1 files changed, 159 insertions, 0 deletions
diff --git a/src/user/lib/file.c b/src/user/lib/file.c
new file mode 100644
index 0000000..44fa194
--- /dev/null
+++ b/src/user/lib/file.c
@@ -0,0 +1,159 @@
+#include "file.h"
+#include <camellia/syscalls.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static FILE _stdin_null  = { .fd = 0 };
+static FILE _stdout_null = { .fd = 1 };
+FILE *const stdin = &_stdin_null, *const stdout = &_stdout_null;
+
+
+FILE *fopen(const char *path, const char *mode) {
+	FILE *f;
+	handle_t h;
+	int flags = 0;
+	if (mode[0] == 'w' || mode[0] == 'a')
+		flags |= OPEN_CREATE;
+	// TODO truncate on w
+
+	h = _syscall_open(path, strlen(path), flags);
+	if (h < 0) {
+		errno = -h;
+		return NULL;
+	}
+	f = fdopen(h, mode);
+	if (!f) close(h);
+	return f;
+}
+
+ FILE *freopen(const char *path, const char *mode, FILE *f) {
+	/* partially based on the musl implementation of freopen */
+	FILE *f2;
+	if (!path) goto fail;
+	f2 = fopen(path, mode);
+	if (!f2) goto fail;
+
+	if (f->fd == f2->fd) {
+		f2->fd = -1;
+	} else {
+		if (_syscall_dup(f2->fd, f->fd, 0) < 0) goto fail2;
+	}
+	f->pos = f2->pos;
+	f->eof = f2->eof;
+	fclose(f2);
+	return f;
+
+fail2:
+	fclose(f2);
+fail:
+	fclose(f);
+	return NULL;
+}
+
+FILE *fdopen(int fd, const char *mode) {
+	FILE *f;
+	f = malloc(sizeof *f);
+	if (!f) return NULL;
+	f->pos = mode[0] == 'a' ? -1 : 0;
+	f->eof = false;
+	f->fd = fd;
+	f->error = false;
+	return f;
+}
+
+FILE *file_clone(const FILE *f) {
+	handle_t h = _syscall_dup(f->fd, -1, 0);
+	FILE *f2;
+	if (h < 0) return NULL;
+
+	f2 = fdopen(h, "r+");
+	if (!f2) {
+		close(h);
+		return NULL;
+	}
+	f2->pos = f->pos;
+	f2->eof = f->eof;
+	f2->fd = h;
+	return f2;
+}
+
+static void fadvance(long amt, FILE *f) {
+	bool pos_neg = f->pos < 0;
+	f->pos += amt;
+	if (pos_neg && f->pos >= 0)
+		f->pos = -1;
+}
+
+size_t fread(void *restrict ptr, size_t size, size_t nitems, FILE *restrict f) {
+	size_t total = size*nitems, pos = 0;
+	unsigned char *buf = ptr;
+
+	if (f->fd < 0) {
+		errno = EBADF;
+		return 0;
+	}
+	if (size == 0)
+		return 0;
+
+	while (pos < total) {
+		long res = _syscall_read(f->fd, buf + pos, total - pos, f->pos);
+		if (res < 0) {
+			f->error = true;
+			errno = -res;
+			return pos/size;
+		} else if (res == 0) {
+			f->eof = true;
+			return pos/size;
+		} else {
+			pos += res;
+			fadvance(res, f);
+		}
+	}
+	return nitems;
+}
+
+size_t fwrite(const void *restrict ptr, size_t size, size_t nitems, FILE *restrict f) {
+	size_t total = size*nitems, pos = 0;
+	const unsigned char *buf = ptr;
+
+	if (f->fd < 0) {
+		errno = EBADF;
+		return 0;
+	}
+	if (size == 0)
+		return 0;
+
+	while (pos < total) {
+		long res = _syscall_write(f->fd, buf + pos, total - pos, f->pos);
+		if (res < 0) {
+			f->error = true;
+			errno = -res;
+			return pos/size;
+		} else if (res == 0) {
+			f->eof = true;
+			return pos/size;
+		} else {
+			pos += res;
+			fadvance(res, f);
+		}
+	}
+	return nitems;
+}
+
+int fclose(FILE *f) {
+	if (f->fd > 0) close(f->fd);
+	if (f != &_stdin_null && f != &_stdout_null)
+		free(f);
+	return 0;
+}
+
+int feof(FILE *f) {
+	return f->eof;
+}
+
+int ferror(FILE *f) {
+	return f->error;
+}