Mercurial > hg
view contrib/chg/chg.c @ 32558:aa91085cadf3
transaction: delete callbacks after use
Before this change, localrepository instances that performed multiple
transactions would leak transaction objects. This could occur when
running `hg convert`. When running `hg convert`, the leak would be
~90 MB per 10,000 changesets as measured with the Mercurial repo itself.
The leak I tracked down involved the "validate" closure from
localrepository.transaction(). It appeared to be keeping a
reference to the original transaction via __closure__. __del__
semantics and a circular reference involving the repo object
may have also come into play.
Attempting to refactor the "validate" closure proved to be
difficult because the "tr" reference in that closure may
reference an object that isn't created until transaction.__init__
is called. And the "validate" closure is passed as an argument to
transaction.__init__. Plus there is a giant warning comment in
"validate" about how hacky it is. I did not want to venture into
the dragon den.
Anyway, we've had problems with transactions causing leaks before.
The solution then (14e683d6b273) is the same as the solution in this
patch: drop references to callbacks after they are called. This
not only breaks cycles in core Mercurial but can help break cycles
in extensions that accidentally introduce them.
While I only tracked down a leak due to self.validator, since this is
the 2nd time I've tracked down leaks due to transaction callbacks I
figure enough is enough and we should prevent the class of leak from
occurring regardless of the variable. That's why all callback variables
are now nuked.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 26 May 2017 13:27:21 -0700 |
parents | ca7af5d15b21 |
children | 50788d1ae6cc |
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/* * A fast client for Mercurial command server * * Copyright (c) 2011 Yuya Nishihara <yuya@tcha.org> * * This software may be used and distributed according to the terms of the * GNU General Public License version 2 or any later version. */ #include <assert.h> #include <errno.h> #include <fcntl.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/file.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/un.h> #include <sys/wait.h> #include <time.h> #include <unistd.h> #include "hgclient.h" #include "procutil.h" #include "util.h" #ifndef PATH_MAX #define PATH_MAX 4096 #endif struct cmdserveropts { char sockname[PATH_MAX]; char initsockname[PATH_MAX]; char redirectsockname[PATH_MAX]; size_t argsize; const char **args; }; static void initcmdserveropts(struct cmdserveropts *opts) { memset(opts, 0, sizeof(struct cmdserveropts)); } static void freecmdserveropts(struct cmdserveropts *opts) { free(opts->args); opts->args = NULL; opts->argsize = 0; } /* * Test if an argument is a sensitive flag that should be passed to the server. * Return 0 if not, otherwise the number of arguments starting from the current * one that should be passed to the server. */ static size_t testsensitiveflag(const char *arg) { static const struct { const char *name; size_t narg; } flags[] = { {"--config", 1}, {"--cwd", 1}, {"--repo", 1}, {"--repository", 1}, {"--traceback", 0}, {"-R", 1}, }; size_t i; for (i = 0; i < sizeof(flags) / sizeof(flags[0]); ++i) { size_t len = strlen(flags[i].name); size_t narg = flags[i].narg; if (memcmp(arg, flags[i].name, len) == 0) { if (arg[len] == '\0') { /* --flag (value) */ return narg + 1; } else if (arg[len] == '=' && narg > 0) { /* --flag=value */ return 1; } else if (flags[i].name[1] != '-') { /* short flag */ return 1; } } } return 0; } /* * Parse argv[] and put sensitive flags to opts->args */ static void setcmdserverargs(struct cmdserveropts *opts, int argc, const char *argv[]) { size_t i, step; opts->argsize = 0; for (i = 0, step = 1; i < (size_t)argc; i += step, step = 1) { if (!argv[i]) continue; /* pass clang-analyse */ if (strcmp(argv[i], "--") == 0) break; size_t n = testsensitiveflag(argv[i]); if (n == 0 || i + n > (size_t)argc) continue; opts->args = reallocx(opts->args, (n + opts->argsize) * sizeof(char *)); memcpy(opts->args + opts->argsize, argv + i, sizeof(char *) * n); opts->argsize += n; step = n; } } static void preparesockdir(const char *sockdir) { int r; r = mkdir(sockdir, 0700); if (r < 0 && errno != EEXIST) abortmsgerrno("cannot create sockdir %s", sockdir); struct stat st; r = lstat(sockdir, &st); if (r < 0) abortmsgerrno("cannot stat %s", sockdir); if (!S_ISDIR(st.st_mode)) abortmsg("cannot create sockdir %s (file exists)", sockdir); if (st.st_uid != geteuid() || st.st_mode & 0077) abortmsg("insecure sockdir %s", sockdir); } /* * Check if a socket directory exists and is only owned by the current user. * Return 1 if so, 0 if not. This is used to check if XDG_RUNTIME_DIR can be * used or not. According to the specification [1], XDG_RUNTIME_DIR should be * ignored if the directory is not owned by the user with mode 0700. * [1]: https://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html */ static int checkruntimedir(const char *sockdir) { struct stat st; int r = lstat(sockdir, &st); if (r < 0) /* ex. does not exist */ return 0; if (!S_ISDIR(st.st_mode)) /* ex. is a file, not a directory */ return 0; return st.st_uid == geteuid() && (st.st_mode & 0777) == 0700; } static void getdefaultsockdir(char sockdir[], size_t size) { /* by default, put socket file in secure directory * (${XDG_RUNTIME_DIR}/chg, or /${TMPDIR:-tmp}/chg$UID) * (permission of socket file may be ignored on some Unices) */ const char *runtimedir = getenv("XDG_RUNTIME_DIR"); int r; if (runtimedir && checkruntimedir(runtimedir)) { r = snprintf(sockdir, size, "%s/chg", runtimedir); } else { const char *tmpdir = getenv("TMPDIR"); if (!tmpdir) tmpdir = "/tmp"; r = snprintf(sockdir, size, "%s/chg%d", tmpdir, geteuid()); } if (r < 0 || (size_t)r >= size) abortmsg("too long TMPDIR (r = %d)", r); } static void setcmdserveropts(struct cmdserveropts *opts) { int r; char sockdir[PATH_MAX]; const char *envsockname = getenv("CHGSOCKNAME"); if (!envsockname) { getdefaultsockdir(sockdir, sizeof(sockdir)); preparesockdir(sockdir); } const char *basename = (envsockname) ? envsockname : sockdir; const char *sockfmt = (envsockname) ? "%s" : "%s/server"; r = snprintf(opts->sockname, sizeof(opts->sockname), sockfmt, basename); if (r < 0 || (size_t)r >= sizeof(opts->sockname)) abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r); r = snprintf(opts->initsockname, sizeof(opts->initsockname), "%s.%u", opts->sockname, (unsigned)getpid()); if (r < 0 || (size_t)r >= sizeof(opts->initsockname)) abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r); } static const char *gethgcmd(void) { static const char *hgcmd = NULL; if (!hgcmd) { hgcmd = getenv("CHGHG"); if (!hgcmd || hgcmd[0] == '\0') hgcmd = getenv("HG"); if (!hgcmd || hgcmd[0] == '\0') #ifdef HGPATH hgcmd = (HGPATH); #else hgcmd = "hg"; #endif } return hgcmd; } static void execcmdserver(const struct cmdserveropts *opts) { const char *hgcmd = gethgcmd(); const char *baseargv[] = { hgcmd, "serve", "--cmdserver", "chgunix", "--address", opts->initsockname, "--daemon-postexec", "chdir:/", }; size_t baseargvsize = sizeof(baseargv) / sizeof(baseargv[0]); size_t argsize = baseargvsize + opts->argsize + 1; const char **argv = mallocx(sizeof(char *) * argsize); memcpy(argv, baseargv, sizeof(baseargv)); memcpy(argv + baseargvsize, opts->args, sizeof(char *) * opts->argsize); argv[argsize - 1] = NULL; if (putenv("CHGINTERNALMARK=") != 0) abortmsgerrno("failed to putenv"); if (execvp(hgcmd, (char **)argv) < 0) abortmsgerrno("failed to exec cmdserver"); free(argv); } /* Retry until we can connect to the server. Give up after some time. */ static hgclient_t *retryconnectcmdserver(struct cmdserveropts *opts, pid_t pid) { static const struct timespec sleepreq = {0, 10 * 1000000}; int pst = 0; debugmsg("try connect to %s repeatedly", opts->initsockname); unsigned int timeoutsec = 60; /* default: 60 seconds */ const char *timeoutenv = getenv("CHGTIMEOUT"); if (timeoutenv) sscanf(timeoutenv, "%u", &timeoutsec); for (unsigned int i = 0; !timeoutsec || i < timeoutsec * 100; i++) { hgclient_t *hgc = hgc_open(opts->initsockname); if (hgc) { debugmsg("rename %s to %s", opts->initsockname, opts->sockname); int r = rename(opts->initsockname, opts->sockname); if (r != 0) abortmsgerrno("cannot rename"); return hgc; } if (pid > 0) { /* collect zombie if child process fails to start */ int r = waitpid(pid, &pst, WNOHANG); if (r != 0) goto cleanup; } nanosleep(&sleepreq, NULL); } abortmsg("timed out waiting for cmdserver %s", opts->initsockname); return NULL; cleanup: if (WIFEXITED(pst)) { if (WEXITSTATUS(pst) == 0) abortmsg("could not connect to cmdserver " "(exited with status 0)"); debugmsg("cmdserver exited with status %d", WEXITSTATUS(pst)); exit(WEXITSTATUS(pst)); } else if (WIFSIGNALED(pst)) { abortmsg("cmdserver killed by signal %d", WTERMSIG(pst)); } else { abortmsg("error while waiting for cmdserver"); } return NULL; } /* Connect to a cmdserver. Will start a new server on demand. */ static hgclient_t *connectcmdserver(struct cmdserveropts *opts) { const char *sockname = opts->redirectsockname[0] ? opts->redirectsockname : opts->sockname; debugmsg("try connect to %s", sockname); hgclient_t *hgc = hgc_open(sockname); if (hgc) return hgc; /* prevent us from being connected to an outdated server: we were * told by a server to redirect to opts->redirectsockname and that * address does not work. we do not want to connect to the server * again because it will probably tell us the same thing. */ if (sockname == opts->redirectsockname) unlink(opts->sockname); debugmsg("start cmdserver at %s", opts->initsockname); pid_t pid = fork(); if (pid < 0) abortmsg("failed to fork cmdserver process"); if (pid == 0) { execcmdserver(opts); } else { hgc = retryconnectcmdserver(opts, pid); } return hgc; } static void killcmdserver(const struct cmdserveropts *opts) { /* resolve config hash */ char *resolvedpath = realpath(opts->sockname, NULL); if (resolvedpath) { unlink(resolvedpath); free(resolvedpath); } } /* Run instructions sent from the server like unlink and set redirect path * Return 1 if reconnect is needed, otherwise 0 */ static int runinstructions(struct cmdserveropts *opts, const char **insts) { int needreconnect = 0; if (!insts) return needreconnect; assert(insts); opts->redirectsockname[0] = '\0'; const char **pinst; for (pinst = insts; *pinst; pinst++) { debugmsg("instruction: %s", *pinst); if (strncmp(*pinst, "unlink ", 7) == 0) { unlink(*pinst + 7); } else if (strncmp(*pinst, "redirect ", 9) == 0) { int r = snprintf(opts->redirectsockname, sizeof(opts->redirectsockname), "%s", *pinst + 9); if (r < 0 || r >= (int)sizeof(opts->redirectsockname)) abortmsg("redirect path is too long (%d)", r); needreconnect = 1; } else if (strncmp(*pinst, "exit ", 5) == 0) { int n = 0; if (sscanf(*pinst + 5, "%d", &n) != 1) abortmsg("cannot read the exit code"); exit(n); } else if (strcmp(*pinst, "reconnect") == 0) { needreconnect = 1; } else { abortmsg("unknown instruction: %s", *pinst); } } return needreconnect; } /* * Test whether the command is unsupported or not. This is not designed to * cover all cases. But it's fast, does not depend on the server and does * not return false positives. */ static int isunsupported(int argc, const char *argv[]) { enum { SERVE = 1, DAEMON = 2, SERVEDAEMON = SERVE | DAEMON, TIME = 4, }; unsigned int state = 0; int i; for (i = 0; i < argc; ++i) { if (strcmp(argv[i], "--") == 0) break; if (i == 0 && strcmp("serve", argv[i]) == 0) state |= SERVE; else if (strcmp("-d", argv[i]) == 0 || strcmp("--daemon", argv[i]) == 0) state |= DAEMON; else if (strcmp("--time", argv[i]) == 0) state |= TIME; } return (state & TIME) == TIME || (state & SERVEDAEMON) == SERVEDAEMON; } static void execoriginalhg(const char *argv[]) { debugmsg("execute original hg"); if (execvp(gethgcmd(), (char **)argv) < 0) abortmsgerrno("failed to exec original hg"); } int main(int argc, const char *argv[], const char *envp[]) { if (getenv("CHGDEBUG")) enabledebugmsg(); if (!getenv("HGPLAIN") && isatty(fileno(stderr))) enablecolor(); if (getenv("CHGINTERNALMARK")) abortmsg("chg started by chg detected.\n" "Please make sure ${HG:-hg} is not a symlink or " "wrapper to chg. Alternatively, set $CHGHG to the " "path of real hg."); if (isunsupported(argc - 1, argv + 1)) execoriginalhg(argv); struct cmdserveropts opts; initcmdserveropts(&opts); setcmdserveropts(&opts); setcmdserverargs(&opts, argc, argv); if (argc == 2) { if (strcmp(argv[1], "--kill-chg-daemon") == 0) { killcmdserver(&opts); return 0; } } hgclient_t *hgc; size_t retry = 0; while (1) { hgc = connectcmdserver(&opts); if (!hgc) abortmsg("cannot open hg client"); hgc_setenv(hgc, envp); const char **insts = hgc_validate(hgc, argv + 1, argc - 1); int needreconnect = runinstructions(&opts, insts); free(insts); if (!needreconnect) break; hgc_close(hgc); if (++retry > 10) abortmsg("too many redirections.\n" "Please make sure %s is not a wrapper which " "changes sensitive environment variables " "before executing hg. If you have to use a " "wrapper, wrap chg instead of hg.", gethgcmd()); } setupsignalhandler(hgc_peerpid(hgc), hgc_peerpgid(hgc)); atexit(waitpager); int exitcode = hgc_runcommand(hgc, argv + 1, argc - 1); restoresignalhandler(); hgc_close(hgc); freecmdserveropts(&opts); return exitcode; }