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-rw-r--r--exec.c144
-rw-r--r--exec.h7
2 files changed, 117 insertions, 34 deletions
diff --git a/exec.c b/exec.c
index 2e1acf3..510d2d1 100644
--- a/exec.c
+++ b/exec.c
@@ -25,6 +25,48 @@
#include <sys/wait.h>
#include <unistd.h>
+extern char **environ;
+
+/** Determine the size of a single argument, for comparison to arg_max. */
+static size_t bfs_exec_arg_size(const char *arg) {
+ return sizeof(arg) + strlen(arg) + 1;
+}
+
+/** Even if we can pass a bigger argument list, cap it here. */
+#define BFS_EXEC_ARG_MAX (16*1024*1024)
+
+/** Determine the maximum argv size. */
+static size_t bfs_exec_arg_max(const struct bfs_exec *execbuf) {
+ long arg_max = sysconf(_SC_ARG_MAX);
+ if (arg_max < 0) {
+ arg_max = _POSIX_ARG_MAX;
+ }
+
+ // We have to share space with the environment variables
+ for (char **envp = environ; *envp; ++envp) {
+ arg_max -= bfs_exec_arg_size(*envp);
+ }
+
+ // Account for the non-placeholder arguments
+ for (size_t i = 0; i < execbuf->placeholder; ++i) {
+ arg_max -= bfs_exec_arg_size(execbuf->tmpl_argv[i]);
+ }
+ for (size_t i = execbuf->placeholder + 1; i < execbuf->tmpl_argc; ++i) {
+ arg_max -= bfs_exec_arg_size(execbuf->tmpl_argv[i]);
+ }
+
+ // POSIX recommends subtracting 2048, for some wiggle room
+ arg_max -= 2048;
+
+ if (arg_max < 0) {
+ arg_max = 0;
+ } else if (arg_max > BFS_EXEC_ARG_MAX) {
+ arg_max = BFS_EXEC_ARG_MAX;
+ }
+
+ return arg_max;
+}
+
struct bfs_exec *parse_bfs_exec(char **argv, enum bfs_exec_flags flags, CFILE *cerr) {
struct bfs_exec *execbuf = malloc(sizeof(*execbuf));
if (!execbuf) {
@@ -36,6 +78,9 @@ struct bfs_exec *parse_bfs_exec(char **argv, enum bfs_exec_flags flags, CFILE *c
execbuf->placeholder = 0;
execbuf->argv = NULL;
execbuf->argc = 0;
+ execbuf->argv_cap = 0;
+ execbuf->arg_size = 0;
+ execbuf->arg_max = 0;
execbuf->wd_fd = -1;
execbuf->wd_path = NULL;
execbuf->wd_len = 0;
@@ -64,18 +109,8 @@ struct bfs_exec *parse_bfs_exec(char **argv, enum bfs_exec_flags flags, CFILE *c
execbuf->tmpl_argv = argv + 1;
execbuf->tmpl_argc = i - 1;
- if (execbuf->flags & BFS_EXEC_MULTI) {
- long arg_max = sysconf(_SC_ARG_MAX);
- if (arg_max < 0) {
- execbuf->arg_max = _POSIX_ARG_MAX;
- } else {
- execbuf->arg_max = arg_max;
- }
- } else {
- execbuf->arg_max = execbuf->tmpl_argc;
- }
-
- execbuf->argv = malloc((execbuf->arg_max + 1)*sizeof(*execbuf->argv));
+ execbuf->argv_cap = execbuf->tmpl_argc + 1;
+ execbuf->argv = malloc(execbuf->argv_cap*sizeof(*execbuf->argv));
if (!execbuf->argv) {
perror("malloc()");
goto fail;
@@ -99,6 +134,8 @@ struct bfs_exec *parse_bfs_exec(char **argv, enum bfs_exec_flags flags, CFILE *c
}
}
+ execbuf->arg_max = bfs_exec_arg_max(execbuf);
+
for (i = 0; i < execbuf->placeholder; ++i) {
execbuf->argv[i] = execbuf->tmpl_argv[i];
}
@@ -358,8 +395,10 @@ out:
return ret;
}
-/** Execute the pending command from a multi-execbuf. */
-static void bfs_exec_flush(struct bfs_exec *execbuf) {
+/** Execute the pending command from a BFS_EXEC_MULTI execbuf. */
+static int bfs_exec_flush(struct bfs_exec *execbuf) {
+ int ret = 0;
+
size_t last_path = execbuf->argc;
if (last_path > execbuf->placeholder) {
for (size_t i = execbuf->placeholder + 1; i < execbuf->tmpl_argc; ++i, ++execbuf->argc) {
@@ -368,7 +407,7 @@ static void bfs_exec_flush(struct bfs_exec *execbuf) {
execbuf->argv[execbuf->argc] = NULL;
if (bfs_exec_spawn(execbuf) != 0) {
- execbuf->ret = -1;
+ ret = -1;
}
}
@@ -378,10 +417,13 @@ static void bfs_exec_flush(struct bfs_exec *execbuf) {
bfs_exec_free_arg(execbuf->argv[i], execbuf->tmpl_argv[execbuf->placeholder]);
}
execbuf->argc = execbuf->placeholder;
+ execbuf->arg_size = 0;
+
+ return ret;
}
/** Check if a flush is needed before a new file is processed. */
-static bool bfs_exec_needs_flush(struct bfs_exec *execbuf, const struct BFTW *ftwbuf) {
+static bool bfs_exec_needs_flush(struct bfs_exec *execbuf, const struct BFTW *ftwbuf, const char *arg) {
if (execbuf->flags & BFS_EXEC_CHDIR) {
if (ftwbuf->nameoff > execbuf->wd_len) {
return true;
@@ -391,48 +433,82 @@ static bool bfs_exec_needs_flush(struct bfs_exec *execbuf, const struct BFTW *ft
}
}
- size_t tail = execbuf->tmpl_argc - execbuf->placeholder - 1;
- if (execbuf->argc + tail >= execbuf->arg_max) {
+ if (execbuf->arg_size + bfs_exec_arg_size(arg) > execbuf->arg_max) {
return true;
}
return false;
}
-/** Push a new file to a multi-execbuf. */
-static void bfs_exec_multi(struct bfs_exec *execbuf, const struct BFTW *ftwbuf) {
- if (bfs_exec_needs_flush(execbuf, ftwbuf)) {
- bfs_exec_flush(execbuf);
- }
+/** Push a new argument to a BFS_EXEC_MULTI execbuf. */
+static int bfs_exec_push(struct bfs_exec *execbuf, char *arg) {
+ execbuf->argv[execbuf->argc] = arg;
- if ((execbuf->flags & BFS_EXEC_CHDIR) && execbuf->wd_fd < 0) {
- if (bfs_exec_openwd(execbuf, ftwbuf) != 0) {
- execbuf->ret = -1;
- return;
+ if (execbuf->argc + 1 >= execbuf->argv_cap) {
+ size_t cap = 2*execbuf->argv_cap;
+ char **argv = realloc(execbuf->argv, cap*sizeof(*argv));
+ if (!argv) {
+ return -1;
}
+ execbuf->argv = argv;
+ execbuf->argv_cap = cap;
}
+ ++execbuf->argc;
+ execbuf->arg_size += bfs_exec_arg_size(arg);
+ return 0;
+}
+
+/** Handle a new path for a BFS_EXEC_MULTI execbuf. */
+static int bfs_exec_multi(struct bfs_exec *execbuf, const struct BFTW *ftwbuf) {
+ int ret = 0;
+
const char *path = bfs_exec_format_path(execbuf, ftwbuf);
if (!path) {
- execbuf->ret = -1;
- return;
+ ret = -1;
+ goto out;
}
char *arg = bfs_exec_format_arg(execbuf->tmpl_argv[execbuf->placeholder], path);
if (!arg) {
- execbuf->ret = -1;
+ ret = -1;
goto out_path;
}
- execbuf->argv[execbuf->argc++] = arg;
+ if (bfs_exec_needs_flush(execbuf, ftwbuf, arg)) {
+ if (bfs_exec_flush(execbuf) != 0) {
+ ret = -1;
+ }
+ }
+ if ((execbuf->flags & BFS_EXEC_CHDIR) && execbuf->wd_fd < 0) {
+ if (bfs_exec_openwd(execbuf, ftwbuf) != 0) {
+ ret = -1;
+ goto out_arg;
+ }
+ }
+
+ if (bfs_exec_push(execbuf, arg) != 0) {
+ ret = -1;
+ goto out_arg;
+ }
+
+ // arg will get cleaned up later by bfs_exec_flush()
+ goto out_path;
+
+out_arg:
+ bfs_exec_free_arg(arg, execbuf->tmpl_argv[execbuf->placeholder]);
out_path:
bfs_exec_free_path(path, ftwbuf);
+out:
+ return ret;
}
int bfs_exec(struct bfs_exec *execbuf, const struct BFTW *ftwbuf) {
if (execbuf->flags & BFS_EXEC_MULTI) {
- bfs_exec_multi(execbuf, ftwbuf);
+ if (bfs_exec_multi(execbuf, ftwbuf) != 0) {
+ execbuf->ret = -1;
+ }
// -exec ... + never returns false
return 0;
} else {
@@ -442,7 +518,9 @@ int bfs_exec(struct bfs_exec *execbuf, const struct BFTW *ftwbuf) {
int bfs_exec_finish(struct bfs_exec *execbuf) {
if (execbuf->flags & BFS_EXEC_MULTI) {
- bfs_exec_flush(execbuf);
+ if (bfs_exec_flush(execbuf) != 0) {
+ execbuf->ret = -1;
+ }
}
return execbuf->ret;
}
diff --git a/exec.h b/exec.h
index ab548af..498013a 100644
--- a/exec.h
+++ b/exec.h
@@ -46,7 +46,12 @@ struct bfs_exec {
char **argv;
/** Number of command line arguments. */
size_t argc;
- /** Maximum argc before E2BIG. */
+ /** Capacity of argv. */
+ size_t argv_cap;
+
+ /** Current size of all arguments. */
+ size_t arg_size;
+ /** Maximum arg_size before E2BIG. */
size_t arg_max;
/** A file descriptor for the working directory, for BFS_EXEC_CHDIR. */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 17:28:49 +0000