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![Johannes Schindelin](/assets/img/avatar_default.png)
In 4ac9006f83
(real_path: have callers use real_pathdup and
strbuf_realpath, 2016-12-12), we changed the xstrdup(real_path())
pattern to use real_pathdup() directly.
The problem with this change is that real_path() calls
strbuf_realpath() with die_on_error = 1 while real_pathdup() calls
it with die_on_error = 0. Meaning that in cases where real_path()
causes Git to die() with an error message, real_pathdup() is silent
and returns NULL instead.
The callers, however, are ill-prepared for that change, as they expect
the return value to be non-NULL (and otherwise the function died
with an appropriate error message).
Fix this by extending real_pathdup()'s signature to accept the
die_on_error flag and simply pass it through to strbuf_realpath(),
and then adjust all callers after a careful audit whether they would
handle NULLs well.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
275 lines
7 KiB
C
275 lines
7 KiB
C
#include "cache.h"
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/*
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* Do not use this for inspecting *tracked* content. When path is a
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* symlink to a directory, we do not want to say it is a directory when
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* dealing with tracked content in the working tree.
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*/
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int is_directory(const char *path)
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{
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struct stat st;
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return (!stat(path, &st) && S_ISDIR(st.st_mode));
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}
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/* removes the last path component from 'path' except if 'path' is root */
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static void strip_last_component(struct strbuf *path)
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{
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size_t offset = offset_1st_component(path->buf);
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size_t len = path->len;
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/* Find start of the last component */
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while (offset < len && !is_dir_sep(path->buf[len - 1]))
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len--;
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/* Skip sequences of multiple path-separators */
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while (offset < len && is_dir_sep(path->buf[len - 1]))
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len--;
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strbuf_setlen(path, len);
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}
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/* get (and remove) the next component in 'remaining' and place it in 'next' */
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static void get_next_component(struct strbuf *next, struct strbuf *remaining)
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{
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char *start = NULL;
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char *end = NULL;
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strbuf_reset(next);
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/* look for the next component */
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/* Skip sequences of multiple path-separators */
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for (start = remaining->buf; is_dir_sep(*start); start++)
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; /* nothing */
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/* Find end of the path component */
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for (end = start; *end && !is_dir_sep(*end); end++)
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; /* nothing */
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strbuf_add(next, start, end - start);
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/* remove the component from 'remaining' */
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strbuf_remove(remaining, 0, end - remaining->buf);
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}
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/* copies root part from remaining to resolved, canonicalizing it on the way */
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static void get_root_part(struct strbuf *resolved, struct strbuf *remaining)
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{
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int offset = offset_1st_component(remaining->buf);
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strbuf_reset(resolved);
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strbuf_add(resolved, remaining->buf, offset);
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#ifdef GIT_WINDOWS_NATIVE
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convert_slashes(resolved->buf);
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#endif
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strbuf_remove(remaining, 0, offset);
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}
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/* We allow "recursive" symbolic links. Only within reason, though. */
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#ifndef MAXSYMLINKS
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#define MAXSYMLINKS 32
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#endif
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/*
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* Return the real path (i.e., absolute path, with symlinks resolved
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* and extra slashes removed) equivalent to the specified path. (If
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* you want an absolute path but don't mind links, use
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* absolute_path().) Places the resolved realpath in the provided strbuf.
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*
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* The directory part of path (i.e., everything up to the last
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* dir_sep) must denote a valid, existing directory, but the last
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* component need not exist. If die_on_error is set, then die with an
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* informative error message if there is a problem. Otherwise, return
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* NULL on errors (without generating any output).
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*/
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char *strbuf_realpath(struct strbuf *resolved, const char *path,
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int die_on_error)
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{
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struct strbuf remaining = STRBUF_INIT;
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struct strbuf next = STRBUF_INIT;
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struct strbuf symlink = STRBUF_INIT;
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char *retval = NULL;
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int num_symlinks = 0;
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struct stat st;
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if (!*path) {
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if (die_on_error)
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die("The empty string is not a valid path");
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else
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goto error_out;
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}
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strbuf_addstr(&remaining, path);
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get_root_part(resolved, &remaining);
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if (!resolved->len) {
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/* relative path; can use CWD as the initial resolved path */
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if (strbuf_getcwd(resolved)) {
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if (die_on_error)
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die_errno("unable to get current working directory");
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else
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goto error_out;
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}
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}
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/* Iterate over the remaining path components */
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while (remaining.len > 0) {
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get_next_component(&next, &remaining);
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if (next.len == 0) {
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continue; /* empty component */
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} else if (next.len == 1 && !strcmp(next.buf, ".")) {
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continue; /* '.' component */
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} else if (next.len == 2 && !strcmp(next.buf, "..")) {
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/* '..' component; strip the last path component */
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strip_last_component(resolved);
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continue;
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}
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/* append the next component and resolve resultant path */
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if (!is_dir_sep(resolved->buf[resolved->len - 1]))
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strbuf_addch(resolved, '/');
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strbuf_addbuf(resolved, &next);
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if (lstat(resolved->buf, &st)) {
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/* error out unless this was the last component */
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if (errno != ENOENT || remaining.len) {
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if (die_on_error)
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die_errno("Invalid path '%s'",
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resolved->buf);
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else
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goto error_out;
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}
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} else if (S_ISLNK(st.st_mode)) {
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ssize_t len;
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strbuf_reset(&symlink);
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if (num_symlinks++ > MAXSYMLINKS) {
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errno = ELOOP;
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if (die_on_error)
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die("More than %d nested symlinks "
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"on path '%s'", MAXSYMLINKS, path);
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else
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goto error_out;
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}
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len = strbuf_readlink(&symlink, resolved->buf,
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st.st_size);
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if (len < 0) {
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if (die_on_error)
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die_errno("Invalid symlink '%s'",
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resolved->buf);
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else
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goto error_out;
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}
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if (is_absolute_path(symlink.buf)) {
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/* absolute symlink; set resolved to root */
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get_root_part(resolved, &symlink);
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} else {
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/*
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* relative symlink
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* strip off the last component since it will
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* be replaced with the contents of the symlink
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*/
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strip_last_component(resolved);
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}
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/*
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* if there are still remaining components to resolve
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* then append them to symlink
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*/
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if (remaining.len) {
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strbuf_addch(&symlink, '/');
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strbuf_addbuf(&symlink, &remaining);
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}
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/*
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* use the symlink as the remaining components that
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* need to be resloved
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*/
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strbuf_swap(&symlink, &remaining);
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}
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}
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retval = resolved->buf;
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error_out:
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strbuf_release(&remaining);
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strbuf_release(&next);
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strbuf_release(&symlink);
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if (!retval)
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strbuf_reset(resolved);
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return retval;
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}
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const char *real_path(const char *path)
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{
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static struct strbuf realpath = STRBUF_INIT;
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return strbuf_realpath(&realpath, path, 1);
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}
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const char *real_path_if_valid(const char *path)
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{
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static struct strbuf realpath = STRBUF_INIT;
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return strbuf_realpath(&realpath, path, 0);
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}
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char *real_pathdup(const char *path, int die_on_error)
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{
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struct strbuf realpath = STRBUF_INIT;
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char *retval = NULL;
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if (strbuf_realpath(&realpath, path, die_on_error))
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retval = strbuf_detach(&realpath, NULL);
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strbuf_release(&realpath);
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return retval;
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}
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/*
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* Use this to get an absolute path from a relative one. If you want
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* to resolve links, you should use real_path.
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*/
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const char *absolute_path(const char *path)
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{
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static struct strbuf sb = STRBUF_INIT;
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strbuf_reset(&sb);
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strbuf_add_absolute_path(&sb, path);
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return sb.buf;
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}
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char *absolute_pathdup(const char *path)
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{
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struct strbuf sb = STRBUF_INIT;
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strbuf_add_absolute_path(&sb, path);
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return strbuf_detach(&sb, NULL);
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}
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/*
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* Unlike prefix_path, this should be used if the named file does
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* not have to interact with index entry; i.e. name of a random file
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* on the filesystem.
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*/
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const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
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{
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static struct strbuf path = STRBUF_INIT;
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#ifndef GIT_WINDOWS_NATIVE
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if (!pfx_len || is_absolute_path(arg))
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return arg;
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strbuf_reset(&path);
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strbuf_add(&path, pfx, pfx_len);
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strbuf_addstr(&path, arg);
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#else
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/* don't add prefix to absolute paths, but still replace '\' by '/' */
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strbuf_reset(&path);
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if (is_absolute_path(arg))
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pfx_len = 0;
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else if (pfx_len)
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strbuf_add(&path, pfx, pfx_len);
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strbuf_addstr(&path, arg);
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convert_slashes(path.buf + pfx_len);
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#endif
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return path.buf;
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}
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