unify execute_command() and execute_program()

[elogind.git] / udev_utils.c

diff --git a/udev_utils.c b/udev_utils.c
index c35b287881a060633f65e530abdf9390c0a48f69..9e2e152763578d3c373d5c69752fd9fe702a4ab4 100644 (file)
--- a/udev_utils.c
+++ b/udev_utils.c
@@ -361,15 +361,20 @@ int add_matching_files(struct list_head *name_list, const char *dirname, const c
        return 0;
 }
 
-int execute_command(const char *command, const char *subsystem)
+int execute_program(const char *command, const char *subsystem,
+                   char *result, size_t ressize, size_t *reslen)
 {
-       int retval;
+       int retval = 0;
+       int count;
+       int status;
+       int pipefds[2];
        pid_t pid;
-       char arg[PATH_SIZE];
-       char *argv[(PATH_SIZE / 2) + 1];
        char *pos;
+       char arg[PATH_SIZE];
+       char *argv[(sizeof(arg) / 2) + 1];
        int devnull;
        int i;
+       size_t len;
 
        strlcpy(arg, command, sizeof(arg));
        i = 0;
@@ -397,27 +402,68 @@ int execute_command(const char *command, const char *subsystem)
                dbg("execute '%s' with subsystem '%s' argument", arg, argv[1]);
        }
 
+       if (result) {
+               if (pipe(pipefds) != 0) {
+                       err("pipe failed");
+                       return -1;
+               }
+       }
+
        pid = fork();
-       switch (pid) {
+       switch(pid) {
        case 0:
-               /* child */
+               /* child dup2 write side of pipe to STDOUT */
                devnull = open("/dev/null", O_RDWR);
                if (devnull >= 0) {
                        dup2(devnull, STDIN_FILENO);
-                       dup2(devnull, STDOUT_FILENO);
+                       if (!result)
+                               dup2(devnull, STDOUT_FILENO);
                        dup2(devnull, STDERR_FILENO);
                        close(devnull);
                }
-               retval = execv(arg, argv);
-               err("exec of child '%s' failed", command);
+               if (result)
+                       dup2(pipefds[1], STDOUT_FILENO);
+               execv(arg, argv);
+               err("exec of program failed");
                _exit(1);
        case -1:
-               dbg("fork of child '%s' failed", command);
-               break;
+               err("fork of '%s' failed", arg);
                return -1;
        default:
-               waitpid(pid, NULL, 0);
+               /* parent reads from pipefds[0] */
+               if (result) {
+                       close(pipefds[1]);
+                       len = 0;
+                       while (1) {
+                               count = read(pipefds[0], result + len, ressize - len-1);
+                               if (count < 0) {
+                                       err("read failed with '%s'", strerror(errno));
+                                       retval = -1;
+                                       break;
+                               }
+
+                               if (count == 0)
+                                       break;
+
+                               len += count;
+                               if (len >= ressize-1) {
+                                       err("ressize %d too short", ressize);
+                                       retval = -1;
+                                       break;
+                               }
+                       }
+                       result[len] = '\0';
+                       close(pipefds[0]);
+                       if (reslen)
+                               *reslen = len;
+               }
+               waitpid(pid, &status, 0);
+
+               if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) {
+                       dbg("exec program status 0x%x", status);
+                       retval = -1;
+               }
        }
 
-       return 0;
+       return retval;
 }