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Diffstat (limited to 'src/backend/utils/misc/ps_status.c')
| -rw-r--r-- | src/backend/utils/misc/ps_status.c | 448 |
1 files changed, 448 insertions, 0 deletions
diff --git a/src/backend/utils/misc/ps_status.c b/src/backend/utils/misc/ps_status.c new file mode 100644 index 0000000..1e8596e --- /dev/null +++ b/src/backend/utils/misc/ps_status.c @@ -0,0 +1,448 @@ +/*-------------------------------------------------------------------- + * ps_status.c + * + * Routines to support changing the ps display of PostgreSQL backends + * to contain some useful information. Mechanism differs wildly across + * platforms. + * + * src/backend/utils/misc/ps_status.c + * + * Copyright (c) 2000-2020, PostgreSQL Global Development Group + * various details abducted from various places + *-------------------------------------------------------------------- + */ + +#include "postgres.h" + +#include <unistd.h> +#ifdef HAVE_SYS_PSTAT_H +#include <sys/pstat.h> /* for HP-UX */ +#endif +#ifdef HAVE_PS_STRINGS +#include <machine/vmparam.h> /* for old BSD */ +#include <sys/exec.h> +#endif +#if defined(__darwin__) +#include <crt_externs.h> +#endif + +#include "libpq/libpq.h" +#include "miscadmin.h" +#include "pgstat.h" +#include "utils/guc.h" +#include "utils/ps_status.h" + +extern char **environ; +bool update_process_title = true; + + +/* + * Alternative ways of updating ps display: + * + * PS_USE_SETPROCTITLE_FAST + * use the function setproctitle_fast(const char *, ...) + * (newer FreeBSD systems) + * PS_USE_SETPROCTITLE + * use the function setproctitle(const char *, ...) + * (newer BSD systems) + * PS_USE_PSTAT + * use the pstat(PSTAT_SETCMD, ) + * (HPUX) + * PS_USE_PS_STRINGS + * assign PS_STRINGS->ps_argvstr = "string" + * (some BSD systems) + * PS_USE_CHANGE_ARGV + * assign argv[0] = "string" + * (some other BSD systems) + * PS_USE_CLOBBER_ARGV + * write over the argv and environment area + * (Linux and most SysV-like systems) + * PS_USE_WIN32 + * push the string out as the name of a Windows event + * PS_USE_NONE + * don't update ps display + * (This is the default, as it is safest.) + */ +#if defined(HAVE_SETPROCTITLE_FAST) +#define PS_USE_SETPROCTITLE_FAST +#elif defined(HAVE_SETPROCTITLE) +#define PS_USE_SETPROCTITLE +#elif defined(HAVE_PSTAT) && defined(PSTAT_SETCMD) +#define PS_USE_PSTAT +#elif defined(HAVE_PS_STRINGS) +#define PS_USE_PS_STRINGS +#elif (defined(BSD) || defined(__hurd__)) && !defined(__darwin__) +#define PS_USE_CHANGE_ARGV +#elif defined(__linux__) || defined(_AIX) || defined(__sgi) || (defined(sun) && !defined(BSD)) || defined(__svr5__) || defined(__darwin__) +#define PS_USE_CLOBBER_ARGV +#elif defined(WIN32) +#define PS_USE_WIN32 +#else +#define PS_USE_NONE +#endif + + +/* Different systems want the buffer padded differently */ +#if defined(_AIX) || defined(__linux__) || defined(__darwin__) +#define PS_PADDING '\0' +#else +#define PS_PADDING ' ' +#endif + + +#ifndef PS_USE_NONE + +#ifndef PS_USE_CLOBBER_ARGV +/* all but one option need a buffer to write their ps line in */ +#define PS_BUFFER_SIZE 256 +static char ps_buffer[PS_BUFFER_SIZE]; +static const size_t ps_buffer_size = PS_BUFFER_SIZE; +#else /* PS_USE_CLOBBER_ARGV */ +static char *ps_buffer; /* will point to argv area */ +static size_t ps_buffer_size; /* space determined at run time */ +static size_t last_status_len; /* use to minimize length of clobber */ +#endif /* PS_USE_CLOBBER_ARGV */ + +static size_t ps_buffer_cur_len; /* nominal strlen(ps_buffer) */ + +static size_t ps_buffer_fixed_size; /* size of the constant prefix */ + +#endif /* not PS_USE_NONE */ + +/* save the original argv[] location here */ +static int save_argc; +static char **save_argv; + + +/* + * Call this early in startup to save the original argc/argv values. + * If needed, we make a copy of the original argv[] array to preserve it + * from being clobbered by subsequent ps_display actions. + * + * (The original argv[] will not be overwritten by this routine, but may be + * overwritten during init_ps_display. Also, the physical location of the + * environment strings may be moved, so this should be called before any code + * that might try to hang onto a getenv() result.) + * + * Note that in case of failure this cannot call elog() as that is not + * initialized yet. We rely on write_stderr() instead. + */ +char ** +save_ps_display_args(int argc, char **argv) +{ + save_argc = argc; + save_argv = argv; + +#if defined(PS_USE_CLOBBER_ARGV) + + /* + * If we're going to overwrite the argv area, count the available space. + * Also move the environment to make additional room. + */ + { + char *end_of_area = NULL; + char **new_environ; + int i; + + /* + * check for contiguous argv strings + */ + for (i = 0; i < argc; i++) + { + if (i == 0 || end_of_area + 1 == argv[i]) + end_of_area = argv[i] + strlen(argv[i]); + } + + if (end_of_area == NULL) /* probably can't happen? */ + { + ps_buffer = NULL; + ps_buffer_size = 0; + return argv; + } + + /* + * check for contiguous environ strings following argv + */ + for (i = 0; environ[i] != NULL; i++) + { + if (end_of_area + 1 == environ[i]) + end_of_area = environ[i] + strlen(environ[i]); + } + + ps_buffer = argv[0]; + last_status_len = ps_buffer_size = end_of_area - argv[0]; + + /* + * move the environment out of the way + */ + new_environ = (char **) malloc((i + 1) * sizeof(char *)); + if (!new_environ) + { + write_stderr("out of memory\n"); + exit(1); + } + for (i = 0; environ[i] != NULL; i++) + { + new_environ[i] = strdup(environ[i]); + if (!new_environ[i]) + { + write_stderr("out of memory\n"); + exit(1); + } + } + new_environ[i] = NULL; + environ = new_environ; + } +#endif /* PS_USE_CLOBBER_ARGV */ + +#if defined(PS_USE_CHANGE_ARGV) || defined(PS_USE_CLOBBER_ARGV) + + /* + * If we're going to change the original argv[] then make a copy for + * argument parsing purposes. + * + * (NB: do NOT think to remove the copying of argv[], even though + * postmaster.c finishes looking at argv[] long before we ever consider + * changing the ps display. On some platforms, getopt() keeps pointers + * into the argv array, and will get horribly confused when it is + * re-called to analyze a subprocess' argument string if the argv storage + * has been clobbered meanwhile. Other platforms have other dependencies + * on argv[]. + */ + { + char **new_argv; + int i; + + new_argv = (char **) malloc((argc + 1) * sizeof(char *)); + if (!new_argv) + { + write_stderr("out of memory\n"); + exit(1); + } + for (i = 0; i < argc; i++) + { + new_argv[i] = strdup(argv[i]); + if (!new_argv[i]) + { + write_stderr("out of memory\n"); + exit(1); + } + } + new_argv[argc] = NULL; + +#if defined(__darwin__) + + /* + * macOS (and perhaps other NeXT-derived platforms?) has a static copy + * of the argv pointer, which we may fix like so: + */ + *_NSGetArgv() = new_argv; +#endif + + argv = new_argv; + } +#endif /* PS_USE_CHANGE_ARGV or PS_USE_CLOBBER_ARGV */ + + return argv; +} + +/* + * Call this once during subprocess startup to set the identification + * values. + * + * If fixed_part is NULL, a default will be obtained from MyBackendType. + * + * At this point, the original argv[] array may be overwritten. + */ +void +init_ps_display(const char *fixed_part) +{ +#ifndef PS_USE_NONE + bool save_update_process_title; +#endif + + Assert(fixed_part || MyBackendType); + if (!fixed_part) + fixed_part = GetBackendTypeDesc(MyBackendType); + +#ifndef PS_USE_NONE + /* no ps display for stand-alone backend */ + if (!IsUnderPostmaster) + return; + + /* no ps display if you didn't call save_ps_display_args() */ + if (!save_argv) + return; + +#ifdef PS_USE_CLOBBER_ARGV + /* If ps_buffer is a pointer, it might still be null */ + if (!ps_buffer) + return; +#endif + + /* + * Overwrite argv[] to point at appropriate space, if needed + */ + +#ifdef PS_USE_CHANGE_ARGV + save_argv[0] = ps_buffer; + save_argv[1] = NULL; +#endif /* PS_USE_CHANGE_ARGV */ + +#ifdef PS_USE_CLOBBER_ARGV + { + int i; + + /* make extra argv slots point at end_of_area (a NUL) */ + for (i = 1; i < save_argc; i++) + save_argv[i] = ps_buffer + ps_buffer_size; + } +#endif /* PS_USE_CLOBBER_ARGV */ + + /* + * Make fixed prefix of ps display. + */ + +#if defined(PS_USE_SETPROCTITLE) || defined(PS_USE_SETPROCTITLE_FAST) + + /* + * apparently setproctitle() already adds a `progname:' prefix to the ps + * line + */ +#define PROGRAM_NAME_PREFIX "" +#else +#define PROGRAM_NAME_PREFIX "postgres: " +#endif + + if (*cluster_name == '\0') + { + snprintf(ps_buffer, ps_buffer_size, + PROGRAM_NAME_PREFIX "%s ", + fixed_part); + } + else + { + snprintf(ps_buffer, ps_buffer_size, + PROGRAM_NAME_PREFIX "%s: %s ", + cluster_name, fixed_part); + } + + ps_buffer_cur_len = ps_buffer_fixed_size = strlen(ps_buffer); + + /* + * On the first run, force the update. + */ + save_update_process_title = update_process_title; + update_process_title = true; + set_ps_display(""); + update_process_title = save_update_process_title; +#endif /* not PS_USE_NONE */ +} + + + +/* + * Call this to update the ps status display to a fixed prefix plus an + * indication of what you're currently doing passed in the argument. + */ +void +set_ps_display(const char *activity) +{ +#ifndef PS_USE_NONE + /* update_process_title=off disables updates */ + if (!update_process_title) + return; + + /* no ps display for stand-alone backend */ + if (!IsUnderPostmaster) + return; + +#ifdef PS_USE_CLOBBER_ARGV + /* If ps_buffer is a pointer, it might still be null */ + if (!ps_buffer) + return; +#endif + + /* Update ps_buffer to contain both fixed part and activity */ + strlcpy(ps_buffer + ps_buffer_fixed_size, activity, + ps_buffer_size - ps_buffer_fixed_size); + ps_buffer_cur_len = strlen(ps_buffer); + + /* Transmit new setting to kernel, if necessary */ + +#ifdef PS_USE_SETPROCTITLE + setproctitle("%s", ps_buffer); +#elif defined(PS_USE_SETPROCTITLE_FAST) + setproctitle_fast("%s", ps_buffer); +#endif + +#ifdef PS_USE_PSTAT + { + union pstun pst; + + pst.pst_command = ps_buffer; + pstat(PSTAT_SETCMD, pst, ps_buffer_cur_len, 0, 0); + } +#endif /* PS_USE_PSTAT */ + +#ifdef PS_USE_PS_STRINGS + PS_STRINGS->ps_nargvstr = 1; + PS_STRINGS->ps_argvstr = ps_buffer; +#endif /* PS_USE_PS_STRINGS */ + +#ifdef PS_USE_CLOBBER_ARGV + /* pad unused memory; need only clobber remainder of old status string */ + if (last_status_len > ps_buffer_cur_len) + MemSet(ps_buffer + ps_buffer_cur_len, PS_PADDING, + last_status_len - ps_buffer_cur_len); + last_status_len = ps_buffer_cur_len; +#endif /* PS_USE_CLOBBER_ARGV */ + +#ifdef PS_USE_WIN32 + { + /* + * Win32 does not support showing any changed arguments. To make it at + * all possible to track which backend is doing what, we create a + * named object that can be viewed with for example Process Explorer. + */ + static HANDLE ident_handle = INVALID_HANDLE_VALUE; + char name[PS_BUFFER_SIZE + 32]; + + if (ident_handle != INVALID_HANDLE_VALUE) + CloseHandle(ident_handle); + + sprintf(name, "pgident(%d): %s", MyProcPid, ps_buffer); + + ident_handle = CreateEvent(NULL, TRUE, FALSE, name); + } +#endif /* PS_USE_WIN32 */ +#endif /* not PS_USE_NONE */ +} + + +/* + * Returns what's currently in the ps display, in case someone needs + * it. Note that only the activity part is returned. On some platforms + * the string will not be null-terminated, so return the effective + * length into *displen. + */ +const char * +get_ps_display(int *displen) +{ +#ifdef PS_USE_CLOBBER_ARGV + /* If ps_buffer is a pointer, it might still be null */ + if (!ps_buffer) + { + *displen = 0; + return ""; + } +#endif + +#ifndef PS_USE_NONE + *displen = (int) (ps_buffer_cur_len - ps_buffer_fixed_size); + + return ps_buffer + ps_buffer_fixed_size; +#else + return ""; +#endif +} |