discover/boot: Allow boot hooks to alter boot data

[petitboot] / lib / system / system.c

diff --git a/lib/system/system.c b/lib/system/system.c
index 65bd6bf57bc5391cd6bc91aec5f8b48a9f553987..528e134127f307f17d9dcfaa70b2b1ef60eb7a52 100644 (file)
--- a/lib/system/system.c
+++ b/lib/system/system.c
@@ -17,13 +17,17 @@
 #include "system.h"
 
 const struct pb_system_apps pb_system_apps = {
-       .cp = "/bin/cp",
-       .kexec = "/sbin/kexec",
-       .mount = "/bin/mount",
-       .sftp = "/usr/bin/sftp",
-       .tftp = "/usr/bin/tftp",
-       .umount = "/bin/umount",
-       .wget = "/usr/bin/wget",
+       .prefix         = PREFIX,
+       .cp             = HOST_PROG_CP,
+       .kexec          = HOST_PROG_KEXEC,
+       .mount          = HOST_PROG_MOUNT,
+       .shutdown       = HOST_PROG_SHUTDOWN,
+       .sftp           = HOST_PROG_SFTP,
+       .tftp           = HOST_PROG_TFTP,
+       .umount         = HOST_PROG_UMOUNT,
+       .wget           = HOST_PROG_WGET,
+       .ip             = HOST_PROG_IP,
+       .udhcpc         = HOST_PROG_UDHCPC,
 };
 
 int pb_mkdir_recursive(const char *dir)
@@ -98,32 +102,96 @@ int pb_rmdir_recursive(const char *base, const char *dir)
        return 0;
 }
 
+static int read_pipe(void *ctx, int fd, char **bufp, int *lenp)
+{
+       int rc, len, alloc_len;
+       char *buf;
+
+       alloc_len = 4096;
+       len = 0;
+
+       buf = talloc_array(ctx, char, alloc_len);
+
+       for (;;) {
+               rc = read(fd, buf, alloc_len - len - 1);
+               if (rc <= 0)
+                       break;
+
+               len += rc;
+               if (len == alloc_len - 1) {
+                       alloc_len *= 2;
+                       buf = talloc_realloc(ctx, buf, char, alloc_len);
+               }
+       }
+
+       if (rc < 0) {
+               talloc_free(buf);
+               return rc;
+       }
+
+       buf[len] = '\0';
+       *bufp = buf;
+       *lenp = len;
+
+       return 0;
+}
+
 /**
  * pb_run_cmd - Run the supplied command.
  * @cmd_argv: An argument list array for execv.
+ * @wait: Wait for the child process to complete before returning.
+ * @dry_run: Don't actually fork and exec.
  */
 
-int pb_run_cmd(const char *const *cmd_argv)
+int pb_run_cmd(const char *const *cmd_argv, int wait, int dry_run)
+{
+       return pb_run_cmd_pipe(cmd_argv, wait, dry_run, NULL, NULL, NULL);
+}
+
+int pb_run_cmd_pipe(const char *const *cmd_argv, int wait, int dry_run,
+               void *ctx, char **stdout_buf, int *stdout_buf_len)
 {
 #if defined(DEBUG)
        enum {do_debug = 1};
 #else
        enum {do_debug = 0};
 #endif
-       int status;
+       int status, pipefd[2];
        pid_t pid;
 
+       assert(!stdout_buf || wait);
+       assert(!stdout_buf || ctx);
+       assert(!stdout_buf || stdout_buf_len);
+
        if (do_debug) {
                const char *const *p = cmd_argv;
 
-               pb_log("%s: ", __func__);
+               pb_log("%s: %s", __func__, (dry_run ? "(dry-run) " : ""));
+
                while (*p) {
                        pb_log("%s ", *p);
                        p++;
                }
                pb_log("\n");
        } else
-               pb_log("%s: %s\n", __func__, cmd_argv[0]);
+               pb_log("%s: %s%s\n", __func__, (dry_run ? "(dry-run) " : ""),
+                       cmd_argv[0]);
+
+       if (stdout_buf) {
+               *stdout_buf = NULL;
+               *stdout_buf_len = 0;
+       }
+
+       if (dry_run)
+               return 0;
+
+       if (stdout_buf) {
+               status = pipe(pipefd);
+               if (status) {
+                       pb_log("pipe failed");
+                       return -1;
+               }
+       }
 
        pid = fork();
 
@@ -132,12 +200,17 @@ int pb_run_cmd(const char *const *cmd_argv)
                return -1;
        }
 
+
        if (pid == 0) {
                int log = fileno(pb_log_get_stream());
 
                /* Redirect child output to log. */
 
-               status = dup2(log, STDOUT_FILENO);
+               if (stdout_buf) {
+                       status = dup2(pipefd[1], STDOUT_FILENO);
+               } else {
+                       status = dup2(log, STDOUT_FILENO);
+               }
                assert(status != -1);
 
                status = dup2(log, STDERR_FILENO);
@@ -148,6 +221,16 @@ int pb_run_cmd(const char *const *cmd_argv)
                exit(EXIT_FAILURE);
        }
 
+       if (!wait && !waitpid(pid, &status, WNOHANG))
+               return 0;
+
+       if (stdout_buf) {
+               close(pipefd[1]);
+               status = read_pipe(ctx, pipefd[0], stdout_buf, stdout_buf_len);
+               if (status)
+                       return -1;
+       }
+
        if (waitpid(pid, &status, 0) == -1) {
                pb_log("%s: waitpid failed: %s\n", __func__,
                                strerror(errno));