usr: libc: Add stdio.h

* Added stdio.h and various definitions
* Added fwrite(), fputc(), putc(), putchar(), fputs(), and puts()

Signed-off-by: Quinn Stephens <quinn@osmora.org>
Signed-off-by: Ian Moffett <ian@osmora.org>

6 files changed, 342 insertions, 0 deletions

diff --git a/lib/libc/include/stdio.h b/lib/libc/include/stdio.h
new file mode 100644
index 0000000..b3bf8df
--- /dev/null
+++ b/lib/libc/include/stdio.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _STDIO_H
+#define _STDIO_H 1
+
+#include <sys/cdefs.h>
+#define __need_NULL
+#define __need_size_t
+#include <stddef.h>
+#define __need_va_list
+#include <stdarg.h>
+
+#if __STDC_VERSION__ >= 202311L
+#define __STDC_VERSION_STDIO_H__ 202311L
+#endif
+
+/* Buffering modes */
+#define _IOFBF 0 /* Fully buffered */
+#define _IOLBF 1 /* Line buffered */
+#define _IONBF 2 /* Unbuffered */
+
+/* Default buffer size */
+#define BUFSIZ 256
+
+/* End-Of-File indicator */
+#define EOF (-1)
+
+/* Spec says these should be defined as macros */
+#define stdin  stdin
+#define stdout stdout
+#define stderr stderr
+
+/* File structure */
+typedef struct _IO_FILE {
+    int fd;
+    int buf_mode;
+} FILE;
+
+extern FILE *stdin;
+extern FILE *stdout;
+extern FILE *stderr;
+
+#define putc(c, stream) fputc((c), (stream))
+
+__BEGIN_DECLS
+
+size_t fwrite(const void *__restrict ptr, size_t size, size_t n, FILE *__restrict stream);
+
+int fputc(int c, FILE *stream);
+int putchar(int c);
+
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
+int fputs(const char *__restrict s, FILE *__restrict stream);
+#else
+int fputs(const char *s, FILE *stream);
+#endif
+int puts(const char *s);
+
+__END_DECLS
+
+#endif /* !_STDIO_H */
diff --git a/lib/libc/src/main.c b/lib/libc/src/main.c
index 1154b21..d16b93e 100644
--- a/lib/libc/src/main.c
+++ b/lib/libc/src/main.c
@@ -30,10 +30,18 @@
 #include <stdint.h>
 #include <stddef.h>
 
+extern int __libc_stdio_init(void);
+
 int main(int argc, char **argv);
 
 int
 __libc_entry(uint64_t *ctx)
 {
+    int status;
+
+    if ((status = __libc_stdio_init()) != 0) {
+        return status;
+    }
+
     return main(0, NULL);
 }
diff --git a/lib/libc/src/stdio/fputc.c b/lib/libc/src/stdio/fputc.c
new file mode 100644
index 0000000..6ac7aac
--- /dev/null
+++ b/lib/libc/src/stdio/fputc.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+
+extern size_t __stdio_write(const void *__restrict ptr, size_t size, FILE *__restrict stream);
+
+int
+fputc(int c, FILE *stream)
+{
+    unsigned char val;
+
+    if (stream == NULL) {
+        return EOF;
+    }
+
+    val = (unsigned char)c;
+    if (__stdio_write(&val, sizeof(val), stream) != sizeof(val)) {
+        return EOF;
+    }
+
+    return (int)val;
+}
+
+int
+putchar(int c)
+{
+    return fputc(c, stdout);
+}
diff --git a/lib/libc/src/stdio/fputs.c b/lib/libc/src/stdio/fputs.c
new file mode 100644
index 0000000..357fd52
--- /dev/null
+++ b/lib/libc/src/stdio/fputs.c
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+extern size_t __stdio_write(const void *__restrict ptr, size_t size, FILE *__restrict stream);
+
+int
+fputs(const char *__restrict s, FILE *__restrict stream)
+{
+    size_t len;
+
+    if (s == NULL || stream == NULL) {
+        return EOF;
+    }
+
+    len = strlen(s);
+    if (len < 1) {
+        return 0;
+    }
+
+    if (__stdio_write(s, sizeof(char) * len, stream) != (sizeof(char) * len)) {
+        return EOF;
+    }
+
+    return 0;
+}
+
+int
+puts(const char *s)
+{
+    if (fputs(s, stdout) < 0) {
+        return EOF;
+    }
+
+    if (fputc('\n', stdout) != '\n') {
+        return EOF;
+    }
+
+    return 0;
+}
diff --git a/lib/libc/src/stdio/fwrite.c b/lib/libc/src/stdio/fwrite.c
new file mode 100644
index 0000000..660034e
--- /dev/null
+++ b/lib/libc/src/stdio/fwrite.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+
+size_t
+__stdio_write(const void *__restrict ptr, size_t size, FILE *__restrict stream)
+{
+    ssize_t count;
+
+    if (stream->buf_mode == _IONBF) {
+        if ((count = write(stream->fd, ptr, size)) < 0) {
+            return 0;
+        }
+
+        return count;
+    }
+
+    /*
+     * TODO: Implement more buffering modes.
+     */
+
+    return 0;
+}
+
+size_t
+fwrite(const void *__restrict ptr, size_t size, size_t n, FILE *__restrict stream)
+{
+    if (ptr == NULL || stream == NULL || (size * n) == 0) {
+        return 0;
+    }
+
+    return __stdio_write(ptr, size * n, stream);
+}
diff --git a/lib/libc/src/stdio/init.c b/lib/libc/src/stdio/init.c
new file mode 100644
index 0000000..5982d59
--- /dev/null
+++ b/lib/libc/src/stdio/init.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <fcntl.h>
+
+FILE *stdin;
+FILE *stdout;
+FILE *stderr;
+
+static FILE cin, cout, cerr;
+
+int
+__libc_stdio_init(void)
+{
+    int cfd;
+
+    if ((cfd = open("/dev/console", O_RDWR)) < 0) {
+        return cfd;
+    }
+
+    cin.buf_mode = _IONBF;
+    cin.fd = cfd;
+
+    cout.buf_mode = _IONBF;
+    cout.fd = cfd;
+
+    cerr.buf_mode = _IONBF;
+    cerr.fd = cfd;
+
+    stdout = &cout;
+    stdin = &cin;
+    stderr = &cerr;
+
+    return 0;
+}