1 files changed, 114 insertions, 0 deletions
diff --git a/src/system.c b/src/system.c
new file mode 100644
index 0000000..df53e99
--- /dev/null
+++ b/src/system.c
@@ -0,0 +1,114 @@
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/sendfile.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "system.h"
+
+int file_exists(const char *path)
+{
+	struct stat statbuf __attribute__((unused));
+	int rc = stat(path, &statbuf);
+	if (rc == 0)
+		return 1;
+	else if ((rc == -1) && (errno == ENOENT))
+		return 0;
+	fprintf(stderr, "stat: \"%s\": ", path);
+	perror("");
+	exit(EXIT_FAILURE);
+}
+
+void copy_file(const char *in, const char *out)
+{
+	int in_fd;
+	int out_fd;
+	int rc;
+	ssize_t written_bytes;
+	in_fd = open(in, O_RDONLY);
+	if (in_fd == -1) {
+		fprintf(stderr, "open: %s:", in);
+		perror("");
+		exit(EXIT_FAILURE);
+	}
+	out_fd = open(out, O_WRONLY | O_CREAT | O_TRUNC, 0600);
+	if (out_fd == -1) {
+		fprintf(stderr, "open: %s:", out);
+		perror("");
+		exit(EXIT_FAILURE);
+	}
+	while ((written_bytes = sendfile(out_fd, in_fd, NULL, 4096)) == 4096)
+		;
+	if (written_bytes == -1) {
+		perror("sendfile");
+		exit(EXIT_FAILURE);
+	}
+	rc = fchmod(out_fd, 0400);
+	if (rc == -1) {
+		fprintf(stderr, "chmod: %s: ", out);
+		perror("");
+		exit(EXIT_FAILURE);
+	}
+	close(in_fd);
+	close(out_fd);
+}
+
+void
+copy_file_with_encryption(const char *in, const char *out, enum encrypt encrypt)
+{
+	char *crypt_param;
+	assert(encrypt == ENCRYPT || encrypt == DECRYPT);
+	if (encrypt == ENCRYPT)
+		crypt_param = "--encrypt";
+	else
+		crypt_param = "--decrypt";
+	/* use dups to suppress "discards const qualifier" warnings */
+	char *in_dup = strdup(in);
+	char *out_dup = strdup(out);
+	char *cmd[] = {
+		"gpg",
+		"--output", out_dup,
+		"--yes",
+		crypt_param, in_dup,
+		NULL
+	};
+	ftag_execvp(cmd, 1);
+	free(in_dup);
+	free(out_dup);
+}
+
+int ftag_execvp(char *const *cmd, int can_exit)
+{
+	int status = 0;
+	int rc = fork();
+	if (rc == 0) {
+		execvp(cmd[0], cmd);
+		fprintf(stderr, "exec: %s: ", cmd[0]);
+		perror("");
+	}
+	else if (rc > 0) {
+		int status;
+		wait(&status);
+		if (!(WIFEXITED(status) && WEXITSTATUS(status) == 0)) {
+			fprintf(stderr,
+				"ftag: child process exited abnormally\n");
+			if (can_exit)
+				exit(EXIT_FAILURE);
+			else
+				status = -1;
+		}
+	}
+	else {
+		perror("fork");
+		if (can_exit)
+			exit(EXIT_FAILURE);
+		else
+			status = -1;
+	}
+	return status;
+}