user/libc: cwd

3 files changed, 120 insertions, 14 deletions

diff --git a/src/user/lib/file.c b/src/user/lib/file.c
index 942b522..080217c 100644
--- a/src/user/lib/file.c
+++ b/src/user/lib/file.c
@@ -18,7 +18,11 @@ FILE *fopen(const char *path, const char *mode) {
 	FILE *f;
 	handle_t h;
 	int flags = 0;
-	if (path && path[0] == '!') {
+	char *tmppath = NULL;
+	if (!path) {
+		errno = -1;
+		return NULL;
+	} else if (path[0] == '!') {
 		/* special handling for "!files" */
 		path++;
 		if (!strcmp(path, "stdin"))  return file_clone(stdin, mode);
@@ -26,23 +30,32 @@ FILE *fopen(const char *path, const char *mode) {
 		if (!strcmp(path, "stderr")) return file_clone(stderr, mode);
 		errno = -1;
 		return NULL;
-	} else {
-		if (mode[0] == 'w' || mode[0] == 'a')
-			flags |= OPEN_CREATE;
+	}
 
-		h = _syscall_open(path, strlen(path), flags);
-		if (h < 0) {
-			errno = -h;
-			return NULL;
-		}
+	if (path && path[0] != '/') {
+		size_t len = absolutepath(NULL, path, 0);
+		tmppath = malloc(len);
+		if (!tmppath) return NULL;
+		absolutepath(tmppath, path, len);
+		path = tmppath;
+	}
 
-		if (mode[0] == 'w')
-			_syscall_write(h, NULL, 0, 0, WRITE_TRUNCATE);
+	if (mode[0] == 'w' || mode[0] == 'a')
+		flags |= OPEN_CREATE;
 
-		f = fdopen(h, mode);
-		if (!f) close(h);
-		return f;
+	h = _syscall_open(path, strlen(path), flags);
+	if (tmppath) free(tmppath);
+	if (h < 0) {
+		errno = -h;
+		return NULL;
 	}
+
+	if (mode[0] == 'w')
+		_syscall_write(h, NULL, 0, 0, WRITE_TRUNCATE);
+
+	f = fdopen(h, mode);
+	if (!f) close(h);
+	return f;
 }
 
  FILE *freopen(const char *path, const char *mode, FILE *f) {
diff --git a/src/user/lib/include/unistd.h b/src/user/lib/include/unistd.h
index 4f367ca..aedca1b 100644
--- a/src/user/lib/include/unistd.h
+++ b/src/user/lib/include/unistd.h
@@ -6,3 +6,12 @@ int close(handle_t h);
 _Noreturn void exit(int);
 
 int execv(const char *path, char *const argv[]);
+
+int chdir(const char *path);
+char *getcwd(char *buf, size_t size);
+/* Converts a relative path to an absolute one, simplifying it if possible.
+ * If in == NULL - return the length of cwd (without a trailing slash)
+ * If size isn't enough to fit the path, returns the amount of bytes needed to fit
+ * it, including the null byte.
+ * @return 0 on failure, length of the path otherwise */
+size_t absolutepath(char *out, const char *in, size_t size);
diff --git a/src/user/lib/stdlib.c b/src/user/lib/stdlib.c
index 94e12d3..566eb3e 100644
--- a/src/user/lib/stdlib.c
+++ b/src/user/lib/stdlib.c
@@ -1,6 +1,8 @@
+#include <camellia/path.h>
 #include <camellia/syscalls.h>
 #include <errno.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <user/lib/elfload.h>
@@ -49,3 +51,85 @@ int execv(const char *path, char *const argv[]) {
 _Noreturn void abort(void) {
 	_syscall_exit(1);
 }
+
+
+static char *cwd = NULL, *cwd2 = NULL;
+static size_t cwdcapacity = 0;
+
+int chdir(const char *path) {
+	handle_t h;
+	char *tmp;
+	size_t len = absolutepath(NULL, path, 0) + 1; /* +1 for the trailing slash */
+	if (cwdcapacity < len) {
+		cwdcapacity = len;
+		if (cwd) {
+			cwd = realloc(cwd, len);
+			cwd2 = realloc(cwd2, len);
+		} else {
+			cwd = malloc(len);
+			cwd[0] = '/';
+			cwd[1] = '\0';
+			cwd2 = malloc(len);
+			cwd2[0] = '/';
+			cwd2[1] = '\0';
+		}
+	}
+	absolutepath(cwd2, path, cwdcapacity);
+	len = strlen(cwd2);
+	if (cwd2[len - 1] != '/') {
+		cwd2[len] = '/';
+		cwd2[len + 1] = '\0';
+	}
+
+	h = _syscall_open(cwd2, strlen(cwd2), 0);
+	if (h < 0) {
+		errno = ENOENT;
+		return -1;
+	}
+	_syscall_close(h);
+
+	tmp  = cwd;
+	cwd  = cwd2;
+	cwd2 = tmp;
+	return 0;
+}
+
+char *getcwd(char *buf, size_t size) {
+	const char *realcwd = cwd ? cwd : "/";
+	// TODO bounds checking
+	memcpy(buf, realcwd, strlen(realcwd) + 1);
+	return buf;
+}
+
+size_t absolutepath(char *out, const char *in, size_t size) {
+	const char *realcwd = cwd ? cwd : "/";
+	size_t len, pos = 0;
+	if (!in) return strlen(realcwd);
+
+	if (!(in[0] == '/')) {
+		len = strlen(realcwd);
+		if (pos + len <= size && out != realcwd)
+			memcpy(out + pos, realcwd, len);
+		pos += len;
+
+		if (realcwd[len - 1] != '/') {
+			if (pos + 1 <= size) out[pos] = '/';
+			pos++;
+		}
+	}
+
+	len = strlen(in);
+	if (pos + len <= size)
+		memcpy(out + pos, in, len);
+	pos += len;
+
+	if (pos <= size) {
+		pos = path_simplify(out, out, pos);
+		if (pos > 0) out[pos] = '\0';
+	}
+
+	if (pos + 1 <= size) out[pos] = '\0';
+	pos++;
+
+	return pos;
+}