add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/scripts/recordmcount.h
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..
@@ -1,3 +1,4 @@
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+/* SPDX-License-Identifier: GPL-2.0-only */
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 /*
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  * recordmcount.h
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  *
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@@ -15,8 +16,6 @@
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  *
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  * This conversion to macros was done by:
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  * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
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- *
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- * Licensed under the GNU General Public License, version 2 (GPLv2).
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  */
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 #undef append_func
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 #undef is_fake_mcount
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@@ -193,15 +192,20 @@
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 				 Elf32_Word const *symtab_shndx)
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 {
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 	unsigned long offset;
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+	unsigned short shndx = w2(sym->st_shndx);
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 	int index;
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-	if (sym->st_shndx != SHN_XINDEX)
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-		return w2(sym->st_shndx);
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+	if (shndx > SHN_UNDEF && shndx < SHN_LORESERVE)
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+		return shndx;
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201
-	offset = (unsigned long)sym - (unsigned long)symtab;
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-	index = offset / sizeof(*sym);
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+	if (shndx == SHN_XINDEX) {
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+		offset = (unsigned long)sym - (unsigned long)symtab;
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+		index = offset / sizeof(*sym);
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-	return w(symtab_shndx[index]);
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+		return w(symtab_shndx[index]);
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+	}
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+
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+	return 0;
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 }
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 static unsigned int get_shnum(Elf_Ehdr const *ehdr, Elf_Shdr const *shdr0)
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@@ -251,7 +255,7 @@
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 }
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 /* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
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-static void append_func(Elf_Ehdr *const ehdr,
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+static int append_func(Elf_Ehdr *const ehdr,
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 			Elf_Shdr *const shstr,
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 			uint_t const *const mloc0,
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 			uint_t const *const mlocp,
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@@ -283,15 +287,20 @@
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 	set_shnum(ehdr, shdr0, new_shnum);
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288
 
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 	/* body for new shstrtab */
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-	ulseek(fd_map, sb.st_size, SEEK_SET);
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-	uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
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-	uwrite(fd_map, mc_name, 1 + strlen(mc_name));
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+	if (ulseek(sb.st_size, SEEK_SET) < 0)
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+		return -1;
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+	if (uwrite(old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size) < 0)
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+		return -1;
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+	if (uwrite(mc_name, 1 + strlen(mc_name)) < 0)
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+		return -1;
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296
 
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 	/* old(modified) Elf_Shdr table, word-byte aligned */
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-	ulseek(fd_map, t, SEEK_SET);
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+	if (ulseek(t, SEEK_SET) < 0)
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+		return -1;
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 	t += sizeof(Elf_Shdr) * old_shnum;
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-	uwrite(fd_map, old_shoff + (void *)ehdr,
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-	       sizeof(Elf_Shdr) * old_shnum);
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+	if (uwrite(old_shoff + (void *)ehdr,
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+	       sizeof(Elf_Shdr) * old_shnum) < 0)
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+		return -1;
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304
 
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 	/* new sections __mcount_loc and .rel__mcount_loc */
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 	t += 2*sizeof(mcsec);
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@@ -306,7 +315,8 @@
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 	mcsec.sh_info = 0;
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 	mcsec.sh_addralign = _w(_size);
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 	mcsec.sh_entsize = _w(_size);
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-	uwrite(fd_map, &mcsec, sizeof(mcsec));
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+	if (uwrite(&mcsec, sizeof(mcsec)) < 0)
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+		return -1;
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320
 
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 	mcsec.sh_name = w(old_shstr_sh_size);
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 	mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
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@@ -320,14 +330,21 @@
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 	mcsec.sh_info = w(old_shnum);
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 	mcsec.sh_addralign = _w(_size);
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 	mcsec.sh_entsize = _w(rel_entsize);
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-	uwrite(fd_map, &mcsec, sizeof(mcsec));
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333
 
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-	uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
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-	uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);
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+	if (uwrite(&mcsec, sizeof(mcsec)) < 0)
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+		return -1;
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+
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+	if (uwrite(mloc0, (void *)mlocp - (void *)mloc0) < 0)
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+		return -1;
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+	if (uwrite(mrel0, (void *)mrelp - (void *)mrel0) < 0)
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+		return -1;
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341
 
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 	ehdr->e_shoff = _w(new_e_shoff);
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-	ulseek(fd_map, 0, SEEK_SET);
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-	uwrite(fd_map, ehdr, sizeof(*ehdr));
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+	if (ulseek(0, SEEK_SET) < 0)
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+		return -1;
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+	if (uwrite(ehdr, sizeof(*ehdr)) < 0)
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+		return -1;
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+	return 0;
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348
 }
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349
 
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 static unsigned get_mcountsym(Elf_Sym const *const sym0,
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@@ -431,9 +448,9 @@
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  * that are not going to be traced. The mcount calls here will be converted
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  * into nops.
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  */
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-static void nop_mcount(Elf_Shdr const *const relhdr,
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-		       Elf_Ehdr const *const ehdr,
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-		       const char *const txtname)
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+static int nop_mcount(Elf_Shdr const *const relhdr,
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+		      Elf_Ehdr const *const ehdr,
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+		      const char *const txtname)
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 {
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 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
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 		+ (void *)ehdr);
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@@ -464,7 +481,7 @@
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 				once = 1;
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 				/* just warn? */
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 				if (!make_nop)
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-					return;
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+					return 0;
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 			}
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 		}
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487
 
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@@ -476,13 +493,15 @@
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 			Elf_Rel rel;
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 			rel = *(Elf_Rel *)relp;
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 			Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop);
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-			ulseek(fd_map, (void *)relp - (void *)ehdr, SEEK_SET);
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-			uwrite(fd_map, &rel, sizeof(rel));
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+			if (ulseek((void *)relp - (void *)ehdr, SEEK_SET) < 0)
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+				return -1;
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+			if (uwrite(&rel, sizeof(rel)) < 0)
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+				return -1;
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 		}
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 		relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
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502
 	}
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+	return 0;
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504
 }
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-
486
505
 
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 /*
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  * Find a symbol in the given section, to be used as the base for relocating
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@@ -494,9 +513,10 @@
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  *    Num:    Value  Size Type    Bind   Vis      Ndx Name
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  *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
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  */
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-static unsigned find_secsym_ndx(unsigned const txtndx,
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+static int find_secsym_ndx(unsigned const txtndx,
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 				char const *const txtname,
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 				uint_t *const recvalp,
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+				unsigned int *sym_index,
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 				Elf_Shdr const *const symhdr,
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 				Elf32_Word const *symtab,
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 				Elf32_Word const *symtab_shndx,
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@@ -520,21 +540,20 @@
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 				continue;
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541
 
522
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 			*recvalp = _w(symp->st_value);
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-			return symp - sym0;
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+			*sym_index = symp - sym0;
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+			return 0;
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545
 		}
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 	}
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 	fprintf(stderr, "Cannot find symbol for section %u: %s.\n",
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 		txtndx, txtname);
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-	fail_file();
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+	return -1;
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550
 }
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551
 
531
-
532
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 /* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
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-static char const *
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-__has_rel_mcount(Elf_Shdr const *const relhdr,  /* is SHT_REL or SHT_RELA */
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-		 Elf_Shdr const *const shdr0,
536
-		 char const *const shstrtab,
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-		 char const *const fname)
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+static char const * __has_rel_mcount(Elf_Shdr const *const relhdr, /* reltype */
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+				     Elf_Shdr const *const shdr0,
555
+				     char const *const shstrtab,
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+				     char const *const fname)
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557
 {
539
558
 	/* .sh_info depends on .sh_type == SHT_REL[,A] */
540
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 	Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
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@@ -543,7 +562,7 @@
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 	if (strcmp("__mcount_loc", txtname) == 0) {
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 		fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
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 			fname);
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-		succeed_file();
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+		return already_has_rel_mcount;
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566
 	}
548
567
 	if (w(txthdr->sh_type) != SHT_PROGBITS ||
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568
 	    !(_w(txthdr->sh_flags) & SHF_EXECINSTR))
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@@ -573,6 +592,10 @@
573
592
 
574
593
 	for (; nhdr; --nhdr, ++shdrp) {
575
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 		txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname);
595
+		if (txtname == already_has_rel_mcount) {
596
+			totrelsz = 0;
597
+			break;
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+		}
576
599
 		if (txtname && is_mcounted_section_name(txtname))
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600
 			totrelsz += _w(shdrp->sh_size);
578
601
 	}
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@@ -580,8 +603,8 @@
580
603
 }
581
604
 
582
605
 /* Overall supervision for Elf32 ET_REL file. */
583
-static void
584
-do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
606
+static int do_func(Elf_Ehdr *const ehdr, char const *const fname,
607
+		   unsigned const reltype)
585
608
 {
586
609
 	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
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610
 		+ (void *)ehdr);
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@@ -597,29 +620,57 @@
597
620
 	Elf32_Word *symtab_shndx;
598
621
 
599
622
 	/* Upper bound on space: assume all relevant relocs are for mcount. */
600
-	unsigned const totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
601
-	Elf_Rel *const mrel0 = umalloc(totrelsz);
602
-	Elf_Rel *      mrelp = mrel0;
623
+	unsigned       totrelsz;
603
624
 
604
-	/* 2*sizeof(address) <= sizeof(Elf_Rel) */
605
-	uint_t *const mloc0 = umalloc(totrelsz>>1);
606
-	uint_t *      mlocp = mloc0;
625
+	Elf_Rel *      mrel0;
626
+	Elf_Rel *      mrelp;
627
+
628
+	uint_t *      mloc0;
629
+	uint_t *      mlocp;
607
630
 
608
631
 	unsigned rel_entsize = 0;
609
632
 	unsigned symsec_sh_link = 0;
633
+
634
+	int result = 0;
635
+
636
+	totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
637
+	if (totrelsz == 0)
638
+		return 0;
639
+	mrel0 = umalloc(totrelsz);
640
+	mrelp = mrel0;
641
+	if (!mrel0)
642
+		return -1;
643
+
644
+	/* 2*sizeof(address) <= sizeof(Elf_Rel) */
645
+	mloc0 = umalloc(totrelsz>>1);
646
+	mlocp = mloc0;
647
+	if (!mloc0) {
648
+		free(mrel0);
649
+		return -1;
650
+	}
610
651
 
611
652
 	find_symtab(ehdr, shdr0, nhdr, &symtab, &symtab_shndx);
612
653
 
613
654
 	for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
614
655
 		char const *const txtname = has_rel_mcount(relhdr, shdr0,
615
656
 			shstrtab, fname);
657
+		if (txtname == already_has_rel_mcount) {
658
+			result = 0;
659
+			file_updated = 0;
660
+			goto out; /* Nothing to be done; don't append! */
661
+		}
616
662
 		if (txtname && is_mcounted_section_name(txtname)) {
663
+			unsigned int recsym;
617
664
 			uint_t recval = 0;
618
-			unsigned const recsym = find_secsym_ndx(
619
-				w(relhdr->sh_info), txtname, &recval,
620
-				&shdr0[symsec_sh_link = w(relhdr->sh_link)],
621
-				symtab, symtab_shndx,
622
-				ehdr);
665
+
666
+			symsec_sh_link = w(relhdr->sh_link);
667
+			result = find_secsym_ndx(w(relhdr->sh_info), txtname,
668
+						&recval, &recsym,
669
+						&shdr0[symsec_sh_link],
670
+						symtab, symtab_shndx,
671
+						ehdr);
672
+			if (result)
673
+				goto out;
623
674
 
624
675
 			rel_entsize = _w(relhdr->sh_entsize);
625
676
 			mlocp = sift_rel_mcount(mlocp,
..
..
@@ -630,13 +681,17 @@
630
681
 			 * This section is ignored by ftrace, but still
631
682
 			 * has mcount calls. Convert them to nops now.
632
683
 			 */
633
-			nop_mcount(relhdr, ehdr, txtname);
684
+			if (nop_mcount(relhdr, ehdr, txtname) < 0) {
685
+				result = -1;
686
+				goto out;
687
+			}
634
688
 		}
635
689
 	}
636
-	if (mloc0 != mlocp) {
637
-		append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
638
-			    rel_entsize, symsec_sh_link);
639
-	}
690
+	if (!result && mloc0 != mlocp)
691
+		result = append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
692
+				     rel_entsize, symsec_sh_link);
693
+out:
640
694
 	free(mrel0);
641
695
 	free(mloc0);
696
+	return result;
642
697
 }