Add passwd by Kyungwan Han.

2 files changed, 147 insertions, 0 deletions

diff --git a/lib/lib.h b/lib/lib.h
index 8028737e..de2e214c 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -168,3 +168,8 @@ int sig_to_num(char *pidstr);
 char *num_to_sig(int sig);
 
 mode_t string_to_mode(char *mode_str, mode_t base);
+
+// password helper functions
+int read_passwd(char * buff, int buflen, char* mesg);
+int update_passwd(char *filename, char* username, char* encrypted);
+
diff --git a/lib/password.c b/lib/password.c
new file mode 100644
index 00000000..2b11144e
--- /dev/null
+++ b/lib/password.c
@@ -0,0 +1,142 @@
+/* vi: set sw=4 ts=4 :                                                                                                                                                          
+ * pwdutils.c - password read/update helper functions.
+ *
+ * Copyright 2012 Ashwini Kumar <ak.ashwini@gmail.com>
+ */
+
+#include "toys.h"
+#include <time.h>
+
+
+int read_passwd(char * buff, int buflen, char* mesg)
+{           
+    int i = 0;
+    struct termios termio, oldtermio;
+    tcgetattr(0, &oldtermio);
+    tcflush(0, TCIFLUSH);
+    termio = oldtermio;
+
+    termio.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
+    termio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
+    tcsetattr(0, TCSANOW, &termio);
+
+    fputs(mesg, stdout);
+    fflush(stdout);
+
+    while (1) {
+        int ret = read(0, &buff[i], 1);
+        if ( ret < 0 ) {   
+            buff[0] = 0;
+            tcsetattr(0, TCSANOW, &oldtermio);
+            return 1;
+        }   
+        else if ( ret == 0 || buff[i] == '\n' ||
+                buff[i] == '\r' || buflen == i+1) {   
+            buff[i] = '\0';
+            break;
+        }   
+        i++;
+    }       
+
+    tcsetattr(0, TCSANOW, &oldtermio);
+    puts("");
+    fflush(stdout);
+    return 0;
+}
+
+static char *get_nextcolon(const char *line, char delim)
+{
+    char *current_ptr = NULL;
+    if((current_ptr = strchr(line, ':')) == NULL) 
+        error_exit("Invalid Entry\n");      
+    return current_ptr;
+}
+
+int update_passwd(char *filename, char* username, char* encrypted)
+{
+    char *filenamesfx = NULL, *namesfx = NULL;
+    char *shadow = NULL, *sfx = NULL;
+    FILE *exfp, *newfp;
+    int ret = -1; //fail
+    struct flock lock;
+    char *line = NULL;
+
+    shadow = strstr(filename, "shadow");
+    filenamesfx = xmsprintf("%s+", filename);
+    sfx = strchr(filenamesfx, '+');
+
+    exfp = fopen(filename, "r+");
+    if(!exfp) {      
+        perror_msg("Couldn't open file %s",filename);
+        goto free_storage;
+    }
+
+    *sfx = '-';
+    ret = unlink(filenamesfx);
+    ret = link(filename, filenamesfx);
+    if(ret < 0) error_msg("can't create backup file");
+
+    *sfx = '+';
+    lock.l_type = F_WRLCK;
+    lock.l_whence = SEEK_SET;
+    lock.l_start = 0;
+    lock.l_len = 0;
+
+    ret = fcntl(fileno(exfp), F_SETLK, &lock);
+    if(ret < 0) perror_msg("Couldn't lock file %s",filename);
+
+    lock.l_type = F_UNLCK; //unlocking at a later stage                                                                                                                         
+
+    newfp = fopen(filenamesfx, "w+");
+    if(!newfp) {       
+        error_msg("couldn't open file for writing");
+        ret = -1;
+        fclose(exfp);
+        goto free_storage;
+    }       
+
+    ret = 0;
+    namesfx = xmsprintf("%s:",username);
+    while((line = get_line(fileno(exfp))) != NULL)
+    {
+        if(strncmp(line, namesfx, strlen(namesfx)) != 0)
+            fprintf(newfp, "%s\n", line);
+        else {
+            char *current_ptr = NULL;
+            fprintf(newfp, "%s%s:",namesfx,encrypted);
+            current_ptr = get_nextcolon(line, ':'); //past username
+            current_ptr++; //past colon ':' after username
+            current_ptr = get_nextcolon(current_ptr, ':'); //past passwd
+            current_ptr++; //past colon ':' after passwd
+            if(shadow) {
+                fprintf(newfp, "%u:",(unsigned)(time(NULL))/(24*60*60));
+                current_ptr = get_nextcolon(current_ptr, ':'); 
+                current_ptr++; //past time stamp colon.
+                fprintf(newfp, "%s\n",current_ptr);
+            }
+            else {
+                fprintf(newfp, "%s\n",current_ptr);
+            }
+        }
+
+        free(line);
+    }
+    free(namesfx);
+    fcntl(fileno(exfp), F_SETLK, &lock);
+    fclose(exfp);
+    
+    errno = 0;
+    fflush(newfp);
+    fsync(fileno(newfp));
+    fclose(newfp);
+    rename(filenamesfx, filename);
+    if(errno) {
+        perror_msg("File Writing/Saving failed: ");
+        unlink(filenamesfx);
+        ret = -1;
+    }      
+
+free_storage:
+    free(filenamesfx);
+    return ret;
+}