Use access() instead of stat() when possible

We were using the stat() system call in quite a few places when we didn't
actually need anything the stat struct returned- we were simply checking for
file existence. access() will be more efficient in those cases.

Before (strace pacman -Ss pacman):
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 33.16    0.005987           0     19016           stat64

After:
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 34.85    0.003863           0     12633         1 access
  7.95    0.000881           0      6391         7 stat64

Signed-off-by: Dan McGee <dan@archlinux.org>

3 files changed, 10 insertions, 15 deletions

diff --git a/lib/libalpm/be_files.c b/lib/libalpm/be_files.c
index 12c60b24..f5d4e826 100644
--- a/lib/libalpm/be_files.c
+++ b/lib/libalpm/be_files.c
@@ -355,7 +355,6 @@ static char *get_pkgpath(pmdb_t *db, pmpkg_t *info)
 int _alpm_db_read(pmdb_t *db, pmpkg_t *info, pmdbinfrq_t inforeq)
 {
 	FILE *fp = NULL;
-	struct stat buf;
 	char path[PATH_MAX];
 	char line[513];
 	char *pkgpath = NULL;
@@ -393,7 +392,7 @@ int _alpm_db_read(pmdb_t *db, pmpkg_t *info, pmdbinfrq_t inforeq)
 
 	pkgpath = get_pkgpath(db, info);
 
-	if(stat(pkgpath, &buf)) {
+	if(access(pkgpath, F_OK)) {
 		/* directory doesn't exist or can't be opened */
 		_alpm_log(PM_LOG_DEBUG, "cannot find '%s-%s' in db '%s'\n",
 				info->name, info->version, db->treename);
@@ -631,7 +630,7 @@ int _alpm_db_read(pmdb_t *db, pmpkg_t *info, pmdbinfrq_t inforeq)
 	/* INSTALL */
 	if(inforeq & INFRQ_SCRIPTLET) {
 		snprintf(path, PATH_MAX, "%sinstall", pkgpath);
-		if(!stat(path, &buf)) {
+		if(access(path, F_OK) == 0) {
 			info->scriptlet = 1;
 		}
 	}
diff --git a/lib/libalpm/trans.c b/lib/libalpm/trans.c
index eb53e952..06084ae9 100644
--- a/lib/libalpm/trans.c
+++ b/lib/libalpm/trans.c
@@ -25,6 +25,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <unistd.h>
 #include <sys/wait.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -451,7 +452,6 @@ int _alpm_runscriptlet(const char *root, const char *installfn,
 	char tmpdir[PATH_MAX];
 	char cwd[PATH_MAX];
 	char *scriptpath;
-	struct stat buf;
 	pid_t pid;
 	int clean_tmpdir = 0;
 	int restore_cwd = 0;
@@ -459,14 +459,14 @@ int _alpm_runscriptlet(const char *root, const char *installfn,
 
 	ALPM_LOG_FUNC;
 
-	if(stat(installfn, &buf)) {
+	if(access(installfn, R_OK)) {
 		/* not found */
 		_alpm_log(PM_LOG_DEBUG, "scriptlet '%s' not found\n", installfn);
 		return(0);
 	}
 
 	/* NOTE: popen will use the PARENT's /bin/sh, not the chroot's */
-	if(stat("/bin/sh", &buf)) {
+	if(access("/bin/sh", X_OK)) {
 		/* not found */
 		_alpm_log(PM_LOG_ERROR, _("No /bin/sh in parent environment, aborting scriptlet\n"));
 		return(0);
@@ -474,7 +474,7 @@ int _alpm_runscriptlet(const char *root, const char *installfn,
 
 	/* creates a directory in $root/tmp/ for copying/extracting the scriptlet */
 	snprintf(tmpdir, PATH_MAX, "%stmp/", root);
-	if(stat(tmpdir, &buf)) {
+	if(access(tmpdir, F_OK) != 0) {
 		_alpm_makepath_mode(tmpdir, 01777);
 	}
 	snprintf(tmpdir, PATH_MAX, "%stmp/alpm_XXXXXX", root);
diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
index 55bd46a8..91995451 100644
--- a/lib/libalpm/util.c
+++ b/lib/libalpm/util.c
@@ -200,12 +200,11 @@ int _alpm_makepath_mode(const char *path, mode_t mode)
 	str = orig;
 	while((ptr = strsep(&str, "/"))) {
 		if(strlen(ptr)) {
-			struct stat buf;
 			/* we have another path component- append the newest component to
 			 * existing string and create one more level of dir structure */
 			strcat(incr, "/");
 			strcat(incr, ptr);
-			if(stat(incr, &buf)) {
+			if(access(incr, F_OK)) {
 				if(mkdir(incr, mode)) {
 					ret = 1;
 					break;
@@ -533,12 +532,11 @@ int _alpm_logaction(unsigned short usesyslog, FILE *f, const char *fmt, va_list
 int _alpm_ldconfig(const char *root)
 {
 	char line[PATH_MAX];
-	struct stat buf;
 
 	snprintf(line, PATH_MAX, "%setc/ld.so.conf", root);
-	if(stat(line, &buf) == 0) {
+	if(access(line, F_OK) == 0) {
 		snprintf(line, PATH_MAX, "%ssbin/ldconfig", root);
-		if(stat(line, &buf) == 0) {
+		if(access(line, X_OK) == 0) {
 			char cmd[PATH_MAX];
 			snprintf(cmd, PATH_MAX, "%s -r %s", line, root);
 			system(cmd);
@@ -561,7 +559,6 @@ int _alpm_str_cmp(const void *s1, const void *s2)
  */
 char *_alpm_filecache_find(const char* filename)
 {
-	struct stat buf;
 	char path[PATH_MAX];
 	char *retpath;
 	alpm_list_t *i;
@@ -570,8 +567,7 @@ char *_alpm_filecache_find(const char* filename)
 	for(i = alpm_option_get_cachedirs(); i; i = alpm_list_next(i)) {
 		snprintf(path, PATH_MAX, "%s%s", (char*)alpm_list_getdata(i),
 				filename);
-		if(stat(path, &buf) == 0) {
-			/* TODO maybe check to make sure it is readable? */
+		if(access(path, R_OK) == 0) {
 			retpath = strdup(path);
 			_alpm_log(PM_LOG_DEBUG, "found cached pkg: %s\n", retpath);
 			return(retpath);