Use Boehm-Demers-Weiser Garbage Collector.

From their own documentation:

  The Boehm-Demers-Weiser conservative garbage collector can be used as a
  garbage collecting replacement for C malloc or C++ new. It allows you to
  allocate memory basically as you normally would, without explicitly
  deallocating memory that is no longer useful. The collector automatically
  recycles memory when it determines that it can no longer be otherwise
  accessed.

In pgcopydb C code base it's been hard to maintain proper malloc/free
concerns while also implementing proper error-handling, which is a common
problem when writing C code. In order to ease the maintenance of the code
and reduce production hazards, the best way to proceed looks like automating
the memory management altogether by using a Garbage Collector.

Dockerfile

@@ -15,6 +15,7 @@ RUN dpkg --add-architecture ${TARGETARCH:-arm64} && apt update \
     valgrind \
     build-essential \
     libedit-dev \
+    libgc-dev \
     libicu-dev \
     libkrb5-dev \
     liblz4-dev \
@@ -65,7 +66,8 @@ RUN dpkg --add-architecture ${TARGETARCH:-arm64} && apt update \
     sudo \
 	passwd \
     ca-certificates \
-    libpq5 \
+    libgc1 \
+	libpq5 \
 	libsqlite3-0 \
 	lsof \
     tmux \

debian/control

@@ -7,6 +7,7 @@ Uploaders:
 Build-Depends:
  debhelper-compat (= 13),
  libedit-dev,
+ libgc-dev,
  libkrb5-dev,
  liblz4-dev,
  libncurses-dev,

src/bin/lib/subcommands.c/runprogram.h

@@ -18,6 +18,21 @@
 
 #include "pqexpbuffer.h"
 
+/*
+ * Setup Boehm-Demers-Weiser conservative garbage collector as a garbage
+ * collecting replacement for malloc. See https://www.hboehm.info/gc/
+ */
+#include <gc/gc.h>
+
+#define malloc(n) GC_malloc(n)
+#define calloc(m,n) GC_malloc((m)*(n))
+#define free(p) GC_free(p)
+#define realloc(p,n) GC_realloc((p),(n))
+#define CHECK_LEAKS() GC_gcollect()
+
+/*
+ * Now setup internal constants
+ */
 #define BUFSIZE 1024
 #define ARGS_INCREMENT 12
 
@@ -51,7 +66,7 @@ typedef struct
 	char *stdErr;
 } Program;
 
-Program run_program(const char *program, ...);
+Program *run_program(const char *program, ...);
 void initialize_program(Program *prog, char **args, bool setsid);
 void execute_subprogram(Program *prog);
 void execute_program(Program *prog);
@@ -77,51 +92,55 @@ static void waitprogram(Program *prog, pid_t childPid);
  * the run and then return a Program struct instance with the result of running
  * the program.
  */
-Program
+Program *
 run_program(const char *program, ...)
 {
 	int nb_args = 0;
 	va_list args;
 	const char *param;
-	Program prog = { 0 };
-
-	prog.program = strdup(program);
-	prog.returnCode = -1;
-	prog.error = 0;
-	prog.setsid = false;
-	prog.capture = true;
-	prog.tty = false;
-	prog.processBuffer = NULL;
-	prog.stdOutFd = -1;
-	prog.stdErrFd = -1;
-	prog.stdOut = NULL;
-	prog.stdErr = NULL;
-
-	prog.args = (char **) malloc(ARGS_INCREMENT * sizeof(char *));
-	prog.args[nb_args++] = prog.program;
+	Program *prog = (Program *) malloc(sizeof(Program));
+
+	if (prog == NULL)
+	{
+		return NULL;
+	}
+
+	prog->program = strdup(program);
+	prog->returnCode = -1;
+	prog->error = 0;
+	prog->setsid = false;
+	prog->capture = true;
+	prog->tty = false;
+	prog->processBuffer = NULL;
+	prog->stdOutFd = -1;
+	prog->stdErrFd = -1;
+	prog->stdOut = NULL;
+	prog->stdErr = NULL;
+
+	prog->args = (char **) malloc(ARGS_INCREMENT * sizeof(char *));
+	prog->args[nb_args++] = prog->program;
 
 	va_start(args, program);
 	while ((param = va_arg(args, const char *)) != NULL)
 	{
 		if (nb_args % ARGS_INCREMENT == 0)
 		{
-			char **newargs = (char **) malloc((ARGS_INCREMENT *
-											   (nb_args / ARGS_INCREMENT + 1)) *
-											  sizeof(char *));
-			for (int i = 0; i < nb_args; i++)
+			int newcount = (ARGS_INCREMENT * (nb_args / ARGS_INCREMENT + 1));
+			size_t newsize = newcount * sizeof(char *);
+
+			prog->args = (char **) realloc(prog->args, newsize);
+
+			if (prog->args == NULL)
 			{
-				newargs[i] = prog.args[i];
+				return NULL;
 			}
-			free(prog.args);
-
-			prog.args = newargs;
 		}
-		prog.args[nb_args++] = strdup(param);
+		prog->args[nb_args++] = strdup(param);
 	}
 	va_end(args);
-	prog.args[nb_args] = NULL;
+	prog->args[nb_args] = NULL;
 
-	execute_subprogram(&prog);
+	execute_subprogram(prog);
 
 	return prog;
 }

src/bin/pgcopydb/Makefile

@@ -80,6 +80,7 @@ LIBS += $(shell $(PG_CONFIG) --libs)
 LIBS += -lpq
 LIBS += -lncurses
 LIBS += -lsqlite3
+LIBS += -lgc
 
 all: $(PGCOPYDB) ;