src/lxc/execute.c

   1 /*
   2  * lxc: linux Container library
   3  *
   4  * (C) Copyright IBM Corp. 2007, 2008
   5  *
   6  * Authors:
   7  * Daniel Lezcano <daniel.lezcano at free.fr>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #define _GNU_SOURCE
  25 #include <sys/types.h>
  26 #include <sys/stat.h>
  27 #include <errno.h>
  28 #include <unistd.h>
  29 #include <stdlib.h>
  30 #include <stdio.h>
  31
  32 #include "conf.h"
  33 #include "log.h"
  34 #include "start.h"
  35 #include "utils.h"
  36
  37 lxc_log_define(execute, start);
  38
  39 static int execute_start(struct lxc_handler *handler, void* data)
  40 {
  41         int argc_add, j;
  42         char **argv;
  43         int argc = 0, i = 0, logfd = -1;
  44         struct execute_args *my_args = data;
  45         char logfile[LXC_PROC_PID_FD_LEN];
  46
  47         while (my_args->argv[argc++]);
  48
  49         /* lxc-init -n name -- [argc] NULL -> 5 */
  50         argc_add = 5;
  51         if (my_args->quiet)
  52                 argc_add++;
  53
  54         if (!handler->conf->rootfs.path)
  55                 argc_add += 2;
  56
  57         if (lxc_log_has_valid_level())
  58                 argc_add += 2;
  59
  60         if (current_config->logfd != -1 || lxc_log_fd != -1)
  61                 argc_add += 2;
  62
  63         argv = malloc((argc + argc_add) * sizeof(*argv));
  64         if (!argv) {
  65                 SYSERROR("Allocating init args failed");
  66                 goto out1;
  67         }
  68
  69         if (my_args->init_path)
  70                 argv[i++] = my_args->init_path;
  71         else
  72                 argv[i++] = "lxc-init";
  73
  74         argv[i++] = "-n";
  75         argv[i++] = (char *)handler->name;
  76
  77         if (lxc_log_has_valid_level()) {
  78                 argv[i++] = "-l";
  79                 argv[i++] = (char *)lxc_log_priority_to_string(lxc_log_get_level());
  80         }
  81
  82         if (current_config->logfd != -1 || lxc_log_fd != -1) {
  83                 int ret;
  84                 int to_dup = current_config->logfd;
  85
  86                 if (current_config->logfd == -1)
  87                         to_dup = lxc_log_fd;
  88
  89                 logfd = dup(to_dup);
  90                 if (logfd < 0) {
  91                         SYSERROR("Failed to duplicate log file descriptor");
  92                         goto out2;
  93                 }
  94
  95                 ret = snprintf(logfile, sizeof(logfile), "/proc/1/fd/%d", logfd);
  96                 if (ret < 0 || (size_t)ret >= sizeof(logfile))
  97                         goto out3;
  98
  99                 argv[i++] = "-o";
 100                 argv[i++] = logfile;
 101         }
 102
 103         if (my_args->quiet)
 104                 argv[i++] = "--quiet";
 105
 106         if (!handler->conf->rootfs.path) {
 107                 argv[i++] = "-P";
 108                 argv[i++] = (char *)handler->lxcpath;
 109         }
 110
 111         argv[i++] = "--";
 112         for (j = 0; j < argc; j++)
 113                 argv[i++] = my_args->argv[j];
 114         argv[i++] = NULL;
 115
 116         NOTICE("Exec'ing \"%s\"", my_args->argv[0]);
 117
 118         if (my_args->init_fd >= 0)
 119 #ifdef __NR_execveat
 120                 syscall(__NR_execveat, my_args->init_fd, "", argv, environ, AT_EMPTY_PATH);
 121 #else
 122                 ERROR("System seems to be missing execveat syscall number");
 123 #endif
 124         else
 125                 execvp(argv[0], argv);
 126         SYSERROR("Failed to exec %s", argv[0]);
 127
 128 out3:
 129         close(logfd);
 130 out2:
 131         free(argv);
 132 out1:
 133         return 1;
 134 }
 135
 136 static int execute_post_start(struct lxc_handler *handler, void* data)
 137 {
 138         struct execute_args *my_args = data;
 139         NOTICE("'%s' started with pid '%d'", my_args->argv[0], handler->pid);
 140         return 0;
 141 }
 142
 143 static struct lxc_operations execute_start_ops = {
 144         .start = execute_start,
 145         .post_start = execute_post_start
 146 };
 147
 148 int lxc_execute(const char *name, char *const argv[], int quiet,
 149                 struct lxc_handler *handler, const char *lxcpath,
 150                 bool backgrounded, int *error_num)
 151 {
 152         struct execute_args args = {.argv = argv, .quiet = quiet};
 153
 154         TRACE("Doing lxc_execute");
 155         handler->conf->is_execute = true;
 156         return __lxc_start(name, handler, &execute_start_ops, &args, lxcpath,
 157                            backgrounded, error_num);
 158 }