Sync state with directory & argument parsing

3 files changed, 325 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..91f8d09
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,8 @@
+.PHONY: all test
+
+all: trivmix
+test: all
+        valgrind ./trivmix testDir
+
+trivmix: trivmix.c
+        gcc -lm -Wall `pkg-config --cflags --libs jack` -o trivmix trivmix.c
diff --git a/trivmix.c b/trivmix.c
new file mode 100644
index 0000000..720c409
--- /dev/null
+++ b/trivmix.c
@@ -0,0 +1,296 @@
+#include <stdio.h>
+#include <errno.h>
+#include <math.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <sys/stat.h>
+#include <sys/inotify.h>
+#include <signal.h>
+
+#include "trivmix.h"
+
+#define PIDFILE "pid"
+#define INPUTFILE "input"
+#define OUTPUTFILE "output"
+#define NAMEFILE "name"
+#define GAINFILE "gain"
+#define DIRMODE S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH
+#define FILEMODE S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH
+#define INOTIFYBUFLEN 1024 * (sizeof(struct inotify_event) + 16)
+#define NOTIFYMASK IN_MODIFY | IN_CREATE | IN_DELETE | IN_ONESHOT
+
+mixState state = { .input = NULL, .output = NULL, .name = NULL, .dBGain = -90 };
+char *workdir;
+char *inotifyBuffer;
+bool changedDir = false;
+
+void initState()
+{
+        const char *defaultName = "mixer";
+        
+        state.input = malloc(sizeof(char));
+        *(state.input) = '\0';
+        state.output = malloc(sizeof(char));
+        *(state.output) = '\0';
+        state.name = malloc(sizeof(char) * (1 + strlen(defaultName)));
+        strcpy(state.name, defaultName);
+}
+
+void signalHandler(int signal)
+{
+        fprintf(stderr, "Received signal: %d\n", signal);
+        cleanExit(1);
+}
+
+void setupSignalHandler()
+{
+        signal(SIGABRT, signalHandler);
+        signal(SIGFPE, SIG_IGN);
+        signal(SIGILL, SIG_IGN);
+        signal(SIGINT, signalHandler);
+        signal(SIGTERM, signalHandler);
+        signal(SIGSEGV, signalHandler);
+}
+
+void parseArgs(int argc, char *argv[])
+{
+        char opt;
+        
+        while ((opt = getopt(argc, argv, "g:n:i:o:")) != -1)
+                {
+                        switch (opt)
+                                {
+                                case 'g':
+                                        sscanf(optarg, "%f", &(state.dBGain));
+                                        break;
+                                case 'n':
+                                        state.name = realloc(state.name, sizeof(char) * (1 + strlen(optarg)));
+                                        strcpy(state.name, optarg);
+                                        break;
+                                case 'i':
+                                        state.input = realloc(state.input, sizeof(char) * (1 + strlen(optarg)));
+                                        strcpy(state.input, optarg);
+                                        break;
+                                case 'o':
+                                        state.output = realloc(state.output, sizeof(char) * (1 + strlen(optarg)));
+                                        strcpy(state.output, optarg);
+                                        break;
+                                }
+                }
+
+        if (optind > argc - 1)
+                {
+                        fprintf(stderr, "Usage: %s [-g {gain}] [-n {name}] [-i {input}] [-o {output}] {working directory}\n", argv[0]);
+                        cleanExit(2);
+                }
+
+        workdir = argv[optind++];
+}
+
+void setWorkdir()
+{
+        if (!(mkdir(workdir, DIRMODE) == 0 || errno == EEXIST) || chdir(workdir) == -1)
+                errMsg(1, &errno, "Failed to change to workdir", workdir);
+        changedDir = true;
+}
+
+void writePid()
+{
+        FILE *pidFile;
+        
+        openSyncFile(&pidFile, PIDFILE, "wx", false);
+        if (fprintf(pidFile, "%d\n", getpid()) <= 1)
+                errMsg(1, &errno, "Failed to write to pidfile", PIDFILE);
+        fclose(pidFile);
+}
+
+void syncState()
+{
+        readState();
+        writeState();
+}
+
+void readState()
+{
+        FILE *pidFile;
+        FILE *inputFile;
+        FILE *outputFile;
+        FILE *nameFile;
+        FILE *gainFile;
+        int newInt;
+        char newString[64];
+        float newFloat;
+        int ret;
+
+        if (openSyncFile(&pidFile, PIDFILE, "r", true) == -1)
+                {
+                        ret = fscanf(pidFile, "%d", &newInt);
+                        fclose(pidFile);
+
+                        if (ret == 0 || ret == EOF || newInt != getpid())
+                                cleanExit(0);
+                }
+        else
+                cleanExit(0);
+
+        if (openSyncFile(&inputFile, INPUTFILE, "r", true) == -1)
+                {
+                        ret = fscanf(inputFile, "%63s", newString);
+                        fclose(inputFile);
+
+                        if (ret != 0 && ret != EOF)
+                                {
+                                        // TODO Try to set new jack input here
+                                        state.input = realloc(state.input, sizeof(char) * (1 + strlen(newString)));
+                                        strcpy(state.input, newString);
+                                }
+                }
+        if (openSyncFile(&outputFile, OUTPUTFILE, "r", true) == -1)
+                {
+                        ret = fscanf(outputFile, "%63s", newString);
+                        fclose(outputFile);
+
+                        if (ret != 0 && ret != EOF)
+                                {
+                                        // TODO Try to set new jack output here
+                                        state.output = realloc(state.output, sizeof(char) * (1 + strlen(newString)));
+                                        strcpy(state.output, newString);
+                                }
+                }
+
+        if (openSyncFile(&gainFile, GAINFILE, "r", true) == -1)
+                {
+                        ret = fscanf(gainFile, "%f", &newFloat);
+                        fclose(gainFile);
+
+                        if (ret != 0 && ret != EOF)
+                                {
+                                        if (newFloat < -90)
+                                                newFloat = -90;
+                                        state.dBGain = newFloat;
+                                }
+                }
+}
+
+void writeState()
+{
+        FILE *pidFile;
+        FILE *inputFile;
+        FILE *outputFile;
+        FILE *nameFile;
+        FILE *gainFile;
+        int ret;
+
+        openSyncFile(&pidFile, PIDFILE, "w", false);
+        ret = fprintf(pidFile, "%d\n", getpid());
+        if (ret < 1)
+                errMsg(1, &errno, "Failed to write pidfile", PIDFILE);
+        fclose(pidFile);
+
+        openSyncFile(&inputFile, INPUTFILE, "w", false);
+        ret = fprintf(inputFile, "%s\n", state.input);
+        if (ret < 1)
+                errMsg(1, &errno, "Failed to write file", INPUTFILE);
+        fclose(inputFile);
+
+        openSyncFile(&outputFile, OUTPUTFILE, "w", false);
+        ret = fprintf(outputFile, "%s\n", state.output);
+        if (ret < 1)
+                errMsg(1, &errno, "Failed to write file", OUTPUTFILE);
+        fclose(outputFile);
+
+        openSyncFile(&nameFile, NAMEFILE, "w", false);
+        ret = fprintf(nameFile, "%s\n", state.name);
+        if (ret < 1)
+                errMsg(1, &errno, "Failed to write file", NAMEFILE);
+        fclose(nameFile);
+
+        openSyncFile(&gainFile, GAINFILE, "w", false);
+        ret = fprintf(gainFile, "%.2f\n", state.dBGain);
+        if (ret < 1)
+                errMsg(1, &errno, "Failed to write file", GAINFILE);
+        fclose(gainFile);
+}
+
+int openSyncFile(FILE **file, char *fileName, char *fileMode, bool errOK)
+{
+        int ret = -1;
+        
+        if ((*file = fopen(fileName, fileMode)) == NULL)
+                {
+                        if (errOK == false)
+                                errMsg(1, &errno, "Failed to open file", fileName);
+                        else
+                                {
+                                        ret = errno;
+                                }
+                }
+
+        return ret;
+}
+
+int main(int argc, char *argv[])
+{       
+        int inotifyFD;
+
+        initState();
+        inotifyBuffer = malloc(INOTIFYBUFLEN);
+        setupSignalHandler();
+        
+        parseArgs(argc, argv);
+        setWorkdir();
+
+        writePid();
+        writeState();
+
+        inotifyFD = inotify_init();
+        if (inotifyFD < 0)
+                errMsg(1, NULL, "Failed to setup inotify", NULL);
+
+        do
+                {
+                        syncState();
+                        printf("State:\n  input = %s\n  output = %s\n  name = %s\n  gain = %.2fdB\n", state.input, state.output, state.name, state.dBGain);
+                        inotify_add_watch(inotifyFD, ".", NOTIFYMASK);
+                }
+        while (read(inotifyFD, inotifyBuffer, INOTIFYBUFLEN) >= 0);
+
+        exit(0);
+}
+
+void cleanExit(int r)
+{
+        if (changedDir == true)
+                {
+                        if (unlink(PIDFILE) != 0 && errno != ENOENT)
+                                errMsg(-1, &errno, "Failed to delete pidfile", PIDFILE);
+                }
+  free(state.input);
+  free(state.output);
+        free(state.name);
+        free(inotifyBuffer);
+        exit(r);
+}
+
+void errMsg(int r, int *errno, char *head, char *detail)
+{
+        int err;
+        bool error = false;
+
+        if (errno != NULL)
+                {
+                        error = true;
+                        err = *errno;
+                }
+        
+        fprintf(stderr, "%s\n", head);
+        if (detail != NULL)
+                fprintf(stderr, "  %s\n", detail);
+        if (error == true)
+                fprintf(stderr, "  (%d) %s\n", err, strerror(err));
+
+        if (r >= 0)
+                cleanExit(r);
+}
diff --git a/trivmix.h b/trivmix.h
new file mode 100644
index 0000000..03b5860
--- /dev/null
+++ b/trivmix.h
@@ -0,0 +1,21 @@
+typedef struct mixState {
+        char *input;
+        char *output;
+        char *name;
+        float dBGain;
+} mixState;
+
+typedef enum bool {
+        false,
+        true
+} bool;
+
+void parseArgs(int argc, char *argv[]);
+void setWorkdir();
+void syncState();
+void readState();
+void writeState();
+int openSyncFile(FILE **file, char *fileName, char *fileMode, bool errOK);
+
+void cleanExit(int r);
+void errMsg(int r, int *errno, char *head, char *detail);