/*-------------------------------------------------------------------------
*
* exec.c
+ * Functions for finding and validating executable files
+ *
*
* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/port/exec.c,v 1.31 2004/11/06 01:16:22 tgl Exp $
+ * $PostgreSQL: pgsql/src/port/exec.c,v 1.32 2004/11/06 23:06:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#define log_error(str, param) (fprintf(stderr, str, param), fputc('\n', stderr))
#endif
+#ifdef WIN32_CLIENT_ONLY
+#define getcwd(cwd,len) GetCurrentDirectory(len, cwd)
+#endif
+
+static int validate_exec(const char *path);
+static int resolve_symlinks(char *path);
+static char *pipe_read_line(char *cmd, char *line, int maxsize);
+
/*
* validate_exec -- validate "path" as an executable file
#endif
}
+
/*
* find_my_exec -- find an absolute path to a valid executable
*
+ * argv0 is the name passed on the command line
+ * retpath is the output area (must be of size MAXPGPATH)
+ * Returns 0 if OK, -1 if error.
+ *
* The reason we have to work so hard to find an absolute path is that
* on some platforms we can't do dynamic loading unless we know the
* executable's location. Also, we need a full path not a relative
- * path because we will later change working directory.
+ * path because we will later change working directory. Finally, we want
+ * a true path not a symlink location, so that we can locate other files
+ * that are part of our installation relative to the executable.
*
* This function is not thread-safe because it calls validate_exec(),
* which calls getgrgid(). This function should be used only in
test_path[MAXPGPATH];
char *path;
-#ifndef WIN32_CLIENT_ONLY
if (!getcwd(cwd, MAXPGPATH))
- strcpy(cwd, "."); /* cheesy, but better than nothing */
-#else
- if (!GetCurrentDirectory(MAXPGPATH, cwd))
- strcpy(cwd, "."); /* cheesy, but better than nothing */
-#endif
+ {
+ log_error(_("could not identify current directory: %s"),
+ strerror(errno));
+ return -1;
+ }
/*
* If argv0 contains a separator, then PATH wasn't used.
canonicalize_path(retpath);
if (validate_exec(retpath) == 0)
- return 0;
+ return resolve_symlinks(retpath);
log_error("invalid binary \"%s\"", retpath);
return -1;
/* Win32 checks the current directory first for names without slashes */
join_path_components(retpath, cwd, argv0);
if (validate_exec(retpath) == 0)
- return 0;
+ return resolve_symlinks(retpath);
#endif
/*
switch (validate_exec(retpath))
{
case 0: /* found ok */
- return 0;
+ return resolve_symlinks(retpath);
case -1: /* wasn't even a candidate, keep looking */
break;
case -2: /* found but disqualified */
return -1;
}
+
+/*
+ * resolve_symlinks - resolve symlinks to the underlying file
+ *
+ * If path does not point to a symlink, leave it alone. If it does,
+ * replace it by the absolute path to the referenced file.
+ *
+ * Returns 0 if OK, -1 if error.
+ *
+ * Note: we are not particularly tense about producing nice error messages
+ * because we are not really expecting error here; we just determined that
+ * the symlink does point to a valid executable.
+ */
+static int
+resolve_symlinks(char *path)
+{
+#ifdef HAVE_READLINK
+ struct stat buf;
+ char orig_wd[MAXPGPATH],
+ link_buf[MAXPGPATH];
+ char *fname;
+
+ /* Quick out if it's not a symlink */
+ if (lstat(path, &buf) < 0 ||
+ (buf.st_mode & S_IFMT) != S_IFLNK)
+ return 0;
+
+ /*
+ * To resolve a symlink properly, we have to chdir into its directory
+ * and then chdir to where the symlink points; otherwise we may fail to
+ * resolve relative links correctly (consider cases involving mount
+ * points, for example). After following the final symlink, we use
+ * getcwd() to figure out where the heck we're at.
+ */
+ if (!getcwd(orig_wd, MAXPGPATH))
+ {
+ log_error(_("could not identify current directory: %s"),
+ strerror(errno));
+ return -1;
+ }
+
+ for (;;)
+ {
+ char *lsep;
+ int rllen;
+
+ lsep = last_dir_separator(path);
+ if (lsep)
+ {
+ *lsep = '\0';
+ if (chdir(path) == -1)
+ {
+ log_error(_("could not change directory to \"%s\""), path);
+ return -1;
+ }
+ fname = lsep + 1;
+ }
+ else
+ fname = path;
+
+ if (lstat(fname, &buf) < 0 ||
+ (buf.st_mode & S_IFMT) != S_IFLNK)
+ break;
+
+ rllen = readlink(fname, link_buf, sizeof(link_buf));
+ if (rllen < 0 || rllen >= sizeof(link_buf))
+ {
+ log_error(_("could not read symbolic link \"%s\""), fname);
+ return -1;
+ }
+ link_buf[rllen] = '\0';
+ strcpy(path, link_buf);
+ }
+
+ /* must copy final component out of 'path' temporarily */
+ strcpy(link_buf, fname);
+
+ if (!getcwd(path, MAXPGPATH))
+ {
+ log_error(_("could not identify current directory: %s"),
+ strerror(errno));
+ return -1;
+ }
+ join_path_components(path, path, link_buf);
+ canonicalize_path(path);
+
+ if (chdir(orig_wd) == -1)
+ {
+ log_error(_("could not change directory to \"%s\""), orig_wd);
+ return -1;
+ }
+
+#endif /* HAVE_READLINK */
+
+ return 0;
+}
+
+
+/*
+ * Find another program in our binary's directory,
+ * then make sure it is the proper version.
+ */
+int
+find_other_exec(const char *argv0, const char *target,
+ const char *versionstr, char *retpath)
+{
+ char cmd[MAXPGPATH];
+ char line[100];
+
+ if (find_my_exec(argv0, retpath) < 0)
+ return -1;
+
+ /* Trim off program name and keep just directory */
+ *last_dir_separator(retpath) = '\0';
+ canonicalize_path(retpath);
+
+ /* Now append the other program's name */
+ snprintf(retpath + strlen(retpath), MAXPGPATH - strlen(retpath),
+ "/%s%s", target, EXE);
+
+ if (validate_exec(retpath) != 0)
+ return -1;
+
+ snprintf(cmd, sizeof(cmd), "\"%s\" -V 2>%s", retpath, DEVNULL);
+
+ if (!pipe_read_line(cmd, line, sizeof(line)))
+ return -1;
+
+ if (strcmp(line, versionstr) != 0)
+ return -2;
+
+ return 0;
+}
+
+
/*
* The runtime library's popen() on win32 does not work when being
* called from a service when running on windows <= 2000, because
* Executing a command in a pipe and reading the first line from it
* is all we need.
*/
-
static char *
pipe_read_line(char *cmd, char *line, int maxsize)
{
return NULL;
return line;
-#else
- /* Win32 */
+
+#else /* WIN32 */
+
SECURITY_ATTRIBUTES sattr;
HANDLE childstdoutrd,
childstdoutwr,
CloseHandle(childstdoutrddup);
return retval;
-#endif
-}
-
-
-/*
- * Find another program in our binary's directory,
- * then make sure it is the proper version.
- */
-int
-find_other_exec(const char *argv0, const char *target,
- const char *versionstr, char *retpath)
-{
- char cmd[MAXPGPATH];
- char line[100];
-
- if (find_my_exec(argv0, retpath) < 0)
- return -1;
-
- /* Trim off program name and keep just directory */
- *last_dir_separator(retpath) = '\0';
- canonicalize_path(retpath);
-
- /* Now append the other program's name */
- snprintf(retpath + strlen(retpath), MAXPGPATH - strlen(retpath),
- "/%s%s", target, EXE);
-
- if (validate_exec(retpath))
- return -1;
-
- snprintf(cmd, sizeof(cmd), "\"%s\" -V 2>%s", retpath, DEVNULL);
-
- if (!pipe_read_line(cmd, line, sizeof(line)))
- return -1;
-
- if (strcmp(line, versionstr) != 0)
- return -2;
-
- return 0;
+#endif /* WIN32 */
}
perror("pclose failed");
}
else if (WIFEXITED(exitstatus))
- {
log_error(_("child process exited with exit code %d"),
WEXITSTATUS(exitstatus));
- }
else if (WIFSIGNALED(exitstatus))
- {
log_error(_("child process was terminated by signal %d"),
WTERMSIG(exitstatus));
- }
else
- {
log_error(_("child process exited with unrecognized status %d"),
exitstatus);
- }
return -1;
}
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