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authorTavian Barnes <tavianator@tavianator.com>2024-04-24 13:17:18 -0400
committerTavian Barnes <tavianator@tavianator.com>2024-04-24 16:15:05 -0400
commit32e50c2faa3e48acb2eae29c23feb5511df2f9ab (patch)
tree9cea7e21e430b1c591c9c4278a5abe87db067e4e /src
parent3a72b93d26ad2bb06ea0b7d39257130084b1ee1e (diff)
downloadbfs-32e50c2faa3e48acb2eae29c23feb5511df2f9ab.tar.xz
printf: Check dynamic format strings more carefully
Diffstat (limited to 'src')
-rw-r--r--src/prelude.h9
-rw-r--r--src/printf.c80
2 files changed, 48 insertions, 41 deletions
diff --git a/src/prelude.h b/src/prelude.h
index 7a646a7..ddeacbd 100644
--- a/src/prelude.h
+++ b/src/prelude.h
@@ -244,6 +244,15 @@ typedef union {
#endif
/**
+ * Annotates functions that potentially modify and return format strings.
+ */
+#if __has_attribute(format_arg)
+# define attr_format_arg(arg) __attribute__((format_arg(arg)))
+#else
+# define attr_format_arg(args)
+#endif
+
+/**
* Annotates allocator-like functions.
*/
#if __has_attribute(malloc)
diff --git a/src/printf.c b/src/printf.c
index e39d756..f8428f7 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -88,22 +88,20 @@ static bool should_color(CFILE *cfile, const struct bfs_fmt *fmt) {
bfs_assert(ret >= 0 && (size_t)ret < sizeof(buf)); \
(void)ret
-/**
- * Common entry point for fprintf() with a dynamic format string.
- */
-static int dyn_fprintf(FILE *file, const struct bfs_fmt *fmt, ...) {
- va_list args;
- va_start(args, fmt);
-
-#if __GNUC__
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wformat-nonliteral"
-#endif
- int ret = vfprintf(file, fmt->str, args);
-#if __GNUC__
-# pragma GCC diagnostic pop
-#endif
+/** Return a dynamic format string. */
+attr(format_arg(2))
+static const char *dyn_fmt(const char *str, const char *fake) {
+ bfs_assert(strcmp(str + strlen(str) - strlen(fake) + 1, fake + 1) == 0,
+ "Mismatched format specifiers: '%s' vs. '%s'", str, fake);
+ return str;
+}
+/** Wrapper for fprintf(). */
+attr(printf(3, 4))
+static int bfs_fprintf(CFILE *cfile, const struct bfs_fmt *fmt, const char *fake, ...) {
+ va_list args;
+ va_start(args, fake);
+ int ret = vfprintf(cfile->file, dyn_fmt(fmt->str, fake), args);
va_end(args);
return ret;
}
@@ -139,7 +137,7 @@ static int bfs_printf_ctime(CFILE *cfile, const struct bfs_fmt *fmt, const struc
(long)ts->tv_nsec,
1900 + tm.tm_year);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %A, %B/%W, %C, %T: strftime() */
@@ -214,7 +212,7 @@ static int bfs_printf_strftime(CFILE *cfile, const struct bfs_fmt *fmt, const st
bfs_assert(ret >= 0 && (size_t)ret < sizeof(buf));
(void)ret;
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %b: blocks */
@@ -226,12 +224,12 @@ static int bfs_printf_b(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
uintmax_t blocks = ((uintmax_t)statbuf->blocks * BFS_STAT_BLKSIZE + 511) / 512;
BFS_PRINTF_BUF(buf, "%ju", blocks);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %d: depth */
static int bfs_printf_d(CFILE *cfile, const struct bfs_fmt *fmt, const struct BFTW *ftwbuf) {
- return dyn_fprintf(cfile->file, fmt, (intmax_t)ftwbuf->depth);
+ return bfs_fprintf(cfile, fmt, "%jd", (intmax_t)ftwbuf->depth);
}
/** %D: device */
@@ -242,7 +240,7 @@ static int bfs_printf_D(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
}
BFS_PRINTF_BUF(buf, "%ju", (uintmax_t)statbuf->dev);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %f: file name */
@@ -250,7 +248,7 @@ static int bfs_printf_f(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
if (should_color(cfile, fmt)) {
return cfprintf(cfile, "%pF", ftwbuf);
} else {
- return dyn_fprintf(cfile->file, fmt, ftwbuf->path + ftwbuf->nameoff);
+ return bfs_fprintf(cfile, fmt, "%s", ftwbuf->path + ftwbuf->nameoff);
}
}
@@ -266,7 +264,7 @@ static int bfs_printf_F(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
return -1;
}
- return dyn_fprintf(cfile->file, fmt, type);
+ return bfs_fprintf(cfile, fmt, "%s", type);
}
/** %G: gid */
@@ -277,7 +275,7 @@ static int bfs_printf_G(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
}
BFS_PRINTF_BUF(buf, "%ju", (uintmax_t)statbuf->gid);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %g: group name */
@@ -293,7 +291,7 @@ static int bfs_printf_g(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
return bfs_printf_G(cfile, fmt, ftwbuf);
}
- return dyn_fprintf(cfile->file, fmt, grp->gr_name);
+ return bfs_fprintf(cfile, fmt, "%s", grp->gr_name);
}
/** %h: leading directories */
@@ -322,7 +320,7 @@ static int bfs_printf_h(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
if (should_color(cfile, fmt)) {
ret = cfprintf(cfile, "${di}%pQ${rs}", buf);
} else {
- ret = dyn_fprintf(cfile->file, fmt, buf);
+ ret = bfs_fprintf(cfile, fmt, "%s", buf);
}
free(copy);
@@ -338,7 +336,7 @@ static int bfs_printf_H(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
return cfprintf(cfile, "${di}%pQ${rs}", ftwbuf->root);
}
} else {
- return dyn_fprintf(cfile->file, fmt, ftwbuf->root);
+ return bfs_fprintf(cfile, fmt, "%s", ftwbuf->root);
}
}
@@ -350,7 +348,7 @@ static int bfs_printf_i(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
}
BFS_PRINTF_BUF(buf, "%ju", (uintmax_t)statbuf->ino);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %k: 1K blocks */
@@ -362,7 +360,7 @@ static int bfs_printf_k(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
uintmax_t blocks = ((uintmax_t)statbuf->blocks * BFS_STAT_BLKSIZE + 1023) / 1024;
BFS_PRINTF_BUF(buf, "%ju", blocks);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %l: link target */
@@ -384,7 +382,7 @@ static int bfs_printf_l(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
}
}
- int ret = dyn_fprintf(cfile->file, fmt, target);
+ int ret = bfs_fprintf(cfile, fmt, "%s", target);
free(buf);
return ret;
}
@@ -396,7 +394,7 @@ static int bfs_printf_m(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
return -1;
}
- return dyn_fprintf(cfile->file, fmt, (unsigned int)(statbuf->mode & 07777));
+ return bfs_fprintf(cfile, fmt, "%o", (unsigned int)(statbuf->mode & 07777));
}
/** %M: symbolic mode */
@@ -408,7 +406,7 @@ static int bfs_printf_M(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
char buf[11];
xstrmode(statbuf->mode, buf);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %n: link count */
@@ -419,7 +417,7 @@ static int bfs_printf_n(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
}
BFS_PRINTF_BUF(buf, "%ju", (uintmax_t)statbuf->nlink);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %p: full path */
@@ -427,7 +425,7 @@ static int bfs_printf_p(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
if (should_color(cfile, fmt)) {
return cfprintf(cfile, "%pP", ftwbuf);
} else {
- return dyn_fprintf(cfile->file, fmt, ftwbuf->path);
+ return bfs_fprintf(cfile, fmt, "%s", ftwbuf->path);
}
}
@@ -448,7 +446,7 @@ static int bfs_printf_P(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
copybuf.nameoff -= offset;
return cfprintf(cfile, "%pP", &copybuf);
} else {
- return dyn_fprintf(cfile->file, fmt, ftwbuf->path + offset);
+ return bfs_fprintf(cfile, fmt, "%s", ftwbuf->path + offset);
}
}
@@ -460,7 +458,7 @@ static int bfs_printf_s(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
}
BFS_PRINTF_BUF(buf, "%ju", (uintmax_t)statbuf->size);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %S: sparseness */
@@ -476,7 +474,7 @@ static int bfs_printf_S(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
} else {
sparsity = (double)BFS_STAT_BLKSIZE * statbuf->blocks / statbuf->size;
}
- return dyn_fprintf(cfile->file, fmt, sparsity);
+ return bfs_fprintf(cfile, fmt, "%g", sparsity);
}
/** %U: uid */
@@ -487,7 +485,7 @@ static int bfs_printf_U(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
}
BFS_PRINTF_BUF(buf, "%ju", (uintmax_t)statbuf->uid);
- return dyn_fprintf(cfile->file, fmt, buf);
+ return bfs_fprintf(cfile, fmt, "%s", buf);
}
/** %u: user name */
@@ -503,7 +501,7 @@ static int bfs_printf_u(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
return bfs_printf_U(cfile, fmt, ftwbuf);
}
- return dyn_fprintf(cfile->file, fmt, pwd->pw_name);
+ return bfs_fprintf(cfile, fmt, "%s", pwd->pw_name);
}
static const char *bfs_printf_type(enum bfs_type type) {
@@ -536,7 +534,7 @@ static const char *bfs_printf_type(enum bfs_type type) {
/** %y: type */
static int bfs_printf_y(CFILE *cfile, const struct bfs_fmt *fmt, const struct BFTW *ftwbuf) {
const char *type = bfs_printf_type(ftwbuf->type);
- return dyn_fprintf(cfile->file, fmt, type);
+ return bfs_fprintf(cfile, fmt, "%s", type);
}
/** %Y: target type */
@@ -558,7 +556,7 @@ static int bfs_printf_Y(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
str = bfs_printf_type(type);
}
- int ret = dyn_fprintf(cfile->file, fmt, str);
+ int ret = bfs_fprintf(cfile, fmt, "%s", str);
if (error != 0) {
ret = -1;
errno = error;
@@ -574,7 +572,7 @@ static int bfs_printf_Z(CFILE *cfile, const struct bfs_fmt *fmt, const struct BF
return -1;
}
- int ret = dyn_fprintf(cfile->file, fmt, con);
+ int ret = bfs_fprintf(cfile, fmt, "%s", con);
bfs_freecon(con);
return ret;
}