diff options
Diffstat (limited to 'util/sbase/uudecode.c')
| -rw-r--r-- | util/sbase/uudecode.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/util/sbase/uudecode.c b/util/sbase/uudecode.c new file mode 100644 index 00000000..1d0bf72a --- /dev/null +++ b/util/sbase/uudecode.c @@ -0,0 +1,282 @@ +/* See LICENSE file for copyright and license details. */ +#include <sys/stat.h> + +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "util.h" + +static int mflag = 0; +static int oflag = 0; + +static FILE * +parsefile(const char *fname) +{ + struct stat st; + int ret; + + if (!strcmp(fname, "/dev/stdout") || !strcmp(fname, "-")) + return stdout; + ret = lstat(fname, &st); + /* if it is a new file, try to open it */ + if (ret < 0 && errno == ENOENT) + goto tropen; + if (ret < 0) { + weprintf("lstat %s:", fname); + return NULL; + } + if (!S_ISREG(st.st_mode)) { + weprintf("for safety uudecode operates only on regular files and /dev/stdout\n"); + return NULL; + } +tropen: + return fopen(fname, "w"); +} + +static void +parseheader(FILE *fp, const char *s, char **header, mode_t *mode, char **fname) +{ + static char bufs[PATH_MAX + 18]; /* len header + mode + maxname */ + char *p, *q; + size_t n; + + if (!fgets(bufs, sizeof(bufs), fp)) + if (ferror(fp)) + eprintf("%s: read error:", s); + if (bufs[0] == '\0' || feof(fp)) + eprintf("empty or nil header string\n"); + if (!(p = strchr(bufs, '\n'))) + eprintf("header string too long or non-newline terminated file\n"); + p = bufs; + if (!(q = strchr(p, ' '))) + eprintf("malformed mode string in header, expected ' '\n"); + *header = bufs; + *q++ = '\0'; + p = q; + /* now header should be null terminated, q points to mode */ + if (!(q = strchr(p, ' '))) + eprintf("malformed mode string in header, expected ' '\n"); + *q++ = '\0'; + /* now mode should be null terminated, q points to fname */ + *mode = parsemode(p, *mode, 0); + n = strlen(q); + while (n > 0 && (q[n - 1] == '\n' || q[n - 1] == '\r')) + q[--n] = '\0'; + if (n > 0) + *fname = q; + else + eprintf("header string does not contain output file\n"); +} + +static const char b64dt[] = { + -1,-1,-1,-1,-1,-1,-1,-1,-1,-2,-2,-2,-2,-2,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, + -1,-1,-1,-1,-1,-1,-1,-1,-2,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63, + 52,53,54,55,56,57,58,59,60,61,-1,-1,-1, 0,-1,-1,-1, 0, 1, 2, 3, 4, 5, 6, + 7, 8, 9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1, + -1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48, + 49,50,51,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, + -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, + -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, + -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, + -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, + -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, +}; + +static void +uudecodeb64(FILE *fp, FILE *outfp) +{ + char bufb[60], *pb; + char out[45], *po; + size_t n; + int b = 0, e, t = -1, l = 1; + unsigned char b24[3] = {0, 0, 0}; + + while ((n = fread(bufb, 1, sizeof(bufb), fp))) { + for (pb = bufb, po = out; pb < bufb + n; pb++) { + if (*pb == '\n') { + l++; + continue; + } else if (*pb == '=') { + switch (b) { + case 0: + /* expected '=' remaining + * including footer */ + if (--t) { + fwrite(out, 1, + (po - out), + outfp); + return; + } + continue; + case 1: + eprintf("%d: unexpected \"=\"" + "appeared\n", l); + case 2: + *po++ = b24[0]; + b = 0; + t = 5; /* expect 5 '=' */ + continue; + case 3: + *po++ = b24[0]; + *po++ = b24[1]; + b = 0; + t = 6; /* expect 6 '=' */ + continue; + } + } else if ((e = b64dt[(int)*pb]) == -1) + eprintf("%d: invalid byte \"%c\"\n", l, *pb); + else if (e == -2) /* whitespace */ + continue; + else if (t > 0) /* state is parsing pad/footer */ + eprintf("%d: invalid byte \"%c\"" + " after padding\n", + l, *pb); + switch (b) { /* decode next base64 chr based on state */ + case 0: b24[0] |= e << 2; break; + case 1: b24[0] |= (e >> 4) & 0x3; + b24[1] |= (e & 0xf) << 4; break; + case 2: b24[1] |= (e >> 2) & 0xf; + b24[2] |= (e & 0x3) << 6; break; + case 3: b24[2] |= e; break; + } + if (++b == 4) { /* complete decoding an octet */ + *po++ = b24[0]; + *po++ = b24[1]; + *po++ = b24[2]; + b24[0] = b24[1] = b24[2] = 0; + b = 0; + } + } + fwrite(out, 1, (po - out), outfp); + } + eprintf("%d: invalid uudecode footer \"====\" not found\n", l); +} + +static void +uudecode(FILE *fp, FILE *outfp) +{ + char *bufb = NULL, *p; + size_t n = 0; + ssize_t len; + int ch, i; + +#define DEC(c) (((c) - ' ') & 077) /* single character decode */ +#define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) ) +#define OUT_OF_RANGE(c) eprintf("character %c out of range: [%d-%d]\n", (c), 1 + ' ', 077 + ' ' + 1) + + while ((len = getline(&bufb, &n, fp)) > 0) { + p = bufb; + /* trim newlines */ + if (!len || bufb[len - 1] != '\n') + eprintf("no newline found, aborting\n"); + bufb[len - 1] = '\0'; + + /* check for last line */ + if ((i = DEC(*p)) <= 0) + break; + for (++p; i > 0; p += 4, i -= 3) { + if (i >= 3) { + if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) && + IS_DEC(*(p + 2)) && IS_DEC(*(p + 3)))) + OUT_OF_RANGE(*p); + + ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4; + putc(ch, outfp); + ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2; + putc(ch, outfp); + ch = DEC(p[2]) << 6 | DEC(p[3]); + putc(ch, outfp); + } else { + if (i >= 1) { + if (!(IS_DEC(*p) && IS_DEC(*(p + 1)))) + OUT_OF_RANGE(*p); + + ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4; + putc(ch, outfp); + } + if (i >= 2) { + if (!(IS_DEC(*(p + 1)) && + IS_DEC(*(p + 2)))) + OUT_OF_RANGE(*p); + + ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2; + putc(ch, outfp); + } + } + } + if (ferror(fp)) + eprintf("read error:"); + } + /* check for end or fail */ + if ((len = getline(&bufb, &n, fp)) < 0) + eprintf("getline:"); + if (len < 3 || strncmp(bufb, "end", 3) || bufb[3] != '\n') + eprintf("invalid uudecode footer \"end\" not found\n"); + free(bufb); +} + +static void +usage(void) +{ + eprintf("usage: %s [-m] [-o output] [file]\n", argv0); +} + +int +main(int argc, char *argv[]) +{ + FILE *fp = NULL, *nfp = NULL; + mode_t mode = 0; + int ret = 0; + char *fname, *header, *ifname, *ofname = NULL; + void (*d) (FILE *, FILE *) = NULL; + + ARGBEGIN { + case 'm': + mflag = 1; /* accepted but unused (autodetect file type) */ + break; + case 'o': + oflag = 1; + ofname = EARGF(usage()); + break; + default: + usage(); + } ARGEND + + if (argc > 1) + usage(); + + if (!argc || !strcmp(argv[0], "-")) { + fp = stdin; + ifname = "<stdin>"; + } else { + if (!(fp = fopen(argv[0], "r"))) + eprintf("fopen %s:", argv[0]); + ifname = argv[0]; + } + + parseheader(fp, ifname, &header, &mode, &fname); + + if (!strncmp(header, "begin", sizeof("begin"))) + d = uudecode; + else if (!strncmp(header, "begin-base64", sizeof("begin-base64"))) + d = uudecodeb64; + else + eprintf("unknown header %s:", header); + + if (oflag) + fname = ofname; + if (!(nfp = parsefile(fname))) + eprintf("fopen %s:", fname); + + d(fp, nfp); + + if (nfp != stdout && chmod(fname, mode) < 0) + eprintf("chmod %s:", fname); + + ret |= fshut(fp, (fp == stdin) ? "<stdin>" : argv[0]); + ret |= fshut(nfp, (nfp == stdout) ? "<stdout>" : fname); + + return ret; +} |