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abspath.c
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327 lines (283 loc) · 8.39 KB
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#include "git-compat-util.h"
#include "abspath.h"
#include "strbuf.h"
/*
* Do not use this for inspecting *tracked* content. When path is a
* symlink to a directory, we do not want to say it is a directory when
* dealing with tracked content in the working tree.
*/
int is_directory(const char *path)
{
struct stat st;
return (!stat(path, &st) && S_ISDIR(st.st_mode));
}
/* removes the last path component from 'path' except if 'path' is root */
static void strip_last_component(struct strbuf *path)
{
size_t offset = offset_1st_component(path->buf);
size_t len = path->len;
/* Find start of the last component */
while (offset < len && !is_dir_sep(path->buf[len - 1]))
len--;
/* Skip sequences of multiple path-separators */
while (offset < len && is_dir_sep(path->buf[len - 1]))
len--;
strbuf_setlen(path, len);
}
/* get (and remove) the next component in 'remaining' and place it in 'next' */
static void get_next_component(struct strbuf *next, struct strbuf *remaining)
{
char *start = NULL;
char *end = NULL;
strbuf_reset(next);
/* look for the next component */
/* Skip sequences of multiple path-separators */
for (start = remaining->buf; is_dir_sep(*start); start++)
; /* nothing */
/* Find end of the path component */
for (end = start; *end && !is_dir_sep(*end); end++)
; /* nothing */
strbuf_add(next, start, end - start);
/* remove the component from 'remaining' */
strbuf_remove(remaining, 0, end - remaining->buf);
}
/* copies root part from remaining to resolved, canonicalizing it on the way */
static void get_root_part(struct strbuf *resolved, struct strbuf *remaining)
{
int offset = offset_1st_component(remaining->buf);
strbuf_reset(resolved);
strbuf_add(resolved, remaining->buf, offset);
#ifdef GIT_WINDOWS_NATIVE
convert_slashes(resolved->buf);
#endif
strbuf_remove(remaining, 0, offset);
}
/* We allow "recursive" symbolic links. Only within reason, though. */
#ifndef MAXSYMLINKS
#define MAXSYMLINKS 32
#endif
/*
* If set, any number of trailing components may be missing; otherwise, only one
* may be.
*/
#define REALPATH_MANY_MISSING (1 << 0)
/* Should we die if there's an error? */
#define REALPATH_DIE_ON_ERROR (1 << 1)
static char *strbuf_realpath_1(struct strbuf *resolved, const char *path,
int flags)
{
struct strbuf remaining = STRBUF_INIT;
struct strbuf next = STRBUF_INIT;
struct strbuf symlink = STRBUF_INIT;
char *retval = NULL;
int num_symlinks = 0;
struct stat st;
if (!*path) {
if (flags & REALPATH_DIE_ON_ERROR)
die("The empty string is not a valid path");
else
goto error_out;
}
strbuf_addstr(&remaining, path);
get_root_part(resolved, &remaining);
if (!resolved->len) {
/* relative path; can use CWD as the initial resolved path */
if (strbuf_getcwd(resolved)) {
if (flags & REALPATH_DIE_ON_ERROR)
die_errno("unable to get current working directory");
else
goto error_out;
}
}
/* Iterate over the remaining path components */
while (remaining.len > 0) {
get_next_component(&next, &remaining);
if (next.len == 0) {
continue; /* empty component */
} else if (next.len == 1 && !strcmp(next.buf, ".")) {
continue; /* '.' component */
} else if (next.len == 2 && !strcmp(next.buf, "..")) {
/* '..' component; strip the last path component */
strip_last_component(resolved);
continue;
}
/* append the next component and resolve resultant path */
if (!is_dir_sep(resolved->buf[resolved->len - 1]))
strbuf_addch(resolved, '/');
strbuf_addbuf(resolved, &next);
if (lstat(resolved->buf, &st)) {
/* error out unless this was the last component */
if (errno != ENOENT ||
(!(flags & REALPATH_MANY_MISSING) && remaining.len)) {
if (flags & REALPATH_DIE_ON_ERROR)
die_errno("Invalid path '%s'",
resolved->buf);
else
goto error_out;
}
} else if (S_ISLNK(st.st_mode)) {
ssize_t len;
strbuf_reset(&symlink);
if (num_symlinks++ > MAXSYMLINKS) {
errno = ELOOP;
if (flags & REALPATH_DIE_ON_ERROR)
die("More than %d nested symlinks "
"on path '%s'", MAXSYMLINKS, path);
else
goto error_out;
}
len = strbuf_readlink(&symlink, resolved->buf,
st.st_size);
if (len < 0) {
if (flags & REALPATH_DIE_ON_ERROR)
die_errno("Invalid symlink '%s'",
resolved->buf);
else
goto error_out;
}
if (is_absolute_path(symlink.buf)) {
/* absolute symlink; set resolved to root */
get_root_part(resolved, &symlink);
} else {
/*
* relative symlink
* strip off the last component since it will
* be replaced with the contents of the symlink
*/
strip_last_component(resolved);
}
/*
* if there are still remaining components to resolve
* then append them to symlink
*/
if (remaining.len) {
strbuf_addch(&symlink, '/');
strbuf_addbuf(&symlink, &remaining);
}
/*
* use the symlink as the remaining components that
* need to be resolved
*/
strbuf_swap(&symlink, &remaining);
}
}
retval = resolved->buf;
error_out:
strbuf_release(&remaining);
strbuf_release(&next);
strbuf_release(&symlink);
if (!retval)
strbuf_reset(resolved);
return retval;
}
/*
* Return the real path (i.e., absolute path, with symlinks resolved
* and extra slashes removed) equivalent to the specified path. (If
* you want an absolute path but don't mind links, use
* absolute_path().) Places the resolved realpath in the provided strbuf.
*
* The directory part of path (i.e., everything up to the last
* dir_sep) must denote a valid, existing directory, but the last
* component need not exist. If die_on_error is set, then die with an
* informative error message if there is a problem. Otherwise, return
* NULL on errors (without generating any output).
*/
char *strbuf_realpath(struct strbuf *resolved, const char *path,
int die_on_error)
{
return strbuf_realpath_1(resolved, path,
die_on_error ? REALPATH_DIE_ON_ERROR : 0);
}
/*
* Just like strbuf_realpath, but allows an arbitrary number of path
* components to be missing.
*/
char *strbuf_realpath_forgiving(struct strbuf *resolved, const char *path,
int die_on_error)
{
return strbuf_realpath_1(resolved, path,
((die_on_error ? REALPATH_DIE_ON_ERROR : 0) |
REALPATH_MANY_MISSING));
}
char *real_pathdup(const char *path, int die_on_error)
{
struct strbuf realpath = STRBUF_INIT;
char *retval = NULL;
if (strbuf_realpath(&realpath, path, die_on_error))
retval = strbuf_detach(&realpath, NULL);
strbuf_release(&realpath);
return retval;
}
/*
* Use this to get an absolute path from a relative one. If you want
* to resolve links, you should use strbuf_realpath.
*/
const char *absolute_path(const char *path)
{
static struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
strbuf_add_absolute_path(&sb, path);
return sb.buf;
}
char *absolute_pathdup(const char *path)
{
struct strbuf sb = STRBUF_INIT;
strbuf_add_absolute_path(&sb, path);
return strbuf_detach(&sb, NULL);
}
char *prefix_filename(const char *pfx, const char *arg)
{
struct strbuf path = STRBUF_INIT;
size_t pfx_len = pfx ? strlen(pfx) : 0;
if (!pfx_len)
; /* nothing to prefix */
else if (is_absolute_path(arg))
pfx_len = 0;
else
strbuf_add(&path, pfx, pfx_len);
strbuf_addstr(&path, arg);
#ifdef GIT_WINDOWS_NATIVE
convert_slashes(path.buf + pfx_len);
#endif
return strbuf_detach(&path, NULL);
}
char *prefix_filename_except_for_dash(const char *pfx, const char *arg)
{
if (!strcmp(arg, "-"))
return xstrdup(arg);
return prefix_filename(pfx, arg);
}
void strbuf_add_absolute_path(struct strbuf *sb, const char *path)
{
if (!*path)
die("The empty string is not a valid path");
if (!is_absolute_path(path)) {
struct stat cwd_stat, pwd_stat;
size_t orig_len = sb->len;
char *cwd = xgetcwd();
char *pwd = getenv("PWD");
if (pwd && strcmp(pwd, cwd) &&
!stat(cwd, &cwd_stat) &&
(cwd_stat.st_dev || cwd_stat.st_ino) &&
!stat(pwd, &pwd_stat) &&
pwd_stat.st_dev == cwd_stat.st_dev &&
pwd_stat.st_ino == cwd_stat.st_ino)
strbuf_addstr(sb, pwd);
else
strbuf_addstr(sb, cwd);
if (sb->len > orig_len && !is_dir_sep(sb->buf[sb->len - 1]))
strbuf_addch(sb, '/');
free(cwd);
}
strbuf_addstr(sb, path);
}
void strbuf_add_real_path(struct strbuf *sb, const char *path)
{
if (sb->len) {
struct strbuf resolved = STRBUF_INIT;
strbuf_realpath(&resolved, path, 1);
strbuf_addbuf(sb, &resolved);
strbuf_release(&resolved);
} else
strbuf_realpath(sb, path, 1);
}