sbase/uudecode.c
dsp 7008d751b2 Initial commit of the uudecode tool and man page
Currently it operates only on regular files and does not
support Base64.
2014-02-02 20:50:31 +00:00

246 lines
5.5 KiB
C

/* See LICENSE file for copyright and license details. */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <limits.h>
#include "util.h"
#include "text.h"
static int uudecode(FILE *, FILE*);
static int checkheader(FILE *, const char *, mode_t *, char **, char **);
static int checkmode(const char *, mode_t *);
static FILE *checkfile(const char *);
static void
usage(void)
{
eprintf("usage: %s [file]\n", argv0);
}
int
main(int argc, char *argv[])
{
FILE *fp, *nfp;
char *fname, *headerr;
mode_t mode = 0;
int chmodtest;
ARGBEGIN {
case 'm':
eprintf("-m not implemented\n");
default:
usage();
} ARGEND;
if (argc > 1)
usage();
if (argc == 0) {
if (checkheader(stdin, "begin ", &mode, &fname, &headerr) < 0)
eprintf("%s\n",headerr);
nfp = checkfile(fname);
if (nfp == NULL)
eprintf("fopen %s:", fname);
if (uudecode(stdin, nfp) < 0)
goto fail;
} else {
if (!(fp = fopen(argv[0], "r")))
eprintf("fopen %s:", argv[0]);
if (checkheader(fp, "begin ", &mode, &fname, &headerr) < 0) {
fclose(fp);
eprintf("%s\n",headerr);
}
nfp = checkfile(fname);
if (nfp == NULL) {
fclose(fp);
eprintf("fopen %s:", fname);
}
if (uudecode(fp, nfp) < 0) {
fclose(fp);
goto fail;
}
}
chmodtest=fchmod(fileno(nfp),mode);
fclose(fp);
fclose(nfp);
if (chmodtest == -1)
eprintf("chmod %s:%s",fname,strerror(errno));
return EXIT_SUCCESS;
fail:
fclose(nfp);
return EXIT_FAILURE;
}
static FILE *
checkfile(const char *fname)
{
struct stat st;
int ret;
if (strcmp(fname,"/dev/stdout") == 0)
return stdout;
ret = lstat(fname, &st);
if (ret < 0 && errno == ENOENT)
goto tropen; /* new file, try to open it */
if (ret < 0) {
weprintf("stat: %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 int
checkheader(FILE *fp, const char *header, mode_t *mode, char **fname, char **headerr)
{
char bufs[PATH_MAX + 11]; /* len header + mode + maxname */
char *p, *q, *bufp = NULL;
size_t n;
fgets(bufs, sizeof(bufs), fp);
if (bufp == NULL || bufp == '\0') { /* empty or null str */
*headerr = "empty or null header string";
return -1;
}
if ((p = strchr(bufs, '\n')) == NULL) { /* line too long or last line on file */
*headerr = "header string too long or non-newline terminated file";
return -1;
}
p = bufs;
if (strncmp(bufs, header, strlen(header)) != 0) {
*headerr = "malformed header prefix";
return -1;
}
p += strlen(header);
if ((q = strchr(p, ' ')) == NULL) { /* malformed mode */
*headerr = "malformed mode string in header";
return -1;
}
*q++ = '\0'; /* now mode should be null terminated,q points to fname */
if (checkmode(p,mode) < 0) { /* error from checkmode */
*headerr = "invalid mode in header";
return -1;
}
n = strlen(q);
while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
q[--n] = '\0';
if (n > 0)
*fname = q;
return 1;
}
static int
checkmode(const char *str,mode_t *validmode)
{
char *end;
int octal;
if (str == NULL || str == '\0')
return -1; /* null str */
octal = strtol(str, &end, 8);
if (*end == '\0') { /* successful conversion from a valid str */
if (octal >= 0 && octal <= 07777) {
if(octal & 04000) *validmode |= S_ISUID;
if(octal & 02000) *validmode |= S_ISGID;
if(octal & 01000) *validmode |= S_ISVTX;
if(octal & 00400) *validmode |= S_IRUSR;
if(octal & 00200) *validmode |= S_IWUSR;
if(octal & 00100) *validmode |= S_IXUSR;
if(octal & 00040) *validmode |= S_IRGRP;
if(octal & 00020) *validmode |= S_IWGRP;
if(octal & 00010) *validmode |= S_IXGRP;
if(octal & 00004) *validmode |= S_IROTH;
if(octal & 00002) *validmode |= S_IWOTH;
if(octal & 00001) *validmode |= S_IXOTH;
*validmode &= 07777;
return 1;
}
}
return -1; /* malformed mode */
}
static int
uudecode(FILE *fp, FILE *outfp)
{
char *bufb=NULL, *p,*nl;
size_t n=0;
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) do { \
weprintf("character %c out of range: [%d-%d]",(c), 1+' ',077+' '+1); \
return -1; \
} while (0)
while (afgets(&bufb,&n,fp)) {
p = bufb;
if ((nl=strchr(bufb, '\n')) != NULL) { /* trim newlines */
*nl = '\0';
} else {
weprintf("no newline found, aborting\n");
return -1;
}
if ((i = DEC(*p)) <= 0) /* check for last line */
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)) {
weprintf("read error");
return -1;
}
}
/* check for end or fail*/
afgets(&bufb,&n,fp);
if (strnlen(bufb,3) < 3 || strncmp(bufb, "end", 3) != 0 || bufb[3] != '\n') {
weprintf("valid uudecode footer \"end\" not found\n");
return -1;
}
return 1;
}