Quoting Tycho Andersen (tycho.ander...@canonical.com):
> Instead of having a parent process that's called whatever the caller of the
> library is called, we instead set it to "[lxc monitor] <lxcpath> <container>"
>
> Signed-off-by: Tycho Andersen <tycho.ander...@canonical.com>
> ---
> src/lxc/lxccontainer.c | 10 +++++++++
> src/lxc/utils.c | 61
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> src/lxc/utils.h | 1 +
> 3 files changed, 72 insertions(+)
>
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 4da1627..1176a6f 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -598,6 +598,7 @@ static bool lxcapi_start(struct lxc_container *c, int
> useinit, char * const argv
> * while container is running...
> */
> if (daemonize) {
> + char title[2048];
> lxc_monitord_spawn(c->config_path);
>
> pid_t pid = fork();
> @@ -612,6 +613,15 @@ static bool lxcapi_start(struct lxc_container *c, int
> useinit, char * const argv
> 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 93de1c3..f517ee6 100644
> --- a/src/lxc/utils.c
> +++ b/src/lxc/utils.c
> @@ -39,6 +39,7 @@
> #include <sys/types.h>
> #include <sys/wait.h>
> #include <assert.h>
> +#include <sys/prctl.h>
>
> #include "utils.h"
> #include "log.h"
> @@ -1540,3 +1541,63 @@ char *get_template_path(const char *t)
>
> return tpath;
> }
> +
> +/*
> + * 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;
> + unsigned long arg_start, arg_end, env_start, env_end;
> +
> + 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 47 fields, column 48-51 are ARG_START and
> + * ARG_END. */
> + tmp = strchr(buf, ' ');
> + for (i = 0; i < 46; i++)
> + tmp = strchr(tmp+1, ' ');
Could you add a check here at each step for tmp != NULL? Or just
for (i = 0; i < 46 && tmp; i++)
tmp = strchr(tmp+1, ' ');
if (!tmp)
return -1;
> +
> + i = sscanf(tmp, "%lu %lu %lu %lu", &arg_start, &arg_end, &env_start,
> &env_end);
> + if (i != 4) {
> + return -1;
> + }
> +
> + /* We're truncating the environment, so we should use at most the
> + * length of the argument + environment for the title. */
> + len = strlen(title);
> + if (len > env_end - arg_start) {
> + arg_end = env_end;
> + len = env_end - arg_start;
> + } else {
> + arg_end = arg_start + len;
> + }
> +
> + env_start = arg_end;
> + env_end = env_start;
> +
> + /* memcpy instead of strcpy since this isn't null terminated */
> + memcpy((void*)arg_start, title, len);
> +
> + ret |= prctl(PR_SET_MM, PR_SET_MM_ARG_START, (long)arg_start, 0, 0);
> + ret |= prctl(PR_SET_MM, PR_SET_MM_ARG_END, (long)arg_end, 0, 0);
> + ret |= prctl(PR_SET_MM, PR_SET_MM_ENV_START, (long)env_start, 0, 0);
> + ret |= prctl(PR_SET_MM, PR_SET_MM_ENV_END, (long)env_end, 0, 0);
> +
> + return ret;
> +}
> diff --git a/src/lxc/utils.h b/src/lxc/utils.h
> index b23cd8e..cc18906 100644
> --- a/src/lxc/utils.h
> +++ b/src/lxc/utils.h
> @@ -286,3 +286,4 @@ 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);
> --
> 2.1.0
>
> _______________________________________________
> lxc-devel mailing list
> lxc-devel@lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel
_______________________________________________
lxc-devel mailing list
lxc-devel@lists.linuxcontainers.org
http://lists.linuxcontainers.org/listinfo/lxc-devel
