lib: remove openat fallback functions (include/at.h)

I have validated that we are still compatible at least back to
  - openSUSE 11.4
  - SLE 11
  - RHEL/CentOS 6
  - OSX 10.10.x, (Xcode 6.3)
  - FreeBSD 10.2

Confirmed incompatibility:
  - OSX 10.9.x, (Xcode 6.2)

Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>

5 files changed, 14 insertions, 138 deletions

diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index 94e845349..25e1ba04e 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -52,7 +52,6 @@ dist_man_MANS += lib/terminal-colors.d.5
 
 
 check_PROGRAMS += \
-	test_at \
 	test_blkdev \
 	test_canonicalize \
 	test_colors \
@@ -91,9 +90,6 @@ test_ismounted_LDADD = $(LDADD) libcommon.la
 test_mangle_SOURCES = lib/mangle.c
 test_mangle_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM
 
-test_at_SOURCES = lib/at.c
-test_at_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM_AT
-
 test_strutils_SOURCES = lib/strutils.c
 test_strutils_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM
 
diff --git a/lib/at.c b/lib/at.c
index 4086a2541..e32a8f5d3 100644
--- a/lib/at.c
+++ b/lib/at.c
@@ -7,138 +7,18 @@
  * Written by Karel Zak <kzak@redhat.com>
  */
 #include <stdio.h>
-#include <stdlib.h>
 #include <fcntl.h>
-#include <sys/stat.h>
 
 #include "at.h"
 #include "c.h"
 
-#ifdef HAVE_FSTATAT
-int fstat_at(int dir, const char *dirname __attribute__ ((__unused__)),
-	     const char *filename, struct stat *st, int nofollow)
-{
-	return fstatat(dir, filename, st,
-			nofollow ? AT_SYMLINK_NOFOLLOW : 0);
-}
-#else
-int fstat_at(int dir __attribute__ ((__unused__)), const char *dirname,
-	     const char *filename, struct stat *st, int nofollow)
-{
-
-	if (*filename != '/') {
-		char path[PATH_MAX];
-		int len;
-
-		len = snprintf(path, sizeof(path), "%s/%s", dirname, filename);
-		if (len < 0 || (size_t)len >= sizeof(path))
-			return -1;
-
-		return nofollow ? lstat(path, st) : stat(path, st);
-	}
-
-	return nofollow ? lstat(filename, st) : stat(filename, st);
-}
-#endif
-
-#ifdef HAVE_FSTATAT
-int open_at(int dir, const char *dirname __attribute__ ((__unused__)),
-	    const char *filename, int flags)
-{
-	return openat(dir, filename, flags);
-}
-#else
-int open_at(int dir __attribute__((__unused__)), const char *dirname,
-	    const char *filename, int flags)
-{
-	if (*filename != '/') {
-		char path[PATH_MAX];
-		int len;
-
-		len = snprintf(path, sizeof(path), "%s/%s", dirname, filename);
-		if (len < 0 || (size_t)len >= sizeof(path))
-			return -1;
-
-		return open(path, flags);
-	}
-	return open(filename, flags);
-}
-#endif
-
-FILE *fopen_at(int dir, const char *dirname, const char *filename, int flags,
+FILE *fopen_at(int dir, const char *filename, int flags,
 			const char *mode)
 {
-	int fd = open_at(dir, dirname, filename, flags);
+	int fd = openat(dir, filename, flags);
 
 	if (fd < 0)
 		return NULL;
 
 	return fdopen(fd, mode);
 }
-
-#ifdef HAVE_FSTATAT
-ssize_t readlink_at(int dir, const char *dirname __attribute__ ((__unused__)),
-		    const char *pathname, char *buf, size_t bufsiz)
-{
-	return readlinkat(dir, pathname, buf, bufsiz);
-}
-#else
-ssize_t readlink_at(int dir __attribute__((__unused__)), const char *dirname,
-		    const char *pathname, char *buf, size_t bufsiz)
-{
-	if (*pathname != '/') {
-		char path[PATH_MAX];
-		int len;
-
-		len = snprintf(path, sizeof(path), "%s/%s", dirname, pathname);
-		if (len < 0 || (size_t)len >= sizeof(path))
-			return -1;
-
-		return readlink(path, buf, bufsiz);
-	}
-	return readlink(pathname, buf, bufsiz);
-}
-#endif
-
-#ifdef TEST_PROGRAM_AT
-#include <errno.h>
-#include <sys/types.h>
-#include <dirent.h>
-#include <string.h>
-
-int main(int argc, char *argv[])
-{
-	DIR *dir;
-	struct dirent *d;
-	char *dirname;
-
-	if (argc != 2) {
-		fprintf(stderr, "usage: %s <directory>\n", argv[0]);
-		exit(EXIT_FAILURE);
-	}
-	dirname = argv[1];
-
-	dir = opendir(dirname);
-	if (!dir)
-		err(EXIT_FAILURE, "cannot open %s", dirname);
-
-	while ((d = readdir(dir))) {
-		struct stat st;
-		FILE *f;
-
-		printf("%32s ", d->d_name);
-
-		if (fstat_at(dirfd(dir), dirname, d->d_name, &st, 0) == 0)
-			printf("%16zd bytes ", st.st_size);
-		else
-			printf("%16s bytes ", "???");
-
-		f = fopen_at(dirfd(dir), dirname, d->d_name, O_RDONLY, "r");
-		printf("   %s\n", f ? "OK" : strerror(errno));
-		if (f)
-			fclose(f);
-	}
-	closedir(dir);
-	return EXIT_SUCCESS;
-}
-#endif
diff --git a/lib/loopdev.c b/lib/loopdev.c
index 5f3c3a246..b2c8b987b 100644
--- a/lib/loopdev.c
+++ b/lib/loopdev.c
@@ -40,7 +40,6 @@
 #include "pathnames.h"
 #include "loopdev.h"
 #include "canonicalize.h"
-#include "at.h"
 #include "blkdev.h"
 #include "debug.h"
 
@@ -546,7 +545,7 @@ static int loopcxt_next_from_sysfs(struct loopdev_cxt *lc)
 			continue;
 
 		snprintf(name, sizeof(name), "%s/loop/backing_file", d->d_name);
-		if (fstat_at(fd, _PATH_SYS_BLOCK, name, &st, 0) != 0)
+		if (fstatat(fd, name, &st, 0) != 0)
 			continue;
 
 		if (loopiter_set_device(lc, d->d_name) == 0)
diff --git a/lib/procutils.c b/lib/procutils.c
index 2e9a0537a..6f016345a 100644
--- a/lib/procutils.c
+++ b/lib/procutils.c
@@ -18,6 +18,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <sys/stat.h>
 #include <sys/types.h>
 #include <dirent.h>
 #include <ctype.h>
@@ -199,7 +200,7 @@ int proc_next_pid(struct proc_processes *ps, pid_t *pid)
 		if (ps->has_fltr_uid) {
 			struct stat st;
 
-			if (fstat_at(dirfd(ps->dir), "/proc", d->d_name, &st, 0))
+			if (fstatat(dirfd(ps->dir), d->d_name, &st, 0))
 				continue;
 			if (ps->fltr_uid != st.st_uid)
 				continue;
@@ -211,8 +212,7 @@ int proc_next_pid(struct proc_processes *ps, pid_t *pid)
 			FILE *f;
 
 			snprintf(buf, sizeof(buf), "%s/stat", d->d_name);
-			f = fopen_at(dirfd(ps->dir), "/proc", buf,
-						O_CLOEXEC|O_RDONLY, "r");
+			f = fopen_at(dirfd(ps->dir), buf, O_CLOEXEC|O_RDONLY, "r");
 			if (!f)
 				continue;
 
diff --git a/lib/sysfs.c b/lib/sysfs.c
index b6e0b7230..9e973a4f7 100644
--- a/lib/sysfs.c
+++ b/lib/sysfs.c
@@ -6,9 +6,11 @@
  */
 #include <ctype.h>
 #include <libgen.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
 
 #include "c.h"
-#include "at.h"
 #include "pathnames.h"
 #include "sysfs.h"
 #include "fileutils.h"
@@ -203,7 +205,7 @@ void sysfs_deinit(struct sysfs_cxt *cxt)
 
 int sysfs_stat(struct sysfs_cxt *cxt, const char *attr, struct stat *st)
 {
-	int rc = fstat_at(cxt->dir_fd, cxt->dir_path, attr, st, 0);
+	int rc = fstatat(cxt->dir_fd, attr, st, 0);
 
 	if (rc != 0 && errno == ENOENT &&
 	    strncmp(attr, "queue/", 6) == 0 && cxt->parent) {
@@ -211,8 +213,7 @@ int sysfs_stat(struct sysfs_cxt *cxt, const char *attr, struct stat *st)
 		/* Exception for "queue/<attr>". These attributes are available
 		 * for parental devices only
 		 */
-		return fstat_at(cxt->parent->dir_fd,
-				cxt->parent->dir_path, attr, st, 0);
+		return fstatat(cxt->parent->dir_fd, attr, st, 0);
 	}
 	return rc;
 }
@@ -226,7 +227,7 @@ int sysfs_has_attribute(struct sysfs_cxt *cxt, const char *attr)
 
 static int sysfs_open(struct sysfs_cxt *cxt, const char *attr, int flags)
 {
-	int fd = open_at(cxt->dir_fd, cxt->dir_path, attr, flags);
+	int fd = openat(cxt->dir_fd, attr, flags);
 
 	if (fd == -1 && errno == ENOENT &&
 	    strncmp(attr, "queue/", 6) == 0 && cxt->parent) {
@@ -234,7 +235,7 @@ static int sysfs_open(struct sysfs_cxt *cxt, const char *attr, int flags)
 		/* Exception for "queue/<attr>". These attributes are available
 		 * for parental devices only
 		 */
-		fd = open_at(cxt->parent->dir_fd, cxt->dir_path, attr, flags);
+		fd = openat(cxt->parent->dir_fd, attr, flags);
 	}
 	return fd;
 }
@@ -246,7 +247,7 @@ ssize_t sysfs_readlink(struct sysfs_cxt *cxt, const char *attr,
 		return -1;
 
 	if (attr)
-		return readlink_at(cxt->dir_fd, cxt->dir_path, attr, buf, bufsiz);
+		return readlinkat(cxt->dir_fd, attr, buf, bufsiz);
 
 	/* read /sys/dev/block/<maj:min> link */
 	return readlink(cxt->dir_path, buf, bufsiz);