diff options
Diffstat (limited to 'abspath.c')
| -rw-r--r-- | abspath.c | 180 |
1 files changed, 150 insertions, 30 deletions
@@ -14,25 +14,65 @@ int is_directory(const char *path) /* We allow "recursive" symbolic links. Only within reason, though. */ #define MAXDEPTH 5 -const char *make_absolute_path(const char *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. + */ +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, len; + + int buf_index = 1; int depth = MAXDEPTH; char *last_elem = NULL; struct stat st; - if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX) - die ("Too long path: %.*s", 60, path); + /* We've already done it */ + if (path == buf || path == next_buf) + return 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 = strrchr(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'; @@ -40,32 +80,57 @@ const char *make_absolute_path(const char *path) } if (*buf) { - if (!*cwd && !getcwd(cwd, sizeof(cwd))) - die ("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 ("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 ("Could not get current working directory"); if (last_elem) { - int len = strlen(buf); - if (len + strlen(last_elem) + 2 > PATH_MAX) - die ("Too long path name: '%s/%s'", - buf, last_elem); - buf[len] = '/'; - strcpy(buf + len + 1, last_elem); + size_t len = strlen(buf); + 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); free(last_elem); last_elem = NULL; } if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) { - len = readlink(buf, next_buf, PATH_MAX); - if (len < 0) - die ("Invalid symlink: %s", buf); - if (PATH_MAX <= len) - die("symbolic link too long: %s", buf); + ssize_t len = readlink(buf, next_buf, PATH_MAX); + 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; @@ -74,10 +139,23 @@ const char *make_absolute_path(const char *path) break; } + retval = buf; +error_out: + free(last_elem); if (*cwd && chdir(cwd)) - die ("Could not change back to '%s'", 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) @@ -90,7 +168,8 @@ static const char *get_pwd_cwd(void) pwd = getenv("PWD"); if (pwd && strcmp(pwd, cwd)) { stat(cwd, &cwd_stat); - if (!stat(pwd, &pwd_stat) && + if ((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) { strlcpy(cwd, pwd, PATH_MAX); @@ -99,19 +178,60 @@ static const char *get_pwd_cwd(void) return cwd; } -const char *make_nonrelative_path(const char *path) +/* + * Use this to get an absolute path from a relative one. If you want + * to resolve links, you should use real_path. + * + * If the path is already absolute, then return path. As the user is + * never meant to free the return value, we're safe. + */ +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 { + size_t len; + const char *fmt; const char *cwd = get_pwd_cwd(); if (!cwd) - die("Cannot determine the current working directory"); - if (snprintf(buf, PATH_MAX, "%s/%s", cwd, path) >= PATH_MAX) + die_errno("Cannot determine the current working directory"); + len = strlen(cwd); + fmt = (len > 0 && is_dir_sep(cwd[len-1])) ? "%s%s" : "%s/%s"; + if (snprintf(buf, PATH_MAX, fmt, cwd, path) >= PATH_MAX) die("Too long path: %.*s", 60, path); } return buf; } + +/* + * Unlike prefix_path, this should be used if the named file does + * not have to interact with index entry; i.e. name of a random file + * on the filesystem. + */ +const char *prefix_filename(const char *pfx, int pfx_len, const char *arg) +{ + static char path[PATH_MAX]; +#ifndef WIN32 + if (!pfx_len || is_absolute_path(arg)) + return arg; + memcpy(path, pfx, pfx_len); + strcpy(path + pfx_len, arg); +#else + char *p; + /* don't add prefix to absolute paths, but still replace '\' by '/' */ + if (is_absolute_path(arg)) + pfx_len = 0; + else if (pfx_len) + memcpy(path, pfx, pfx_len); + strcpy(path + pfx_len, arg); + for (p = path + pfx_len; *p; p++) + if (*p == '\\') + *p = '/'; +#endif + return path; +} |