[lxc-devel] [PATCH] get rid of fancy proctitles
Serge Hallyn
serge.hallyn at ubuntu.com
Mon Nov 16 21:00:24 UTC 2015
Hey Tycho,
I'm not sure what the best way to handle this is, but I dont' like
having an ephemeral pastebin link in the changelog. Can you just stick
the test program in the commit msg?
Quoting Tycho Andersen (tycho.andersen at canonical.com):
> 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 <tycho.andersen at canonical.com>
> ---
> 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
>
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