abspath.con commit Merge branch 'dl/rebase-i-keep-base' (640f9cd)
   1#include "cache.h"
   2
   3/*
   4 * Do not use this for inspecting *tracked* content.  When path is a
   5 * symlink to a directory, we do not want to say it is a directory when
   6 * dealing with tracked content in the working tree.
   7 */
   8int is_directory(const char *path)
   9{
  10        struct stat st;
  11        return (!stat(path, &st) && S_ISDIR(st.st_mode));
  12}
  13
  14/* removes the last path component from 'path' except if 'path' is root */
  15static void strip_last_component(struct strbuf *path)
  16{
  17        size_t offset = offset_1st_component(path->buf);
  18        size_t len = path->len;
  19
  20        /* Find start of the last component */
  21        while (offset < len && !is_dir_sep(path->buf[len - 1]))
  22                len--;
  23        /* Skip sequences of multiple path-separators */
  24        while (offset < len && is_dir_sep(path->buf[len - 1]))
  25                len--;
  26
  27        strbuf_setlen(path, len);
  28}
  29
  30/* get (and remove) the next component in 'remaining' and place it in 'next' */
  31static void get_next_component(struct strbuf *next, struct strbuf *remaining)
  32{
  33        char *start = NULL;
  34        char *end = NULL;
  35
  36        strbuf_reset(next);
  37
  38        /* look for the next component */
  39        /* Skip sequences of multiple path-separators */
  40        for (start = remaining->buf; is_dir_sep(*start); start++)
  41                ; /* nothing */
  42        /* Find end of the path component */
  43        for (end = start; *end && !is_dir_sep(*end); end++)
  44                ; /* nothing */
  45
  46        strbuf_add(next, start, end - start);
  47        /* remove the component from 'remaining' */
  48        strbuf_remove(remaining, 0, end - remaining->buf);
  49}
  50
  51/* copies root part from remaining to resolved, canonicalizing it on the way */
  52static void get_root_part(struct strbuf *resolved, struct strbuf *remaining)
  53{
  54        int offset = offset_1st_component(remaining->buf);
  55
  56        strbuf_reset(resolved);
  57        strbuf_add(resolved, remaining->buf, offset);
  58#ifdef GIT_WINDOWS_NATIVE
  59        convert_slashes(resolved->buf);
  60#endif
  61        strbuf_remove(remaining, 0, offset);
  62}
  63
  64/* We allow "recursive" symbolic links. Only within reason, though. */
  65#ifndef MAXSYMLINKS
  66#define MAXSYMLINKS 32
  67#endif
  68
  69/*
  70 * Return the real path (i.e., absolute path, with symlinks resolved
  71 * and extra slashes removed) equivalent to the specified path.  (If
  72 * you want an absolute path but don't mind links, use
  73 * absolute_path().)  Places the resolved realpath in the provided strbuf.
  74 *
  75 * The directory part of path (i.e., everything up to the last
  76 * dir_sep) must denote a valid, existing directory, but the last
  77 * component need not exist.  If die_on_error is set, then die with an
  78 * informative error message if there is a problem.  Otherwise, return
  79 * NULL on errors (without generating any output).
  80 */
  81char *strbuf_realpath(struct strbuf *resolved, const char *path,
  82                      int die_on_error)
  83{
  84        struct strbuf remaining = STRBUF_INIT;
  85        struct strbuf next = STRBUF_INIT;
  86        struct strbuf symlink = STRBUF_INIT;
  87        char *retval = NULL;
  88        int num_symlinks = 0;
  89        struct stat st;
  90
  91        if (!*path) {
  92                if (die_on_error)
  93                        die("The empty string is not a valid path");
  94                else
  95                        goto error_out;
  96        }
  97
  98        strbuf_addstr(&remaining, path);
  99        get_root_part(resolved, &remaining);
 100
 101        if (!resolved->len) {
 102                /* relative path; can use CWD as the initial resolved path */
 103                if (strbuf_getcwd(resolved)) {
 104                        if (die_on_error)
 105                                die_errno("unable to get current working directory");
 106                        else
 107                                goto error_out;
 108                }
 109        }
 110
 111        /* Iterate over the remaining path components */
 112        while (remaining.len > 0) {
 113                get_next_component(&next, &remaining);
 114
 115                if (next.len == 0) {
 116                        continue; /* empty component */
 117                } else if (next.len == 1 && !strcmp(next.buf, ".")) {
 118                        continue; /* '.' component */
 119                } else if (next.len == 2 && !strcmp(next.buf, "..")) {
 120                        /* '..' component; strip the last path component */
 121                        strip_last_component(resolved);
 122                        continue;
 123                }
 124
 125                /* append the next component and resolve resultant path */
 126                if (!is_dir_sep(resolved->buf[resolved->len - 1]))
 127                        strbuf_addch(resolved, '/');
 128                strbuf_addbuf(resolved, &next);
 129
 130                if (lstat(resolved->buf, &st)) {
 131                        /* error out unless this was the last component */
 132                        if (errno != ENOENT || remaining.len) {
 133                                if (die_on_error)
 134                                        die_errno("Invalid path '%s'",
 135                                                  resolved->buf);
 136                                else
 137                                        goto error_out;
 138                        }
 139                } else if (S_ISLNK(st.st_mode)) {
 140                        ssize_t len;
 141                        strbuf_reset(&symlink);
 142
 143                        if (num_symlinks++ > MAXSYMLINKS) {
 144                                errno = ELOOP;
 145
 146                                if (die_on_error)
 147                                        die("More than %d nested symlinks "
 148                                            "on path '%s'", MAXSYMLINKS, path);
 149                                else
 150                                        goto error_out;
 151                        }
 152
 153                        len = strbuf_readlink(&symlink, resolved->buf,
 154                                              st.st_size);
 155                        if (len < 0) {
 156                                if (die_on_error)
 157                                        die_errno("Invalid symlink '%s'",
 158                                                  resolved->buf);
 159                                else
 160                                        goto error_out;
 161                        }
 162
 163                        if (is_absolute_path(symlink.buf)) {
 164                                /* absolute symlink; set resolved to root */
 165                                get_root_part(resolved, &symlink);
 166                        } else {
 167                                /*
 168                                 * relative symlink
 169                                 * strip off the last component since it will
 170                                 * be replaced with the contents of the symlink
 171                                 */
 172                                strip_last_component(resolved);
 173                        }
 174
 175                        /*
 176                         * if there are still remaining components to resolve
 177                         * then append them to symlink
 178                         */
 179                        if (remaining.len) {
 180                                strbuf_addch(&symlink, '/');
 181                                strbuf_addbuf(&symlink, &remaining);
 182                        }
 183
 184                        /*
 185                         * use the symlink as the remaining components that
 186                         * need to be resolved
 187                         */
 188                        strbuf_swap(&symlink, &remaining);
 189                }
 190        }
 191
 192        retval = resolved->buf;
 193
 194error_out:
 195        strbuf_release(&remaining);
 196        strbuf_release(&next);
 197        strbuf_release(&symlink);
 198
 199        if (!retval)
 200                strbuf_reset(resolved);
 201
 202        return retval;
 203}
 204
 205/*
 206 * Resolve `path` into an absolute, cleaned-up path. The return value
 207 * comes from a shared buffer.
 208 */
 209const char *real_path(const char *path)
 210{
 211        static struct strbuf realpath = STRBUF_INIT;
 212        return strbuf_realpath(&realpath, path, 1);
 213}
 214
 215const char *real_path_if_valid(const char *path)
 216{
 217        static struct strbuf realpath = STRBUF_INIT;
 218        return strbuf_realpath(&realpath, path, 0);
 219}
 220
 221char *real_pathdup(const char *path, int die_on_error)
 222{
 223        struct strbuf realpath = STRBUF_INIT;
 224        char *retval = NULL;
 225
 226        if (strbuf_realpath(&realpath, path, die_on_error))
 227                retval = strbuf_detach(&realpath, NULL);
 228
 229        strbuf_release(&realpath);
 230
 231        return retval;
 232}
 233
 234/*
 235 * Use this to get an absolute path from a relative one. If you want
 236 * to resolve links, you should use real_path.
 237 */
 238const char *absolute_path(const char *path)
 239{
 240        static struct strbuf sb = STRBUF_INIT;
 241        strbuf_reset(&sb);
 242        strbuf_add_absolute_path(&sb, path);
 243        return sb.buf;
 244}
 245
 246char *absolute_pathdup(const char *path)
 247{
 248        struct strbuf sb = STRBUF_INIT;
 249        strbuf_add_absolute_path(&sb, path);
 250        return strbuf_detach(&sb, NULL);
 251}
 252
 253char *prefix_filename(const char *pfx, const char *arg)
 254{
 255        struct strbuf path = STRBUF_INIT;
 256        size_t pfx_len = pfx ? strlen(pfx) : 0;
 257
 258        if (!pfx_len)
 259                ; /* nothing to prefix */
 260        else if (is_absolute_path(arg))
 261                pfx_len = 0;
 262        else
 263                strbuf_add(&path, pfx, pfx_len);
 264
 265        strbuf_addstr(&path, arg);
 266#ifdef GIT_WINDOWS_NATIVE
 267        convert_slashes(path.buf + pfx_len);
 268#endif
 269        return strbuf_detach(&path, NULL);
 270}