gebs_cmd_run_collect() for collecting command output, Add examples/commands.c

gebs.h

@@ -236,6 +236,14 @@ int gebs_cmd_run_sync_alloc(Gebs_Allocator *alloc, Gebs_Cmd *cmd);
     gebs_cmd_run(&__cmd); \
 })
 
+int gebs_cmd_run_sync_collect_alloc(Gebs_Allocator *alloc,
+                                    Gebs_Cmd *cmd, Gebs_String_Builder *sb_out);
+
+#define gebs_cmd_run_collect_alloc gebs_cmd_run_sync_collect_alloc
+
+#define gebs_cmd_run_collect(cmd, out) \
+    gebs_cmd_run_collect_alloc(&gebs_default_allocator, (cmd), (out))
+
 // ----------------------------------------------------------------------------
 // The build system
 // ----------------------------------------------------------------------------
@@ -330,6 +338,69 @@ int gebs_cmd_run_sync_alloc(Gebs_Allocator *alloc, Gebs_Cmd *cmd)
 #endif
 }
 
+int gebs_cmd_run_sync_collect_alloc(Gebs_Allocator *alloc, Gebs_Cmd *cmd, Gebs_String_Builder *sb_out)
+{
+    Gebs_String_Builder sb = {0};
+    gebs_nsl_join_alloc(alloc, cmd, &sb, " ");
+    GEBS_LOGI("cmd `%s`\n", sb.items);
+
+#if GEBS_PLATFORM == GEBS_PLATFORM_POSIX
+    // Clone the list
+    Gebs_Cmd new_cmd = {0};
+    defer { gebs_cmd_free_alloc(alloc, &new_cmd); }
+    for (size_t i = 0; i < cmd->count; i++) {
+        gebs_cmd_append_alloc(alloc, &new_cmd, cmd->items[i]);
+    }
+    gebs_cmd_append_alloc((alloc), &new_cmd, NULL);
+
+    int pipe_ends[2];
+    pipe(pipe_ends);
+
+    pid_t pid = vfork();
+    switch (pid) {
+        case -1:
+            close(pipe_ends[0]);
+            close(pipe_ends[1]);
+            GEBS_LOGE("Could not vfork\n");
+            return -1;
+        case 0:
+            close(pipe_ends[0]);
+            dup2(pipe_ends[1], 1);
+            close(pipe_ends[1]);
+
+            execvp(new_cmd.items[0], (char * const *)new_cmd.items);
+            exit(EXIT_FAILURE);
+        default: {
+            close(pipe_ends[1]);
+            char c;
+            while (read(pipe_ends[0], &c, 1) > 0) {
+                gebs_sb_append_char_alloc(alloc, sb_out, c);
+            }
+            gebs_sb_finish_alloc(alloc, sb_out);
+
+            int wstatus;
+            do {
+                if (waitpid(pid, &wstatus, WUNTRACED | WCONTINUED) == -1) {
+                    return -1;
+                }
+
+                if (WIFEXITED(wstatus)) {
+                    return WEXITSTATUS(wstatus);
+                } else if (WIFSIGNALED(wstatus)) {
+                    GEBS_LOGI("%d killed by %d\n", pid, WTERMSIG(wstatus));
+                    return -1;
+                } else if (WIFSTOPPED(wstatus)) {
+                    GEBS_LOGI("%d stopped by %d\n", pid, WSTOPSIG(wstatus));
+                    return -1;
+                }
+            } while(!WIFEXITED(wstatus) && !WIFSIGNALED(wstatus));
+        } 
+    }
+#else
+#   error "gebs_cmd_run_sync_alloc unknown command"
+#endif
+}
+
 // ----------------------------------------------------------------------------
 // Allocators
 // ----------------------------------------------------------------------------