X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=src%2Fcoloredstderr.c;h=44726899e4fb7590345d0890410cc6ee57abf3ca;hb=31a1fdf921bf767154470e94f0f28c299d56cd5a;hp=b2ef2975ef8d6e5ffae8625e925ae5caf46e3523;hpb=f369605227fb876e2edb0957a7c6ace98c49f7d3;p=coloredstderr%2Fcoloredstderr.git

diff --git a/src/coloredstderr.c b/src/coloredstderr.c
index b2ef297..4472689 100644
--- a/src/coloredstderr.c
+++ b/src/coloredstderr.c
@@ -18,14 +18,11 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "config.h"
+#include <config.h>
 
 /* Must be loaded before the following headers. */
 #include "ldpreload.h"
 
-/* FIXME: use correct declaration for fcntl() */
-#define fcntl fcntl_ignore
-
 #include <errno.h>
 #include <fcntl.h>
 #include <stdarg.h>
@@ -33,15 +30,24 @@
 #include <string.h>
 #include <unistd.h>
 
-#undef fcntl
+#ifdef HAVE_ERROR_H
+# include <error.h>
+#endif
+
 /* Conflicting declaration in glibc. */
 #undef fwrite_unlocked
 
 
 /* Used by various functions, including debug(). */
-static ssize_t (*real_write)(int, const void *, size_t);
+static ssize_t (*real_write)(int, void const *, size_t);
 static int (*real_close)(int);
-static size_t (*real_fwrite)(const void *, size_t, size_t, FILE *);
+static size_t (*real_fwrite)(void const *, size_t, size_t, FILE *);
+
+/* Did we already (try to) parse the environment and setup the necessary
+ * variables? */
+static int initialized;
+/* Force hooked writes even when not writing to a tty. Used for tests. */
+static int force_write_to_non_tty;
 
 
 #include "constants.h"
@@ -56,62 +62,57 @@ static size_t (*real_fwrite)(const void *, size_t, size_t, FILE *);
 
 /* Should the "action" handler be invoked for this file descriptor? */
 static int check_handle_fd(int fd) {
-    /* Never touch anything not going to a terminal. */
-    if (!isatty(fd)) {
-        return 0;
-    }
-
     /* Load state from environment. Only necessary once per process. */
-    if (!tracked_fds) {
+    if (!initialized) {
         init_from_environment();
     }
 
-    if (tracked_fds_count == 0) {
+    /* tracked_fds_find() is most likely faster than calling isatty(),
+     * therefore check if we are tracking this file descriptor first. */
+    if (!tracked_fds_find(fd)) {
+        return 0;
+    }
+
+    /* Never touch anything not going to a terminal - unless we are explicitly
+     * asked to do so. */
+    if (!force_write_to_non_tty && !isatty(fd)) {
         return 0;
     }
-    return tracked_fds_find(fd);
+
+    return 1;
 }
 
 static void dup_fd(int oldfd, int newfd) {
 #ifdef DEBUG
-    debug("%d -> %d\t\t\t[%d]\n", oldfd, newfd, getpid());
+    debug("%3d -> %3d\t\t\t[%d]\n", oldfd, newfd, getpid());
 #endif
 
-    if (!tracked_fds) {
+    if (!initialized) {
         init_from_environment();
     }
-    if (tracked_fds_count == 0) {
-        return;
-    }
 
     /* We are already tracking this file descriptor, add newfd to the list as
      * it will reference the same descriptor. */
     if (tracked_fds_find(oldfd)) {
         if (!tracked_fds_find(newfd)) {
             tracked_fds_add(newfd);
-            update_environment();
         }
     /* We are not tracking this file descriptor, remove newfd from the list
      * (if present). */
     } else {
-        if (tracked_fds_remove(newfd)) {
-            update_environment();
-        }
+        tracked_fds_remove(newfd);
     }
 }
 
 static void close_fd(int fd) {
 #ifdef DEBUG
-    debug("%d -> .\t\t\t[%d]\n", fd, getpid());
+    debug("%3d ->   .\t\t\t[%d]\n", fd, getpid());
 #endif
 
-    if (!tracked_fds) {
+    if (!initialized) {
         init_from_environment();
     }
 
-    if (tracked_fds_count == 0) {
-        return;
-    }
     tracked_fds_remove(fd);
 }
 
@@ -178,13 +179,13 @@ static void handle_file_post(FILE *stream, int action) {
 /* Hook all important output functions to manipulate their output. */
 
 HOOK_FD3(ssize_t, write, fd,
-         int, fd, const void *, buf, size_t, count)
+         int, fd, void const *, buf, size_t, count)
 HOOK_FILE4(size_t, fwrite, stream,
-           const void *, ptr, size_t, size, size_t, nmemb, FILE *, stream)
+           void const *, ptr, size_t, size, size_t, nmemb, FILE *, stream)
 
 /* puts(3) */
 HOOK_FILE2(int, fputs, stream,
-           const char *, s, FILE *, stream)
+           char const *, s, FILE *, stream)
 HOOK_FILE2(int, fputc, stream,
            int, c, FILE *, stream)
 HOOK_FILE2(int, putc, stream,
@@ -192,32 +193,32 @@ HOOK_FILE2(int, putc, stream,
 HOOK_FILE1(int, putchar, stdout,
            int, c)
 HOOK_FILE1(int, puts, stdout,
-           const char *, s)
+           char const *, s)
 
 /* printf(3), excluding all s*() and vs*() functions (no output) */
 HOOK_VAR_FILE1(int, printf, stdout, vprintf,
-               const char *, format)
+               char const *, format)
 HOOK_VAR_FILE2(int, fprintf, stream, vfprintf,
-               FILE *, stream, const char *, format)
+               FILE *, stream, char const *, format)
 HOOK_FILE2(int, vprintf, stdout,
-           const char *, format, va_list, ap)
+           char const *, format, va_list, ap)
 HOOK_FILE3(int, vfprintf, stream,
-           FILE *, stream, const char *, format, va_list, ap)
-/* Hardening functions (-D_FORTIFY_SOURCE=2). */
+           FILE *, stream, char const *, format, va_list, ap)
+/* Hardening functions (-D_FORTIFY_SOURCE=2), only functions from above */
 HOOK_VAR_FILE2(int, __printf_chk, stdout, __vprintf_chk,
-               int, flag, const char *, format)
+               int, flag, char const *, format)
 HOOK_VAR_FILE3(int, __fprintf_chk, fp, __vfprintf_chk,
-               FILE *, fp, int, flag, const char *, format)
+               FILE *, fp, int, flag, char const *, format)
 HOOK_FILE3(int, __vprintf_chk, stdout,
-           int, flag, const char *, format, va_list, ap)
+           int, flag, char const *, format, va_list, ap)
 HOOK_FILE4(int, __vfprintf_chk, stream,
-           FILE *, stream, int, flag, const char *, format, va_list, ap)
+           FILE *, stream, int, flag, char const *, format, va_list, ap)
 
 /* unlocked_stdio(3), only functions from above are hooked */
 HOOK_FILE4(size_t, fwrite_unlocked, stream,
-           const void *, ptr, size_t, size, size_t, nmemb, FILE *, stream)
+           void const *, ptr, size_t, size, size_t, nmemb, FILE *, stream)
 HOOK_FILE2(int, fputs_unlocked, stream,
-           const char *, s, FILE *, stream)
+           char const *, s, FILE *, stream)
 HOOK_FILE2(int, fputc_unlocked, stream,
            int, c, FILE *, stream)
 HOOK_FILE2(int, putc_unlocked, stream,
@@ -225,7 +226,79 @@ HOOK_FILE2(int, putc_unlocked, stream,
 HOOK_FILE1(int, putchar_unlocked, stdout,
            int, c)
 HOOK_FILE1(int, puts_unlocked, stdout,
-           const char *, s)
+           char const *, s)
+
+/* perror(3) */
+HOOK_VOID1(void, perror, STDERR_FILENO,
+           char const *, s)
+
+/* error(3) */
+#ifdef HAVE_ERROR_H
+static void  error_vararg(int status, int errnum,
+                   char const *filename, unsigned int linenum,
+                   char const *format, va_list ap) {
+    static char const *last_filename;
+    static unsigned int last_linenum;
+
+    /* Skip this error message if requested and if there was already an error
+     * in the same file/line. */
+    if (error_one_per_line
+            && filename != NULL && linenum != 0
+            && filename == last_filename && linenum == last_linenum) {
+        return;
+    }
+    last_filename = filename;
+    last_linenum  = linenum;
+
+    error_message_count++;
+
+    fflush(stdout);
+
+    if (error_print_progname) {
+        error_print_progname();
+    } else {
+        fprintf(stderr, "%s:", program_invocation_name);
+    }
+    if (filename != NULL && linenum != 0) {
+        fprintf(stderr, "%s:%u:", filename, linenum);
+        if (error_print_progname) {
+            fprintf(stderr, " ");
+        }
+    }
+    if (!error_print_progname) {
+        fprintf(stderr, " ");
+    }
+
+
+    vfprintf(stderr, format, ap);
+
+    if (errnum != 0) {
+        fprintf(stderr, ": %s", strerror(errnum));
+    }
+
+    fprintf(stderr, "\n");
+
+    if (status != 0) {
+        exit(status);
+    }
+}
+void error_at_line(int status, int errnum,
+                   char const *filename, unsigned int linenum,
+                   char const *format, ...) {
+    va_list ap;
+
+    va_start(ap, format);
+    error_vararg(status, errnum, filename, linenum, format, ap);
+    va_end(ap);
+}
+void error(int status, int errnum, char const *format, ...) {
+    va_list ap;
+
+    va_start(ap, format);
+    error_vararg(status, errnum, NULL, 0, format, ap);
+    va_end(ap);
+}
+#endif
 
 
 /* Hook functions which duplicate file descriptors to track them. */
@@ -272,13 +345,30 @@ int dup3(int oldfd, int newfd, int flags) {
     return newfd;
 }
 
-static int (*real_fcntl)(int, int, int);
-int fcntl(int fd, int cmd, int arg) {
+static int (*real_fcntl)(int, int, ...);
+int fcntl(int fd, int cmd, ...) {
     int result;
+    va_list ap;
 
     DLSYM_FUNCTION(real_fcntl, "fcntl");
 
-    result = real_fcntl(fd, cmd, arg);
+    /* fcntl() takes different types of arguments depending on the cmd type
+     * (int, void and pointers are used at the moment). Handling these
+     * arguments for different systems and with possible changes in the future
+     * is error prone.
+     *
+     * Therefore always retrieve a void-pointer from our arguments (even if it
+     * wasn't there) and pass it to real_fcntl(). This shouldn't cause any
+     * problems because a void-pointer is most-likely bigger than an int
+     * (something which is not true in reverse) and shouldn't cause
+     * truncation. For register based calling conventions an invalid register
+     * content is passed, but ignored by real_fcntl(). Not perfect, but should
+     * work fine.
+     */
+    va_start(ap, cmd);
+    result = real_fcntl(fd, cmd, va_arg(ap, void *));
+    va_end(ap);
+
     /* We only care about duping fds. */
     if (cmd == F_DUPFD && result != -1) {
         int saved_errno = errno;
@@ -303,3 +393,145 @@ int fclose(FILE *fp) {
     close_fd(fileno(fp));
     return real_fclose(fp);
 }
+
+
+/* Hook functions which are necessary for correct tracking. */
+
+#if defined(HAVE_VFORK) && defined(HAVE_FORK)
+pid_t vfork(void) {
+    /* vfork() is similar to fork() but the address space is shared between
+     * father and child. It's designed for fork()/exec() usage because it's
+     * faster than fork(). However according to the POSIX standard the "child"
+     * isn't allowed to perform any memory-modifications before the exec()
+     * (except the pid_t result variable of vfork()).
+     *
+     * As some programs don't adhere to the standard (e.g. the "child" closes
+     * or dups a descriptor before the exec()) and this breaks our tracking of
+     * file descriptors (e.g. it gets closed in the parent as well), we just
+     * fork() instead. This is in compliance with the POSIX standard and as
+     * most systems use copy-on-write anyway not a performance issue. */
+    return fork();
+}
+#endif
+
+
+/* Hook execve() and the other exec*() functions. Some shells use exec*() with
+ * a custom environment which doesn't necessarily contain our updates to
+ * ENV_NAME_FDS. It's also faster to update the environment only when
+ * necessary, right before the exec() to pass it to the new process. */
+
+static int (*real_execve)(char const *filename, char * const argv[], char * const env[]);
+int execve(char const *filename, char * const argv[], char * const env[]) {
+    DLSYM_FUNCTION(real_execve, "execve");
+
+    int found = 0;
+    size_t index = 0;
+
+    /* Count arguments and search for existing ENV_NAME_FDS environment
+     * variable. */
+    size_t count = 0;
+    char * const *x = env;
+    while (*x) {
+        if (!strncmp(*x, ENV_NAME_FDS "=", strlen(ENV_NAME_FDS) + 1)) {
+            found = 1;
+            index = count;
+        }
+
+        x++;
+        count++;
+    }
+    /* Terminating NULL. */
+    count++;
+
+    char *env_copy[count + 1 /* space for our new entry if necessary */];
+    memcpy(env_copy, env, count * sizeof(char *));
+
+    /* Make sure the information from the environment is loaded. We can't just
+     * do nothing (like update_environment()) because the caller might pass a
+     * different environment which doesn't include any of our settings. */
+    if (!initialized) {
+        init_from_environment();
+    }
+
+    char fds_env[strlen(ENV_NAME_FDS) + 1 + update_environment_buffer_size()];
+    strcpy(fds_env, ENV_NAME_FDS "=");
+    update_environment_buffer(fds_env + strlen(ENV_NAME_FDS) + 1);
+
+    if (found) {
+        env_copy[index] = fds_env;
+    } else {
+        /* If the process removed ENV_NAME_FDS from the environment, re-add
+         * it. */
+        env_copy[count-1] = fds_env;
+        env_copy[count] = NULL;
+    }
+
+    return real_execve(filename, argv, env_copy);
+}
+
+#define EXECL_COPY_VARARGS_START(args) \
+    va_list ap; \
+    char *x; \
+    \
+    /* Count arguments. */ \
+    size_t count = 1; /* arg */ \
+    va_start(ap, arg); \
+    while (va_arg(ap, const char *)) { \
+        count++; \
+    } \
+    va_end(ap); \
+    \
+    /* Copy varargs. */ \
+    char *args[count + 1 /* terminating NULL */]; \
+    args[0] = (char *)arg; \
+    \
+    size_t i = 1; \
+    va_start(ap, arg); \
+    while ((x = va_arg(ap, char *))) { \
+        args[i++] = x; \
+    } \
+    args[i] = NULL;
+#define EXECL_COPY_VARARGS_END(args) \
+    va_end(ap);
+#define EXECL_COPY_VARARGS(args) \
+    EXECL_COPY_VARARGS_START(args); \
+    EXECL_COPY_VARARGS_END(args);
+
+int execl(char const *path, char const *arg, ...) {
+    EXECL_COPY_VARARGS(args);
+
+    update_environment();
+    return execv(path, args);
+}
+
+int execlp(char const *file, char const *arg, ...) {
+    EXECL_COPY_VARARGS(args);
+
+    update_environment();
+    return execvp(file, args);
+}
+
+int execle(char const *path, char const *arg, ... /*, char * const envp[] */) {
+    EXECL_COPY_VARARGS_START(args);
+    /* Get envp[] located after arguments. */
+    char * const *envp = va_arg(ap, char * const *);
+    EXECL_COPY_VARARGS_END(args);
+
+    return execve(path, args, envp);
+}
+
+static int (*real_execv)(char const *path, char * const argv[]);
+int execv(char const *path, char * const argv[]) {
+    DLSYM_FUNCTION(real_execv, "execv");
+
+    update_environment();
+    return real_execv(path, argv);
+}
+
+static int (*real_execvp)(char const *path, char * const argv[]);
+int execvp(char const *path, char * const argv[]) {
+    DLSYM_FUNCTION(real_execvp, "execvp");
+
+    update_environment();
+    return real_execvp(path, argv);
+}