ulib fstatat

b6be3a2f · Silas Boyd-Wickizer · 3d00ccd2 · b6be3a2f · b6be3a2f · b6be3a2f
--- a/bin/xls.cc
+++ b/bin/xls.cc
@@ -12,6 +12,7 @@
 #define ST_ISDIR(st) S_ISDIR((st).st_mode)
 #define ST_ISREG(st) S_ISREG((st).st_mode)
 #define BSIZ 256
+#define xfstatat(fd, n, st) fstatat(fd, n, st, 0)
 #else // assume xv6
 #include "types.h"
 #include "stat.h"
@@ -26,12 +27,12 @@
 #define ST_ISREG(st) ((st).type == T_FILE)
 #define BSIZ (DIRSIZ + 1)
 #define stderr 2
+#define xfstatat fstatat
 #endif

 void
 ls(const char *path)
 {
-  char buf[512], *p;
  int fd;
  struct stat st;
  
@@ -49,21 +50,13 @@ ls(const char *path)
  if (ST_ISREG(st)) {
    printf("%u %10lu %10lu %s\n", ST_TYPE(st), ST_INO(st), ST_SIZE(st), path);
  } else if (ST_ISDIR(st)) {
-    if(strlen(path) + 1 + BSIZ > sizeof buf) {
-      printf("ls: path too long\n");
-    }
-    strcpy(buf, path);
-    p = buf+strlen(buf);
-    *p++ = '/';
    dirit di(fd);
    for (; !di.end(); ++di) {
      const char *name = *di;
-      size_t len = strlen(name);
-      memmove(p, name, len);
-      p[len] = 0;
-      if (stat(buf, &st) < 0){
+      
+      if (xfstatat(fd, name, &st) < 0){
+        printf("ls: cannot stat %s\n", name);
        free((void*)name);
-        printf("ls: cannot stat %s\n", buf);
        continue;
      }


--- a/include/user.h
+++ b/include/user.h
@@ -34,6 +34,7 @@ int setfs(u64 base);

 // ulib.c
 int stat(char*, struct stat*);
+int fstatat(int dirfd, const char*, struct stat*);
 char* strcpy(char*, const char*);
 void *memmove(void*, const void*, int);
 char* strchr(const char*, char c);

--- a/lib/ulib.c
+++ b/lib/ulib.c
@@ -102,6 +102,20 @@ stat(char *n, struct stat *st)
 }

 int
+fstatat(int dirfd, const char *n, struct stat *st)
+{
+  int fd;
+  int r;
+
+  fd = openat(dirfd, n, O_RDONLY);
+  if(fd < 0)
+    return -1;
+  r = fstat(fd, st);
+  close(fd);
+  return r;
+}
+
+int
 atoi(const char *s)
 {
  int n;