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chpasswd: fixes and code shrink

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update_passwd                                        732     734      +2
chpasswd_main                                        318     292     -26
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 2/-26)             Total: -24 bytes
   text    data     bss     dec     hex filename
 781564    1168   11900  794632   c2008 busybox_old
 781548    1168   11900  794616   c1ff8 busybox_unstripped
This commit is contained in:
Denis Vlasenko
2007-07-21 13:25:28 +00:00
parent 1ec5eaecba
commit 557fb713e0
5 changed files with 36 additions and 39 deletions
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40
libbb/update_passwd.c
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@@ -18,18 +18,18 @@ int update_passwd(const char *filename, const char *username,
struct flock lock;
FILE *old_fp;
FILE *new_fp;
char *new_name;
char *last_char;
char *fnamesfx;
char *sfx_char;
unsigned user_len;
int old_fd;
int new_fd;
int i;
int cnt = 0;
int ret = 1; /* failure */
int ret = -1; /* failure */
/* New passwd file, "/etc/passwd+" for now */
new_name = xasprintf("%s+", filename);
last_char = &new_name[strlen(new_name)-1];
fnamesfx = xasprintf("%s+", filename);
sfx_char = &fnamesfx[strlen(fnamesfx)-1];
username = xasprintf("%s:", username);
user_len = strlen(username);
@@ -42,12 +42,12 @@ int update_passwd(const char *filename, const char *username,
i = 30;
do {
// FIXME: on last iteration try w/o O_EXCL but with O_TRUNC?
new_fd = open(new_name, O_WRONLY|O_CREAT|O_EXCL,0600);
new_fd = open(fnamesfx, O_WRONLY|O_CREAT|O_EXCL, 0600);
if (new_fd >= 0) goto created;
if (errno != EEXIST) break;
usleep(100000); /* 0.1 sec */
} while (--i);
bb_perror_msg("cannot create '%s'", new_name);
bb_perror_msg("cannot create '%s'", fnamesfx);
goto close_old_fp;
created:
@@ -62,12 +62,13 @@ int update_passwd(const char *filename, const char *username,
}
/* Backup file is "/etc/passwd-" */
last_char[0] = '-';
/* Delete old one, create new as a hardlink to current */
i = (unlink(new_name) && errno != ENOENT);
if (i || link(filename, new_name))
bb_perror_msg("warning: cannot create backup copy '%s'", new_name);
last_char[0] = '+';
*sfx_char = '-';
/* Delete old backup */
i = (unlink(fnamesfx) && errno != ENOENT);
/* Create backup as a hardlink to current */
if (i || link(filename, fnamesfx))
bb_perror_msg("warning: cannot create backup copy '%s'", fnamesfx);
*sfx_char = '+';
/* Lock the password file before updating */
lock.l_type = F_WRLCK;
@@ -78,7 +79,7 @@ int update_passwd(const char *filename, const char *username,
bb_perror_msg("warning: cannot lock '%s'", filename);
lock.l_type = F_UNLCK;
/* Read current password file, write updated one */
/* Read current password file, write updated /etc/passwd+ */
while (1) {
char *line = xmalloc_fgets(old_fp);
if (!line) break; /* EOF/error */
@@ -86,8 +87,7 @@ int update_passwd(const char *filename, const char *username,
/* we have a match with "username:"... */
const char *cp = line + user_len;
/* now cp -> old passwd, skip it: */
cp = strchr(cp, ':');
if (!cp) cp = "";
cp = strchrnul(cp, ':');
/* now cp -> ':' after old passwd or -> "" */
fprintf(new_fp, "%s%s%s", username, new_pw, cp);
cnt++;
@@ -99,7 +99,7 @@ int update_passwd(const char *filename, const char *username,
/* We do want all of them to execute, thus | instead of || */
if ((ferror(old_fp) | fflush(new_fp) | fsync(new_fd) | fclose(new_fp))
|| rename(new_name, filename)
|| rename(fnamesfx, filename)
) {
/* At least one of those failed */
goto unlink_new;
@@ -107,13 +107,13 @@ int update_passwd(const char *filename, const char *username,
ret = cnt; /* whee, success! */
unlink_new:
if (ret) unlink(new_name);
if (ret < 0) unlink(fnamesfx);
close_old_fp:
fclose(old_fp);
free_mem:
if (ENABLE_FEATURE_CLEAN_UP) free(new_name);
if (ENABLE_FEATURE_CLEAN_UP) free((char*)username);
free(fnamesfx);
free((char*)username);
return ret;
}