It turns out clobbering the environ kernel stack does actually affect the kernel environment (viz [1]), regardless of what previous behavior or man pages said. For the 1.1 series, we should simply not try to clobber proctitles.
[1]: http://paste.ubuntu.com/13300018/ Signed-off-by: Tycho Andersen <[email protected]> --- src/lxc/criu.c | 9 ---- src/lxc/lxccontainer.c | 9 ---- src/lxc/utils.c | 123 ------------------------------------------------- src/lxc/utils.h | 1 - 4 files changed, 142 deletions(-) diff --git a/src/lxc/criu.c b/src/lxc/criu.c index 7ee6cbe..a76f02d 100644 --- a/src/lxc/criu.c +++ b/src/lxc/criu.c @@ -465,7 +465,6 @@ void do_restore(struct lxc_container *c, int pipe, char *directory, bool verbose goto out_fini_handler; } else { int ret; - char title[2048]; pid_t w = waitpid(pid, &status, 0); if (w == -1) { @@ -511,14 +510,6 @@ void do_restore(struct lxc_container *c, int pipe, char *directory, bool verbose goto out_fini_handler; } - /* - * See comment in lxcapi_start; we don't care if these - * fail because it's just a beauty thing. We just - * assign the return here to silence potential. - */ - ret = snprintf(title, sizeof(title), "[lxc monitor] %s %s", c->config_path, c->name); - ret = setproctitle(title); - ret = lxc_poll(c->name, handler); if (ret) lxc_abort(c->name, handler); diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c index 11d1822..503925e 100644 --- a/src/lxc/lxccontainer.c +++ b/src/lxc/lxccontainer.c @@ -689,7 +689,6 @@ static bool do_lxcapi_start(struct lxc_container *c, int useinit, char * const a * while container is running... */ if (daemonize) { - char title[2048]; lxc_monitord_spawn(c->config_path); pid_t pid = fork(); @@ -704,14 +703,6 @@ static bool do_lxcapi_start(struct lxc_container *c, int useinit, char * const a return wait_on_daemonized_start(c, pid); } - /* We don't really care if this doesn't print all the - * characters; all that it means is that the proctitle will be - * ugly. Similarly, we also don't care if setproctitle() - * fails. */ - snprintf(title, sizeof(title), "[lxc monitor] %s %s", c->config_path, c->name); - INFO("Attempting to set proc title to %s", title); - setproctitle(title); - /* second fork to be reparented by init */ pid = fork(); if (pid < 0) { diff --git a/src/lxc/utils.c b/src/lxc/utils.c index d9e769d..3f83865 100644 --- a/src/lxc/utils.c +++ b/src/lxc/utils.c @@ -1341,129 +1341,6 @@ char *get_template_path(const char *t) } /* - * Sets the process title to the specified title. Note: - * 1. this function requires root to succeed - * 2. it clears /proc/self/environ - * 3. it may not succed (e.g. if title is longer than /proc/self/environ + - * the original title) - */ -int setproctitle(char *title) -{ - char buf[2048], *tmp; - FILE *f; - int i, len, ret = 0; - - /* We don't really need to know all of this stuff, but unfortunately - * PR_SET_MM_MAP requires us to set it all at once, so we have to - * figure it out anyway. - */ - unsigned long start_data, end_data, start_brk, start_code, end_code, - start_stack, arg_start, arg_end, env_start, env_end, - brk_val; - struct prctl_mm_map prctl_map; - - f = fopen_cloexec("/proc/self/stat", "r"); - if (!f) { - return -1; - } - - tmp = fgets(buf, sizeof(buf), f); - fclose(f); - if (!tmp) { - return -1; - } - - /* Skip the first 25 fields, column 26-28 are start_code, end_code, - * and start_stack */ - tmp = strchr(buf, ' '); - for (i = 0; i < 24; i++) { - if (!tmp) - return -1; - tmp = strchr(tmp+1, ' '); - } - if (!tmp) - return -1; - - i = sscanf(tmp, "%lu %lu %lu", &start_code, &end_code, &start_stack); - if (i != 3) - return -1; - - /* Skip the next 19 fields, column 45-51 are start_data to arg_end */ - for (i = 0; i < 19; i++) { - if (!tmp) - return -1; - tmp = strchr(tmp+1, ' '); - } - - if (!tmp) - return -1; - - i = sscanf(tmp, "%lu %lu %lu %lu %lu %lu %lu", - &start_data, - &end_data, - &start_brk, - &arg_start, - &arg_end, - &env_start, - &env_end); - if (i != 7) - return -1; - - /* Include the null byte here, because in the calculations below we - * want to have room for it. */ - len = strlen(title) + 1; - - /* We're truncating the environment, so we should use at most the - * length of the argument + environment for the title. */ - if (len > env_end - arg_start) { - arg_end = env_end; - len = env_end - arg_start; - title[len-1] = '\0'; - } else { - /* Only truncate the environment if we're actually going to - * overwrite part of it. */ - if (len >= arg_end - arg_start) { - env_start = env_end; - } - - arg_end = arg_start + len; - - /* check overflow */ - if (arg_end < len || arg_end < arg_start) { - return -1; - } - - } - - brk_val = syscall(__NR_brk, 0); - - prctl_map = (struct prctl_mm_map) { - .start_code = start_code, - .end_code = end_code, - .start_stack = start_stack, - .start_data = start_data, - .end_data = end_data, - .start_brk = start_brk, - .brk = brk_val, - .arg_start = arg_start, - .arg_end = arg_end, - .env_start = env_start, - .env_end = env_end, - .auxv = NULL, - .auxv_size = 0, - .exe_fd = -1, - }; - - ret = prctl(PR_SET_MM, PR_SET_MM_MAP, (long) &prctl_map, sizeof(prctl_map), 0); - if (ret == 0) - strcpy((char*)arg_start, title); - else - SYSERROR("setting cmdline failed"); - - return ret; -} - -/* * @path: a pathname where / replaced with '\0'. * @offsetp: pointer to int showing which path segment was last seen. * Updated on return to reflect the next segment. diff --git a/src/lxc/utils.h b/src/lxc/utils.h index 059026f..5cd58da 100644 --- a/src/lxc/utils.h +++ b/src/lxc/utils.h @@ -278,7 +278,6 @@ int print_to_file(const char *file, const char *content); bool switch_to_ns(pid_t pid, const char *ns); int is_dir(const char *path); char *get_template_path(const char *t); -int setproctitle(char *title); int safe_mount(const char *src, const char *dest, const char *fstype, unsigned long flags, const void *data, const char *rootfs); int mount_proc_if_needed(const char *rootfs); -- 2.5.0 _______________________________________________ lxc-devel mailing list [email protected] http://lists.linuxcontainers.org/listinfo/lxc-devel
