diff options
Diffstat (limited to 'abspath.c')
| -rw-r--r-- | abspath.c | 110 |
1 files changed, 89 insertions, 21 deletions
@@ -15,16 +15,34 @@ int is_directory(const char *path) #define MAXDEPTH 5 /* - * Use this to get the real path, i.e. resolve links. If you want an - * absolute path but don't mind links, use absolute_path. + * 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().) The return value is a pointer to a static + * buffer. + * + * The input and all intermediate paths must be shorter than MAX_PATH. + * 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). * * If path is our buffer, then return path, as it's already what the * user wants. */ -const char *real_path(const char *path) +static const char *real_path_internal(const char *path, int die_on_error) { static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1]; + char *retval = NULL; + + /* + * If we have to temporarily chdir(), store the original CWD + * here so that we can chdir() back to it at the end of the + * function: + */ char cwd[1024] = ""; + int buf_index = 1; int depth = MAXDEPTH; @@ -35,15 +53,26 @@ const char *real_path(const char *path) if (path == buf || path == next_buf) return path; - if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) - die ("Too long path: %.*s", 60, path); + if (!*path) { + if (die_on_error) + die("The empty string is not a valid path"); + else + goto error_out; + } + + if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) { + if (die_on_error) + die("Too long path: %.*s", 60, path); + else + goto error_out; + } while (depth--) { if (!is_directory(buf)) { char *last_slash = find_last_dir_sep(buf); if (last_slash) { - *last_slash = '\0'; last_elem = xstrdup(last_slash + 1); + last_slash[1] = '\0'; } else { last_elem = xstrdup(buf); *buf = '\0'; @@ -51,20 +80,36 @@ const char *real_path(const char *path) } if (*buf) { - if (!*cwd && !getcwd(cwd, sizeof(cwd))) - die_errno ("Could not get current working directory"); + if (!*cwd && !getcwd(cwd, sizeof(cwd))) { + if (die_on_error) + die_errno("Could not get current working directory"); + else + goto error_out; + } - if (chdir(buf)) - die_errno ("Could not switch to '%s'", buf); + if (chdir(buf)) { + if (die_on_error) + die_errno("Could not switch to '%s'", buf); + else + goto error_out; + } + } + if (!getcwd(buf, PATH_MAX)) { + if (die_on_error) + die_errno("Could not get current working directory"); + else + goto error_out; } - if (!getcwd(buf, PATH_MAX)) - die_errno ("Could not get current working directory"); if (last_elem) { size_t len = strlen(buf); - if (len + strlen(last_elem) + 2 > PATH_MAX) - die ("Too long path name: '%s/%s'", - buf, last_elem); + if (len + strlen(last_elem) + 2 > PATH_MAX) { + if (die_on_error) + die("Too long path name: '%s/%s'", + buf, last_elem); + else + goto error_out; + } if (len && !is_dir_sep(buf[len-1])) buf[len++] = '/'; strcpy(buf + len, last_elem); @@ -74,10 +119,18 @@ const char *real_path(const char *path) if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) { ssize_t len = readlink(buf, next_buf, PATH_MAX); - if (len < 0) - die_errno ("Invalid symlink '%s'", buf); - if (PATH_MAX <= len) - die("symbolic link too long: %s", buf); + if (len < 0) { + if (die_on_error) + die_errno("Invalid symlink '%s'", buf); + else + goto error_out; + } + if (PATH_MAX <= len) { + if (die_on_error) + die("symbolic link too long: %s", buf); + else + goto error_out; + } next_buf[len] = '\0'; buf = next_buf; buf_index = 1 - buf_index; @@ -86,10 +139,23 @@ const char *real_path(const char *path) break; } + retval = buf; +error_out: + free(last_elem); if (*cwd && chdir(cwd)) die_errno ("Could not change back to '%s'", cwd); - return buf; + return retval; +} + +const char *real_path(const char *path) +{ + return real_path_internal(path, 1); +} + +const char *real_path_if_valid(const char *path) +{ + return real_path_internal(path, 0); } static const char *get_pwd_cwd(void) @@ -123,7 +189,9 @@ const char *absolute_path(const char *path) { static char buf[PATH_MAX + 1]; - if (is_absolute_path(path)) { + if (!*path) { + die("The empty string is not a valid path"); + } else if (is_absolute_path(path)) { if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) die("Too long path: %.*s", 60, path); } else { |