+/*
+ * m_mktemp.c -- Construct a temporary file.
+ *
+ * $Id$
+ *
+ * This code is Copyright (c) 2010, by the authors of nmh. See the
+ * COPYRIGHT file in the root directory of the nmh distribution for
+ * complete copyright information.
+ */
+
+#include <errno.h>
+#include <h/mh.h>
+
+static char *get_temp_dir();
+
+/* Create a temporary file. If pfx_in is null, the temporary file
+ * will be created in the temporary directory (more on that later).
+ * If pfx_in is not null, then the temporary file location will be
+ * defined by the value pfx_in.
+ *
+ * The file created will be at the pathname specified appended with
+ * 6 random (we hope :) characters.
+ *
+ * The return value will be the pathname to the file created.
+ *
+ * CAUTION: The return pointer references static data. If
+ * you need to modify, or save, the return string, make a copy of it
+ * first.
+ *
+ * When pfx_in is null, the temporary directory is determined as
+ * follows, in order:
+ *
+ * MHTMPDIR envvar
+ * TMPDIR envvar
+ * TMP envvar
+ * User's mail directory.
+ *
+ * NOTE: One will probably use m_mktemp2() instead of this function.
+ * For example, if you want to create a temp file in the defined
+ * temporary directory, but with a custom basename prefix, do
+ * something like the following:
+ *
+ * char *tmp_pathname = m_mktemp2(NULL, "mypre", ...);
+ */
+char *
+m_mktemp (
+ const char *pfx_in, /* Pathname prefix for temporary file. */
+ int *fd_ret, /* (return,optional) File descriptor to temp file. */
+ FILE **fp_ret /* (return,optional) FILE pointer to temp file. */
+)
+{
+ static char tmpfil[BUFSIZ];
+ int fd = -1;
+ int keep_open = 0;
+ mode_t oldmode = umask(077);
+
+ if (pfx_in == NULL) {
+ snprintf(tmpfil, sizeof(tmpfil), "%s/nmhXXXXXX", get_temp_dir());
+ } else {
+ snprintf(tmpfil, sizeof(tmpfil), "%sXXXXXX", pfx_in);
+ }
+
+ fd = mkstemp(tmpfil);
+ if (fd < 0) {
+ umask(oldmode);
+ return NULL;
+ }
+ if (fd_ret != NULL) {
+ *fd_ret = fd;
+ keep_open = 1;
+ }
+ if (fp_ret != NULL) {
+ FILE *fp = fdopen(fd, "w+");
+ if (fp == NULL) {
+ int olderr = errno;
+ unlink(tmpfil);
+ close(fd);
+ errno = olderr;
+ umask(oldmode);
+ return NULL;
+ }
+ *fp_ret = fp;
+ keep_open = 1;
+ }
+ if (!keep_open) {
+ close(fd);
+ }
+ umask(oldmode);
+ return tmpfil;
+}
+
+/* This version allows one to specify the directory the temp file should
+ * by created based on a given pathname. Although m_mktemp() technically
+ * supports this, this version is when the directory is defined by
+ * a separate variable from the prefix, eliminating the caller from having
+ * to do string manipulation to generate the desired. pathname prefix.
+ *
+ * The pfx_in parameter specifies a basename prefix for the file. If dir_in
+ * is NULL, then the defined temporary directory (see comments to m_mktemp()
+ * above) is used to create the temp file.
+ */
+char *
+m_mktemp2 (
+ const char *dir_in, /* Directory to place temp file. */
+ const char *pfx_in, /* Basename prefix for temp file. */
+ int *fd_ret, /* (return,optional) File descriptor to temp file. */
+ FILE **fp_ret /* (return,optional) FILE pointer to temp file. */
+)
+{
+ static char buffer[BUFSIZ];
+ char *cp;
+
+ if (dir_in == NULL) {
+ if (pfx_in == NULL) {
+ return m_mktemp(NULL, fd_ret, fp_ret);
+ }
+ snprintf(buffer, sizeof(buffer), "%s/%s", get_temp_dir(), pfx_in);
+ return m_mktemp(buffer, fd_ret, fp_ret);
+ }
+
+ if ((cp = r1bindex ((char *)dir_in, '/')) == dir_in) {
+ /* No directory component */
+ return m_mktemp(pfx_in, fd_ret, fp_ret);
+ }
+ int n = (int)(cp-dir_in-1); /* Length of dir component */
+ snprintf(buffer, sizeof(buffer), "%.*s%s", n, dir_in, pfx_in);
+ return m_mktemp(buffer, fd_ret, fp_ret);
+}
+
+
+static char *
+get_temp_dir()
+{
+ // Ignore envvars if we are setuid
+ if ((getuid()==geteuid()) && (getgid()==getegid())) {
+ char *tmpdir = NULL;
+ tmpdir = getenv("MHTMPDIR");
+ if (tmpdir != NULL && *tmpdir != '\0') return tmpdir;
+
+ tmpdir = getenv("TMPDIR");
+ if (tmpdir != NULL && *tmpdir != '\0') return tmpdir;
+
+ tmpdir = getenv("TMP");
+ if (tmpdir != NULL && *tmpdir != '\0') return tmpdir;
+ }
+ return m_maildir("");
+}