feat: small filesystem walker added

2 files changed, 203 insertions, 0 deletions

diff --git a/sys/libn/arg.c b/sys/libn/arg.c
new file mode 100644
index 0000000..64e4dd6
--- /dev/null
+++ b/sys/libn/arg.c
@@ -0,0 +1 @@
+char *argv0;
diff --git a/sys/libn/fs.c b/sys/libn/fs.c
new file mode 100644
index 0000000..5d06997
--- /dev/null
+++ b/sys/libn/fs.c
@@ -0,0 +1,202 @@
+#include <u.h>
+#include <libn.h>
+#include <libn/macro/map.h>
+#include <dirent.h>
+
+/*
+ * path history
+ */
+
+struct Key
+{
+    ino_t ino;
+    dev_t dev;
+};
+
+static
+void*
+xalloc(void *_, int n, uintptr size)
+{
+    return malloc(n*size);
+}
+
+static
+void
+xfree(void *_, void *ptr)
+{
+    return free(ptr);
+}
+
+#define hash(k) ((int32)k.ino ^ (int32)k.dev)
+#define equal(k1, k2) (k1.ino == k2.ino && k1.dev == k2.dev)
+
+struct fs·History
+{
+    SET_STRUCT_BODY(struct Key);
+};
+
+static
+int
+morehistory(fs·History *h, int n)
+{
+    SET_GROW(h, struct Key, n, hash, xalloc, xfree, nil);
+}
+
+static
+int
+addentry(fs·History *h, struct Key key, int *err)
+{
+    SET_PUT(h, key, hash, equal, morehistory, err);
+}
+
+static
+void
+forget(fs·History *h)
+{
+    if (!h)
+        return;
+
+    SET_RESET(h);
+}
+
+static
+void
+delete(fs·History *h)
+{
+    SET_FREE(h, xfree, nil);
+}
+
+#undef hash
+#undef equal
+
+static
+char *
+strcpyn(char *dst, char *src, int n)
+{
+    while(*src && n-- > 0)
+        *dst++ = *src++;
+
+    *dst = 0;
+    return dst;
+}
+
+/*
+ * main functions
+ */
+
+int
+fs·init(fs·Walker *fs, char *path)
+{
+    fs->base = fs->end = fs->path;
+
+    if (!path || !path[0]) {
+        path = getcwd(fs->path, arrlen(fs->path));
+        if (!path)
+            return 1;
+        fs->end += strlen(path);
+    } else 
+        fs->end = strcpyn(fs->base, path, arrlen(fs->path));
+
+    if (fs->path[0] != '/')
+        fs->fd = AT_FDCWD;
+
+    if (!fs->hist && !(fs->flags & fs·nolinks))
+        fs->hist = calloc(1, sizeof(*fs->hist));
+
+    return 0;
+}
+
+void
+fs·fini(fs·Walker *fs)
+{
+    if (fs->hist) {
+        delete(fs->hist);
+        free(fs->hist);
+    }
+}
+
+void
+fs·walk(fs·Walker *fs)
+{
+    char *e, *b;
+    DIR *dir;
+    int new, fd, ofd, flags;
+    fs·History *h;
+    struct dirent *d;
+    io·Stat cwd;
+    struct fs·Entry *it;
+
+    flags = 0;
+    if(fs->flags & fs·nolinks)
+        flags |= AT_SYMLINK_NOFOLLOW;
+
+    /* get info for base relative to current fd */
+    if(fstatat(fs->fd, fs->base, &cwd, flags) < 0){
+        if(fs->flags & fs·verbose)
+            errorf("stat: %s", fs->path);
+        return;
+    }
+
+    /* if we hit a file, finish! */
+    if(!S_ISDIR(cwd.st_mode)) {
+        fs->func(fs->data, fs->base, fs->path, &cwd);
+        return;
+    }
+
+    /* have we been here before? (cycle detection) */
+    /* if not, add to our path history */
+    if (!(fs->flags & fs·nolinks)) {
+        addentry(fs->hist, (struct Key){.dev=cwd.st_dev, .ino=cwd.st_ino}, &new);
+        if (!new)
+            return;
+    }
+
+    /* operate on directory if preorder traversal */
+    if (fs->flags & fs·preorder)
+        fs->func(fs->data, fs->base, fs->path, &cwd);
+
+    /* open directory */
+    if(!fs->max || fs->lev + 1 < fs->max) {
+        fd = openat(fs->fd, fs->base, O_RDONLY | O_CLOEXEC | O_DIRECTORY);
+        if (fd < 0)
+            errorf("open %s:", fs->path);
+
+        if (!(dir=fdopendir(fd))) {
+            if(fs->flags & fs·verbose)
+                errorf("fdopendir: %s", fs->path);
+            return;
+        }
+
+        ofd = fs->fd, fs->fd = fd;
+
+        /* traverse children */
+        e = fs->end, b = fs->base;
+        if (fs->end[-1] != '/')
+            *fs->end++ = '/';
+
+        fs->base = fs->end;
+        while((d = readdir(dir))) {
+            if (*d->d_name == '.') 
+            if (d->d_name[1] == 0 ||                       /* . */ 
+               (d->d_name[1] == '.' && d->d_name[2] == 0)) /* .. */ 
+                continue;
+
+            fs->end = strcpyn(fs->base, d->d_name, arrend(fs->path) - fs->base);
+
+            fs->lev++;
+            fs·walk(fs);
+            fs->lev--;
+        }
+        *e      = 0;
+        fs->fd  = ofd;
+        fs->end = e, fs->base = b;
+        closedir(dir);
+    }
+
+    /* operate on directory if postorder (default) traversal */
+    if (!(fs->flags & fs·preorder))
+        fs->func(fs->data, fs->base, fs->path, &cwd);
+
+    if (!fs->lev)
+        forget(fs->hist);
+}