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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 14:30:35 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 14:30:35 +0000
commit378c18e5f024ac5a8aef4cb40d7c9aa9633d144c (patch)
tree44dfb6ca500d32cabd450649b322a42e70a30683 /login-utils/setpwnam.c
parentInitial commit. (diff)
downloadutil-linux-378c18e5f024ac5a8aef4cb40d7c9aa9633d144c.tar.xz
util-linux-378c18e5f024ac5a8aef4cb40d7c9aa9633d144c.zip
Adding upstream version 2.38.1.upstream/2.38.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'login-utils/setpwnam.c')
-rw-r--r--login-utils/setpwnam.c216
1 files changed, 216 insertions, 0 deletions
diff --git a/login-utils/setpwnam.c b/login-utils/setpwnam.c
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+/*
+ * setpwnam.c -- edit an entry in a password database.
+ *
+ * (c) 1994 Salvatore Valente <svalente@mit.edu>
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Edited 11/10/96 (DD/MM/YY ;-) by Nicolai Langfeldt (janl@math.uio.no)
+ * to read /etc/passwd directly so that passwd, chsh and chfn can work on
+ * machines that run NIS (previously YP). Changes will not be made to
+ * usernames starting with +.
+ *
+ * This file is distributed with no warranty.
+ *
+ * Usage:
+ * 1) get a struct passwd * from getpwnam().
+ * You should assume a struct passwd has an infinite number of fields, so
+ * you should not try to create one from scratch.
+ * 2) edit the fields you want to edit.
+ * 3) call setpwnam() with the edited struct passwd.
+ *
+ * A _normal user_ program should never directly manipulate etc/passwd but
+ * /use getpwnam() and (family, as well as) setpwnam().
+ *
+ * But, setpwnam was made to _edit_ the password file. For use by chfn,
+ * chsh and passwd. _I_ _HAVE_ to read and write /etc/passwd directly. Let
+ * those who say nay be forever silent and think about how getpwnam (and
+ * family) works on a machine running YP.
+ *
+ * Added checks for failure of malloc() and removed error reporting to
+ * stderr, this is a library function and should not print on the screen,
+ * but return appropriate error codes.
+ * 27-Jan-97 - poe@daimi.aau.dk
+ *
+ * Thanks to "two guys named Ian".
+ *
+ * $Author: poer $
+ * $Revision: 1.13 $
+ * $Date: 1997/06/23 08:26:29 $
+ */
+
+#undef DEBUG
+
+#include <errno.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <pwd.h>
+#include <shadow.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "c.h"
+#include "fileutils.h"
+#include "closestream.h"
+#include "setpwnam.h"
+
+static void pw_init(void);
+
+/*
+ * setpwnam () --
+ * takes a struct passwd in which every field is filled in and valid.
+ * If the given username exists in the passwd file, the entry is
+ * replaced with the given entry.
+ */
+int setpwnam(struct passwd *pwd, const char *prefix)
+{
+ FILE *fp = NULL, *pwf = NULL;
+ int save_errno, rc;
+ uint8_t found = 0;
+ size_t namelen;
+ size_t contlen;
+ size_t buflen = 256;
+ char *linebuf = NULL;
+ char *tmpname = NULL;
+
+ pw_init();
+
+ if ((fp = xfmkstemp(&tmpname, "/etc", prefix)) == NULL)
+ return -1;
+
+ /* ptmp should be owned by root.root or root.wheel */
+ if (fchown(fileno(fp), (uid_t) 0, (gid_t) 0) < 0)
+ goto fail;
+
+ /* acquire exclusive lock */
+ if (lckpwdf() < 0)
+ goto fail;
+ pwf = fopen(PASSWD_FILE, "r");
+ if (!pwf)
+ goto fail;
+
+ namelen = strlen(pwd->pw_name);
+
+ linebuf = malloc(buflen);
+ if (!linebuf)
+ goto fail;
+
+ /* parse the passwd file */
+ /* Do you wonder why I don't use getpwent? Read comments at top of
+ * file */
+ while (fgets(linebuf, buflen, pwf) != NULL) {
+ contlen = strlen(linebuf);
+ while (linebuf[contlen - 1] != '\n' && !feof(pwf)) {
+ char *tmp;
+ /* Extend input buffer if it failed getting the whole line,
+ * so now we double the buffer size */
+ buflen *= 2;
+ tmp = realloc(linebuf, buflen);
+ if (tmp == NULL)
+ goto fail;
+ linebuf = tmp;
+ /* And fill the rest of the buffer */
+ if (fgets(&linebuf[contlen], buflen / 2, pwf) == NULL)
+ break;
+ contlen = strlen(linebuf);
+ /* That was a lot of work for nothing. Gimme perl! */
+ }
+
+ /* Is this the username we were sent to change? */
+ if (!found && linebuf[namelen] == ':' &&
+ !strncmp(linebuf, pwd->pw_name, namelen)) {
+ /* Yes! So go forth in the name of the Lord and
+ * change it! */
+ if (putpwent(pwd, fp) < 0)
+ goto fail;
+ found = 1;
+ continue;
+ }
+ /* Nothing in particular happened, copy input to output */
+ fputs(linebuf, fp);
+ }
+
+ /* xfmkstemp is too restrictive by default for passwd file */
+ if (fchmod(fileno(fp), 0644) < 0)
+ goto fail;
+ rc = close_stream(fp);
+ fp = NULL;
+ if (rc != 0)
+ goto fail;
+
+ fclose(pwf); /* I don't think I want to know if this failed */
+ pwf = NULL;
+
+ if (!found) {
+ errno = ENOENT; /* give me something better */
+ goto fail;
+ }
+
+ /* we don't care if we can't remove the backup file */
+ unlink(PASSWD_FILE ".OLD");
+ /* we don't care if we can't create the backup file */
+ ignore_result(link(PASSWD_FILE, PASSWD_FILE ".OLD"));
+ /* we DO care if we can't rename to the passwd file */
+ if (rename(tmpname, PASSWD_FILE) < 0)
+ goto fail;
+ /* finally: success */
+ ulckpwdf();
+ free(linebuf);
+ return 0;
+
+ fail:
+ save_errno = errno;
+ ulckpwdf();
+ if (fp != NULL)
+ fclose(fp);
+ if (tmpname != NULL)
+ unlink(tmpname);
+ free(tmpname);
+ if (pwf != NULL)
+ fclose(pwf);
+ free(linebuf);
+ errno = save_errno;
+ return -1;
+}
+
+/* Set up the limits so that we're not foiled */
+static void pw_init(void)
+{
+ struct rlimit rlim;
+
+ /* Unlimited resource limits. */
+ rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
+ setrlimit(RLIMIT_CPU, &rlim);
+ setrlimit(RLIMIT_FSIZE, &rlim);
+ setrlimit(RLIMIT_STACK, &rlim);
+ setrlimit(RLIMIT_DATA, &rlim);
+ setrlimit(RLIMIT_RSS, &rlim);
+
+#ifndef DEBUG
+ /* Don't drop core (not really necessary, but GP's). */
+ rlim.rlim_cur = rlim.rlim_max = 0;
+ setrlimit(RLIMIT_CORE, &rlim);
+#endif
+
+ /* Turn off signals. */
+ signal(SIGALRM, SIG_IGN);
+ signal(SIGHUP, SIG_IGN);
+ signal(SIGINT, SIG_IGN);
+ signal(SIGPIPE, SIG_IGN);
+ signal(SIGQUIT, SIG_IGN);
+ signal(SIGTERM, SIG_IGN);
+ signal(SIGTSTP, SIG_IGN);
+ signal(SIGTTOU, SIG_IGN);
+
+ /* Create with exact permissions. */
+ umask(0);
+}