(bufs), fp))
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if (ferror(fp))
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eprintf("%s: read error:", s);
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if (bufs[0] == '\0' || feof(fp))
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eprintf("empty or nil header string\n");
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if (!(p = strchr(bufs, '\n')))
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eprintf("header string too long or non-newline terminated file\n");
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p = bufs;
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if (!(q = strchr(p, ' ')))
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eprintf("malformed mode string in header, expected ' '\n");
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*header = bufs;
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*q++ = '\0';
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p = q;
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/* now header should be null terminated, q points to mode */
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if (!(q = strchr(p, ' ')))
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eprintf("malformed mode string in header, expected ' '\n");
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*q++ = '\0';
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/* now mode should be null terminated, q points to fname */
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*mode = parsemode(p, *mode, 0);
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n = strlen(q);
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while (n > 0 && (q[n - 1] == '\n' || q[n - 1] == '\r'))
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q[--n] = '\0';
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if (n > 0)
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*fname = q;
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else
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eprintf("header string does not contain output file\n");
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}
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static const char b64dt[] = {
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-2,-2,-2,-2,-2,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-2,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,
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52,53,54,55,56,57,58,59,60,61,-1,-1,-1, 0,-1,-1,-1, 0, 1, 2, 3, 4, 5, 6,
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7, 8, 9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
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-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,
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49,50,51,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
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};
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static void
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uudecodeb64(FILE *fp, FILE *outfp)
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{
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char bufb[60], *pb;
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char out[45], *po;
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size_t n;
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int b = 0, e, t = -1, l = 1;
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unsigned char b24[3] = {0, 0, 0};
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while ((n = fread(bufb, 1, sizeof(bufb), fp))) {
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for (pb = bufb, po = out; pb < bufb + n; pb++) {
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if (*pb == '\n') {
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l++;
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continue;
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} else if (*pb == '=') {
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switch (b) {
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case 0:
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/* expected '=' remaining
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* including footer */
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if (--t) {
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fwrite(out, 1,
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(po - out),
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outfp);
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return;
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}
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continue;
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case 1:
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eprintf("%d: unexpected \"=\""
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"appeared\n", l);
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case 2:
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*po++ = b24[0];
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b = 0;
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t = 5; /* expect 5 '=' */
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continue;
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case 3:
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*po++ = b24[0];
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*po++ = b24[1];
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b = 0;
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t = 6; /* expect 6 '=' */
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continue;
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}
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} else if ((e = b64dt[(int)*pb]) == -1)
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eprintf("%d: invalid byte \"%c\"\n", l, *pb);
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else if (e == -2) /* whitespace */
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continue;
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else if (t > 0) /* state is parsing pad/footer */
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eprintf("%d: invalid byte \"%c\""
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" after padding\n",
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l, *pb);
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switch (b) { /* decode next base64 chr based on state */
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case 0: b24[0] |= e << 2; break;
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case 1: b24[0] |= (e >> 4) & 0x3;
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b24[1] |= (e & 0xf) << 4; break;
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case 2: b24[1] |= (e >> 2) & 0xf;
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b24[2] |= (e & 0x3) << 6; break;
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case 3: b24[2] |= e; break;
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}
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if (++b == 4) { /* complete decoding an octet */
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*po++ = b24[0];
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*po++ = b24[1];
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*po++ = b24[2];
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b24[0] = b24[1] = b24[2] = 0;
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b = 0;
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}
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}
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fwrite(out, 1, (po - out), outfp);
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}
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eprintf("%d: invalid uudecode footer \"====\" not found\n", l);
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}
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static void
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uudecode(FILE *fp, FILE *outfp)
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{
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char *bufb = NULL, *p;
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size_t n = 0;
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ssize_t len;
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int ch, i;
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#define DEC(c) (((c) - ' ') & 077) /* single character decode */
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#define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
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#define OUT_OF_RANGE(c) eprintf("character %c out of range: [%d-%d]\n", (c), 1 + ' ', 077 + ' ' + 1)
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while ((len = getline(&bufb, &n, fp)) > 0) {
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p = bufb;
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/* trim newlines */
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if (!len || bufb[len - 1] != '\n')
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eprintf("no newline found, aborting\n");
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bufb[len - 1] = '\0';
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/* check for last line */
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if ((i = DEC(*p)) <= 0)
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break;
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for (++p; i > 0; p += 4, i -= 3) {
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if (i >= 3) {
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if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
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IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
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OUT_OF_RANGE(*p);
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ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
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putc(ch, outfp);
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ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
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putc(ch, outfp);
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ch = DEC(p[2]) << 6 | DEC(p[3]);
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putc(ch, outfp);
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} else {
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if (i >= 1) {
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if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
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OUT_OF_RANGE(*p);
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ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
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putc(ch, outfp);
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}
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if (i >= 2) {
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if (!(IS_DEC(*(p + 1)) &&
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IS_DEC(*(p + 2))))
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OUT_OF_RANGE(*p);
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ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
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putc(ch, outfp);
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}
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}
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}
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if (ferror(fp))
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eprintf("read error:");
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}
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/* check for end or fail */
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if ((len = getline(&bufb, &n, fp)) < 0)
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eprintf("getline:");
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if (len < 3 || strncmp(bufb, "end", 3) || bufb[3] != '\n')
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eprintf("invalid uudecode footer \"end\" not found\n");
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free(bufb);
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}
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static void
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usage(void)
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{
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eprintf("usage: %s [-m] [-o output] [file]\n", argv0);
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}
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int
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main(int argc, char *argv[])
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{
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FILE *fp = NULL, *nfp = NULL;
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mode_t mode = 0;
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char *fname, *header, *ifname, *ofname = NULL;
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void (*d) (FILE *, FILE *) = NULL;
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ARGBEGIN {
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case 'm':
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mflag = 1; /* accepted but unused (autodetect file type) */
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break;
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case 'o':
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oflag = 1;
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ofname = EARGF(usage());
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break;
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default:
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usage();
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} ARGEND;
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if (argc > 1)
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usage();
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if (!argc || !strcmp(argv[0], "-")) {
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fp = stdin;
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ifname = "<stdin>";
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} else {
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if (!(fp = fopen(argv[0], "r")))
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eprintf("fopen %s:", argv[0]);
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ifname = argv[0];
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}
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parseheader(fp, ifname, &header, &mode, &fname);
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if (!strncmp(header, "begin", sizeof("begin")))
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d = uudecode;
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else if (!strncmp(header, "begin-base64", sizeof("begin-base64")))
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d = uudecodeb64;
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else
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eprintf("unknown header %s:", header);
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if (oflag)
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fname = ofname;
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if (!(nfp = parsefile(fname)))
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eprintf("fopen %s:", fname);
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d(fp, nfp);
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if (nfp != stdout && chmod(fname, mode) < 0)
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eprintf("chmod %s:", fname);
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return !!(fshut(fp, fp == stdin ? "<stdin>" : argv[0]) +
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fshut(nfp, nfp == stdout ? "<stdout>" : fname));
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}
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