libc: expose execvpe for Linux compat

We already implemented execvpe internally with an _ prefix in libc so
go ahead and expose it for compatibility with Linux.

This reverts c605eea952.

Bump __FreeBSD_version for the addition and add definitions to supress
compat shims in libzfs (zfs changes were merged from upstream).

PR:		275370 (request and exp-run (thanks antoine!))
Reviewed by:	kevans
Differential Revision:	https://reviews.freebsd.org/D42846

cddl/lib/libzfs/Makefile

@@ -99,6 +99,7 @@ CFLAGS+= -I${SRCTOP}/cddl/compat/opensolaris/include
 CFLAGS+= -I${SRCTOP}/sys/contrib/openzfs/module/icp/include
 CFLAGS+= -include ${SRCTOP}/sys/contrib/openzfs/include/os/freebsd/spl/sys/ccompile.h
 CFLAGS+= -DHAVE_ISSETUGID
+CFLAGS+= -DHAVE_EXECVPE
 CFLAGS+= -include ${SRCTOP}/sys/modules/zfs/zfs_config.h
 CFLAGS+= -DSYSCONFDIR=\"/etc\"
 CFLAGS+= -DPKGDATADIR=\"/usr/share/zfs\"

cddl/usr.sbin/zfsd/Makefile.common

@@ -22,8 +22,8 @@ CFLAGS+= -I${SRCTOP}/sys
 CFLAGS+= -include ${SRCTOP}/sys/contrib/openzfs/include/os/freebsd/spl/sys/ccompile.h
 CFLAGS+= -I${SRCTOP}/cddl/usr.sbin
 
-# use issetugid(2)
 CFLAGS+= -DHAVE_ISSETUGID
+CFLAGS+= -DHAVE_EXECVPE
 
 LIBADD+=	devdctl zfs util geom bsdxml sbuf nvpair avl uutil zutil
 

include/unistd.h

@@ -501,6 +501,7 @@ int	 eaccess(const char *, int);
 void	 endusershell(void);
 int	 exect(const char *, char * const *, char * const *);
 int	 execvP(const char *, const char *, char * const *);
+int	 execvpe(const char *, char * const *, char * const *);
 int	 feature_present(const char *);
 char	*fflagstostr(u_long);
 int	 getdomainname(char *, int);

lib/libc/gen/Symbol.map

@@ -457,6 +457,10 @@ FBSD_1.7 {
 	 __cpuset_free;
 };
 
+FBSD_1.8 {
+	execvpe;
+};
+
 FBSDprivate_1.0 {
 	/* needed by thread libraries */
 	__thr_jtable;

lib/libc/gen/exec.3

@@ -25,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd March 22, 2020
+.Dd December 11, 2023
 .Dt EXEC 3
 .Os
 .Sh NAME
@@ -35,6 +35,7 @@
 .Nm exect ,
 .Nm execv ,
 .Nm execvp ,
+.Nm execvpe ,
 .Nm execvP
 .Nd execute a file
 .Sh LIBRARY
@@ -56,6 +57,8 @@
 .Ft int
 .Fn execvp "const char *file" "char *const argv[]"
 .Ft int
+.Fn execvpe "const char *file" "char *const argv[]" "char *const envp[]"
+.Ft int
 .Fn execvP "const char *file" "const char *search_path" "char *const argv[]"
 .Sh DESCRIPTION
 The
@@ -97,6 +100,7 @@ The
 .Fn exect ,
 .Fn execv ,
 .Fn execvp ,
+.Fn execvpe ,
 and
 .Fn execvP
 functions provide an array of pointers to null-terminated strings that
@@ -110,9 +114,10 @@ be terminated by a
 pointer.
 .Pp
 The
-.Fn execle
+.Fn execle ,
+.Fn exect ,
 and
-.Fn exect
+.Fn execvpe
 functions also specify the environment of the executed process by following
 the
 .Dv NULL
@@ -134,6 +139,7 @@ Some of these functions have special semantics.
 The functions
 .Fn execlp ,
 .Fn execvp ,
+.Fn execvpe ,
 and
 .Fn execvP
 will duplicate the actions of the shell in searching for an executable file
@@ -144,6 +150,7 @@ For
 .Fn execlp
 and
 .Fn execvp ,
+.Fn execvpe ,
 search path is the path specified in the environment by
 .Dq Ev PATH
 variable.
@@ -269,7 +276,8 @@ The
 .Fn execl ,
 .Fn execle ,
 .Fn execlp ,
-.Fn execvp
+.Fn execvp ,
+.Fn execvpe ,
 and
 .Fn execvP
 functions
@@ -307,6 +315,9 @@ and
 functions
 conform to
 .St -p1003.1-88 .
+The
+.Fn execvpe
+function is a GNU extension.
 .Sh HISTORY
 The
 .Fn exec
@@ -330,6 +341,10 @@ The
 .Fn execvP
 function first appeared in
 .Fx 5.2 .
+The
+.Fn execvpe
+function first appeared in
+.Fx 15.0 .
 .Sh BUGS
 The type of the
 .Fa argv
@@ -340,6 +355,7 @@ parameters to
 .Fn exect ,
 .Fn execv ,
 .Fn execvp ,
+.Fn execvpe ,
 and
 .Fn execvP
 is a historical accident and no sane implementation should modify the provided

lib/libc/gen/exec.c

@@ -136,7 +136,7 @@ execv(const char *name, char * const *argv)
 int
 execvp(const char *name, char * const *argv)
 {
-	return (_execvpe(name, argv, environ));
+	return (execvpe(name, argv, environ));
 }
 
 static int
@@ -288,7 +288,7 @@ execvP(const char *name, const char *path, char * const argv[])
 }
 
 int
-_execvpe(const char *name, char * const argv[], char * const envp[])
+execvpe(const char *name, char * const argv[], char * const envp[])
 {
 	const char *path;
 

lib/libc/gen/posix_spawn.c

@@ -226,7 +226,7 @@ struct posix_spawn_args {
 #if defined(__i386__) || defined(__amd64__)
 /*
  * Below we'll assume that _RFORK_THREAD_STACK_SIZE is appropriately aligned for
- * the posix_spawn() case where we do not end up calling _execvpe and won't ever
+ * the posix_spawn() case where we do not end up calling execvpe and won't ever
  * try to allocate space on the stack for argv[].
  */
 #define	_RFORK_THREAD_STACK_SIZE	4096
@@ -253,7 +253,7 @@ _posix_spawn_thr(void *data)
 	}
 	envp = psa->envp != NULL ? psa->envp : environ;
 	if (psa->use_env_path)
-		_execvpe(psa->path, psa->argv, envp);
+		execvpe(psa->path, psa->argv, envp);
 	else
 		_execve(psa->path, psa->argv, envp);
 	psa->error = errno;

lib/libc/include/libc_private.h

@@ -422,9 +422,6 @@ int		__sys_futimens(int fd, const struct timespec *times) __hidden;
 int		__sys_utimensat(int fd, const char *path,
 		    const struct timespec *times, int flag) __hidden;
 
-/* execve() with PATH processing to implement posix_spawnp() */
-int _execvpe(const char *, char * const *, char * const *);
-
 int _elf_aux_info(int aux, void *buf, int buflen);
 struct dl_phdr_info;
 int __elf_phdr_match_addr(struct dl_phdr_info *, void *);

sys/sys/param.h

@@ -73,7 +73,7 @@
  * cannot include sys/param.h and should only be updated here.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1500006
+#define __FreeBSD_version 1500007
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,