cmd_line: read executable name from /proc/self/exe

8 files changed, 91 insertions, 16 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 30fb3fd..6f2cc6b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -36,6 +36,7 @@ generate_sql_header(sqlite)
 add_my_executable(server server_main.c server.c
     ci_queue.c
     cmd_line.c
+    file.c
     msg.c
     net.c
     signal.c
@@ -49,6 +50,7 @@ target_include_directories(server PRIVATE "${CMAKE_CURRENT_BINARY_DIR}")
 
 add_my_executable(client client_main.c client.c
     cmd_line.c
+    file.c
     msg.c
     net.c)
 
diff --git a/src/client_main.c b/src/client_main.c
index 4574e44..a895ccf 100644
--- a/src/client_main.c
+++ b/src/client_main.c
@@ -39,7 +39,7 @@ static int parse_settings(struct settings *settings, int argc, char *argv[])
 	while ((opt = getopt_long(argc, argv, "hVH:p:", long_options, &longind)) != -1) {
 		switch (opt) {
 		case 'h':
-			exit_with_usage(0, argv[0]);
+			exit_with_usage(0);
 			break;
 		case 'V':
 			exit_with_version();
@@ -51,7 +51,7 @@ static int parse_settings(struct settings *settings, int argc, char *argv[])
 			settings->port = optarg;
 			break;
 		default:
-			exit_with_usage(1, argv[0]);
+			exit_with_usage(1);
 			break;
 		}
 	}
diff --git a/src/cmd_line.c b/src/cmd_line.c
index 9527d6f..fee18d4 100644
--- a/src/cmd_line.c
+++ b/src/cmd_line.c
@@ -6,29 +6,68 @@
  */
 
 #include "cmd_line.h"
+#include "file.h"
+#include "log.h"
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
-void exit_with_usage(int ec, const char *argv0)
+static char *get_current_binary_path()
 {
-	FILE *dest = stdout;
+	return my_readlink("/proc/self/exe");
+}
+
+static char *get_current_binary_name()
+{
+	char *path, *name, *result;
+
+	path = get_current_binary_path();
+	if (!path)
+		return NULL;
+
+	name = basename(path);
+
+	result = strdup(name);
+	if (!result) {
+		log_errno("strdup");
+		goto free_path;
+	}
+
+free_path:
+	free(path);
+
+	return result;
+}
+
+void exit_with_usage(int ec)
+{
+	char *binary;
+	FILE *dest;
+
+	dest = stdout;
 	if (ec)
 		dest = stderr;
 
-	fprintf(dest, "usage: %s %s\n", argv0, get_usage_string());
+	binary = get_current_binary_name();
+
+	fprintf(dest, "usage: %s %s\n", binary ?: "prog", get_usage_string());
+	free(binary);
 	exit(ec);
 }
 
-void exit_with_usage_err(const char *argv0, const char *msg)
+void exit_with_usage_err(const char *msg)
 {
 	if (msg)
 		fprintf(stderr, "usage error: %s\n", msg);
-	exit_with_usage(1, argv0);
+	exit_with_usage(1);
 }
 
 void exit_with_version()
 {
-	printf("%s\n", VERSION);
+	char *binary = get_current_binary_name();
+
+	printf("%s %s\n", binary ?: "prog", VERSION);
+	free(binary);
 	exit(0);
 }
diff --git a/src/cmd_line.h b/src/cmd_line.h
index a661825..58cdb9a 100644
--- a/src/cmd_line.h
+++ b/src/cmd_line.h
@@ -10,8 +10,8 @@
 
 const char *get_usage_string();
 
-void exit_with_usage(int ec, const char *argv0);
-void exit_with_usage_err(const char *argv0, const char *msg);
+void exit_with_usage(int ec);
+void exit_with_usage_err(const char *msg);
 void exit_with_version();
 
 #endif
diff --git a/src/file.c b/src/file.c
index 55e1691..bc7af8e 100644
--- a/src/file.c
+++ b/src/file.c
@@ -63,6 +63,40 @@ free_old:
 	return ret;
 }
 
+char *my_readlink(const char *path)
+{
+	size_t current_size = 256;
+	char *buf = NULL;
+
+	while (1) {
+		buf = realloc(buf, current_size);
+		if (!buf) {
+			log_errno("realloc");
+			goto free;
+		}
+
+		ssize_t res = readlink(path, buf, current_size);
+		if (res < 0) {
+			log_errno("readlink");
+			goto free;
+		}
+
+		if ((size_t)res == current_size) {
+			current_size *= 2;
+			continue;
+		}
+
+		break;
+	}
+
+	return buf;
+
+free:
+	free(buf);
+
+	return NULL;
+}
+
 int file_exists(const char *path)
 {
 	struct stat stat;
diff --git a/src/file.h b/src/file.h
index a68f628..ec3701c 100644
--- a/src/file.h
+++ b/src/file.h
@@ -13,9 +13,9 @@
 int rm_rf(const char *dir);
 
 int my_chdir(const char *dir, char **old);
+char *my_readlink(const char *path);
 
 int file_exists(const char *path);
-
 int file_read(int fd, char **output, size_t *len);
 
 #endif
diff --git a/src/server_main.c b/src/server_main.c
index 02304b2..cdd73b3 100644
--- a/src/server_main.c
+++ b/src/server_main.c
@@ -39,7 +39,7 @@ static int parse_settings(struct settings *settings, int argc, char *argv[])
 	while ((opt = getopt_long(argc, argv, "hVp:s:", long_options, &longind)) != -1) {
 		switch (opt) {
 		case 'h':
-			exit_with_usage(0, argv[0]);
+			exit_with_usage(0);
 			break;
 		case 'V':
 			exit_with_version();
@@ -51,13 +51,13 @@ static int parse_settings(struct settings *settings, int argc, char *argv[])
 			settings->sqlite_path = optarg;
 			break;
 		default:
-			exit_with_usage(1, argv[0]);
+			exit_with_usage(1);
 			break;
 		}
 	}
 
 	if (!settings->sqlite_path) {
-		exit_with_usage_err(argv[0], "must specify the path to a SQLite database");
+		exit_with_usage_err("must specify the path to a SQLite database");
 		return -1;
 	}
 
diff --git a/src/worker_main.c b/src/worker_main.c
index 9e9a0b9..540eea1 100644
--- a/src/worker_main.c
+++ b/src/worker_main.c
@@ -40,7 +40,7 @@ static int parse_settings(struct settings *settings, int argc, char *argv[])
 	while ((opt = getopt_long(argc, argv, "hVH:p:", long_options, &longind)) != -1) {
 		switch (opt) {
 		case 'h':
-			exit_with_usage(0, argv[0]);
+			exit_with_usage(0);
 			break;
 		case 'V':
 			exit_with_version();
@@ -52,7 +52,7 @@ static int parse_settings(struct settings *settings, int argc, char *argv[])
 			settings->port = optarg;
 			break;
 		default:
-			exit_with_usage(1, argv[0]);
+			exit_with_usage(1);
 			break;
 		}
 	}