abspath.c

   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  */
   8 int is_directory(const char *path)
   9 {
  10         struct stat st;
  11         return (!stat(path, &st) && S_ISDIR(st.st_mode));
  12 }
  13
  14 /* We allow "recursive" symbolic links. Only within reason, though. */
  15 #define MAXDEPTH 5
  16
  17 /*
  18  * Return the real path (i.e., absolute path, with symlinks resolved
  19  * and extra slashes removed) equivalent to the specified path.  (If
  20  * you want an absolute path but don't mind links, use
  21  * absolute_path().)  The return value is a pointer to a static
  22  * buffer.
  23  *
  24  * The input and all intermediate paths must be shorter than MAX_PATH.
  25  * The directory part of path (i.e., everything up to the last
  26  * dir_sep) must denote a valid, existing directory, but the last
  27  * component need not exist.  If die_on_error is set, then die with an
  28  * informative error message if there is a problem.  Otherwise, return
  29  * NULL on errors (without generating any output).
  30  *
  31  * If path is our buffer, then return path, as it's already what the
  32  * user wants.
  33  */
  34 static const char *real_path_internal(const char *path, int die_on_error)
  35 {
  36         static struct strbuf sb = STRBUF_INIT;
  37         char *retval = NULL;
  38
  39         /*
  40          * If we have to temporarily chdir(), store the original CWD
  41          * here so that we can chdir() back to it at the end of the
  42          * function:
  43          */
  44         struct strbuf cwd = STRBUF_INIT;
  45
  46         int depth = MAXDEPTH;
  47         char *last_elem = NULL;
  48         struct stat st;
  49
  50         /* We've already done it */
  51         if (path == sb.buf)
  52                 return path;
  53
  54         if (!*path) {
  55                 if (die_on_error)
  56                         die("The empty string is not a valid path");
  57                 else
  58                         goto error_out;
  59         }
  60
  61         strbuf_reset(&sb);
  62         strbuf_addstr(&sb, path);
  63
  64         while (depth--) {
  65                 if (!is_directory(sb.buf)) {
  66                         char *last_slash = find_last_dir_sep(sb.buf);
  67                         if (last_slash) {
  68                                 last_elem = xstrdup(last_slash + 1);
  69                                 strbuf_setlen(&sb, last_slash - sb.buf + 1);
  70                         } else {
  71                                 last_elem = xmemdupz(sb.buf, sb.len);
  72                                 strbuf_reset(&sb);
  73                         }
  74                 }
  75
  76                 if (sb.len) {
  77                         if (!cwd.len && strbuf_getcwd(&cwd)) {
  78                                 if (die_on_error)
  79                                         die_errno("Could not get current working directory");
  80                                 else
  81                                         goto error_out;
  82                         }
  83
  84                         if (chdir(sb.buf)) {
  85                                 if (die_on_error)
  86                                         die_errno("Could not switch to '%s'",
  87                                                   sb.buf);
  88                                 else
  89                                         goto error_out;
  90                         }
  91                 }
  92                 if (strbuf_getcwd(&sb)) {
  93                         if (die_on_error)
  94                                 die_errno("Could not get current working directory");
  95                         else
  96                                 goto error_out;
  97                 }
  98
  99                 if (last_elem) {
 100                         if (sb.len && !is_dir_sep(sb.buf[sb.len - 1]))
 101                                 strbuf_addch(&sb, '/');
 102                         strbuf_addstr(&sb, last_elem);
 103                         free(last_elem);
 104                         last_elem = NULL;
 105                 }
 106
 107                 if (!lstat(sb.buf, &st) && S_ISLNK(st.st_mode)) {
 108                         struct strbuf next_sb = STRBUF_INIT;
 109                         ssize_t len = strbuf_readlink(&next_sb, sb.buf, 0);
 110                         if (len < 0) {
 111                                 if (die_on_error)
 112                                         die_errno("Invalid symlink '%s'",
 113                                                   sb.buf);
 114                                 else
 115                                         goto error_out;
 116                         }
 117                         strbuf_swap(&sb, &next_sb);
 118                         strbuf_release(&next_sb);
 119                 } else
 120                         break;
 121         }
 122
 123         retval = sb.buf;
 124 error_out:
 125         free(last_elem);
 126         if (cwd.len && chdir(cwd.buf))
 127                 die_errno("Could not change back to '%s'", cwd.buf);
 128         strbuf_release(&cwd);
 129
 130         return retval;
 131 }
 132
 133 const char *real_path(const char *path)
 134 {
 135         return real_path_internal(path, 1);
 136 }
 137
 138 const char *real_path_if_valid(const char *path)
 139 {
 140         return real_path_internal(path, 0);
 141 }
 142
 143 static const char *get_pwd_cwd(void)
 144 {
 145         static char cwd[PATH_MAX + 1];
 146         char *pwd;
 147         struct stat cwd_stat, pwd_stat;
 148         if (getcwd(cwd, PATH_MAX) == NULL)
 149                 return NULL;
 150         pwd = getenv("PWD");
 151         if (pwd && strcmp(pwd, cwd)) {
 152                 stat(cwd, &cwd_stat);
 153                 if ((cwd_stat.st_dev || cwd_stat.st_ino) &&
 154                     !stat(pwd, &pwd_stat) &&
 155                     pwd_stat.st_dev == cwd_stat.st_dev &&
 156                     pwd_stat.st_ino == cwd_stat.st_ino) {
 157                         strlcpy(cwd, pwd, PATH_MAX);
 158                 }
 159         }
 160         return cwd;
 161 }
 162
 163 /*
 164  * Use this to get an absolute path from a relative one. If you want
 165  * to resolve links, you should use real_path.
 166  *
 167  * If the path is already absolute, then return path. As the user is
 168  * never meant to free the return value, we're safe.
 169  */
 170 const char *absolute_path(const char *path)
 171 {
 172         static char buf[PATH_MAX + 1];
 173
 174         if (!*path) {
 175                 die("The empty string is not a valid path");
 176         } else if (is_absolute_path(path)) {
 177                 if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
 178                         die("Too long path: %.*s", 60, path);
 179         } else {
 180                 size_t len;
 181                 const char *fmt;
 182                 const char *cwd = get_pwd_cwd();
 183                 if (!cwd)
 184                         die_errno("Cannot determine the current working directory");
 185                 len = strlen(cwd);
 186                 fmt = (len > 0 && is_dir_sep(cwd[len - 1])) ? "%s%s" : "%s/%s";
 187                 if (snprintf(buf, PATH_MAX, fmt, cwd, path) >= PATH_MAX)
 188                         die("Too long path: %.*s", 60, path);
 189         }
 190         return buf;
 191 }
 192
 193 /*
 194  * Unlike prefix_path, this should be used if the named file does
 195  * not have to interact with index entry; i.e. name of a random file
 196  * on the filesystem.
 197  */
 198 const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
 199 {
 200         static struct strbuf path = STRBUF_INIT;
 201 #ifndef GIT_WINDOWS_NATIVE
 202         if (!pfx_len || is_absolute_path(arg))
 203                 return arg;
 204         strbuf_reset(&path);
 205         strbuf_add(&path, pfx, pfx_len);
 206         strbuf_addstr(&path, arg);
 207 #else
 208         char *p;
 209         /* don't add prefix to absolute paths, but still replace '\' by '/' */
 210         strbuf_reset(&path);
 211         if (is_absolute_path(arg))
 212                 pfx_len = 0;
 213         else if (pfx_len)
 214                 strbuf_add(&path, pfx, pfx_len);
 215         strbuf_addstr(&path, arg);
 216         for (p = path.buf + pfx_len; *p; p++)
 217                 if (*p == '\\')
 218                         *p = '/';
 219 #endif
 220         return path.buf;
 221 }