Transform readline into a globally accessible function.

libc/inc/readline.h

@@ -0,0 +1,14 @@
+/// @file readline.h
+/// @brief
+/// @copyright (c) 2014-2023 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include "stddef.h"
+
+/// @brief Reads a line from the file.
+/// @param fd the file descriptor.
+/// @param buffer the buffer where we place the line.
+/// @param buflen the length of the buffer.
+/// @param readlen the amount we read, if negative, we did not encounter a newline.
+/// @return 0 if we are done reading, 1 if we encountered a newline, -1 if otherwise.
+int readline(int fd, char *buffer, size_t buflen, ssize_t *read_len);

libc/src/pwd.c

@@ -7,6 +7,7 @@
 #include "assert.h"
 #include "fcntl.h"
 #include "io/debug.h"
+#include "readline.h"
 #include "stdio.h"
 #include "string.h"
 #include "sys/errno.h"
@@ -57,41 +58,6 @@ static inline void __parse_line(passwd_t *pwd, char *buf)
     }
 }
 
-/// @brief Reads a line from the file.
-/// @param fd the file descriptor.
-/// @param buffer the buffer where we place the line.
-/// @param buflen the length of the buffer.
-/// @return the amount we read.
-ssize_t __readline(int fd, char *buffer, size_t buflen)
-{
-    memset(buffer, 0, buflen);
-    long num_read = read(fd, buffer, buflen);
-    if (num_read == 0) {
-        return 0;
-    }
-    char *newline = strchr(buffer, '\n');
-    if (newline == NULL) {
-        newline = strchr(buffer, EOF);
-        if (newline == NULL) {
-            newline = strchr(buffer, 0);
-            if (newline == NULL) {
-                return 0;
-            }
-        }
-    }
-    long newline_len = (newline - buffer);
-    if (newline_len <= 0) {
-        return 0;
-    }
-    buffer[newline_len] = 0;
-    long rollback       = newline_len - num_read + 1;
-    if (rollback > 1) {
-        return 0;
-    }
-    lseek(fd, rollback, SEEK_CUR);
-    return newline_len;
-}
-
 /// @brief Searches for the given entry inside the buffer.
 /// @param fd the file descriptor of the file.
 /// @param buffer the support buffer we use to read the file.
@@ -101,7 +67,7 @@ ssize_t __readline(int fd, char *buffer, size_t buflen)
 /// @return the buffer itself if we have found the entry, NULL otherwise.
 static inline char *__search_entry(int fd, char *buffer, int buflen, const char *name, uid_t uid)
 {
-    while (__readline(fd, buffer, buflen)) {
+    while (readline(fd, buffer, buflen, NULL) != 0) {
         if (name != NULL) {
             char *name_end = strchr(buffer, ':');
             if (name_end) {

libc/src/readline.c

@@ -0,0 +1,57 @@
+/// @file readline.c
+/// @author Enrico Fraccaroli (enry.frak@gmail.com)
+/// @brief
+/// @version 0.1
+/// @date 2023-08-30
+///
+/// @copyright Copyright (c) 2023
+///
+
+#include "readline.h"
+
+#include "stdio.h"
+#include "string.h"
+#include "sys/unistd.h"
+
+int readline(int fd, char *buffer, size_t buflen, ssize_t *read_len)
+{
+    ssize_t length, rollback, num_read;
+    memset(buffer, 0, buflen);
+    unsigned char found_newline = 1;
+    // Read from the file.
+    num_read = read(fd, buffer, buflen);
+    if (num_read == 0) {
+        return 0;
+    }
+    // Search for termination character.
+    char *newline = strchr(buffer, '\n');
+    if (newline == NULL) {
+        found_newline = 0;
+        newline       = strchr(buffer, EOF);
+        if (newline == NULL) {
+            newline = strchr(buffer, 0);
+            if (newline == NULL) {
+                return 0;
+            }
+        }
+    }
+    // Compute the length of the string.
+    length = (newline - buffer);
+    if (length <= 0) {
+        return 0;
+    }
+    // Close the string.
+    buffer[length] = 0;
+    // Compute how much we need to rollback.
+    rollback = length - num_read + 1;
+    if (rollback > 1) {
+        return 0;
+    }
+    // Rollback the reading position in the file.
+    lseek(fd, rollback, SEEK_CUR);
+    // Set how much we were able to read from the file.
+    if (read_len) {
+        *read_len = length;
+    }
+    return (found_newline) ? 1 : -1;
+}