diff options
| -rw-r--r-- | src/backend/postmaster/pgstat.c | 73 | ||||
| -rw-r--r-- | src/backend/postmaster/postmaster.c | 22 | ||||
| -rw-r--r-- | src/backend/utils/adt/ascii.c | 34 | ||||
| -rw-r--r-- | src/include/pgstat.h | 2 | ||||
| -rw-r--r-- | src/include/utils/ascii.h | 1 |
5 files changed, 125 insertions, 7 deletions
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c index 44956c15b5a..ba64f2395c0 100644 --- a/src/backend/postmaster/pgstat.c +++ b/src/backend/postmaster/pgstat.c @@ -58,6 +58,7 @@ #include "storage/pg_shmem.h" #include "storage/pmsignal.h" #include "storage/procsignal.h" +#include "utils/ascii.h" #include "utils/guc.h" #include "utils/memutils.h" #include "utils/ps_status.h" @@ -2228,6 +2229,7 @@ static PgBackendStatus *MyBEEntry = NULL; static char *BackendClientHostnameBuffer = NULL; static char *BackendAppnameBuffer = NULL; static char *BackendActivityBuffer = NULL; +static Size BackendActivityBufferSize = 0; /* @@ -2310,9 +2312,12 @@ CreateSharedBackendStatus(void) } /* Create or attach to the shared activity buffer */ - size = mul_size(pgstat_track_activity_query_size, MaxBackends); + BackendActivityBufferSize = mul_size(pgstat_track_activity_query_size, + MaxBackends); BackendActivityBuffer = (char *) - ShmemInitStruct("Backend Activity Buffer", size, &found); + ShmemInitStruct("Backend Activity Buffer", + BackendActivityBufferSize, + &found); if (!found) { @@ -2751,6 +2756,70 @@ pgstat_get_backend_current_activity(int pid, bool checkUser) return "<backend information not available>"; } +/* ---------- + * pgstat_get_crashed_backend_activity() - + * + * Return a string representing the current activity of the backend with + * the specified PID. Like the function above, but reads shared memory with + * the expectation that it may be corrupt. Returns either a pointer to a + * constant string, or writes into the 'buffer' argument and returns it. + * + * This function is only intended to be used by postmaster to report the + * query that crashed the backend. In particular, no attempt is made to + * follow the correct concurrency protocol when accessing the + * BackendStatusArray. But that's OK, in the worst case we'll return a + * corrupted message. We also must take care not to trip on ereport(ERROR). + * + * Note: return strings for special cases match pg_stat_get_backend_activity. + * ---------- + */ +const char * +pgstat_get_crashed_backend_activity(int pid, char *buffer, + int len) +{ + volatile PgBackendStatus *beentry; + int i; + + beentry = BackendStatusArray; + for (i = 1; i <= MaxBackends; i++) + { + if (beentry->st_procpid == pid) + { + /* Read pointer just once, so it can't change after validation */ + const char *activity = beentry->st_activity; + const char *activity_last; + + /* + * We can't access activity pointer before we verify that it + * falls into BackendActivityBuffer. To make sure that the entire + * string including its ending is contained within the buffer, + * we subtract one activity length from it. + */ + activity_last = BackendActivityBuffer + BackendActivityBufferSize + - pgstat_track_activity_query_size; + + if (activity < BackendActivityBuffer || + activity > activity_last) + return "<command string corrupt>"; + + if (*(activity) == '\0') + return "<command string empty>"; + + /* + * Copy only ASCII-safe characters so we don't run into encoding + * problems when reporting the message. + */ + ascii_safe_strncpy(buffer, activity, len); + + return buffer; + } + + beentry++; + } + + /* PID not found */ + return "<backend information not available>"; +} /* ------------------------------------------------------------ * Local support functions follow diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index dd7493cf9dd..5476975f765 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -2777,6 +2777,13 @@ HandleChildCrash(int pid, int exitstatus, const char *procname) static void LogChildExit(int lev, const char *procname, int pid, int exitstatus) { + char activity_buffer[1024]; /* default track_activity_query_size */ + const char *activity; + + activity = pgstat_get_crashed_backend_activity(pid, + activity_buffer, + sizeof(activity_buffer)); + if (WIFEXITED(exitstatus)) ereport(lev, @@ -2784,7 +2791,8 @@ LogChildExit(int lev, const char *procname, int pid, int exitstatus) translator: %s is a noun phrase describing a child process, such as "server process" */ (errmsg("%s (PID %d) exited with exit code %d", - procname, pid, WEXITSTATUS(exitstatus)))); + procname, pid, WEXITSTATUS(exitstatus)), + errdetail("Running query: %s", activity))); else if (WIFSIGNALED(exitstatus)) #if defined(WIN32) ereport(lev, @@ -2794,7 +2802,8 @@ LogChildExit(int lev, const char *procname, int pid, int exitstatus) "server process" */ (errmsg("%s (PID %d) was terminated by exception 0x%X", procname, pid, WTERMSIG(exitstatus)), - errhint("See C include file \"ntstatus.h\" for a description of the hexadecimal value."))); + errhint("See C include file \"ntstatus.h\" for a description of the hexadecimal value."), + errdetail("Running query: %s", activity))); #elif defined(HAVE_DECL_SYS_SIGLIST) && HAVE_DECL_SYS_SIGLIST ereport(lev, @@ -2804,7 +2813,8 @@ LogChildExit(int lev, const char *procname, int pid, int exitstatus) (errmsg("%s (PID %d) was terminated by signal %d: %s", procname, pid, WTERMSIG(exitstatus), WTERMSIG(exitstatus) < NSIG ? - sys_siglist[WTERMSIG(exitstatus)] : "(unknown)"))); + sys_siglist[WTERMSIG(exitstatus)] : "(unknown)"), + errdetail("Running query: %s", activity))); #else ereport(lev, @@ -2812,7 +2822,8 @@ LogChildExit(int lev, const char *procname, int pid, int exitstatus) translator: %s is a noun phrase describing a child process, such as "server process" */ (errmsg("%s (PID %d) was terminated by signal %d", - procname, pid, WTERMSIG(exitstatus)))); + procname, pid, WTERMSIG(exitstatus)), + errdetail("Running query: %s", activity))); #endif else ereport(lev, @@ -2821,7 +2832,8 @@ LogChildExit(int lev, const char *procname, int pid, int exitstatus) translator: %s is a noun phrase describing a child process, such as "server process" */ (errmsg("%s (PID %d) exited with unrecognized status %d", - procname, pid, exitstatus))); + procname, pid, exitstatus), + errdetail("Running query: %s", activity))); } /* diff --git a/src/backend/utils/adt/ascii.c b/src/backend/utils/adt/ascii.c index 7ecf4949b5f..7c9e96a04f6 100644 --- a/src/backend/utils/adt/ascii.c +++ b/src/backend/utils/adt/ascii.c @@ -158,3 +158,37 @@ to_ascii_default(PG_FUNCTION_ARGS) PG_RETURN_TEXT_P(encode_to_ascii(data, enc)); } + +/* ---------- + * "Escape" a string in unknown encoding to a valid ASCII string. + * Replace non-ASCII bytes with '?' + * This must not trigger ereport(ERROR), as it is called from postmaster. + * + * Unlike C strncpy(), the result is always terminated with exactly one null + * byte. + * ---------- + */ +void +ascii_safe_strncpy(char *dest, const char *src, int len) +{ + int i; + + for (i = 0; i < (len - 1); i++) + { + unsigned char ch = src[i]; /* use unsigned char here to avoid compiler warning */ + + if (ch == '\0') + break; + /* Keep printable ASCII characters */ + if (32 <= ch && ch <= 127) + dest[i] = ch; + /* White-space is also OK */ + else if (ch == '\n' || ch == '\r' || ch == '\t') + dest[i] = ch; + /* Everything else is replaced with '?' */ + else + dest[i] = '?'; + } + + dest[i] = '\0'; +} diff --git a/src/include/pgstat.h b/src/include/pgstat.h index 20c4d4354e9..d0f1927efb2 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -720,6 +720,8 @@ extern void pgstat_report_appname(const char *appname); extern void pgstat_report_xact_timestamp(TimestampTz tstamp); extern void pgstat_report_waiting(bool waiting); extern const char *pgstat_get_backend_current_activity(int pid, bool checkUser); +extern const char *pgstat_get_crashed_backend_activity(int pid, char *buffer, + int len); extern PgStat_TableStatus *find_tabstat_entry(Oid rel_id); extern PgStat_BackendFunctionEntry *find_funcstat_entry(Oid func_id); diff --git a/src/include/utils/ascii.h b/src/include/utils/ascii.h index ad70e037bd7..adeddb5626f 100644 --- a/src/include/utils/ascii.h +++ b/src/include/utils/ascii.h @@ -16,5 +16,6 @@ extern Datum to_ascii_encname(PG_FUNCTION_ARGS); extern Datum to_ascii_enc(PG_FUNCTION_ARGS); extern Datum to_ascii_default(PG_FUNCTION_ARGS); +extern void ascii_safe_strncpy(char *dest, const char *src, int len); #endif /* _ASCII_H_ */ |