Add missing const and document where it can't be used.

[coloredstderr/coloredstderr.git] / src / coloredstderr.c

diff --git a/src/coloredstderr.c b/src/coloredstderr.c
index d4ffdb6aa5bcb84cc3d9450e5ea8052b534a06cd..3fe2053ce251bb33fc06dd9b59397212466a75c6 100644 (file)
--- a/src/coloredstderr.c
+++ b/src/coloredstderr.c
@@ -25,6 +25,12 @@
 /* Must be loaded before the following headers. */
 #include "ldpreload.h"
 
+/* Disable assert()s if not compiled with --enable-debug. */
+#ifndef DEBUG
+# define NDEBUG
+#endif
+
+#include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdarg.h>
@@ -35,9 +41,17 @@
 #ifdef HAVE_ERROR_H
 # include <error.h>
 #endif
+#ifdef HAVE_STRUCT__IO_FILE__FILENO
+# include <libio.h>
+#endif
 
 /* Conflicting declaration in glibc. */
 #undef fwrite_unlocked
+/* These functions may be macros when compiling with hardening flags (fortify)
+ * which cause build failures when used in our hook macros below. Observed
+ * with Clang on Debian Wheezy. */
+#undef printf
+#undef fprintf
 
 
 /* Used by various functions, including debug(). */
@@ -70,6 +84,8 @@ static int force_write_to_non_tty;
  * additional call. */
 static int isatty_noinline(int fd) noinline;
 static int isatty_noinline(int fd) {
+    assert(fd >= 0);
+
     int saved_errno = errno;
     int result = isatty(fd);
     errno = saved_errno;
@@ -83,6 +99,8 @@ static void dup_fd(int oldfd, int newfd) {
     debug("%3d -> %3d\t\t\t[%d]\n", oldfd, newfd, getpid());
 #endif
 
+    assert(oldfd >= 0 && newfd >= 0);
+
     if (unlikely(!initialized)) {
         init_from_environment();
     }
@@ -105,6 +123,8 @@ static void close_fd(int fd) {
     debug("%3d ->   .\t\t\t[%d]\n", fd, getpid());
 #endif
 
+    assert(fd >= 0);
+
     if (unlikely(!initialized)) {
         init_from_environment();
     }
@@ -236,6 +256,10 @@ HOOK_FILE2(int, putc_unlocked, stream,
            int, c, FILE *, stream)
 HOOK_FILE1(int, putchar_unlocked, stdout,
            int, c)
+/* glibc defines (_IO_)putc_unlocked() to __overflow() in some cases. */
+#ifdef HAVE_STRUCT__IO_FILE__FILENO
+HOOK_FD2(int, __overflow, f->_fileno, _IO_FILE *, f, int, ch)
+#endif
 
 /* perror(3) */
 HOOK_VOID1(void, perror, STDERR_FILENO,
@@ -384,14 +408,20 @@ static int (*real_close)(int);
 int close(int fd) {
     DLSYM_FUNCTION(real_close, "close");
 
-    close_fd(fd);
+    if (fd >= 0) {
+        close_fd(fd);
+    }
     return real_close(fd);
 }
 static int (*real_fclose)(FILE *);
 int fclose(FILE *fp) {
+    int fd;
+
     DLSYM_FUNCTION(real_fclose, "fclose");
 
-    close_fd(fileno(fp));
+    if (fp != NULL && (fd = fileno(fp)) >= 0) {
+        close_fd(fd);
+    }
     return real_fclose(fp);
 }
 
@@ -477,14 +507,14 @@ int execve(char const *filename, char * const argv[], char * const env[]) {
     /* Count arguments. */ \
     size_t count = 1; /* arg */ \
     va_start(ap, arg); \
-    while (va_arg(ap, char const *)) { \
+    while (va_arg(ap, char *)) { \
         count++; \
     } \
     va_end(ap); \
     \
     /* Copy varargs. */ \
     char *args[count + 1 /* terminating NULL */]; \
-    args[0] = (char *)arg; \
+    args[0] = (char *)arg; /* there's no other way around the cast */ \
     \
     size_t i = 1; \
     va_start(ap, arg); \
@@ -501,23 +531,24 @@ int execve(char const *filename, char * const argv[], char * const env[]) {
 int execl(char const *path, char const *arg, ...) {
     EXECL_COPY_VARARGS(args);
 
-    update_environment();
+    /* execv() updates the environment. */
     return execv(path, args);
 }
-
 int execlp(char const *file, char const *arg, ...) {
     EXECL_COPY_VARARGS(args);
 
-    update_environment();
+    /* execvp() updates the environment. */
     return execvp(file, args);
 }
-
 int execle(char const *path, char const *arg, ... /*, char * const envp[] */) {
+    char * const *envp;
+
     EXECL_COPY_VARARGS_START(args);
     /* Get envp[] located after arguments. */
-    char * const *envp = va_arg(ap, char * const *);
+    envp = va_arg(ap, char * const *);
     EXECL_COPY_VARARGS_END(args);
 
+    /* execve() updates the environment. */
     return execve(path, args, envp);
 }
 
@@ -543,6 +574,7 @@ int execvpe(char const *file, char * const argv[], char * const envp[]) {
     /* Fake the environment so we can reuse execvp(). */
     environ = (char **)envp;
 
+    /* execvp() updates the environment. */
     return execvp(file, argv);
 }
 #endif