discover: fix segfault on failed boot image load

[petitboot] / discover / boot.c

diff --git a/discover/boot.c b/discover/boot.c
index ae44717523f6df24e36674321186b067023cf65e..e57810d54d46a10687c0182d9004d63b0349d188 100644 (file)
--- a/discover/boot.c
+++ b/discover/boot.c
@@ -1,6 +1,13 @@
 
+#define _GNU_SOURCE
+
 #include <stdbool.h>
+#include <stdlib.h>
 #include <assert.h>
+#include <dirent.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/types.h>
 
 #include <log/log.h>
 #include <pb-protocol/pb-protocol.h>
@@ -13,11 +20,18 @@
 #include "paths.h"
 #include "resource.h"
 
+static const char *boot_hook_dir = PKG_SYSCONF_DIR "/boot.d";
+enum {
+       BOOT_HOOK_EXIT_OK       = 0,
+       BOOT_HOOK_EXIT_UPDATE   = 2,
+};
+
+
 struct boot_task {
        char *local_image;
        char *local_initrd;
        char *local_dtb;
-       const char *args;
+       char *args;
 
        bool dry_run;
 };
@@ -139,6 +153,128 @@ static void update_status(boot_status_fn fn, void *arg, int type,
        fn(arg, &status);
 }
 
+static void boot_hook_update_param(void *ctx, struct boot_task *task,
+               const char *name, const char *value)
+{
+       struct p {
+               const char *name;
+               char **p;
+       } *param, params[] = {
+               { "boot_image",         &task->local_image },
+               { "boot_initrd",        &task->local_initrd },
+               { "boot_dtb",           &task->local_dtb },
+               { "boot_args",          &task->args },
+               { NULL, NULL },
+       };
+
+       for (param = params; param->name; param++) {
+               if (strcmp(param->name, name))
+                       continue;
+
+               *param->p = talloc_strdup(ctx, value);
+               return;
+       }
+}
+
+static void boot_hook_update(void *ctx, const char *hookname,
+               struct boot_task *task, char *buf)
+{
+       char *line, *name, *val, *sep;
+       char *saveptr;
+
+       for (;; buf = NULL) {
+
+               line = strtok_r(buf, "\n", &saveptr);
+               if (!line)
+                       break;
+
+               sep = strchr(line, '=');
+               if (!sep)
+                       continue;
+
+               *sep = '\0';
+               name = line;
+               val = sep + 1;
+
+               boot_hook_update_param(ctx, task, name, val);
+
+               pb_log("boot hook %s specified %s=%s\n",
+                               hookname, name, val);
+       }
+}
+
+static void boot_hook_setenv(struct boot_task *task)
+{
+       unsetenv("boot_image");
+       unsetenv("boot_initrd");
+       unsetenv("boot_dtb");
+       unsetenv("boot_args");
+
+       setenv("boot_image", task->local_image, 1);
+       if (task->local_initrd)
+               setenv("boot_initrd", task->local_initrd, 1);
+       if (task->local_dtb)
+               setenv("boot_dtb", task->local_dtb, 1);
+       if (task->args)
+               setenv("boot_args", task->args, 1);
+}
+
+static int hook_filter(const struct dirent *dirent)
+{
+       return dirent->d_type == DT_REG || dirent->d_type == DT_LNK;
+}
+
+static int hook_cmp(const struct dirent **a, const struct dirent **b)
+{
+       return strcmp((*a)->d_name, (*b)->d_name);
+}
+
+static void run_boot_hooks(void *ctx, struct boot_task *task,
+               boot_status_fn status_fn, void *status_arg)
+{
+       struct dirent **hooks;
+       int i, n;
+
+       n = scandir(boot_hook_dir, &hooks, hook_filter, hook_cmp);
+       if (n < 1)
+               return;
+
+       update_status(status_fn, status_arg, BOOT_STATUS_INFO,
+                       "running boot hooks");
+
+       boot_hook_setenv(task);
+
+       for (i = 0; i < n; i++) {
+               const char *argv[2] = { NULL, NULL };
+               char *path, *buf;
+               int buf_len, rc;
+
+               path = join_paths(ctx, boot_hook_dir, hooks[i]->d_name);
+
+               if (access(path, X_OK))
+                       continue;
+
+               pb_log("running boot hook %s\n", hooks[i]->d_name);
+
+               argv[0] = path;
+               rc = pb_run_cmd_pipe(argv, 1, task->dry_run, ctx,
+                               &buf, &buf_len);
+
+               /* if the hook returned with BOOT_HOOK_EXIT_UPDATE,
+                * then we process stdout to look for updated params
+                */
+               if (rc == BOOT_HOOK_EXIT_UPDATE) {
+                       boot_hook_update(ctx, hooks[i]->d_name, task, buf);
+                       boot_hook_setenv(task);
+               }
+
+               talloc_free(buf);
+               talloc_free(path);
+       }
+
+       free(hooks);
+}
+
 int boot(void *ctx, struct discover_boot_option *opt, struct boot_command *cmd,
                int dry_run, boot_status_fn status_fn, void *status_arg)
 {
@@ -185,6 +321,9 @@ int boot(void *ctx, struct discover_boot_option *opt, struct boot_command *cmd,
 
        result = -1;
 
+       boot_task.local_initrd = NULL;
+       boot_task.local_dtb = NULL;
+
        update_status(status_fn, status_arg, BOOT_STATUS_INFO,
                        "loading kernel");
        boot_task.local_image = load_url(NULL, image, &clean_image);
@@ -194,7 +333,6 @@ int boot(void *ctx, struct discover_boot_option *opt, struct boot_command *cmd,
                goto no_load;
        }
 
-       boot_task.local_initrd = NULL;
        if (initrd) {
                update_status(status_fn, status_arg, BOOT_STATUS_INFO,
                                "loading initrd");
@@ -206,7 +344,6 @@ int boot(void *ctx, struct discover_boot_option *opt, struct boot_command *cmd,
                }
        }
 
-       boot_task.local_dtb = NULL;
        if (dtb) {
                update_status(status_fn, status_arg, BOOT_STATUS_INFO,
                                "loading device tree");
@@ -218,6 +355,8 @@ int boot(void *ctx, struct discover_boot_option *opt, struct boot_command *cmd,
                }
        }
 
+       run_boot_hooks(ctx, &boot_task, status_fn, status_arg);
+
        update_status(status_fn, status_arg, BOOT_STATUS_INFO,
                        "performing kexec_load");