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This commit is contained in:
Max Khon 2003-03-29 21:56:59 +00:00
parent bb25efadc4
commit 839e119ec8
1 changed files with 89 additions and 79 deletions
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168
lib/libc/stdlib/realpath.c
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@ -37,151 +37,161 @@ __FBSDID("$FreeBSD$");
#include <sys/stat.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "un-namespace.h"
/*
* char *realpath(const char *path, char resolved_path[PATH_MAX]);
* char *realpath(const char *path, char resolved[PATH_MAX]);
*
* Find the real name of path, by removing all ".", ".." and symlink
* components. Returns (resolved) on success, or (NULL) on failure,
* in which case the path which caused trouble is left in (resolved).
*/
char *
realpath(const char *path, char resolved_path[PATH_MAX])
realpath(const char *path, char resolved[PATH_MAX])
{
unsigned num_symlinks = 0;
int saved_errno = errno;
char left[PATH_MAX];
struct stat sb;
char *p, *q, *s;
size_t left_len, resolved_len;
unsigned symlinks;
int serrno, slen;
char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
serrno = errno;
symlinks = 0;
if (path[0] == '/') {
resolved_path[0] = '/';
resolved_path[1] = '\0';
resolved[0] = '/';
resolved[1] = '\0';
if (path[1] == '\0')
return resolved_path;
return (resolved);
resolved_len = 1;
left_len = strlcpy(left, path + 1, PATH_MAX);
left_len = strlcpy(left, path + 1, sizeof(left));
} else {
if (getcwd(resolved_path, PATH_MAX) == NULL) {
strlcpy(resolved_path, ".", PATH_MAX);
return NULL;
if (getcwd(resolved, PATH_MAX) == NULL) {
strlcpy(resolved, ".", PATH_MAX);
return (NULL);
}
resolved_len = strlen(resolved_path);
left_len = strlcpy(left, path, PATH_MAX);
resolved_len = strlen(resolved);
left_len = strlcpy(left, path, sizeof(left));
}
if (left_len >= PATH_MAX || resolved_len >= PATH_MAX) {
if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
errno = ENAMETOOLONG;
return NULL;
return (NULL);
}
while (left_len > 0) {
struct stat st;
char next_token[PATH_MAX];
char *p;
char *s = (p = strchr(left, '/')) ? p : left + left_len;
memmove(next_token, left, s - left);
/*
* Iterate over path components in `left'.
*/
while (left_len != 0) {
/*
* Extract the next path component and adjust `left'
* and its length.
*/
p = strchr(left, '/');
s = p ? p : left + left_len;
if (s - left >= sizeof(next_token)) {
errno = ENAMETOOLONG;
return (NULL);
}
memcpy(next_token, left, s - left);
next_token[s - left] = '\0';
left_len -= s - left;
if (p != NULL)
memmove(left, s + 1, left_len + 1);
next_token[s - left] = '\0';
if (resolved_path[resolved_len - 1] != '/') {
if (resolved[resolved_len - 1] != '/') {
if (resolved_len + 1 >= PATH_MAX) {
errno = ENAMETOOLONG;
return NULL;
return (NULL);
}
resolved_path[resolved_len++] = '/';
resolved_path[resolved_len] = '\0';
resolved[resolved_len++] = '/';
resolved[resolved_len] = '\0';
}
if (next_token[0] == '\0')
continue;
else if (!strcmp(next_token, "."))
else if (strcmp(next_token, ".") == 0)
continue;
else if (!strcmp(next_token, "..")) {
else if (strcmp(next_token, "..") == 0) {
/*
* Strip the last path component except when we have
* single "/"
*/
if (resolved_len > 1) {
char *q;
/* trailing slash */
resolved_path[resolved_len - 1] = '\0';
q = strrchr(resolved_path, '/');
resolved[resolved_len - 1] = '\0';
q = strrchr(resolved, '/');
*q = '\0';
resolved_len = q - resolved_path;
resolved_len = q - resolved;
}
continue;
}
/* filename */
resolved_len = strlcat(resolved_path, next_token, PATH_MAX);
/*
* Append the next path component and lstat() it. If
* lstat() fails we still can return successfully if
* there are no more path components left.
*/
resolved_len = strlcat(resolved, next_token, PATH_MAX);
if (resolved_len >= PATH_MAX) {
errno = ENAMETOOLONG;
return NULL;
return (NULL);
}
if (lstat(resolved_path, &st) < 0) {
if (lstat(resolved, &sb) != 0) {
if (errno == ENOENT && p == NULL) {
errno = saved_errno;
return resolved_path;
errno = serrno;
return (resolved);
}
return NULL;
return (NULL);
}
if ((st.st_mode & S_IFLNK) == S_IFLNK) {
char symlink[PATH_MAX];
int slen;
if (num_symlinks++ > MAXSYMLINKS) {
if (S_ISLNK(sb.st_mode)) {
if (symlinks++ > MAXSYMLINKS) {
errno = ELOOP;
return NULL;
return (NULL);
}
slen = readlink(resolved_path, symlink, PATH_MAX - 1);
slen = readlink(resolved, symlink, sizeof(symlink) - 1);
if (slen < 0)
return NULL;
return (NULL);
symlink[slen] = '\0';
if (symlink[0] == '/') {
/* absolute link */
resolved_path[1] = 0;
resolved[1] = 0;
resolved_len = 1;
} else if (resolved_len > 1) {
char *q;
/* trailing slash */
resolved_path[resolved_len - 1] = '\0';
q = strrchr(resolved_path, '/');
/* Strip the last path component. */
resolved[resolved_len - 1] = '\0';
q = strrchr(resolved, '/');
*q = '\0';
resolved_len = q - resolved_path;
resolved_len = q - resolved;
}
/*
* If there are any path components left, then
* append them to symlink. The result is placed
* in `left'.
*/
if (p != NULL) {
if (symlink[slen - 1] != '/') {
if (slen + 1 >= PATH_MAX) {
if (slen + 1 >= sizeof(symlink)) {
errno = ENAMETOOLONG;
return NULL;
return (NULL);
}
symlink[slen] = '/';
symlink[slen + 1] = 0;
}
left_len = strlcat(symlink, left, PATH_MAX);
if (left_len >= PATH_MAX) {
left_len = strlcat(symlink, left, sizeof(left));
if (left_len >= sizeof(left)) {
errno = ENAMETOOLONG;
return NULL;
return (NULL);
}
}
left_len = strlcpy(left, symlink, PATH_MAX);
left_len = strlcpy(left, symlink, sizeof(left));
}
}
if (resolved_len > 1 && resolved_path[resolved_len - 1] == '/')
resolved_path[resolved_len - 1] = '\0';
return resolved_path;
/*
* Remove trailing slash except when the resolved pathname
* is a single "/".
*/
if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
resolved[resolved_len - 1] = '\0';
return (resolved);
}