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/*
* exec.c
*
* execution functions
*
* Copyright (c) 2010-2011, PostgreSQL Global Development Group
* contrib/pg_upgrade/exec.c
*/
#include "pg_upgrade.h"
#include <fcntl.h>
#include <unistd.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);
/*
* exec_prog()
*
* Formats a command from the given argument list and executes that
* command. If the command executes, exec_prog() returns 1 otherwise
* exec_prog() logs an error message and returns 0.
*
* If throw_error is TRUE, this function will throw a PG_FATAL error
* instead of returning should an error occur.
*/
int
exec_prog(bool throw_error, const char *fmt,...)
{
va_list args;
int result;
char cmd[MAXPGPATH];
va_start(args, fmt);
vsnprintf(cmd, MAXPGPATH, fmt, args);
va_end(args);
pg_log(PG_INFO, "%s\n", cmd);
result = system(cmd);
if (result != 0)
{
pg_log(throw_error ? PG_FATAL : PG_INFO,
"There were problems executing %s\n", cmd);
return 1;
}
return 0;
}
/*
* is_server_running()
*
* checks whether postmaster on the given data directory is running or not.
* The check is performed by looking for the existence of postmaster.pid file.
*/
bool
is_server_running(const char *datadir)
{
char path[MAXPGPATH];
int fd;
snprintf(path, sizeof(path), "%s/postmaster.pid", datadir);
if ((fd = open(path, O_RDONLY, 0)) < 0)
{
if (errno != ENOENT)
pg_log(PG_FATAL, "could not open file \"%s\" for reading\n",
path);
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)
{
if (access(".", R_OK | W_OK | X_OK) != 0)
pg_log(PG_FATAL,
"You must have read and write access in the current directory.\n");
prep_status("Checking old data directory (%s)", old_cluster.pgdata);
check_data_dir(old_cluster.pgdata);
check_ok();
prep_status("Checking old bin directory (%s)", old_cluster.bindir);
check_bin_dir(&old_cluster);
check_ok();
prep_status("Checking new data directory (%s)", new_cluster.pgdata);
check_data_dir(new_cluster.pgdata);
check_ok();
prep_status("Checking new bin directory (%s)", new_cluster.bindir);
check_bin_dir(&new_cluster);
check_ok();
}
/*
* 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;
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", pg_data,
requiredSubdirs[subdirnum]);
if (stat(subDirName, &statBuf) != 0)
report_status(PG_FATAL, "check for %s failed: %s\n",
requiredSubdirs[subdirnum], getErrorText(errno));
else if (!S_ISDIR(statBuf.st_mode))
report_status(PG_FATAL, "%s is not a directory\n",
requiredSubdirs[subdirnum]);
}
}
/*
* 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)
{
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, "pg_config");
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_log(PG_FATAL, "check for %s failed - %s\n",
cmdName, getErrorText(errno));
if (!S_ISREG(buf.st_mode))
pg_log(PG_FATAL, "check for %s failed - not an executable file\n",
cmdName);
/*
* 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_log(PG_FATAL, "check for %s failed - cannot read file (permission denied)\n",
cmdName);
#ifndef WIN32
if (access(path, X_OK) != 0)
#else
if ((buf.st_mode & S_IXUSR) == 0)
#endif
pg_log(PG_FATAL, "check for %s failed - cannot execute (permission denied)\n",
cmdName);
}
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