don't print function name in dbg_handle_sigsegv()

.debugusrc1.js

@@ -0,0 +1,2 @@
+lif("Loading user init script for program ./test");
+lsf();

.debugusrc1.js.txt

@@ -1,35 +0,0 @@
-// User script
-
-lif("Loading user init script for program ./test");
-ler("Test error message");
-
-var offset = "@DUPA_ADDR"; // dupa(), objdump -d ./test
-
-// Testing...
-// pf();
-// ppid();
-// pplo();
-// baddr(offset);
-bfn("dupa");
-// rmbfn("dupa");
-lsbrk();
-lsf();
-
-// lif("1 --------------------------------------------");
-// dr();
-// var r14 = gr("r14");
-// sr("r14", "0x0");
-// lif("2 --------------------------------------------");
-// dr();
-// sr("r14", r14);
-// lif("3 --------------------------------------------");
-// dr();
-
-// var r14_mem = mrdr("r14");
-// lif("Memory at r14 " + r14_mem);
-// mwrr("r14", "0x696969");
-// lif("Memory at r14 " + mrdr("r14"));
-// mwrr("r14", r14_mem);
-// lif("Memory at r14 " + mrdr("r14"));
-
-// cont();

.gitignore

@@ -2,4 +2,3 @@
 *.d
 debugus
 test
-.debugusrc1.js

Makefile

@@ -6,17 +6,14 @@ SRCS=debugus.c linenoise.c hash.c pmparser.c
 OBJS=$(patsubst %.c,%.o,$(SRCS))
 DEPS=$(patsubst %.c,%.d,$(SRCS))
 
-all: debugus .debugusrc1.js test
+all: debugus test
 
-test: test.o
-	$(CC) $(CFLAGS) -o $@ $^
+test: test.o test2.o
+	$(CC) -o $@ $^
 
 debugus: $(OBJS) ./mujs/build/debug/libmujs.o ./libelfin_wrap.o
 	$(CC) -o $@ $^ $(LDFLAGS)
 
-.debugusrc1.js: test .debugusrc1.js.txt
-	cat .debugusrc1.js.txt | sed "s/@DUPA_ADDR/0x$$(nm ./test | grep 'dupa' | awk '{ print $$1 }')/g" > .debugusrc1.js
-
 ./mujs/build/debug/libmujs.o:
 	make -C mujs -j$(shell nproc)
 
@@ -25,7 +22,7 @@ debugus: $(OBJS) ./mujs/build/debug/libmujs.o ./libelfin_wrap.o
 
 -include $(DEPS)
 
-clean: $(OBJS) test.o $(DEPS) .debugusrc1.js
+clean: $(OBJS) test.o test2.o $(DEPS)
 	rm -f $^
 	make -C mujs clean
 

debugus.c

@@ -9,6 +9,7 @@
 #include <string.h>
 #include <errno.h>
 #include <signal.h>
+#include <time.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/ptrace.h>
@@ -22,6 +23,27 @@
 #include "da.h"
 #include "libelfin_wrap.h"
 
+
+// They took my usleep() away >;( fuck u POSIX
+int msleep(long msec)
+{
+    struct timespec  ts;
+    int res;
+
+    if (msec < 0) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    ts.tv_sec = msec/1000;
+    ts.tv_nsec = (msec%1000) * 1000000;
+
+    do {
+        res = nanosleep(&ts, &ts);
+    } while(res && errno == EINTR);
+    return res;
+}
+
 #define LOG_ERR(fmt, ...) fprintf(stderr, "Error: " fmt, ##__VA_ARGS__)
 #define LOG_INF(fmt, ...) fprintf(stdout, "Info:  " fmt, ##__VA_ARGS__)
 
@@ -32,6 +54,53 @@
 #define INIT_SCRIPT ".debugusrc.js"
 #define MAX_JS_FUNCS 100
 
+#define SOURCE_EXPANSION 4
+
+void print_source(const char *file, size_t line)
+{
+    FILE *src = fopen(file, "r");
+    if (src == NULL) {
+        LOG_ERR("No source file found\n");
+        return;
+    }
+    fseek(src, 0L, SEEK_END);
+    long sz = ftell(src);
+    rewind(src);
+    
+    char *srcbuf = malloc(sz+1);
+    fread(srcbuf, sz, 1, src);
+    srcbuf[sz] = '\0';                    
+
+    const int expand = SOURCE_EXPANSION;
+
+    char *p = srcbuf;
+    size_t i = 0;
+    while (p) {
+        char *next = strchr(p, '\n');
+        if (next) {
+            *next = '\0';
+        }
+
+        int lo = line - expand;
+        int hi = line + expand;
+        if (i >= (lo < 0 ? 0 : lo) && i <= hi ) {
+            char prefix[20];
+            snprintf(prefix, sizeof(prefix), "%2s %6zu", i == line ? "->" : "", i);
+            printf("%s %s\n", prefix, p);
+        }
+
+        if (next) {
+            *next = '\n';
+        }
+
+        p = next ? (next + 1) : NULL;
+        i++;
+    }
+
+    free(srcbuf);
+    fclose(src);
+}
+
 // Registers
 // Taken from da goat https://source.winehq.org/source/dlls/dbghelp/cpu_x86_64.c
 
@@ -119,7 +188,6 @@ static RegisterDescriptor reg_descriptors[MAX_REGISTERS] = {
 
 typedef struct {
     pid_t pid;
-    pid_t proc_pid;
     uintptr_t addr;
     bool enabled;
     uint8_t data;
@@ -145,14 +213,6 @@ void brk_disable(Brk *brk)
     brk->enabled = false;
 }
 
-void symbols_deinit(Symbols *s)
-{
-    for (int i = 0; i < s->count; i++) {
-        free((char *)s->items[i].name);
-    }
-    da_deinit(s);
-}
-
 typedef struct {
     const char *file;
     pid_t pid;
@@ -160,11 +220,22 @@ typedef struct {
     HashTable brks;
     uintptr_t program_load_offset;
     HashTable js_descs;
-    Symbols symbols;
+    Funcs funcs;
     FILE *binfile;
     PLibelfinBinding plibelfin;
 } Dbg;
 
+void funcs_deinit(Funcs *fs)
+{
+    for (int i = 0; i < fs->count; i++) {
+        free((char *)fs->items[i].name);
+        if (fs->items[i].ai != NULL) {
+            libelfin_wrap_free_info(fs->items[i].ai);
+        }
+    }
+    da_deinit(fs);
+}
+
 siginfo_t dbg_get_siginfo(Dbg *dbg)
 {
     siginfo_t i;
@@ -178,23 +249,13 @@ void dbg_handle_sigsegv(Dbg *dbg, siginfo_t info)
     uint64_t dbg_get_rip(Dbg *dbg);
     LOG_ERR("Caught a segfault %d. SKILL ISSUE BRO\n", info.si_code);
     uintptr_t rip = (uintptr_t)dbg_get_rip(dbg);
-    uintptr_t nearest = rip - dbg->symbols.items[0].addr;
-    for (int i = 0; i < dbg->symbols.count; i++) {
-        if (rip - dbg->symbols.items[i].addr < nearest) {
-            nearest = rip - dbg->symbols.items[i].addr;
-        }
-    }
-    uintptr_t addr = rip - nearest;
-    for (int i = 0; i < dbg->symbols.count; i++) {
-        if (dbg->symbols.items[i].addr == addr) {
-            AddrInfo *ai = libelfin_wrap_info_from_rip(dbg->plibelfin, (uint64_t)(addr - dbg->program_load_offset));
+
+        
+    AddrInfo *ai = libelfin_wrap_info_from_rip(dbg->plibelfin, (uint64_t)(rip - dbg->program_load_offset));
     if (ai != NULL) {
-                LOG_INF("%s:%zu in function %s()\n", ai->file, (size_t)ai->line, dbg->symbols.items[i].name);
+        print_source(ai->file, ai->line);
         libelfin_wrap_free_info(ai);
     }
-            break;
-        }
-    }
 }
 
 void dbg_handle_sigtrap(Dbg *dbg, siginfo_t info)
@@ -211,6 +272,7 @@ void dbg_handle_sigtrap(Dbg *dbg, siginfo_t info)
             ai = libelfin_wrap_info_from_rip(dbg->plibelfin, dbg_get_rip(dbg) - (uint64_t)dbg->program_load_offset);
             if (ai != NULL) {
                 LOG_INF("Hit breakpoint at 0x%"PRIxPTR", %s:%zu\n", dbg_get_rip(dbg), ai->file, (size_t)ai->line);
+                print_source(ai->file, (size_t)ai->line);
                 libelfin_wrap_free_info(ai);
             } else {
                 LOG_INF("Hit breakpoint at 0x%"PRIxPTR"\n", dbg_get_rip(dbg));
@@ -326,7 +388,7 @@ void dbg_js_cont(js_State *js)
     js_pushundefined(js);
 }
 
-void dbg_js_baddr(js_State *js)
+void dbg_js_boff(js_State *js)
 {
     Dbg *dbg = getdbg();
     const char *addr_str = js_tostring(js, 1);
@@ -345,13 +407,13 @@ void dbg_js_bfn(js_State *js)
 {
     Dbg *dbg = getdbg();
     const char *fn_name = js_tostring(js, 1);
-    for (int i = 0; i < dbg->symbols.count; i++) {
-        Symbol *s = &dbg->symbols.items[i];
-        if (strcmp(fn_name, s->name) == 0) {
-            uintptr_t addr = s->addr;
+    for (int i = 0; i < dbg->funcs.count; i++) {
+        Func *f = &dbg->funcs.items[i];
+        if (strcmp(fn_name, f->name) == 0) {
             char addr_str2[20];
-            snprintf(addr_str2, sizeof(addr_str2), "0x%"PRIxPTR, addr);
-            Brk brk = { .pid = dbg->pid, .addr = addr };
+            snprintf(addr_str2, sizeof(addr_str2), "0x%"PRIxPTR,
+                    libelfin_wrap_func_addr(dbg->plibelfin, f));
+            Brk brk = { .pid = dbg->pid, .addr = libelfin_wrap_func_addr(dbg->plibelfin, f) };
             brk_enable(&brk);
             hashtable_set(&dbg->brks, addr_str2, &brk, sizeof(brk));
             break;
@@ -365,12 +427,12 @@ void dbg_js_rmbfn(js_State *js)
     Dbg *dbg = getdbg();
     const char *fn_name = js_tostring(js, 1);
 
-    for (int i = 0; i < dbg->symbols.count; i++) {
-        Symbol *s = &dbg->symbols.items[i];
-        if (strcmp(fn_name, s->name) == 0) {
-            uintptr_t addr = s->addr;
+    for (int i = 0; i < dbg->funcs.count; i++) {
+        Func *f = &dbg->funcs.items[i];
+        if (strcmp(fn_name, f->name) == 0) {
             char addr_str2[20];
-            snprintf(addr_str2, sizeof(addr_str2), "0x%"PRIxPTR, addr);
+            snprintf(addr_str2, sizeof(addr_str2), "0x%"PRIxPTR,
+                    libelfin_wrap_func_addr(dbg->plibelfin, f));
     
             Brk *brk = (Brk *)hashtable_get(&dbg->brks, addr_str2);
             if (brk == NULL) {
@@ -449,12 +511,12 @@ void dbg_js_lsbrk(js_State *js)
 void dbg_js_lsf(js_State *js)
 {
     Dbg *dbg = getdbg();
-    for (int i = 0; i < dbg->symbols.count; i++) {
-        Symbol *s = &dbg->symbols.items[i];
-        AddrInfo *ai = libelfin_wrap_info_from_rip(dbg->plibelfin, (uint64_t)(s->addr - dbg->program_load_offset));
-        if (ai != NULL) {
-            LOG_INF("Sym %s 0x%"PRIxPTR" %s:%zu\n", s->name, s->addr, ai->file, (size_t)ai->line);
-            libelfin_wrap_free_info(ai);
+    for (int i = 0; i < dbg->funcs.count; i++) {
+        Func *f = &dbg->funcs.items[i];
+        if (f->ai != NULL) {
+            LOG_INF("Sym %s 0x%"PRIxPTR" %s:%zu\n", f->name,
+                    libelfin_wrap_func_addr(dbg->plibelfin, f), f->ai->file,
+                    (size_t)f->ai->line);
         }
     }
 
@@ -557,6 +619,122 @@ void dbg_js_help(js_State *js)
     js_pushundefined(js);
 }
 
+void dbg_js_ebaddr(js_State *js)
+{
+    Dbg *dbg = getdbg();
+    const char *addr_str = js_tostring(js, 1);
+    Brk *brk = (Brk *)hashtable_get(&dbg->brks, addr_str);
+    if (brk == NULL) {
+        LOG_ERR("No breakpoint at address: %s\n", addr_str);
+        goto done;
+    }
+    brk_enable(brk);
+done:
+    js_pushundefined(js);
+}
+
+void dbg_js_dbaddr(js_State *js)
+{
+    Dbg *dbg = getdbg();
+    const char *addr_str = js_tostring(js, 1);
+    Brk *brk = (Brk *)hashtable_get(&dbg->brks, addr_str);
+    if (brk == NULL) {
+        LOG_ERR("No breakpoint at address: %s\n", addr_str);
+        goto done;
+    }
+    brk_disable(brk);
+done:
+    js_pushundefined(js);
+}
+
+void dbg_js_ebfn(js_State *js)
+{
+    Dbg *dbg = getdbg();
+    const char *fn_name = js_tostring(js, 1);
+
+    for (int i = 0; i < dbg->funcs.count; i++) {
+        Func *f = &dbg->funcs.items[i];
+        if (strcmp(fn_name, f->name) == 0) {
+            char addr_str2[20];
+            snprintf(addr_str2, sizeof(addr_str2), "0x%"PRIxPTR,
+                    libelfin_wrap_func_addr(dbg->plibelfin, f));
+    
+            Brk *brk = (Brk *)hashtable_get(&dbg->brks, addr_str2);
+            if (brk == NULL) {
+                LOG_ERR("No breakpoint at function: %s\n", fn_name);
+                goto done;
+            }
+            brk_enable(brk);
+            break;
+        }
+    }
+
+done:
+    js_pushundefined(js);
+}
+
+void dbg_js_dbfn(js_State *js)
+{
+    Dbg *dbg = getdbg();
+    const char *fn_name = js_tostring(js, 1);
+
+    for (int i = 0; i < dbg->funcs.count; i++) {
+        Func *f = &dbg->funcs.items[i];
+        if (strcmp(fn_name, f->name) == 0) {
+            char addr_str2[20];
+            snprintf(addr_str2, sizeof(addr_str2), "0x%"PRIxPTR,
+                    libelfin_wrap_func_addr(dbg->plibelfin, f));
+    
+            Brk *brk = (Brk *)hashtable_get(&dbg->brks, addr_str2);
+            if (brk == NULL) {
+                LOG_ERR("No breakpoint at function: %s\n", fn_name);
+                goto done;
+            }
+            brk_disable(brk);
+            break;
+        }
+    }
+
+done:
+    js_pushundefined(js);
+}
+
+void dbg_js_bl(js_State *js)
+{
+    Dbg *dbg = getdbg();
+    const char *filepath = js_tostring(js, 1);
+    size_t line = (size_t)js_tonumber(js, 2);
+    AddrInfo *ai = libelfin_wrap_info_from_line(dbg->plibelfin, filepath, line);
+    if (ai != NULL) {
+        char addr_str[20];
+        snprintf(addr_str, sizeof(addr_str), "0x%"PRIxPTR, ai->addr);
+        Brk brk = { .pid = dbg->pid, .addr = ai->addr };
+        brk_enable(&brk);
+        hashtable_set(&dbg->brks, addr_str, &brk, sizeof(brk));
+        libelfin_wrap_free_info(ai);
+    }
+    js_pushundefined(js);
+}
+
+void dbg_js_rmbl(js_State *js)
+{
+    Dbg *dbg = getdbg();
+    const char *filepath = js_tostring(js, 1);
+    size_t line = (size_t)js_tonumber(js, 2);
+    AddrInfo *ai = libelfin_wrap_info_from_line(dbg->plibelfin, filepath, line);
+    if (ai != NULL) {
+        char addr_str[20];
+        snprintf(addr_str, sizeof(addr_str), "0x%"PRIxPTR, ai->addr);
+        Brk *brk = (Brk *)hashtable_get(&dbg->brks, addr_str);
+        if (brk != NULL) {
+            brk_disable(brk);
+            hashtable_delete(&dbg->brks, addr_str);
+        }
+        libelfin_wrap_free_info(ai);
+    }
+    js_pushundefined(js);
+}
+
 void dbg_init_js(Dbg *dbg)
 {
     dbg->js   = js_newstate(NULL, NULL, JS_STRICT);
@@ -569,7 +747,7 @@ void dbg_init_js(Dbg *dbg)
     } while(0)
 
     make_js_func(cont, 0, "Continue execution, ARGS=None");
-    make_js_func(baddr, 1, "Place breakpoint at address, ARGS=Address:hex string");
+    make_js_func(boff, 1, "Place breakpoint at offset, ARGS=Offset:hex string");
     make_js_func(rmbaddr, 1, "Remove breakpoint at address, ARGS=Address:hex string");
     make_js_func(lsbrk, 0, "List all breakpoints");
     make_js_func(splo, 1, "Set program load offset, ARGS=Offset:hex string");
@@ -587,12 +765,22 @@ void dbg_init_js(Dbg *dbg)
     make_js_func(lsf, 0, "List functions in executable, ARGS=None");
     make_js_func(bfn, 1, "Set breakpoint at function, ARGS=Function name:string");
     make_js_func(rmbfn, 1, "Remove breakpoint at function, ARGS=Function name:string");
+    make_js_func(ebaddr, 1, "Enable breakpoint at address, ARGS=Address:hex string");
+    make_js_func(dbaddr, 1, "Disable breakpoint at address, ARGS=Address:hex string");
+    make_js_func(ebfn, 1, "Enable breakpoint at function, ARGS=Function name:string");
+    make_js_func(dbfn, 1, "Disable breakpoint at function, ARGS=Function name:string");
+    make_js_func(bl, 2, "Set breakpoint at line in file, ARGS=File:string,Line:int");
+    make_js_func(rmbl, 2, "Remove breakpoint at line in file, ARGS=File:string,Line:int");
 
     #undef make_js_func
 }
 
 void dbg_init_load_offset(Dbg *dbg)
 {
+    msleep(500); // We need to sleep for a bit, because we need to ensure that our debuggee
+                 // program has already been loaded into memory. This is technically a bad
+                 // practice since we're sleeping for 500ms and praying that it's enough
+                 // time to ensure that debuggee has been loaded, but if it works, it works.
     procmaps_iterator maps_iter = {0};
     procmaps_error_t parser_err = PROCMAPS_SUCCESS;
 
@@ -645,9 +833,9 @@ void dbg_libelfin_wrap_init(Dbg *dbg)
     dbg->plibelfin = libelfin_wrap_get_binding(fileno(dbg->binfile), dbg->program_load_offset);
 }
 
-void dbg_load_symbols(Dbg *dbg)
+void dbg_load_funcs(Dbg *dbg)
 {
-    libelfin_wrap_get_syms(dbg->plibelfin, &dbg->symbols);
+    libelfin_wrap_get_funcs(dbg->plibelfin, &dbg->funcs);
 }
 
 void dbg_init(Dbg *dbg, const char *file, pid_t pid)
@@ -660,7 +848,7 @@ void dbg_init(Dbg *dbg, const char *file, pid_t pid)
     dbg_init_load_offset(dbg);
     dbg_init_bin(dbg);
     dbg_libelfin_wrap_init(dbg);
-    dbg_load_symbols(dbg);
+    dbg_load_funcs(dbg);
     hashtable_init(&dbg->brks, MAX_BRKS);
     dbg_load_script(dbg, INIT_SCRIPT);
 }
@@ -670,7 +858,7 @@ void dbg_deinit(Dbg *dbg)
     js_freestate(dbg->js);
     hashtable_deinit(&dbg->brks);
     hashtable_deinit(&dbg->js_descs);
-    symbols_deinit(&dbg->symbols);
+    funcs_deinit(&dbg->funcs);
     libelfin_wrap_free_binding(dbg->plibelfin);
     fclose(dbg->binfile);
 }

libelfin_wrap.cpp

@@ -19,7 +19,7 @@ class LibelfinBinding
         uintptr_t loadoffset;
 };
 
-DEBUGUS_EXTERNC void libelfin_wrap_get_syms(PLibelfinBinding *pbind, Symbols *syms)
+DEBUGUS_EXTERNC void libelfin_wrap_get_funcs(PLibelfinBinding pbind, Funcs *funcs)
 {
     LibelfinBinding *bind = (LibelfinBinding *)pbind;
     for (auto &section : bind->elf.sections()) {
@@ -27,18 +27,43 @@ DEBUGUS_EXTERNC void libelfin_wrap_get_syms(PLibelfinBinding *pbind, Symbols *sy
             for (auto sym : section.as_symtab()) {
                 auto &d = sym.get_data();
                 if (d.type() == elf::stt::func) {
-                    Symbol s = {
+                    Func f = {
                         .name = (const char *)malloc(strlen(sym.get_name().c_str())+1),
-                        .addr = bind->loadoffset + (uintptr_t)d.value,
+                        .ai = libelfin_wrap_info_from_rip(pbind, (uintptr_t)d.value),
                     };
-                    strcpy((char*)s.name, sym.get_name().c_str());
-                    da_append(syms, s);
+                    strcpy((char*)f.name, sym.get_name().c_str());
+                    da_append(funcs, f);
                 }
             }
         }
     }
 }
 
+DEBUGUS_EXTERNC AddrInfo *libelfin_wrap_info_from_line(PLibelfinBinding pbind, const char *file, size_t line)
+{
+    LibelfinBinding *bind = (LibelfinBinding *)pbind;
+    for (auto &cu : bind->dwarf.compilation_units()) {
+        auto &lt = cu.get_line_table();
+        for (auto &ent : lt) {
+            if (ent.is_stmt && ent.line == line) {
+                AddrInfo *ai = (AddrInfo *)malloc(sizeof(*ai));
+                ai->addr = bind->loadoffset + (uintptr_t)ent.address;
+                ai->line = (ssize_t)line;
+                ai->file = (const char*)malloc(strlen(file)+1);
+                strcpy((char*)ai->file, file);
+                return ai;
+            }
+        }
+    }
+    return NULL;
+}
+
+DEBUGUS_EXTERNC uintptr_t libelfin_wrap_func_addr(PLibelfinBinding pbind, Func *f)
+{
+    LibelfinBinding *bind = (LibelfinBinding *)pbind;
+    return bind->loadoffset + f->ai->addr;
+}
+
 DEBUGUS_EXTERNC PLibelfinBinding libelfin_wrap_get_binding(int fd, uintptr_t loadoffset)
 {
     return (PLibelfinBinding)new LibelfinBinding(fd, loadoffset);

libelfin_wrap.h

@@ -17,18 +17,18 @@
 typedef struct {
     ssize_t line;
     const char *file;
-    uint64_t addr;
+    uintptr_t addr;
 } AddrInfo;
 
 typedef struct {
     const char *name;
-    uintptr_t addr;
-} Symbol;
+    AddrInfo *ai;
+} Func;
 
 typedef struct {
-    Symbol *items;
+    Func *items;
     size_t count, capacity;
-} Symbols;
+} Funcs;
 
 typedef void * PLibelfinBinding;
 
@@ -36,6 +36,8 @@ DEBUGUS_EXTERNC PLibelfinBinding libelfin_wrap_get_binding(int fd, uintptr_t loa
 DEBUGUS_EXTERNC void libelfin_wrap_free_binding(PLibelfinBinding pbind);
 DEBUGUS_EXTERNC AddrInfo *libelfin_wrap_info_from_rip(PLibelfinBinding pbind, uint64_t rip);
 DEBUGUS_EXTERNC void libelfin_wrap_free_info(AddrInfo *ai);
-DEBUGUS_EXTERNC void libelfin_wrap_get_syms(PLibelfinBinding *pbind, Symbols *syms);
+DEBUGUS_EXTERNC void libelfin_wrap_get_funcs(PLibelfinBinding pbind, Funcs *funcs);
+DEBUGUS_EXTERNC uintptr_t libelfin_wrap_func_addr(PLibelfinBinding pbind, Func *f);
+DEBUGUS_EXTERNC AddrInfo *libelfin_wrap_info_from_line(PLibelfinBinding pbind, const char *file, size_t line);
 
 #endif // LIBELFIN_WRAP_H_

test.c

@@ -2,8 +2,12 @@
 #include <inttypes.h>
 #include <stdlib.h>
 
+extern void dupa2(void);
+
 void dupa(void) {
-    printf("KSKSKKSKSKSK\n");
+    printf("a\n");
+    printf("b\n");
+    printf("c\n");
 }
 
 int main(void)
@@ -17,6 +21,8 @@ int main(void)
         }
     }
 
+    dupa2();
+
     int *a = NULL;
     *a = 6969;
 

test2.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+void dupa2(void)
+{
+    printf("function in test2.c\n");
+}
+