Eliminate wopen()

It was large and mostly unnecessary. Prefer wopen() followed by
fdopen().

src/fish_tests.cpp

@@ -3369,7 +3369,7 @@ static void test_universal_ok_to_save() {
     say(L"Testing universal Ok to save");
     if (system("mkdir -p test/fish_uvars_test/")) err(L"mkdir failed");
     const char *contents = "# VERSION: 99999.99\n";
-    FILE *fp = wfopen(UVARS_TEST_PATH, "w");
+    FILE *fp = fopen(wcs2string(UVARS_TEST_PATH).c_str(), "w");
     assert(fp && "Failed to open UVARS_TEST_PATH for writing");
     fwrite(contents, std::strlen(contents), 1, fp);
     fclose(fp);

src/proc.cpp

@@ -7,6 +7,7 @@
 #include "config.h"
 
 #include <errno.h>
+#include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -620,15 +621,11 @@ bool job_reap(parser_t &parser, bool allow_interactive) {
     return printed;
 }
 
-/// Maximum length of a /proc/[PID]/stat filename.
-#define FN_SIZE 256
-
 /// Get the CPU time for the specified process.
 unsigned long proc_get_jiffies(process_t *p) {
     if (!have_proc_stat()) return 0;
     if (p->pid <= 0) return 0;
 
-    wchar_t fn[FN_SIZE];
     char state;
     int pid, ppid, pgrp, session, tty_nr, tpgid, exit_signal, processor;
     long int cutime, cstime, priority, nice, placeholder, itrealvalue, rss;
@@ -637,11 +634,16 @@ unsigned long proc_get_jiffies(process_t *p) {
         wchan, nswap, cnswap;
     char comm[1024];
 
-    std::swprintf(fn, FN_SIZE, L"/proc/%d/stat", p->pid);
-    FILE *f = wfopen(fn, "r");
-    if (!f) return 0;
+    /// Maximum length of a /proc/[PID]/stat filename.
+    constexpr size_t FN_SIZE = 256;
+    char fn[FN_SIZE];
+    std::snprintf(fn, FN_SIZE, "/proc/%d/stat", p->pid);
+    // Don't use autoclose_fd here, we will fdopen() and then fclose() instead.
+    int fd = open_cloexec(fn, O_RDONLY);
+    if (fd < 0) return 0;
 
     // TODO: replace the use of fscanf() as it is brittle and should never be used.
+    FILE *f = fdopen(fd, "r");
     int count = fscanf(f,
                        "%9d %1023s %c %9d %9d %9d %9d %9d %9lu "
                        "%9lu %9lu %9lu %9lu %9lu %9lu %9ld %9ld %9ld "

src/reader.cpp

@@ -2174,8 +2174,9 @@ void reader_import_history_if_necessary() {
         const auto var = data->vars().get(L"HISTFILE");
         wcstring path = (var ? var->as_string() : L"~/.bash_history");
         expand_tilde(path, data->vars());
-        FILE *f = wfopen(path, "r");
-        if (f) {
+        int fd = wopen_cloexec(path, O_RDONLY);
+        if (fd >= 0) {
+            FILE *f = fdopen(fd, "r");
             data->history->populate_from_bash(f);
             fclose(f);
         }

src/wutil.cpp

@@ -141,42 +141,6 @@ wcstring wgetcwd() {
     return wcstring();
 }
 
-FILE *wfopen(const wcstring &path, const char *mode) {
-    int permissions = 0, options = 0;
-    size_t idx = 0;
-    switch (mode[idx++]) {
-        case 'r': {
-            permissions = O_RDONLY;
-            break;
-        }
-        case 'w': {
-            permissions = O_WRONLY;
-            options = O_CREAT | O_TRUNC;
-            break;
-        }
-        case 'a': {
-            permissions = O_WRONLY;
-            options = O_CREAT | O_APPEND;
-            break;
-        }
-        default: {
-            errno = EINVAL;
-            return nullptr;
-        }
-    }
-    // Skip binary.
-    if (mode[idx] == 'b') idx++;
-
-    // Consider append option.
-    if (mode[idx] == '+') permissions = O_RDWR;
-
-    int fd = wopen_cloexec(path, permissions | options, 0666);
-    if (fd < 0) return nullptr;
-    FILE *result = fdopen(fd, mode);
-    if (result == nullptr) close(fd);
-    return result;
-}
-
 int set_cloexec(int fd, bool should_set) {
     // Note we don't want to overwrite existing flags like O_NONBLOCK which may be set. So fetch the
     // existing flags and modify them.

src/wutil.h

@@ -19,9 +19,6 @@
 #include "common.h"
 #include "maybe.h"
 
-/// Wide character version of fopen(). This sets CLO_EXEC.
-FILE *wfopen(const wcstring &path, const char *mode);
-
 /// Sets CLO_EXEC on a given fd according to the value of \p should_set.
 int set_cloexec(int fd, bool should_set = true);