1 files changed, 180 insertions, 0 deletions
diff --git a/user/include/unistd.h b/user/include/unistd.h
new file mode 100644
index 0000000..1f83abc
--- /dev/null
+++ b/user/include/unistd.h
@@ -0,0 +1,180 @@
+/**
+ * @file unistd.h
+ * @author Freya Murphy <freya@freyacat.org>
+ * @author Warren R. Carithers
+ *
+ * Universial system definitions for userspace.
+ */
+
+#ifndef UNISTD_H_
+#define UNISTD_H_
+
+#include <stdint.h>
+#include <stddef.h>
+
+/* System Call Definitions */
+
+typedef unsigned short pid_t;
+
+/**
+ * terminates the calling process and does not return.
+ *
+ * @param status - the status code to exit with
+ */
+__attribute__((noreturn)) extern void exit(int status);
+
+/**
+ * sleeps current process until a child process terminates
+ *
+ * @param pid - pid of the desired child, or 0 for any child
+ * @param status - pointer to int32_t into which the child's status is placed,
+ *                 or NULL
+ * @return The pid of the terminated child, or an error code
+ *
+ * If there are no children in the system, returns an error code (*status
+ * is unchanged).
+ *
+ * If there are one or more children in the system and at least one has
+ * terminated but hasn't yet been cleaned up, cleans up that process and
+ * returns its information; otherwise, blocks until a child terminates.
+ */
+extern int waitpid(pid_t pid, int *status);
+
+/**
+ * create a duplicate of the calling process
+ *
+ * @return parent - the pid of the new child, or an error code
+ *         child  - 0
+ */
+extern int fork(void);
+
+/**
+ * replace the memory image of the calling process
+ *
+ * @param prog - program table index of the program to exec
+ * @param args - the command-line argument vector
+ *
+ * Does not return if it succeeds; if it returns, something has
+ * gone wrong.
+ */
+extern void exec(const char *filename, char **args);
+
+/**
+ * open a stream with a given filename
+ *
+ * @param filename - the name of the file to open
+ * @return the file descriptior of the open file or a negative error code.
+ */
+extern int open(const char *filename);
+
+/**
+ * closes a stream with the given file descriptior
+ *
+ * @param fd - the file descriptior of the open stream
+ */
+extern void close(int fd);
+
+/**
+ * read into a buffer from a stream
+ *
+ * @param fd - file stream to read from
+ * @param buf - buffer to read into
+ * @param nbytes - maximum capacity of the buffer
+ * @return - The count of bytes transferred, or an error code
+ */
+extern int read(int fd, void *buffer, size_t nbytes);
+
+/**
+ * write from a buffer to a stream
+ *
+ * @param fd - file stream to write to
+ * @param buf - buffer to write from
+ * @param nbytes - maximum capacity of the buffer
+ * @return - The count of bytes transferred, or an error code
+ */
+extern int write(int fd, const void *buffer, size_t nbytes);
+
+/**
+ * gets the pid of the calling process
+ *
+ * @return the pid of this process
+ */
+extern pid_t getpid(void);
+
+/**
+ * gets the parent pid of the current process
+ *
+ * @return the parent pid of the current process, or 0 if init
+ */
+extern pid_t getppid(void);
+
+/**
+ * gets the current system time
+ *
+ * @return the system time
+ */
+extern unsigned long gettime(void);
+
+/**
+ * gets the scheduling priority of the calling process
+ *
+ * @return the process' priority
+ */
+extern unsigned int getprio(void);
+
+/**
+ * sets the scheduling priority of the calling process
+ *
+ * @param new - the desired new priority
+ * @return the old priority value
+ */
+extern unsigned int setprio(unsigned int new);
+
+/**
+ * terminates a process
+ *
+ * @param pid - the pid of the process to kill
+ * @return 0 on success, else an error code
+ */
+extern int kill(pid_t pid);
+
+/**
+ * put the current process to sleep for some length of time
+ *
+ * @param ms - desired sleep time (in ms), or 0 to yield the CPU
+ * @return the time the process spent sleeping (in ms)
+ */
+extern int sleep(unsigned long ms);
+
+/**
+ * Wait for any child to exit
+ *
+ * @param status - pointer to int32_t into which the child's status is placed,
+ *                 or NULL
+ * @return  The pid of the terminated child, or an error code
+ *
+ * Analogous to waitpid(0,status)
+ */
+extern int wait(int *status);
+
+/**
+ * Spawn a new process running a different program
+ *
+ * @param prog - program table index of the program to spawn
+ * @param args - the command-line argument vector for the process
+ * @return the pid of the child, or an error code
+ *
+ * Analogous to calling fork and exec
+ */
+extern int spawn(pid_t prog, char **args);
+
+/**
+ * Increment the program's data space by increment bytes.
+ *
+ * @param increment - the amount in bytes to increment the heap
+ * @return the previos program break on success, or NULL on failure
+ *
+ */
+extern void *sbrk(intptr_t increment);
+
+#endif /* unistd.h */