Print /proc/<pid>/maps on segfault

3 files changed, 47 insertions, 1 deletions

diff --git a/common/log.c b/common/log.c
index f9242bf4..0c0ecf89 100644
--- a/common/log.c
+++ b/common/log.c
@@ -1,5 +1,6 @@
 #include "log.h"
 #include "sway.h"
+#include "readline.h"
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -142,6 +143,9 @@ void error_handler(int sig) {
         void *array[max_lines];
         char **bt;
         size_t bt_len;
+        char maps_file[256];
+        char maps_buffer[1024];
+        FILE *maps;
 
         sway_log(L_ERROR, "Error: Signal %d. Printing backtrace", sig);
         bt_len = backtrace(array, max_lines);
@@ -155,6 +159,22 @@ void error_handler(int sig) {
         for (i = 0; (size_t)i < bt_len; i++) {
                 sway_log(L_ERROR, "Backtrace: %s", bt[i]);
         }
+
+        sway_log(L_ERROR, "Maps:");
+        pid_t pid = getpid();
+        if (snprintf(maps_file, 255, "/proc/%zd/maps", (size_t)pid) < 255) {
+                maps = fopen(maps_file, "r");
+                while (!feof(maps)) {
+                        char *m = read_line_buffer(maps, maps_buffer, 1024);
+                        if (!m) {
+                                fclose(maps);
+                                sway_log(L_ERROR, "Unable to allocate memory to show maps");
+                                break;
+                        }
+                        sway_log(L_ERROR, m);
+                }
+                fclose(maps);
+        }
 #else
         sway_log(L_ERROR, "Error: Signal %d.", sig);
 #endif
diff --git a/common/readline.c b/common/readline.c
index e75b183f..76ed6926 100644
--- a/common/readline.c
+++ b/common/readline.c
@@ -3,7 +3,7 @@
 #include <stdio.h>
 
 char *read_line(FILE *file) {
-        int length = 0, size = 128;
+        size_t length = 0, size = 128;
         char *string = malloc(size);
         if (!string) {
                 return NULL;
@@ -37,3 +37,28 @@ char *read_line(FILE *file) {
         string[length] = '\0';
         return string;
 }
+
+char *read_line_buffer(FILE *file, char *string, size_t string_len) {
+        size_t length = 0;
+        if (!string) {
+                return NULL;
+        }
+        while (1) {
+                int c = getc(file);
+                if (c == EOF || c == '\n' || c == '\0') {
+                        break;
+                }
+                if (c == '\r') {
+                        continue;
+                }
+                string[length++] = c;
+                if (string_len <= length) {
+                        return NULL;
+                }
+        }
+        if (length + 1 == string_len) {
+                return NULL;
+        }
+        string[length] = '\0';
+        return string;
+}
diff --git a/include/readline.h b/include/readline.h
index dbe937c1..b3e06d4b 100644
--- a/include/readline.h
+++ b/include/readline.h
@@ -4,5 +4,6 @@
 #include <stdio.h>
 
 char *read_line(FILE *file);
+char *read_line_buffer(FILE *file, char *string, size_t string_len);
 
 #endif