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#include <stdio.h>
#ifdef TEST_PROGRAM
#include <stdlib.h>
#include <unistd.h>
#include <err.h>
#define _GNU_SOURCE
#define __USE_GNU
#endif
#include <string.h>
#include "canonicalize.h"
/*
* This routine is written with the assumption that
* the library string functions will be faster than
* trying to do a character-by-character search.
*
* It also assumes that using memmove() will be
* faster, so even if we have multiple hits on a path
* and have to call it multiple times, overall things
* will still be faster.
*/
void canonicalize(char * filename)
{
char *p1, *p2, *ep = NULL;
char c;
/*
* Strip out all multiple slashes, and then we
* won't have to worry about them again.
*/
if ((p1 = strstr(filename, "//")) != NULL) {
ep = strchr(p1, '\0') + 1;
do {
for (p2 = ++p1 + 1; *p2 == '/'; p2++)
continue;
memmove(p1, p2, ep - p2);
ep -= (p2 - p1);
} while ((p1 = strstr(p1, "//")) != NULL);
}
p1 = filename;
/* Now we search for "." and ".." in the path. */
for (;;) {
if ((p1 = strstr(p1, "/.")) == NULL)
return;
/* Check for: "/..", "/./" and "/.\000" */
if ((c = *(p1+2)) != '.' && c != '/') {
if (c == '\0') {
*p1 = '\0';
return;
}
p1 += 3;
continue;
}
if (c == '/') {
if (ep == NULL)
ep = strchr(p1 + 2, '\0') + 1;
ep -= 2;
memmove(p1, p1 + 2, ep - p1);
continue;
}
/* At this point, p1 is pointing at "/.." */
if ((c = *(p1+3)) != '/' && (c != '\0')) {
p1 += 4;
continue;
}
/*
* If the previous component is the first
* component, and equal to '.', don't strip
*/
if (p1 == filename + 1 && *filename == '.') {
p1 += 4;
continue;
}
/* Don't strip out if previous component is ".." */
if (((p1 - filename) >= 2) &&
*(p1-1) == '.' &&
*(p1-2) == '.' &&
((p1 - filename == 2) || *(p1-3) == '/')) {
p1 +=4;
continue;
}
/*
* Ok, strip out prev/..
* Back up p1 over the previous component, leaving
* it pointing at the slash, and backup p2 by one
* so that it is pointing at the slash/null.
*/
p2 = p1 + 3;
while (p1 > filename && *--p1 != '/')
continue;
if (ep == NULL)
ep = strchr(p2, '\0') + 1;
memmove(p1, p2, ep - p2);
ep -= p2 - p1;
}
}
#ifdef TEST_PROGRAM
/*
* This is a set of test path strings with the
* expected result after being canonicalized.
*/
struct tests {
char *test;
char *ans;
} tests[] = {
{ "./skip../../one", "./one" },
{ "./../one/./two/./three", "./../one/two/three" },
{ "/one/two/three", "/one/two/three" },
{ "///one/two/three", "/one/two/three" },
{ "/../one/two/three", "/one/two/three" },
{ "///..///../one///skip/../two", "/one/two" },
{ "/one/skip/../three", "/one/three" },
{ "/one/skip1/skip2/../../two/three", "/one/two/three" },
{ "//one/skip1//..//two/three", "/one/two/three" },
{ "../one/two", "../one/two" },
{ "../../one/two", "../../one/two" },
{ "/one/./two/./three", "/one/two/three" },
{ "./one/./two/./three", "./one/two/three" },
{ ".././../one/./two/./three", "../../one/two/three" },
{ "/a/b/../../../c/d", "/c/d" },
{ "/one/two/..three/four", "/one/two/..three/four" },
{ 0 }
};
char *input_file = NULL;
int internal_tests = 0;
int quiet_flag;
int
verify(char *strp, char *ans)
{
int len;
len = (int)strlen(strp) + 3;
if (!quiet_flag)
printf("%s -> ", strp);
canonicalize(strp);
if (!quiet_flag)
printf("%s\n", strp);
if (ans && strcmp(strp, ans) != 0) {
if (!quiet_flag)
printf("%*s %s\n", len, "EXPECTED ->", ans);
return(0);
}
return(1);
}
void
usage()
{
fprintf(stderr, "Usage: canonicalize [-iq] [-f input_file]\n");
exit(1);
}
int
main(int argc, char **argv)
{
int failed = 0;
int parsed = 0;
struct tests *tp;
char tbuf[1024];
char *test, *ans;
int opt;
char *ep;
FILE *fd;
while ((opt = getopt(argc, argv, "if:q")) != -1) {
switch (opt) {
case 'i':
++internal_tests;
break;
case 'f':
input_file = optarg;
break;
case 'q':
quiet_flag++;
break;
default:
usage();
/* NOT_REACHED */
}
}
if (input_file) {
if ((fd = fopen(input_file, "r")) == NULL) {
err(1, "%s", input_file);
/* NOT_REACHED */
}
while (fgets(tbuf, sizeof(tbuf), fd) != NULL) {
/* Make sure it's null terminated */
tbuf[sizeof(tbuf)-1] = '\0';
test = tbuf;
while (*test == ' ' || *test == '\t')
test++;
/* Find the (optional) expected answer */
ans = strchrnul(test, ' ');
if (*ans == '\0')
ans = strchrnul(test, '\t');
if (*ans != '\0') {
*ans++ = '\0';
while (*ans == ' ' || *ans == '\t')
ans++;
ep = strchrnul(ans, '\n');
} else {
ep = ans - 1;
ans = NULL;
}
/* Strip off the trailing \n */
if (*ep == '\n')
*ep-- = '\0';
if (*test == '\0')
continue;
parsed++;
if (!verify(test, ans))
failed++;
}
} else
internal_tests++;
if (internal_tests) {
for (tp = tests; tp->test; tp++) {
strncpy(tbuf, tp->test, sizeof(tbuf));
parsed++;
if (!verify(tbuf, tp->ans))
failed++;
}
}
printf("%d paths parsed\n", parsed);
if (failed)
printf("%d FAILURES\n", failed);
exit(0);
}
#endif
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