Get memory regions as string

src/files.c

@@ -7,7 +7,17 @@
 HiloadResult read_file_to_str(str *s, const char *filename) {
 
   int copied = str_from_file(s, filename);
-  if (copied == 0) {
+  if (copied != 0) {
+    sc_log_error("Failed to read file: %s\n", filename);
+    return HILOAD_FAIL;
+  }
+  return HILOAD_OK;
+}
+
+HiloadResult read_stream_to_str(str *s, const char *filename) {
+  int nread = 0;
+  int copied = str_from_stream(s, filename, &nread);
+  if (copied != 0) {
     sc_log_error("Failed to read file: %s\n", filename);
     return HILOAD_FAIL;
   }

src/files.h

@@ -5,5 +5,6 @@
 #include "types.h"
 
 HiloadResult read_file_to_str(str *s, const char *);
+HiloadResult read_stream_to_str(str *s, const char *);
 
 #endif // FILES_H_

src/memory.c

@@ -1,14 +1,18 @@
 #include "memory.h"
 
-#include "logger.h"
 #include "files.h"
+#include "logger.h"
 #include "types.h"
 
+static
 str read_memory_maps_self() {
   str memory_str = str_null;
 
-    HiloadResult res = read_file_to_str(&memory_str, "/proc/self/maps");
-    sc_log_debug("Memory Map (/proc/self/maps):\n%s\n", str_ptr(memory_str));
+  HiloadResult res = read_stream_to_str(&memory_str, "/proc/self/maps");
+  if (res == HILOAD_FAIL)
+      return str_null;
+
+  sc_log_debug("Memory Map\n-- /proc/self/maps:\n%s\n", str_ptr(memory_str));
 
   return memory_str;
 }

src/memory.h

@@ -13,16 +13,13 @@ enum MemoryPermissions {
   HI_MEMORY_PRIVATE = 1 << 4
 };
 
+#define REGIONS_MAX 256
 typedef struct {
-  void *region_start;
-  void *redion_end;
-  u32 region_flags; // enum MemoryPermissions
-  u32 offset;
-  str pathname;
-} MemoryRegion;
-
-str read_memory_maps_self();
-
-sc_array_def(MemoryRegion, memreg);
+  void *region_starts[REGIONS_MAX];
+  void *region_end[REGIONS_MAX];
+  u32 region_flags[REGIONS_MAX]; // enum MemoryPermissions
+  u32 offset[REGIONS_MAX];
+  str pathname[REGIONS_MAX];
+} MemoryRegions;
 
 #endif // MEMORY_H_

src/str.c

@@ -74,6 +74,14 @@ void str_free_auto(const str* const ps)
 	___p;	\
 })
 
+#define REALLOC(p, n) \
+	({ \
+	void* const ___p = realloc((p), (n)); \
+	if(!___p) return ENOMEM; \
+	___p; \
+})
+
+
 // errno checker
 #define RETURN_ON_ERROR(expr)	\
 	while((expr) < 0) do { const int __err = errno; if(__err != EINTR) return __err; } while(0)
@@ -231,6 +239,35 @@ int read_from_fd(const int fd, void* p, off_t* const psize)
 	return 0;
 }
 
+static
+int read_from_fd_cont(const int fd, void* p, off_t* const psize)
+{
+	const void* end = p + *psize;
+	void *buf = p;
+	ssize_t n;
+	ssize_t nread = 0;
+
+	do
+	{
+		RETURN_ON_ERROR(n = read(fd, p, end - p));
+
+		p += n;
+		nread += n;
+
+		// pre-emptively realloc, even though we could potentially be at the end
+		if (p == end) {
+			*psize *= 2;
+			buf = REALLOC(buf, *psize);
+			p = buf + nread;
+			end = buf + *psize;
+		}
+
+	} while(n > 0);
+
+	return 0;
+}
+
+
 static
 int str_from_fd(const int fd, const off_t size, str* const dest)
 {
@@ -275,6 +312,46 @@ int str_from_fd(const int fd, const off_t size, str* const dest)
 	return 0;
 }
 
+static
+int str_from_stream_cont(const int fd, str* const dest, int *nmax)
+{
+	const size_t start_size = 8192;
+
+	char* buff = ALLOC(start_size + 1);
+	off_t n = start_size;
+	const int err = read_from_fd_cont(fd, buff, &n);
+
+	if(err != 0)
+	{
+		free(buff);
+		return err;
+	}
+
+	if(n == 0)
+	{
+		free(buff);
+		str_clear(dest);
+		return 0;
+	}
+
+	if(n < start_size)
+	{
+		char* const p = realloc(buff, n + 1);
+
+		if(!p)
+		{
+			free(buff);
+			return ENOMEM;
+		}
+
+		buff = p;
+	}
+
+	buff[n] = '\0';
+	str_assign(dest, str_acquire_chars(buff, n));
+	return 0;
+}
+
 int str_from_file(str* const dest, const char* const file_name)
 {
 	int fd;
@@ -291,6 +368,28 @@ int str_from_file(str* const dest, const char* const file_name)
 	return err;
 }
 
+int str_from_stream(str* const dest, const char* const file_name, int *nread)
+{
+	int fd;
+
+	RETURN_ON_ERROR(fd = open(file_name, O_CLOEXEC | O_RDONLY));
+
+	int nmax = nread ? *nread : 0;
+
+	off_t chunk_size = 4096;
+	int err = 0;
+	if (nmax == 0)
+		err = str_from_stream_cont(fd, dest, &nmax);
+	else
+		err = str_from_fd(fd, nmax, dest);
+
+	if (nread)
+		*nread = nmax;
+
+	close(fd);
+	return err;
+}
+
 // string composition -----------------------------------------------------------------------
 // append string
 static inline

src/str.h

@@ -216,6 +216,9 @@ str str_acquire(const char* const s);
 // string from file
 int str_from_file(str* const dest, const char* const file_name);
 
+// read maximum nread bytes from file, write bytes read. 0 reads until EOS.
+int str_from_stream(str* const dest, const char* const file_name, int *nread);
+
 // searching and sorting --------------------------------------------------------------------
 // string partitioning (substring search)
 bool str_partition(const str src, const str patt, str* const prefix, str* const suffix);