From 210494ea54b930e9a0fc941c45b75f190efdf26e Mon Sep 17 00:00:00 2001
From: Silvan Calarco <silvan.calarco@mambasoft.it>
Date: Tue, 9 Jul 2024 11:15:22 +0200
Subject: [PATCH] functions.c: fix backtrace handler distroquery.cpp: fix
 sigsegv when PATH_INFO environment var is not set

---
 src/distroquery.cpp |  4 +--
 src/functions.c     | 74 ++++++---------------------------------------
 2 files changed, 12 insertions(+), 66 deletions(-)

diff --git a/src/distroquery.cpp b/src/distroquery.cpp
index 939211a..1f1940f 100644
--- a/src/distroquery.cpp
+++ b/src/distroquery.cpp
@@ -1537,11 +1537,11 @@ main(int argc, char *argv[])
    path_info = getenv("PATH_INFO");
    query_string = getenv("QUERY_STRING");
 
-   if (strncmp(path_info, "/api/v1/", strlen(API_PREFIX)) == 0) {
+   if (path_info && strncmp(path_info, "/api/v1/", strlen(API_PREFIX)) == 0) {
       DistroqueryAPI *api = new DistroqueryAPI(firstconfigtag);
       api->getApiResponse(&path_info[strlen(API_PREFIX)]);
       exit(0);
-   } else if (strlen(path_info) > 0) {
+   } else {
       cout << "Content-Type: text/html;charset=utf-8" << endl;
       cout << "Status: 400 Bad request" << endl << endl;
       cout << "ERROR: invalid path: " << path_info;
diff --git a/src/functions.c b/src/functions.c
index a418d61..ca052c9 100644
--- a/src/functions.c
+++ b/src/functions.c
@@ -23,6 +23,7 @@
 #include <sys/stat.h>
 #include <dirent.h>
 #include <libiberty/libiberty.h>
+#include <execinfo.h>
 
 /* Tell glibc's <time.h> to provide a prototype for strptime() */
 #ifndef __USE_XOPEN
@@ -44,72 +45,17 @@ static struct configDefaults configdefaults;
 static struct configTag *firstconfigtag = NULL;
 
 /* Obtain a backtrace and print it to stdout. */
-static void debugInfo(FILE *out, const void* ip)
-{
-	char *debuginfo_path=NULL;
+void backtraceHandler(int sig) {
+  void *array[10];
+  size_t size;
 
-	Dwfl_Callbacks callbacks={
-		.find_elf=dwfl_linux_proc_find_elf,
-		.find_debuginfo=dwfl_standard_find_debuginfo,
-		.debuginfo_path=&debuginfo_path,
-	};
+  // get void*'s for all entries on the stack
+  size = backtrace(array, 10);
 
-	Dwfl* dwfl=dwfl_begin(&callbacks);
-	assert(dwfl!=NULL);
-
-	assert(dwfl_linux_proc_report (dwfl, getpid())==0);
-	assert(dwfl_report_end (dwfl, NULL, NULL)==0);
-
-	Dwarf_Addr addr = (uintptr_t)ip;
-
-	Dwfl_Module* module=dwfl_addrmodule (dwfl, addr);
-
-	const char* function_name = dwfl_module_addrname(module, addr);
-
-	fprintf(out, "%s(",function_name);
-
-	Dwfl_Line *line=dwfl_getsrc (dwfl, addr);
-	if(line!=NULL)
-	{
-		int nline;
-		Dwarf_Addr addr;
-		const char* filename=dwfl_lineinfo (line, &addr,&nline,NULL,NULL,NULL);
-		fprintf(out, "%s:%d",strrchr(filename,'/')+1,nline);
-	}
-	else
-	{
-    const char *module_name = dwfl_module_info(module,
-            NULL, NULL, NULL, NULL, NULL, NULL, NULL);
-    fprintf(out, "in %s", module_name);
-	}
-}
-
-void backtraceHandler(int sig)
-{
-  unw_context_t uc;
-  unw_getcontext(&uc);
-
-  unw_cursor_t cursor;
-  unw_init_local(&cursor, &uc);
-
-  fprintf(stderr, "*** Received signal %d; stack trace: ***\n", sig);
-
-  while(unw_step(&cursor)>0) {
-    unw_word_t ip;
-    unw_get_reg(&cursor, UNW_REG_IP, &ip);
-
-    unw_word_t offset;
-    char name[32];
-    assert(unw_get_proc_name(&cursor, name,sizeof(name), &offset)==0);
-
-    fprintf(stderr, "\tat ");
-    debugInfo(stderr, (void*)(ip-4));
-    fprintf(stderr, ")\n");
-
-    if(strcmp(name,"main")==0)
-      break;
-  }
-   exit(1);
+  // print out all the frames to stderr
+  fprintf(stderr, "Error: signal %d:\n", sig);
+  backtrace_symbols_fd(array, size, STDERR_FILENO);
+  exit(1);
 }
 
 struct configTag* findRepositoryByTag(const char *tag)