postgresql/contrib/pg_upgrade/exec.c
Peter Eisentraut 264aa14a2f pg_upgrade: Split off pg_fatal() from pg_log()
This allows decorating pg_fatal() with noreturn compiler hints, leading
to better diagnostics.

Reviewed-by: Marko Tiikkaja <marko@joh.to>
2013-10-09 22:48:41 -04:00

378 lines
9.6 KiB
C

/*
* exec.c
*
* execution functions
*
* Copyright (c) 2010-2013, PostgreSQL Global Development Group
* contrib/pg_upgrade/exec.c
*/
#include "postgres_fe.h"
#include "pg_upgrade.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
static void check_data_dir(const char *pg_data);
static void check_bin_dir(ClusterInfo *cluster);
static void validate_exec(const char *dir, const char *cmdName);
#ifdef WIN32
static int win32_check_directory_write_permissions(void);
#endif
/*
* exec_prog()
* Execute an external program with stdout/stderr redirected, and report
* errors
*
* Formats a command from the given argument list, logs it to the log file,
* and attempts to execute that command. If the command executes
* successfully, exec_prog() returns true.
*
* If the command fails, an error message is saved to the specified log_file.
* If throw_error is true, this raises a PG_FATAL error and pg_upgrade
* terminates; otherwise it is just reported as PG_REPORT and exec_prog()
* returns false.
*
* The code requires it be called first from the primary thread on Windows.
*/
bool
exec_prog(const char *log_file, const char *opt_log_file,
bool throw_error, const char *fmt,...)
{
int result = 0;
int written;
#define MAXCMDLEN (2 * MAXPGPATH)
char cmd[MAXCMDLEN];
FILE *log;
va_list ap;
#ifdef WIN32
static DWORD mainThreadId = 0;
/* We assume we are called from the primary thread first */
if (mainThreadId == 0)
mainThreadId = GetCurrentThreadId();
#endif
written = strlcpy(cmd, SYSTEMQUOTE, sizeof(cmd));
va_start(ap, fmt);
written += vsnprintf(cmd + written, MAXCMDLEN - written, fmt, ap);
va_end(ap);
if (written >= MAXCMDLEN)
pg_fatal("command too long\n");
written += snprintf(cmd + written, MAXCMDLEN - written,
" >> \"%s\" 2>&1" SYSTEMQUOTE, log_file);
if (written >= MAXCMDLEN)
pg_fatal("command too long\n");
pg_log(PG_VERBOSE, "%s\n", cmd);
#ifdef WIN32
/*
* For some reason, Windows issues a file-in-use error if we write data
* to the log file from a non-primary thread just before we create a
* subprocess that also writes to the same log file. One fix is to
* sleep for 100ms. A cleaner fix is to write to the log file _after_
* the subprocess has completed, so we do this only when writing from
* a non-primary thread. fflush(), running system() twice, and
* pre-creating the file do not see to help.
*/
if (mainThreadId != GetCurrentThreadId())
result = system(cmd);
#endif
log = fopen(log_file, "a");
#ifdef WIN32
{
/*
* "pg_ctl -w stop" might have reported that the server has stopped
* because the postmaster.pid file has been removed, but "pg_ctl -w
* start" might still be in the process of closing and might still be
* holding its stdout and -l log file descriptors open. Therefore,
* try to open the log file a few more times.
*/
int iter;
for (iter = 0; iter < 4 && log == NULL; iter++)
{
sleep(1);
log = fopen(log_file, "a");
}
}
#endif
if (log == NULL)
pg_fatal("cannot write to log file %s\n", log_file);
#ifdef WIN32
/* Are we printing "command:" before its output? */
if (mainThreadId == GetCurrentThreadId())
fprintf(log, "\n\n");
#endif
fprintf(log, "command: %s\n", cmd);
#ifdef WIN32
/* Are we printing "command:" after its output? */
if (mainThreadId != GetCurrentThreadId())
fprintf(log, "\n\n");
#endif
/*
* In Windows, we must close the log file at this point so the file is not
* open while the command is running, or we get a share violation.
*/
fclose(log);
#ifdef WIN32
/* see comment above */
if (mainThreadId == GetCurrentThreadId())
#endif
result = system(cmd);
if (result != 0)
{
/* we might be in on a progress status line, so go to the next line */
report_status(PG_REPORT, "\n*failure*");
fflush(stdout);
pg_log(PG_VERBOSE, "There were problems executing \"%s\"\n", cmd);
if (opt_log_file)
pg_log(throw_error ? PG_FATAL : PG_REPORT,
"Consult the last few lines of \"%s\" or \"%s\" for\n"
"the probable cause of the failure.\n",
log_file, opt_log_file);
else
pg_log(throw_error ? PG_FATAL : PG_REPORT,
"Consult the last few lines of \"%s\" for\n"
"the probable cause of the failure.\n",
log_file);
}
#ifndef WIN32
/*
* We can't do this on Windows because it will keep the "pg_ctl start"
* output filename open until the server stops, so we do the \n\n above on
* that platform. We use a unique filename for "pg_ctl start" that is
* never reused while the server is running, so it works fine. We could
* log these commands to a third file, but that just adds complexity.
*/
if ((log = fopen(log_file, "a")) == NULL)
pg_fatal("cannot write to log file %s\n", log_file);
fprintf(log, "\n\n");
fclose(log);
#endif
return result == 0;
}
/*
* pid_lock_file_exists()
*
* Checks whether the postmaster.pid file exists.
*/
bool
pid_lock_file_exists(const char *datadir)
{
char path[MAXPGPATH];
int fd;
snprintf(path, sizeof(path), "%s/postmaster.pid", datadir);
if ((fd = open(path, O_RDONLY, 0)) < 0)
{
/* ENOTDIR means we will throw a more useful error later */
if (errno != ENOENT && errno != ENOTDIR)
pg_fatal("could not open file \"%s\" for reading: %s\n",
path, getErrorText(errno));
return false;
}
close(fd);
return true;
}
/*
* verify_directories()
*
* does all the hectic work of verifying directories and executables
* of old and new server.
*
* NOTE: May update the values of all parameters
*/
void
verify_directories(void)
{
#ifndef WIN32
if (access(".", R_OK | W_OK | X_OK) != 0)
#else
if (win32_check_directory_write_permissions() != 0)
#endif
pg_fatal("You must have read and write access in the current directory.\n");
check_bin_dir(&old_cluster);
check_data_dir(old_cluster.pgdata);
check_bin_dir(&new_cluster);
check_data_dir(new_cluster.pgdata);
}
#ifdef WIN32
/*
* win32_check_directory_write_permissions()
*
* access() on WIN32 can't check directory permissions, so we have to
* optionally create, then delete a file to check.
* http://msdn.microsoft.com/en-us/library/1w06ktdy%28v=vs.80%29.aspx
*/
static int
win32_check_directory_write_permissions(void)
{
int fd;
/*
* We open a file we would normally create anyway. We do this even in
* 'check' mode, which isn't ideal, but this is the best we can do.
*/
if ((fd = open(GLOBALS_DUMP_FILE, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) < 0)
return -1;
close(fd);
return unlink(GLOBALS_DUMP_FILE);
}
#endif
/*
* check_data_dir()
*
* This function validates the given cluster directory - we search for a
* small set of subdirectories that we expect to find in a valid $PGDATA
* directory. If any of the subdirectories are missing (or secured against
* us) we display an error message and exit()
*
*/
static void
check_data_dir(const char *pg_data)
{
char subDirName[MAXPGPATH];
int subdirnum;
/* start check with top-most directory */
const char *requiredSubdirs[] = {"", "base", "global", "pg_clog",
"pg_multixact", "pg_subtrans", "pg_tblspc", "pg_twophase",
"pg_xlog"};
for (subdirnum = 0;
subdirnum < sizeof(requiredSubdirs) / sizeof(requiredSubdirs[0]);
++subdirnum)
{
struct stat statBuf;
snprintf(subDirName, sizeof(subDirName), "%s%s%s", pg_data,
/* Win32 can't stat() a directory with a trailing slash. */
*requiredSubdirs[subdirnum] ? "/" : "",
requiredSubdirs[subdirnum]);
if (stat(subDirName, &statBuf) != 0)
report_status(PG_FATAL, "check for \"%s\" failed: %s\n",
subDirName, getErrorText(errno));
else if (!S_ISDIR(statBuf.st_mode))
report_status(PG_FATAL, "%s is not a directory\n",
subDirName);
}
}
/*
* check_bin_dir()
*
* This function searches for the executables that we expect to find
* in the binaries directory. If we find that a required executable
* is missing (or secured against us), we display an error message and
* exit().
*/
static void
check_bin_dir(ClusterInfo *cluster)
{
struct stat statBuf;
/* check bindir */
if (stat(cluster->bindir, &statBuf) != 0)
report_status(PG_FATAL, "check for \"%s\" failed: %s\n",
cluster->bindir, getErrorText(errno));
else if (!S_ISDIR(statBuf.st_mode))
report_status(PG_FATAL, "%s is not a directory\n",
cluster->bindir);
validate_exec(cluster->bindir, "postgres");
validate_exec(cluster->bindir, "pg_ctl");
validate_exec(cluster->bindir, "pg_resetxlog");
if (cluster == &new_cluster)
{
/* these are only needed in the new cluster */
validate_exec(cluster->bindir, "psql");
validate_exec(cluster->bindir, "pg_dumpall");
}
}
/*
* validate_exec()
*
* validate "path" as an executable file
*/
static void
validate_exec(const char *dir, const char *cmdName)
{
char path[MAXPGPATH];
struct stat buf;
snprintf(path, sizeof(path), "%s/%s", dir, cmdName);
#ifdef WIN32
/* Windows requires a .exe suffix for stat() */
if (strlen(path) <= strlen(EXE_EXT) ||
pg_strcasecmp(path + strlen(path) - strlen(EXE_EXT), EXE_EXT) != 0)
strlcat(path, EXE_EXT, sizeof(path));
#endif
/*
* Ensure that the file exists and is a regular file.
*/
if (stat(path, &buf) < 0)
pg_fatal("check for \"%s\" failed: %s\n",
path, getErrorText(errno));
else if (!S_ISREG(buf.st_mode))
pg_fatal("check for \"%s\" failed: not an executable file\n",
path);
/*
* Ensure that the file is both executable and readable (required for
* dynamic loading).
*/
#ifndef WIN32
if (access(path, R_OK) != 0)
#else
if ((buf.st_mode & S_IRUSR) == 0)
#endif
pg_fatal("check for \"%s\" failed: cannot read file (permission denied)\n",
path);
#ifndef WIN32
if (access(path, X_OK) != 0)
#else
if ((buf.st_mode & S_IXUSR) == 0)
#endif
pg_fatal("check for \"%s\" failed: cannot execute (permission denied)\n",
path);
}