proot: Clear errno before ptrace(PTRACE_PEEKDATA)

[termux-packages] / disabled-packages / proot / src-tracee-mem.c.patch

--- PRoot-5.1.0/src/tracee/mem.c	2014-12-15 15:18:11.000000000 +0100
+++ src/src/tracee/mem.c	2016-03-20 10:37:46.288702967 +0100
@@ -131,6 +131,9 @@
 	/* Copy the bytes in the last word carefully since we have to
 	 * overwrite only the relevant ones. */
 
+	/* Clear errno so we won't detect previous syscall failure as ptrace one */
+	errno = 0;
+
 	word = ptrace(PTRACE_PEEKDATA, tracee->pid, dest + i, NULL);
 	if (errno != 0) {
 		note(tracee, WARNING, SYSTEM, "ptrace(PEEKDATA)");
@@ -236,6 +239,9 @@
 	nb_trailing_bytes = size % sizeof(word_t);
 	nb_full_words     = (size - nb_trailing_bytes) / sizeof(word_t);
 
+	/* Clear errno so we won't detect previous syscall failure as ptrace one */
+	errno = 0;
+
 	/* Copy one word by one word, except for the last one. */
 	for (i = 0; i < nb_full_words; i++) {
 		word = ptrace(PTRACE_PEEKDATA, tracee->pid, src + i, NULL);
@@ -366,6 +372,9 @@
 	nb_trailing_bytes = max_size % sizeof(word_t);
 	nb_full_words     = (max_size - nb_trailing_bytes) / sizeof(word_t);
 
+	/* Clear errno so we won't detect previous syscall failure as ptrace one */
+	errno = 0;
+
 	/* Copy one word by one word, except for the last one. */
 	for (i = 0; i < nb_full_words; i++) {
 		word = ptrace(PTRACE_PEEKDATA, tracee->pid, src + i, NULL);