[lxc-devel] [PATCH] get rid of fancy proctitles
Tycho Andersen
tycho.andersen at canonical.com
Mon Nov 16 21:38:13 UTC 2015
On Mon, Nov 16, 2015 at 09:00:24PM +0000, Serge Hallyn wrote:
> 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?
Actually I think we can drop this one for now, there may be a better
way.
Thanks,
Tycho
> 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
> >
> > _______________________________________________
> > lxc-devel mailing list
> > lxc-devel at lists.linuxcontainers.org
> > http://lists.linuxcontainers.org/listinfo/lxc-devel
> _______________________________________________
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