[lxc-devel] [PATCH] get rid of fancy proctitles
Tycho Andersen
tycho.andersen at canonical.com
Mon Nov 16 17:44:05 UTC 2015
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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