add rudimentary unit tests, and logging timestamps

Signed-off-by: Aidan Hahn <aidan@aidanis.online>

Makefile

@@ -1,8 +1,8 @@
 CC ?= gcc
-CFLAGS = -fPIC -Wall -Wextra -O2 -c
-LDFLAGS = -shared
 BUILD_DIR ?= $(shell pwd)/build
 TARGET_DIR ?= $(shell pwd)/target
+CFLAGS = -Wall -Wextra -O2
+LDFLAGS = -shared
 
 ifdef ALOG_HIJACK_PRINTF
 CFLAGS += -DALOG_HIJACK_PRINTF
@@ -12,17 +12,20 @@ ifdef ALOG_DEBUG
 CFLAGS += -g
 endif
 
-OBJ = $(BUILD_DIR)/alog.o
-LIB = $(TARGET_DIR)/alog.so
+ALOG_SRC = alog.c
+ALOG_OBJ = $(BUILD_DIR)/alog.o
+ALOG_LIB = $(TARGET_DIR)/alog.so
+
+include tests/tests.mk
 
 .PHONY: so
-so: $(if $(shell stat $(LIB)), clean) $(LIB)
+so: $(if $(shell stat $(ALOG_LIB)), clean) $(ALOG_LIB)
 
-$(LIB): $(TARGET_DIR) $(OBJ)
-	$(CC) $(LDFLAGS) -o $(LIB) $(OBJ)
+$(ALOG_LIB): $(TARGET_DIR) $(ALOG_OBJ)
+	$(CC) $(LDFLAGS) -o $(ALOG_LIB) $(ALOG_OBJ)
 
-$(OBJ): $(BUILD_DIR)
-	$(CC) $(CFLAGS) alog.c -o $(OBJ)
+$(ALOG_OBJ): $(BUILD_DIR)
+	$(CC) $(CFLAGS) -fPIC -c alog.c -o $(ALOG_OBJ)
 
 $(BUILD_DIR):
 	mkdir $(BUILD_DIR)
@@ -32,4 +35,4 @@ $(TARGET_DIR):
 
 .PHONY: clean
 clean:
-	rm $(LIB) $(OBJ)
+	rm $(ALOG_LIB) $(ALOG_OBJ)

README.md

@@ -1,13 +1,28 @@
 # Introduction
 - *alog* or *a logger* is a lightweight, portable logger written in C.
 - It is entirely unremarkable
-- Usage of *alog* is extremely simple. [See the API](alog.h)
+- Usage of *alog* is extremely simple.
+
+### What kind of things can I log to?
+Anything that is a file descriptor and can be written to with write() and fsync(). This includes the following:
+- pipes
+- files
+- stdout
+- stderr
+- sockets (untested)
+
+### How do I use this library?
+- [See the API](alog.h)
+- [See the tests](tests/log_test.c)
 
 # How to build
 ```bash
 $ make so
 ```
 
+# How to test
+```
+
 # Variables
 The following (shell) variables can be set to influence behavior at runtime:
 

alog.c

@@ -20,6 +20,8 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <string.h>
+#include <time.h>
 
 #define TEST_ALOG_STATE() if (!ALOG_LOGGING_STATE) { _init_alog(); }
 
@@ -37,7 +39,7 @@ void _init_alog() {
   _alog_num_err_fds = 1;
   _alog_err_fds = malloc(sizeof(int) * 1);
   // stderr
-  _alog_err_fds[1] = 2;
+  _alog_err_fds[0] = 2;
 }
 
 // TODO: should I dont close stdin and stdout?
@@ -81,6 +83,12 @@ void alog_remove_target(int fd) {
     }
   }
 
+  if (!out_fds) {
+    _alog_num_out_fds = 0;
+    free(_alog_out_fds);
+    _alog_out_fds = NULL;
+
+  } else {
     int *tmp_outs = malloc(sizeof(int) * out_fds);
     int tmp_iter_idx = 0;
     for (int i = 0; i < _alog_num_out_fds; i++) {
@@ -93,6 +101,7 @@ void alog_remove_target(int fd) {
     free(_alog_out_fds);
     _alog_out_fds = tmp_outs;
     _alog_num_out_fds = out_fds;
+  }
 
   int err_fds = 0;
   for (int i = 0; i < _alog_num_err_fds; i++) {
@@ -101,8 +110,14 @@ void alog_remove_target(int fd) {
     }
   }
 
+  if (!err_fds) {
+    _alog_num_err_fds = 0;
+    free(_alog_err_fds);
+    _alog_err_fds = NULL;
+
+  } else {
     int *tmp_errs = malloc(sizeof(int) * err_fds);
-  tmp_iter_idx = 0;
+    int tmp_iter_idx = 0;
     for (int i = 0; i < _alog_num_err_fds; i++) {
       if (_alog_err_fds[i] != fd) {
         tmp_errs[tmp_iter_idx] = _alog_err_fds[i];
@@ -113,8 +128,11 @@ void alog_remove_target(int fd) {
     free(_alog_err_fds);
     _alog_err_fds = tmp_errs;
     _alog_num_err_fds = err_fds;
+  }
 }
 
+// TODO: use preprocessor directives to gate off the posix timestamp stuff
+// unless the right variable is passed in at compile time
 void alog (
   alog_sev severity,
   const char * message,
@@ -130,9 +148,28 @@ void alog (
   va_list fmt_list;
   va_start(fmt_list, message);
 
-  int size = snprintf(NULL, 0, message, fmt_list);
-  char *buffer = malloc(size + 1);
+  char *buffer;
+  int size;
+  if (severity != PRINT) {
+    // GET TIMESTAMP
+    time_t t = time(NULL);
+    struct tm * p = localtime(&t);
+    int timestamp_size = strftime(NULL, 0, "[%c]", p);
+    char *timestamp = malloc(sizeof(char) * (timestamp_size+1));
+    strftime(timestamp, timestamp_size, "[%c]", p);
+    char *msg_and_timestamp = malloc(sizeof(char) * (timestamp_size + strlen(message) + 3));
+    sprintf(msg_and_timestamp, "%s %s\n", timestamp, message);
+    free(timestamp);
+    size = snprintf(NULL, 0, msg_and_timestamp, fmt_list);
+    buffer = malloc(size + 1);
+    sprintf(buffer, msg_and_timestamp, fmt_list);
+    free(msg_and_timestamp);
+  // if severity is PRINT we avoid timestamp
+  } else {
+    size = snprintf(NULL, 0, message, fmt_list);
+    buffer = malloc(size + 1);
     sprintf(buffer, message, fmt_list);
+  }
 
   for (int i = 0; i < _alog_num_out_fds; i++) {
     if (write(_alog_out_fds[i], buffer, size) < size) {

alog.h

@@ -71,6 +71,8 @@ void deinit_alog();
 
 /* adds an fd to out fds or (iff char arg is set to 0x01) err fds */
 void alog_add_target(int, char);
+#define ALOG_OUT 0x00
+#define ALOG_ERR 0x01
 
 /* removes an fd from both out fds and err fds */
 void alog_remove_target(int);

tests/log_test.c

@@ -0,0 +1,82 @@
+#include "../alog.h"
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <string.h>
+
+int out_fd[2];
+int err_fd[2];
+
+const char *out_message = "standard message";
+const char *err_message = "error message";
+
+int main() {
+  // make RPC pipe
+  pipe(out_fd);
+  pipe(err_fd);
+
+  // remove stdout and stderr
+  _init_alog();
+  alog_remove_target(1);
+  alog_remove_target(2);
+
+  pid_t childpid;
+  if ((childpid = fork()) == -1) {
+    perror("fork fail");
+    return 1;
+  }
+
+  // child process
+  if (childpid == 0) {
+    close(out_fd[0]);
+    close(err_fd[0]);
+
+    // add alog targets in this pipe
+    alog_add_target(out_fd[1], ALOG_OUT);
+    alog_add_target(err_fd[1], ALOG_ERR);
+
+    // write to the things
+    alog(ERROR, err_message);
+    alog(PRINT, out_message);
+
+    exit(0);
+  // parent process
+  } else {
+    // we can do checks from here
+    char out_read_buffer[128] = {0};
+    char err_read_buffer[128] = {0};
+
+    usleep(10);
+
+    read(err_fd[0], err_read_buffer, 128);
+    // cant check read len because of timestamp
+    if (!strstr(err_read_buffer, err_message)) {
+      printf("err log should contain '%s'.\ninstead reads '%s'\n",
+             err_message, err_read_buffer);
+      return 1;
+    }
+
+    int num_out = read(out_fd[0], out_read_buffer, 128);
+    if (num_out != (int) (strlen(out_message) + strlen(err_read_buffer))) {
+      printf("Read %i bytes from out log when %lu were written!\n",
+             num_out, strlen(out_message) + strlen(err_read_buffer) + 1);
+      return 1;
+    }
+    if (strncmp(out_read_buffer, err_read_buffer, strlen(err_read_buffer))) {
+      printf("out log first message should read '%s'.\ninstead reads '%s'\n",
+             err_read_buffer, out_read_buffer);
+    }
+    if (strcmp(&out_read_buffer[strlen(err_read_buffer)], out_message)) {
+      printf("out log second message should read '%s'.\ninstead reads '%s'\n",
+             out_message, &out_read_buffer[strlen(err_read_buffer)]);
+      return 1;
+    }
+
+
+    printf("out and err log printing are successfull.\n");
+  }
+
+  deinit_alog();
+  return 0;
+}

tests/tests.mk

@@ -0,0 +1,12 @@
+ALOG_TEST_SRCS = $(shell find tests -iname "*.c" -exec basename {} \;)
+ALOG_TESTS = $(ALOG_TEST_SRCS:.c=)
+
+$(ALOG_TESTS): $(ALOG_LIB)
+	$(CC) $(CFLAGS) -g -o $(BUILD_DIR)/$@.o -c tests/$@.c
+	$(CC) -o $(TARGET_DIR)/$@ $(BUILD_DIR)/$@.o $(ALOG_LIB)
+	chmod +x $(TARGET_DIR)/$@
+
+run-tests: $(ALOG_TESTS)
+	for test in $^ ; do \
+		$(TARGET_DIR)/$$test ; \
+	done