/*-------------------------------------------------------------------- * ps_status.c * * Routines to support changing the ps display of PostgreSQL backends * to contain some useful information. Mechanism differs wildly across * platforms. * * $Header: /cvsroot/pgsql/src/backend/utils/misc/ps_status.c,v 1.7 2001/10/22 19:41:38 tgl Exp $ * * Copyright 2000 by PostgreSQL Global Development Group * various details abducted from various places *-------------------------------------------------------------------- */ #include "postgres.h" #include #ifdef HAVE_SYS_PSTAT_H #include /* for HP-UX */ #endif #ifdef HAVE_PS_STRINGS #include /* for old BSD */ #include #endif #include "miscadmin.h" #include "utils/ps_status.h" extern char **environ; /*------ * Alternative ways of updating ps display: * * 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 * (most SysV-like systems) * PS_USE_NONE * don't update ps display * (This is the default, as it is safest.) */ #if 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(__bsdi__) || defined(__hurd__) #define PS_USE_CHANGE_ARGV #elif defined(__linux__) || defined(_AIX) || defined(__sgi) || (defined(sun) && !defined(BSD)) || defined(ultrix) || defined(__ksr__) || defined(__osf__) || defined(__QNX__) || defined(__svr4__) || defined(__svr5__) #define PS_USE_CLOBBER_ARGV #else #define PS_USE_NONE #endif /* Different systems want the buffer padded differently */ #if defined(_AIX) || defined(__linux__) || defined(__QNX__) || defined(__svr4__) #define PS_PADDING '\0' #else #define PS_PADDING ' ' #endif #ifndef PS_USE_CLOBBER_ARGV /* all but one options 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 */ #endif /* PS_USE_CLOBBER_ARGV */ static size_t ps_buffer_fixed_size; /* size of the constant prefix */ /* 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. * * 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. */ void save_ps_display_args(int argc, char *argv[]) { save_argc = argc; save_argv = argv; #ifdef 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; } /* * 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]; ps_buffer_size = end_of_area - argv[0] - 1; /* * move the environment out of the way */ new_environ = malloc(sizeof(char *) * (i + 1)); for (i = 0; environ[i] != NULL; i++) new_environ[i] = strdup(environ[i]); new_environ[i] = NULL; environ = new_environ; } #endif /* PS_USE_CLOBBER_ARGV */ } /* * Call this once during subprocess startup to set the identification * values. At this point, the original argv[] array may be overwritten. */ void init_ps_display(const char *username, const char *dbname, const char *host_info) { Assert(username); Assert(dbname); Assert(host_info); #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 save_argv[1] = NULL; #endif /* PS_USE_CLOBBER_ARGV */ /* * Make fixed prefix of ps display. */ #ifdef PS_USE_SETPROCTITLE /* * apparently setproctitle() already adds a `progname:' prefix to the * ps line */ snprintf(ps_buffer, ps_buffer_size, "%s %s %s ", username, dbname, host_info); #else snprintf(ps_buffer, ps_buffer_size, "postgres: %s %s %s ", username, dbname, host_info); #endif ps_buffer_fixed_size = strlen(ps_buffer); #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 /* 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 */ StrNCpy(ps_buffer + ps_buffer_fixed_size, activity, ps_buffer_size - ps_buffer_fixed_size); /* Transmit new setting to kernel, if necessary */ #ifdef PS_USE_SETPROCTITLE setproctitle("%s", ps_buffer); #endif #ifdef PS_USE_PSTAT { union pstun pst; pst.pst_command = ps_buffer; pstat(PSTAT_SETCMD, pst, strlen(ps_buffer), 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 { char *cp; /* pad unused memory */ for (cp = ps_buffer + strlen(ps_buffer); cp < ps_buffer + ps_buffer_size; cp++) *cp = PS_PADDING; } #endif /* PS_USE_CLOBBER_ARGV */ #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. */ const char * get_ps_display(void) { #ifdef PS_USE_CLOBBER_ARGV /* If ps_buffer is a pointer, it might still be null */ if (!ps_buffer) return ""; #endif return ps_buffer + ps_buffer_fixed_size; }