From 0ee54dd4e2f0f834ffb0b0ae2bb89e5ae5296e36 Mon Sep 17 00:00:00 2001 From: Yu Watanabe Date: Sat, 1 May 2021 01:57:28 +0900 Subject: [PATCH] path-util: introduce path_find_first_component() The function may be useful to iterate on each path component. --- src/basic/path-util.c | 84 ++++++++++++++++++++++++++++++++++++++ src/basic/path-util.h | 1 + src/test/test-path-util.c | 85 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 170 insertions(+) diff --git a/src/basic/path-util.c b/src/basic/path-util.c index 08dace775dc..ed4fbcca235 100644 --- a/src/basic/path-util.c +++ b/src/basic/path-util.c @@ -808,6 +808,90 @@ char* dirname_malloc(const char *path) { return dir2; } +static const char *skip_slash_or_dot(const char *p) { + for (; !isempty(p); p++) { + if (*p == '/') + continue; + if (startswith(p, "./")) { + p++; + continue; + } + break; + } + return p; +} + +int path_find_first_component(const char **p, bool accept_dot_dot, const char **ret) { + const char *q, *first, *end_first, *next; + size_t len; + + assert(p); + + /* When a path is input, then returns the pointer to the first component and its length, and + * move the input pointer to the next component or nul. This skips both over any '/' + * immediately *before* and *after* the first component before returning. + * + * Examples + * Input: p: "//.//aaa///bbbbb/cc" + * Output: p: "bbbbb///cc" + * ret: "aaa///bbbbb/cc" + * return value: 3 (== strlen("aaa")) + * + * Input: p: "aaa//" + * Output: p: (pointer to NUL) + * ret: "aaa//" + * return value: 3 (== strlen("aaa")) + * + * Input: p: "/", ".", "" + * Output: p: (pointer to NUL) + * ret: NULL + * return value: 0 + * + * Input: p: NULL + * Output: p: NULL + * ret: NULL + * return value: 0 + * + * Input: p: "(too long component)" + * Output: return value: -EINVAL + * + * (when accept_dot_dot is false) + * Input: p: "//..//aaa///bbbbb/cc" + * Output: return value: -EINVAL + */ + + q = *p; + + first = skip_slash_or_dot(q); + if (isempty(first)) { + *p = first; + if (ret) + *ret = NULL; + return 0; + } + if (streq(first, ".")) { + *p = first + 1; + if (ret) + *ret = NULL; + return 0; + } + + end_first = strchrnul(first, '/'); + len = end_first - first; + + if (len > NAME_MAX) + return -EINVAL; + if (!accept_dot_dot && len == 2 && first[0] == '.' && first[1] == '.') + return -EINVAL; + + next = skip_slash_or_dot(end_first); + + *p = next + streq(next, "."); + if (ret) + *ret = first; + return len; +} + const char *last_path_component(const char *path) { /* Finds the last component of the path, preserving the optional trailing slash that signifies a directory. diff --git a/src/basic/path-util.h b/src/basic/path-util.h index 238a76ea733..d83a1effdae 100644 --- a/src/basic/path-util.h +++ b/src/basic/path-util.h @@ -149,6 +149,7 @@ int fsck_exists(const char *fstype); }) char* dirname_malloc(const char *path); +int path_find_first_component(const char **p, bool accept_dot_dot, const char **ret); const char *last_path_component(const char *path); int path_extract_filename(const char *p, char **ret); int path_extract_directory(const char *p, char **ret); diff --git a/src/test/test-path-util.c b/src/test/test-path-util.c index c93a21a4754..bb175145746 100644 --- a/src/test/test-path-util.c +++ b/src/test/test-path-util.c @@ -577,6 +577,90 @@ static void test_file_in_same_dir(void) { free(t); } +static void test_path_find_first_component_one( + const char *path, + bool accept_dot_dot, + char **expected, + int ret) { + + log_debug("/* %s(\"%s\", accept_dot_dot=%s) */", __func__, strnull(path), yes_no(accept_dot_dot)); + + for (const char *p = path;;) { + const char *e; + int r; + + r = path_find_first_component(&p, accept_dot_dot, &e); + if (r <= 0) { + if (r == 0) { + if (path) + assert_se(p == path + strlen_ptr(path)); + else + assert_se(!p); + assert_se(!e); + } + assert_se(r == ret); + assert_se(strv_isempty(expected)); + return; + } + + assert_se(e); + assert_se(strcspn(e, "/") == (size_t) r); + assert_se(strlen_ptr(*expected) == (size_t) r); + assert_se(strneq(e, *expected++, r)); + } +} + +static void test_path_find_first_component(void) { + _cleanup_free_ char *hoge = NULL; + char foo[NAME_MAX * 2]; + + log_info("/* %s */", __func__); + + test_path_find_first_component_one(NULL, false, NULL, 0); + test_path_find_first_component_one("", false, NULL, 0); + test_path_find_first_component_one("/", false, NULL, 0); + test_path_find_first_component_one(".", false, NULL, 0); + test_path_find_first_component_one("./", false, NULL, 0); + test_path_find_first_component_one("./.", false, NULL, 0); + test_path_find_first_component_one("..", false, NULL, -EINVAL); + test_path_find_first_component_one("/..", false, NULL, -EINVAL); + test_path_find_first_component_one("./..", false, NULL, -EINVAL); + test_path_find_first_component_one("////./././//.", false, NULL, 0); + test_path_find_first_component_one("a/b/c", false, STRV_MAKE("a", "b", "c"), 0); + test_path_find_first_component_one("././//.///aa/bbb//./ccc", false, STRV_MAKE("aa", "bbb", "ccc"), 0); + test_path_find_first_component_one("././//.///aa/.../../bbb//./ccc/.", false, STRV_MAKE("aa", "..."), -EINVAL); + test_path_find_first_component_one("//./aaa///.//./.bbb/..///c.//d.dd///..eeee/.", false, STRV_MAKE("aaa", ".bbb"), -EINVAL); + test_path_find_first_component_one("a/foo./b", false, STRV_MAKE("a", "foo.", "b"), 0); + + test_path_find_first_component_one(NULL, true, NULL, 0); + test_path_find_first_component_one("", true, NULL, 0); + test_path_find_first_component_one("/", true, NULL, 0); + test_path_find_first_component_one(".", true, NULL, 0); + test_path_find_first_component_one("./", true, NULL, 0); + test_path_find_first_component_one("./.", true, NULL, 0); + test_path_find_first_component_one("..", true, STRV_MAKE(".."), 0); + test_path_find_first_component_one("/..", true, STRV_MAKE(".."), 0); + test_path_find_first_component_one("./..", true, STRV_MAKE(".."), 0); + test_path_find_first_component_one("////./././//.", true, NULL, 0); + test_path_find_first_component_one("a/b/c", true, STRV_MAKE("a", "b", "c"), 0); + test_path_find_first_component_one("././//.///aa/bbb//./ccc", true, STRV_MAKE("aa", "bbb", "ccc"), 0); + test_path_find_first_component_one("././//.///aa/.../../bbb//./ccc/.", true, STRV_MAKE("aa", "...", "..", "bbb", "ccc"), 0); + test_path_find_first_component_one("//./aaa///.//./.bbb/..///c.//d.dd///..eeee/.", true, STRV_MAKE("aaa", ".bbb", "..", "c.", "d.dd", "..eeee"), 0); + test_path_find_first_component_one("a/foo./b", true, STRV_MAKE("a", "foo.", "b"), 0); + + memset(foo, 'a', sizeof(foo) -1); + char_array_0(foo); + + test_path_find_first_component_one(foo, false, NULL, -EINVAL); + test_path_find_first_component_one(foo, true, NULL, -EINVAL); + + hoge = strjoin("a/b/c/", foo, "//d/e/.//f/"); + assert_se(hoge); + + test_path_find_first_component_one(hoge, false, STRV_MAKE("a", "b", "c"), -EINVAL); + test_path_find_first_component_one(hoge, true, STRV_MAKE("a", "b", "c"), -EINVAL); +} + static void test_last_path_component(void) { assert_se(last_path_component(NULL) == NULL); assert_se(streq(last_path_component("a/b/c"), "c")); @@ -894,6 +978,7 @@ int main(int argc, char **argv) { test_path_startswith(); test_prefix_root(); test_file_in_same_dir(); + test_path_find_first_component(); test_last_path_component(); test_path_extract_filename(); test_path_extract_directory(); -- 2.47.3