Restructure files and libraries

Rename a bunch of files to make the consistent
	Create two new subdirectories for common code, and utilities

common/common-external.c

@@ -0,0 +1,191 @@
+/*
+
+Copyright (c) 2017-2019, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * 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.
+ * Neither the name of Feral Interactive 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.
+
+ */
+
+#define _GNU_SOURCE
+
+#include "common-external.h"
+#include "common-logging.h"
+
+#include <linux/limits.h>
+#include <stdio.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+static const int DEFAULT_TIMEOUT = 5;
+
+static int read_child_stdout(int pipe_fd, char buffer[EXTERNAL_BUFFER_MAX], int tsec)
+{
+	fd_set fds;
+	struct timeval timeout;
+	int num_readable = 0;
+	ssize_t buffer_bytes_read = 0;
+	ssize_t just_read = 0;
+	bool buffer_full = false;
+	char discard_buffer[EXTERNAL_BUFFER_MAX];
+
+	/* Set up the timout */
+	timeout.tv_sec = tsec;
+	timeout.tv_usec = 0;
+
+	FD_ZERO(&fds);
+
+	/* Wait for the child to finish up with a timout */
+	while (true) {
+		FD_SET(pipe_fd, &fds);
+		num_readable = select(pipe_fd + 1, &fds, NULL, NULL, &timeout);
+
+		if (num_readable < 0) {
+			if (errno == EINTR) {
+				continue;
+			} else {
+				LOG_ERROR("sigtimedwait failed: %s\n", strerror(errno));
+				return -1;
+			}
+		} else if (num_readable == 0) {
+			return -2;
+		}
+
+		if (!buffer_full) {
+			just_read = read(pipe_fd,
+			                 buffer + buffer_bytes_read,
+			                 EXTERNAL_BUFFER_MAX - (size_t)buffer_bytes_read - 1);
+		} else {
+			just_read = read(pipe_fd, discard_buffer, EXTERNAL_BUFFER_MAX - 1);
+		}
+
+		if (just_read < 0) {
+			return -1;
+		} else if (just_read == 0) {
+			// EOF encountered
+			break;
+		}
+
+		if (!buffer_full) {
+			buffer_bytes_read += just_read;
+
+			if (buffer_bytes_read == EXTERNAL_BUFFER_MAX - 1) {
+				// our buffer is exhausted, discard the rest
+				// of the output
+				buffer_full = true;
+			}
+		}
+	}
+
+	buffer[buffer_bytes_read] = 0;
+
+	return 0;
+}
+
+/**
+ * Call an external process
+ */
+int run_external_process(const char *const *exec_args, char buffer[EXTERNAL_BUFFER_MAX], int tsec)
+{
+	pid_t p;
+	int status = 0;
+	int pipes[2];
+	int ret = 0;
+	char internal[EXTERNAL_BUFFER_MAX] = { 0 };
+
+	if (pipe(pipes) == -1) {
+		LOG_ERROR("Could not create pipe: %s!\n", strerror(errno));
+		return -1;
+	}
+
+	/* Set the default timeout */
+	if (tsec == -1) {
+		tsec = DEFAULT_TIMEOUT;
+	}
+
+	if ((p = fork()) < 0) {
+		close(pipes[0]);
+		close(pipes[1]);
+		LOG_ERROR("Failed to fork(): %s\n", strerror(errno));
+		return false;
+	} else if (p == 0) {
+		/* Send STDOUT to the pipe */
+		dup2(pipes[1], STDOUT_FILENO);
+		close(pipes[0]);
+		close(pipes[1]);
+		/* Execute the command */
+		/* Note about cast:
+		 *   The statement about argv[] and envp[] being constants is
+		 *   included to make explicit to future writers of language
+		 *   bindings that these objects are completely constant.
+		 * http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html
+		 */
+		if (execv(exec_args[0], (char *const *)exec_args) != 0) {
+			LOG_ERROR("Failed to execute external process: %s %s\n", exec_args[0], strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+		// should never be reached
+		abort();
+	}
+
+	// close the write end of the pipe so we get signaled EOF once the
+	// child exits
+	close(pipes[1]);
+	ret = read_child_stdout(pipes[0], internal, tsec);
+	close(pipes[0]);
+
+	if (ret != 0) {
+		if (ret == -2) {
+			LOG_ERROR("Child process timed out for %s, killing and returning\n", exec_args[0]);
+			kill(p, SIGKILL);
+		} else {
+			LOG_ERROR("Failed to read from process %s: %s\n", exec_args[0], strerror(errno));
+		}
+		if (buffer) {
+			// make sure the buffer is a terminated empty string on error
+			buffer[0] = 0;
+		}
+	} else if (buffer) {
+		memcpy(buffer, internal, EXTERNAL_BUFFER_MAX);
+	}
+
+	if (waitpid(p, &status, 0) < 0) {
+		LOG_ERROR("Failed to waitpid(%d): %s\n", (int)p, strerror(errno));
+		return -1;
+	}
+
+	/* i.e. sigsev */
+	if (!WIFEXITED(status)) {
+		LOG_ERROR("Child process '%s' exited abnormally\n", exec_args[0]);
+	} else if (WEXITSTATUS(status) != 0) {
+		LOG_ERROR("External process failed with exit code %d\n", WEXITSTATUS(status));
+		LOG_ERROR("Output was: %s\n", internal);
+		return -1;
+	}
+
+	return 0;
+}