finish os.h amalgamation

1 files changed, 196 insertions, 0 deletions

diff --git a/os-posix.c b/os-posix.c
index 68e1d4f..193897a 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -1,6 +1,8 @@
 #include "os.h"
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/wait.h>
+#include <signal.h>
 #include <unistd.h>
 #include <dirent.h>
 #include <errno.h>
@@ -132,3 +134,197 @@ void time_sleep_ns(u64 ns) {
 	while (nanosleep(&req, &rem) == EINTR) // sleep interrupted by signal
 		req = rem;
 }
+
+
+struct Process {
+	pid_t pid;
+	int stdout_pipe;
+	// only applicable if separate_stderr was specified.
+	int stderr_pipe;
+	int stdin_pipe;
+	char error[64];
+};
+
+int process_get_id(void) {
+	return getpid();
+}
+
+static void set_nonblocking(int fd) {
+	fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
+}
+
+bool process_run_ex(Process *proc, const char *command, const ProcessSettings *settings) {
+	memset(proc, 0, sizeof *proc);
+
+	int stdin_pipe[2] = {0}, stdout_pipe[2] = {0}, stderr_pipe[2] = {0};
+	if (pipe(stdin_pipe) != 0) {
+		strbuf_printf(proc->error, "%s", strerror(errno));
+		return false; 
+	}
+	if (pipe(stdout_pipe) != 0) {
+		strbuf_printf(proc->error, "%s", strerror(errno));
+		close(stdin_pipe[0]);
+		close(stdin_pipe[1]);
+		return false;
+	}
+	if (settings->separate_stderr) {
+		if (pipe(stderr_pipe) != 0) {
+			strbuf_printf(proc->error, "%s", strerror(errno));
+			close(stdin_pipe[0]);
+			close(stdin_pipe[1]);
+			close(stdout_pipe[0]);
+			close(stdout_pipe[1]);
+			return false;
+		}
+	}
+	
+	bool success = false;
+	pid_t pid = fork();
+	if (pid == 0) {
+		// child process
+		chdir(settings->working_directory);
+		// put child in its own group. it will be in this group with all of its descendents,
+		// so by killing everything in the group, we kill all the descendents of this process.
+		// if we didn't do this, we would just be killing the sh process in process_kill.
+		setpgid(0, 0);
+		// pipe stuff
+		dup2(stdout_pipe[1], STDOUT_FILENO);
+		if (stderr_pipe[1])
+			dup2(stderr_pipe[1], STDERR_FILENO);
+		else
+			dup2(stdout_pipe[1], STDERR_FILENO);
+		dup2(stdin_pipe[0],  STDIN_FILENO);
+		// don't need these file descriptors anymore
+		close(stdin_pipe[0]);
+		close(stdin_pipe[1]);
+		close(stdout_pipe[0]);
+		close(stdout_pipe[1]);
+		if (stderr_pipe[0]) {
+			close(stderr_pipe[0]);
+			close(stderr_pipe[1]);
+		}
+		
+		char *program = "/bin/sh";
+		char *argv[] = {program, "-c", (char *)command, NULL};
+		if (execv(program, argv) == -1) {
+			dprintf(STDERR_FILENO, "%s: %s\n", program, strerror(errno));
+			exit(127);
+		}
+	} else if (pid > 0) {
+		// parent process
+		
+		// we're reading from (the child's) stdout/stderr and writing to stdin,
+		// so we don't need the write end of the stdout pipe or the
+		// read end of the stdin pipe.
+		close(stdout_pipe[1]);
+		if (stderr_pipe[1])	
+			close(stderr_pipe[1]);
+		close(stdin_pipe[0]);
+		// set pipes to non-blocking
+		if (!settings->stdout_blocking)
+			set_nonblocking(stdout_pipe[0]);
+		if (stderr_pipe[0] && !settings->stderr_blocking)
+			set_nonblocking(stderr_pipe[0]);
+		if (!settings->stdin_blocking)
+			set_nonblocking(stdin_pipe[1]);
+		proc->pid = pid;
+		proc->stdout_pipe = stdout_pipe[0];
+		if (stderr_pipe[0])
+			proc->stderr_pipe = stderr_pipe[0];
+		proc->stdin_pipe = stdin_pipe[1];
+		success = true;
+	}
+	return success;
+}
+
+bool process_run(Process *proc, char const *command) {
+	const ProcessSettings settings = {0};
+	return process_run_ex(proc, command, &settings);
+}
+
+
+char const *process_geterr(Process *p) {
+	return *p->error ? p->error : NULL;
+}
+
+long long process_write(Process *proc, const char *data, size_t size) {
+	assert(proc->stdin_pipe); // check that process hasn't been killed
+	ssize_t bytes_written = write(proc->stdin_pipe, data, size);
+	if (bytes_written >= 0) {
+		return (long long)bytes_written;
+	} else if (errno == EAGAIN) {
+		return 0;
+	} else {
+		strbuf_printf(proc->error, "%s", strerror(errno));
+		return -2;
+	}
+}
+
+static long long process_read_fd(Process *proc, int fd, char *data, size_t size) {
+	assert(fd);
+	ssize_t bytes_read = read(fd, data, size);
+	if (bytes_read >= 0) {
+		return (long long)bytes_read;
+	} else if (errno == EAGAIN) {
+		return -1;
+	} else {
+		strbuf_printf(proc->error, "%s", strerror(errno));
+		return -2;
+	}
+}
+
+long long process_read(Process *proc, char *data, size_t size) {
+	return process_read_fd(proc, proc->stdout_pipe, data, size);
+}
+
+long long process_read_stderr(Process *proc, char *data, size_t size) {
+	return process_read_fd(proc, proc->stderr_pipe, data, size);
+}
+
+static void process_close_pipes(Process *proc) {
+	close(proc->stdin_pipe);
+	close(proc->stdout_pipe);
+	close(proc->stderr_pipe);
+	proc->stdin_pipe = 0;
+	proc->stdout_pipe = 0;
+	proc->stderr_pipe = 0;
+}
+
+void process_kill(Process *proc) {
+	kill(-proc->pid, SIGKILL); // kill everything in process group
+	// get rid of zombie process
+	waitpid(proc->pid, NULL, 0);
+	proc->pid = 0;
+	process_close_pipes(proc);
+}
+
+int process_check_status(Process *proc, char *message, size_t message_size) {
+	int wait_status = 0;
+	int ret = waitpid(proc->pid, &wait_status, WNOHANG);
+	if (ret == 0) {
+		// process still running
+		return 0;
+	} else if (ret > 0) {
+		if (WIFEXITED(wait_status)) {
+			process_close_pipes(proc);
+			int code = WEXITSTATUS(wait_status);
+			if (code == 0) {
+				str_printf(message, message_size, "exited successfully");
+				return +1;
+			} else {
+				str_printf(message, message_size, "exited with code %d", code);
+				return -1;
+			}
+		} else if (WIFSIGNALED(wait_status)) {
+			process_close_pipes(proc);
+			str_printf(message, message_size, "terminated by signal %d", WTERMSIG(wait_status));
+			return -1;
+		}
+		return 0;
+	} else {
+		// this process is gone or something?
+		process_close_pipes(proc);
+		str_printf(message, message_size, "process ended unexpectedly");
+		return -1;
+	}
+}