osl.h depends on Makefile.

[osl.git] / fd.c

diff --git a/fd.c b/fd.c
index 84877602f943ee5893caaaab9db93b1292ccbab8..b889d9d2144a4ad78cf6442997d80fec643aad87 100644 (file)
--- a/fd.c
+++ b/fd.c
@@ -16,6 +16,33 @@
 #include "osl.h"
 #include "error.h"
 
+/**
+ * Wrapper for the write system call.
+ *
+ * \param fd The file descriptor to write to.
+ * \param buf The buffer to write.
+ * \param size The length of \a buf in bytes.
+ *
+ * This function writes out the given buffer and retries if an interrupt
+ * occurred during the write.
+ *
+ * \return On success, the number of bytes written is returned, otherwise, a
+ * negative error code is returned.
+ *
+ * \sa write(2).
+ */
+static ssize_t __write(int fd, const void *buf, size_t size)
+{
+       ssize_t ret;
+
+       for (;;) {
+               ret = write(fd, buf, size);
+               if ((ret < 0) && (errno == EAGAIN || errno == EINTR))
+                       continue;
+               return ret >= 0? ret : -ERRNO_TO_ERROR(errno);
+       }
+}
+
 /**
  * Write a buffer to a file descriptor, re-write on short writes.
  *
@@ -33,9 +60,9 @@ int write_all(int fd, const char *buf, size_t *len)
        assert(total);
        *len = 0;
        while (*len < total) {
-               int ret = write(fd, buf + *len, total - *len);
-               if (ret == -1)
-                       return -ERRNO_TO_ERROR(errno);
+               int ret = __write(fd, buf + *len, total - *len);
+               if (ret < 0)
+                       return ret;
                *len += ret;
        }
        return 1;
@@ -64,6 +91,32 @@ int osl_open(const char *path, int flags, mode_t mode)
        return -ERRNO_TO_ERROR(errno);
 }
 
+/**
+ * Open a file, write the given buffer and close the file.
+ *
+ * \param filename Full path to the file to open.
+ * \param buf The buffer to write to the file.
+ * \param size The size of \a buf.
+ *
+ * \return Standard.
+ */
+int write_file(const char *filename, const void *buf, size_t size)
+{
+       int ret, fd;
+
+       ret = osl_open(filename, O_WRONLY | O_CREAT | O_EXCL, 0644);
+       if (ret < 0)
+               return ret;
+       fd = ret;
+       ret = write_all(fd, buf, &size);
+       if (ret < 0)
+               goto out;
+       ret = 1;
+out:
+       close(fd);
+       return ret;
+}
+
 /**
  * Wrapper for chdir(2).
  *
@@ -222,3 +275,50 @@ int osl_munmap(void *start, size_t length)
                strerror(err));
        return -ERRNO_TO_ERROR(err);
 }
+
+/**
+ * Allocate a sufficiently large string and print into it.
+ *
+ * \param fmt A usual format string.
+ *
+ * Produce output according to \p fmt. No artificial bound on the length of the
+ * resulting string is imposed.
+ *
+ * \return This function either returns a pointer to a string that must be
+ * freed by the caller or \p NULL if memory allocation failed.
+ *
+ * \sa printf(3).
+ */
+__must_check __printf_1_2 __malloc char *make_message(const char *fmt, ...)
+{
+       int n;
+       size_t size = 100;
+       char *p = malloc(size);
+
+       if (!p)
+               return NULL;
+       while (1) {
+               char *q;
+               va_list ap;
+               /* Try to print in the allocated space. */
+               va_start(ap, fmt);
+               n = vsnprintf(p, size, fmt, ap);
+               va_end(ap);
+               /* If that worked, return the string. */
+               if (n > -1 && n < size)
+                       break;
+               /* Else try again with more space. */
+               if (n > -1) /* glibc 2.1 */
+                       size = n + 1; /* precisely what is needed */
+               else /* glibc 2.0 */
+                       size *= 2; /* twice the old size */
+               q = realloc(p, size);
+               if (!q) {
+                       free(p);
+                       return NULL;
+               }
+               p = q;
+       }
+       return p;
+}
+