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-rw-r--r--lib/libc/stdlib/realpath.312
-rw-r--r--lib/libc/stdlib/realpath.c14
-rw-r--r--lib/libc/tests/gen/realpath2_test.c106
3 files changed, 112 insertions, 20 deletions
diff --git a/lib/libc/stdlib/realpath.3 b/lib/libc/stdlib/realpath.3
index 065ba312c2ef..76f40249963b 100644
--- a/lib/libc/stdlib/realpath.3
+++ b/lib/libc/stdlib/realpath.3
@@ -28,7 +28,7 @@
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
-.Dd May 11, 2012
+.Dd October 10, 2025
.Dt REALPATH 3
.Os
.Sh NAME
@@ -108,11 +108,11 @@ and
.Xr getcwd 3 .
.Sh SEE ALSO
.Xr getcwd 3
-.\" .Sh STANDARDS
-.\" The
-.\" .Fn realpath
-.\" function conforms to
-.\" .St -p1003.1-2001 .
+.Sh STANDARDS
+The
+.Fn realpath
+function conforms to
+.St -p1003.1-2001 .
.Sh HISTORY
The
.Fn realpath
diff --git a/lib/libc/stdlib/realpath.c b/lib/libc/stdlib/realpath.c
index 4c52b73319ab..18f29e95ee6b 100644
--- a/lib/libc/stdlib/realpath.c
+++ b/lib/libc/stdlib/realpath.c
@@ -49,7 +49,7 @@ realpath1(const char *path, char *resolved)
{
struct stat sb;
char *p, *q;
- size_t left_len, resolved_len, next_token_len;
+ size_t left_len, prev_len, resolved_len, next_token_len;
unsigned symlinks;
ssize_t slen;
char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
@@ -98,6 +98,7 @@ realpath1(const char *path, char *resolved)
left_len = 0;
}
+ prev_len = resolved_len;
if (resolved[resolved_len - 1] != '/') {
if (resolved_len + 1 >= PATH_MAX) {
errno = ENAMETOOLONG;
@@ -133,8 +134,17 @@ realpath1(const char *path, char *resolved)
errno = ENAMETOOLONG;
return (NULL);
}
- if (lstat(resolved, &sb) != 0)
+ if (lstat(resolved, &sb) != 0) {
+ /*
+ * EACCES means the parent directory is not
+ * readable, while ENOTDIR means the parent
+ * directory is not a directory. Rewind the path
+ * to correctly indicate where the error lies.
+ */
+ if (errno == EACCES || errno == ENOTDIR)
+ resolved[prev_len] = '\0';
return (NULL);
+ }
if (S_ISLNK(sb.st_mode)) {
if (symlinks++ > MAXSYMLINKS) {
errno = ELOOP;
diff --git a/lib/libc/tests/gen/realpath2_test.c b/lib/libc/tests/gen/realpath2_test.c
index f89dd99cbb72..431df8721ae0 100644
--- a/lib/libc/tests/gen/realpath2_test.c
+++ b/lib/libc/tests/gen/realpath2_test.c
@@ -1,6 +1,7 @@
/*
* Copyright (c) 2017 Jan Kokemüller
* All rights reserved.
+ * Copyright (c) 2025 Klara, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -25,6 +26,8 @@
*/
#include <sys/param.h>
+#include <sys/stat.h>
+
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
@@ -34,6 +37,31 @@
#include <atf-c.h>
+ATF_TC(realpath_null);
+ATF_TC_HEAD(realpath_null, tc)
+{
+ atf_tc_set_md_var(tc, "descr", "Test null input");
+}
+ATF_TC_BODY(realpath_null, tc)
+{
+ ATF_REQUIRE_ERRNO(EINVAL, realpath(NULL, NULL) == NULL);
+}
+
+ATF_TC(realpath_empty);
+ATF_TC_HEAD(realpath_empty, tc)
+{
+ atf_tc_set_md_var(tc, "descr", "Test empty input");
+}
+ATF_TC_BODY(realpath_empty, tc)
+{
+ char resb[PATH_MAX] = "";
+
+ ATF_REQUIRE_EQ(0, mkdir("foo", 0755));
+ ATF_REQUIRE_EQ(0, chdir("foo"));
+ ATF_REQUIRE_ERRNO(ENOENT, realpath("", resb) == NULL);
+ ATF_REQUIRE_STREQ("", resb);
+}
+
ATF_TC(realpath_buffer_overflow);
ATF_TC_HEAD(realpath_buffer_overflow, tc)
{
@@ -44,16 +72,11 @@ ATF_TC_HEAD(realpath_buffer_overflow, tc)
ATF_TC_BODY(realpath_buffer_overflow, tc)
{
- char path[MAXPATHLEN] = { 0 };
- char resb[MAXPATHLEN] = { 0 };
- size_t i;
+ char path[PATH_MAX] = "";
+ char resb[PATH_MAX] = "";
- path[0] = 'a';
+ memset(path, 'a', sizeof(path) - 1);
path[1] = '/';
- for (i = 2; i < sizeof(path) - 1; ++i) {
- path[i] = 'a';
- }
-
ATF_REQUIRE(realpath(path, resb) == NULL);
}
@@ -66,9 +89,9 @@ ATF_TC_HEAD(realpath_empty_symlink, tc)
ATF_TC_BODY(realpath_empty_symlink, tc)
{
- char path[MAXPATHLEN] = { 0 };
- char slnk[MAXPATHLEN] = { 0 };
- char resb[MAXPATHLEN] = { 0 };
+ char path[PATH_MAX] = "";
+ char slnk[PATH_MAX] = "";
+ char resb[PATH_MAX] = "";
int fd;
(void)strlcat(slnk, "empty_symlink", sizeof(slnk));
@@ -89,11 +112,70 @@ ATF_TC_BODY(realpath_empty_symlink, tc)
ATF_REQUIRE(unlink(slnk) == 0);
}
-ATF_TP_ADD_TCS(tp)
+ATF_TC(realpath_partial);
+ATF_TC_HEAD(realpath_partial, tc)
+{
+ atf_tc_set_md_var(tc, "descr",
+ "Test that failure leaves a partial result");
+ atf_tc_set_md_var(tc, "require.user", "unprivileged");
+}
+
+ATF_TC_BODY(realpath_partial, tc)
{
+ char resb[PATH_MAX] = "";
+ size_t len;
+
+ /* scenario 1: missing directory */
+ ATF_REQUIRE_EQ(0, mkdir("foo", 0755));
+ ATF_REQUIRE_ERRNO(ENOENT, realpath("foo/bar/baz", resb) == NULL);
+ len = strnlen(resb, sizeof(resb));
+ ATF_REQUIRE(len > 8 && len < sizeof(resb));
+ ATF_REQUIRE_STREQ("/foo/bar", resb + len - 8);
+
+ /* scenario 2: dead link 1 */
+ ATF_REQUIRE_EQ(0, symlink("nix", "foo/bar"));
+ ATF_REQUIRE_ERRNO(ENOENT, realpath("foo/bar/baz", resb) == NULL);
+ len = strnlen(resb, sizeof(resb));
+ ATF_REQUIRE(len > 8 && len < sizeof(resb));
+ ATF_REQUIRE_STREQ("/foo/nix", resb + len - 8);
+
+ /* scenario 3: missing file */
+ ATF_REQUIRE_EQ(0, unlink("foo/bar"));
+ ATF_REQUIRE_EQ(0, mkdir("foo/bar", 0755));
+ ATF_REQUIRE_ERRNO(ENOENT, realpath("foo/bar/baz", resb) == NULL);
+ len = strnlen(resb, sizeof(resb));
+ ATF_REQUIRE(len > 12 && len < sizeof(resb));
+ ATF_REQUIRE_STREQ("/foo/bar/baz", resb + len - 12);
+
+ /* scenario 4: dead link 2 */
+ ATF_REQUIRE_EQ(0, symlink("nix", "foo/bar/baz"));
+ ATF_REQUIRE_ERRNO(ENOENT, realpath("foo/bar/baz", resb) == NULL);
+ len = strnlen(resb, sizeof(resb));
+ ATF_REQUIRE(len > 12 && len < sizeof(resb));
+ ATF_REQUIRE_STREQ("/foo/bar/nix", resb + len - 12);
+
+ /* scenario 5: unreadable directory */
+ ATF_REQUIRE_EQ(0, chmod("foo", 000));
+ ATF_REQUIRE_ERRNO(EACCES, realpath("foo/bar/baz", resb) == NULL);
+ len = strnlen(resb, sizeof(resb));
+ ATF_REQUIRE(len > 4 && len < sizeof(resb));
+ ATF_REQUIRE_STREQ("/foo", resb + len - 4);
+
+ /* scenario 6: not a directory */
+ ATF_REQUIRE_EQ(0, close(creat("bar", 0644)));
+ ATF_REQUIRE_ERRNO(ENOTDIR, realpath("bar/baz", resb) == NULL);
+ len = strnlen(resb, sizeof(resb));
+ ATF_REQUIRE(len > 4 && len < sizeof(resb));
+ ATF_REQUIRE_STREQ("/bar", resb + len - 4);
+}
+ATF_TP_ADD_TCS(tp)
+{
+ ATF_TP_ADD_TC(tp, realpath_null);
+ ATF_TP_ADD_TC(tp, realpath_empty);
ATF_TP_ADD_TC(tp, realpath_buffer_overflow);
ATF_TP_ADD_TC(tp, realpath_empty_symlink);
+ ATF_TP_ADD_TC(tp, realpath_partial);
return atf_no_error();
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-14 11:39:33 +0000