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| | /*
* Copyright (C) 2012-2020 all contributors <cmogstored-public@yhbt.net>
* License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
*/
#include "cmogstored.h"
#include "compat_memstream.h"
static struct {
char **argv;
char **envp;
} start;
#define FD_PFX "CMOGSTORED_FD="
MOG_NOINLINE static void free_list(char **head)
{
char **tmp = head;
if (tmp) {
for (; *tmp; tmp++)
free(*tmp);
free(head);
}
}
/* only needed to make valgrind happy */
__attribute__((destructor)) static void upgrade_atexit(void)
{
free_list(start.argv);
free_list(start.envp);
}
void mog_upgrade_prepare(int argc, char *argv[], char *envp[])
{
int i;
size_t env_count = 2; /* extra for NULL-termination and CMOGSTORED_FD */
char **e;
/* duplicate argv */
start.argv = xmalloc(sizeof(char *) * (argc + 1));
for (i = 0; i < argc; i++)
start.argv[i] = xstrdup(argv[i]);
start.argv[argc] = NULL;
/* allocate slots for envp */
for (e = envp; *e; e++)
env_count++;
start.envp = xmalloc(sizeof(char *) * env_count);
/* duplicate envp */
e = start.envp;
*e++ = xstrdup(FD_PFX); /* placeholder */
for (; *envp; envp++) {
if (strncmp(*envp, FD_PFX, strlen(FD_PFX)))
*e++ = xstrdup(*envp);
}
*e = NULL;
}
/* writes one comma-delimited fd to fp */
static bool emit_fd(FILE *fp, struct mog_fd *mfd)
{
int r;
/* no error, just the FD isn't used */
if (mfd == NULL)
return true;
errno = 0;
r = fprintf(fp, "%d,", mfd->fd);
if (r > 0)
return true;
if (errno == 0)
errno = ENOSPC;
syslog(LOG_ERR, "fprintf() failed: %m");
return false;
}
static bool svc_emit_fd_i(void *svcptr, void *_fp)
{
FILE *fp = _fp;
struct mog_svc *svc = svcptr;
return (emit_fd(fp, svc->mgmt_mfd)
&& emit_fd(fp, svc->http_mfd)
&& emit_fd(fp, svc->httpget_mfd));
}
/* returns the PID of the newly spawned child */
pid_t mog_upgrade_spawn(void)
{
pid_t pid = -1;
FILE *fp;
size_t bytes;
char *dst = NULL;
int rc;
const char *execfile;
if (!mog_pidfile_upgrade_prepare())
return pid;
fp = open_memstream(&dst, &bytes);
if (fp == NULL) {
syslog(LOG_ERR, "open_memstream failed for upgrade: %m");
return pid;
}
execfile = find_in_path(start.argv[0]);
errno = 0;
rc = fputs(FD_PFX, fp);
if (rc < 0 || rc == EOF) {
if (errno == 0)
errno = ferror(fp);
PRESERVE_ERRNO( (void)fclose(fp) );
syslog(LOG_ERR, "fputs returned %d on memstream: %m", rc);
goto out;
}
mog_svc_each(svc_emit_fd_i, fp);
errno = 0;
if ((my_memstream_close(fp, &dst, &bytes) != 0) && (errno != EINTR)) {
syslog(LOG_ERR, "fclose on memstream failed for upgrade: %m");
goto out;
}
assert(dst[bytes - 1] == ',' && "not comma-terminated no listeners?");
dst[bytes - 1] = '\0'; /* kill the last comma */
start.envp[0] = dst;
pid = mog_fork_for_exec();
if (pid == 0) {
mog_svc_upgrade_prepare();
execve(execfile, start.argv, start.envp);
_exit(2);
} else if (pid > 0) {
mog_process_register(pid, MOG_PROC_UPGRADE);
syslog(LOG_INFO, "upgrade spawned PID:%d", pid);
} else {
syslog(LOG_ERR, "fork failed for upgrade: %m");
}
out:
/* find_in_path does not malloc if output == input */
if (execfile != start.argv[0])
mog_free(execfile);
start.envp[0] = 0;
free(dst);
return pid;
}
|