Merge commit 'meins/master'

[paraslash.git] / fd.c

diff --git a/fd.c b/fd.c
index abad80a86ce368660c1ed3b88a1c0e088488a422..c675aaffd4b99083d3ab0e26445574c2b87ad51b 100644 (file)
--- a/fd.c
+++ b/fd.c
@@ -15,6 +15,31 @@
 #include "para.h"
 #include "error.h"
 
+/**
+ * Write a buffer to a file descriptor, re-write on short writes.
+ *
+ * \param fd The file descriptor.
+ * \param buf The buffer to be sent.
+ * \param len The length of \a buf.
+ *
+ * \return Standard. In any case, the number of bytes that have been written is
+ * stored in \a len.
+ */
+int write_all(int fd, const char *buf, size_t *len)
+{
+       size_t total = *len;
+
+       assert(total);
+       *len = 0;
+       while (*len < total) {
+               int ret = write(fd, buf + *len, total - *len);
+               if (ret == -1)
+                       return -ERRNO_TO_PARA_ERROR(errno);
+               *len += ret;
+       }
+       return 1;
+}
+
 /**
  * Check whether a file exists.
  *
@@ -129,16 +154,16 @@ void para_fd_set(int fd, fd_set *fds, int *max_fileno)
 }
 
 /**
-* Paraslash's wrapper for fgets(3).
-
-* \param line Pointer to the buffer to store the line.
-* \param size The size of the buffer given by \a line.
-* \param f The stream to read from.
-*
-* \return Unlike the standard fgets() function, an integer value
-* is returned. On success, this function returns 1. On errors, -E_FGETS
-* is returned. A zero return value indicates an end of file condition.
-*/
+ * Paraslash's wrapper for fgets(3).
+ *
+ * \param line Pointer to the buffer to store the line.
+ * \param size The size of the buffer given by \a line.
+ * \param f The stream to read from.
+ *
+ * \return Unlike the standard fgets() function, an integer value
+ * is returned. On success, this function returns 1. On errors, -E_FGETS
+ * is returned. A zero return value indicates an end of file condition.
+ */
 __must_check int para_fgets(char *line, int size, FILE *f)
 {
 again:
@@ -260,9 +285,10 @@ int para_opendir(const char *dirname, DIR **dir, int *cwd)
        if (*dir)
                return 1;
        ret = -ERRNO_TO_PARA_ERROR(errno);
-/* Ignore return value of fchdir() and close(). We're busted anyway. */
-       if (cwd)
-               fchdir(*cwd);
+       /* Ignore return value of fchdir() and close(). We're busted anyway. */
+       if (cwd) {
+               int __a_unused ret2 = fchdir(*cwd); /* STFU, gcc */
+       }
 close_cwd:
        if (cwd)
                close(*cwd);
@@ -368,17 +394,19 @@ out:
  */
 int para_munmap(void *start, size_t length)
 {
+       int err;
        if (munmap(start, length) >= 0)
                return 1;
+       err = errno;
        PARA_ERROR_LOG("munmap (%p/%zu) failed: %s\n", start, length,
-               strerror(errno));
-       return -E_MUNMAP;
+               strerror(err));
+       return -ERRNO_TO_PARA_ERROR(err);
 }
 
 /**
- * check a file descriptor for writability
+ * Check a file descriptor for writability.
  *
- * \param fd the file descriptor
+ * \param fd The file descriptor.
  *
  * \return positive if fd is ready for writing, zero if it isn't, negative if
  * an error occurred.
@@ -399,3 +427,24 @@ again:
                goto again;
        return ret;
 }
+
+/**
+ * Ensure that file descriptors 0, 1, and 2 are valid.
+ *
+ * Common approach that opens /dev/null until it gets a file descriptor greater
+ * than two.
+ *
+ * \sa okir's Black Hats Manual.
+ */
+void valid_fd_012(void)
+{
+       while (1) {
+               int fd = open("/dev/null", O_RDWR);
+               if (fd < 0)
+                       exit(EXIT_FAILURE);
+               if (fd > 2) {
+                       close(fd);
+                       break;
+               }
+       }
+}