From 0fbc34f028e9eb7705e1f4ee1591ecd6d05160e8 Mon Sep 17 00:00:00 2001 From: Daniel Palmer Date: Thu, 2 Jul 2026 17:50:59 +0900 Subject: [PATCH] tools/nolibc: unistd: Add getcwd() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add getcwd() for getting the current working directory. The behaviour matches what musl is doing except for one important difference: If the passed buf is NULL musl (and glibc) uses a big buffer on the stack and that is then strdup()'d and returned. According to the man page for getcwd() this is a glibc extension and I don't think we need it in nolibc. Signed-off-by: Daniel Palmer Acked-by: Willy Tarreau Link: https://patch.msgid.link/20260702085101.3304547-2-daniel@thingy.jp Signed-off-by: Thomas Weißschuh --- tools/include/nolibc/unistd.h | 42 +++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/tools/include/nolibc/unistd.h b/tools/include/nolibc/unistd.h index 79599ceef45d..2e0edbc26315 100644 --- a/tools/include/nolibc/unistd.h +++ b/tools/include/nolibc/unistd.h @@ -73,6 +73,48 @@ int ftruncate(int fd, off_t length) return __sysret(_sys_ftruncate(fd, length)); } +/* + * char *getcwd(char *buf, size_t size); + */ + +static __attribute__((unused)) +int _sys_getcwd(char *buf, size_t size) +{ + return __nolibc_syscall2(__NR_getcwd, buf, size); +} + +static __attribute__((unused)) +char *getcwd(char *buf, size_t size) +{ + int ret; + + /* Unlike other libc's we don't handle passing NULL for buf */ + if (!buf || !size) { + SET_ERRNO(EINVAL); + return NULL; + } + + ret = __sysret(_sys_getcwd(buf, size)); + + /* On error return NULL, __sysret() above will have set errno */ + if (ret < 0) + return NULL; + + /* Handle no path being written or the kernel putting + * "(unreachable)" into the buffer instead of a path. + * This matches what musl is doing. + */ + if (ret == 0 || buf[0] != '/') { + SET_ERRNO(ENOENT); + return NULL; + } + + /* ret must be the number of bytes written at this point, + * so return the pointer to buf. + */ + return buf; +} + static __attribute__((unused)) int msleep(unsigned int msecs) {