diff options
Diffstat (limited to 'abspath.c')
| -rw-r--r-- | abspath.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/abspath.c b/abspath.c new file mode 100644 index 0000000000..ca33558a91 --- /dev/null +++ b/abspath.c @@ -0,0 +1,239 @@ +#include "cache.h" + +/* + * Do not use this for inspecting *tracked* content. When path is a + * symlink to a directory, we do not want to say it is a directory when + * dealing with tracked content in the working tree. + */ +int is_directory(const char *path) +{ + struct stat st; + return (!stat(path, &st) && S_ISDIR(st.st_mode)); +} + +/* We allow "recursive" symbolic links. Only within reason, though. */ +#define MAXDEPTH 5 + +/* + * 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; + + int depth = MAXDEPTH; + char *last_elem = NULL; + struct stat st; + + /* 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 = find_last_dir_sep(buf); + if (last_slash) { + last_elem = xstrdup(last_slash + 1); + last_slash[1] = '\0'; + } else { + last_elem = xstrdup(buf); + *buf = '\0'; + } + } + + if (*buf) { + 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)) { + 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 (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)) { + 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; + next_buf = bufs[buf_index]; + } else + break; + } + + retval = buf; +error_out: + free(last_elem); + if (*cwd && chdir(cwd)) + die_errno("Could not change back to '%s'", cwd); + + 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) +{ + static char cwd[PATH_MAX + 1]; + char *pwd; + struct stat cwd_stat, pwd_stat; + if (getcwd(cwd, PATH_MAX) == NULL) + return NULL; + pwd = getenv("PWD"); + if (pwd && strcmp(pwd, cwd)) { + stat(cwd, &cwd_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); + } + } + return cwd; +} + +/* + * 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 (!*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_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 struct strbuf path = STRBUF_INIT; +#ifndef GIT_WINDOWS_NATIVE + if (!pfx_len || is_absolute_path(arg)) + return arg; + strbuf_reset(&path); + strbuf_add(&path, pfx, pfx_len); + strbuf_addstr(&path, arg); +#else + char *p; + /* don't add prefix to absolute paths, but still replace '\' by '/' */ + strbuf_reset(&path); + if (is_absolute_path(arg)) + pfx_len = 0; + else if (pfx_len) + strbuf_add(&path, pfx, pfx_len); + strbuf_addstr(&path, arg); + for (p = path.buf + pfx_len; *p; p++) + if (*p == '\\') + *p = '/'; +#endif + return path.buf; +} |